// widgetTextInput.c  -- TextInput and TextArea widgets
//
// This file implements two text editing widgets:
//
// 1. TextInput  -- single-line text field with scroll, selection,
//    undo, password masking, and masked input (e.g., phone/SSN).
// 2. TextArea  -- multi-line text editor with row/col cursor,
//    dual-axis scrolling, and full selection/clipboard support.
//
// Shared infrastructure (clipboard, multi-click detection, word
// boundary logic, cross-widget selection clearing, and the
// single-line editing engine widgetTextEditOnKey) lives in
// widgetCore.c so it can be linked from any widget DXE.
//
// All text editing is done in-place in fixed-size char buffers
// allocated at widget creation. No dynamic resizing -- this keeps
// memory management simple and predictable on DOS where heap
// fragmentation is a real concern.
//
// Undo is single-level swap: before each mutation, the current
// buffer is copied to undoBuf. Ctrl+Z swaps current<->undo, so
// a second Ctrl+Z is "redo". This is simpler than a multi-level
// undo stack and sufficient for typical DOS text entry.
//
// Selection model: selStart/selEnd (single-line) or selAnchor/
// selCursor (multi-line) form a directed range. selStart is where
// the user began selecting, selEnd is where they stopped. The
// "low" end for deletion/copy is always min(start, end). The
// -1 sentinel means "no selection".
//
// Clipboard is a simple static buffer (4KB). This is a process-wide
// clipboard, not per-widget and not OS-integrated (DOS has no
// clipboard API). Text cut/copied from any widget is available to
// paste in any other widget.
//
// Multi-click detection uses clock() timestamps with a 500ms
// threshold and 4px spatial tolerance. Double-click selects word,
// triple-click selects line (TextArea) or all (TextInput).
//
// Cross-widget selection clearing: when a widget gains selection,
// clearOtherSelections() deselects any other widget that had an
// active selection. This prevents the confusing visual state of
// multiple selected ranges across different widgets. The tracking
// uses sLastSelectedWidget to achieve O(1) clearing rather than
// walking the entire widget tree.
//
// Masked input: a special TextInput mode where the buffer is
// pre-filled from a mask pattern (e.g., "###-##-####" for SSN).
// '#' accepts digits, 'A' accepts letters, '*' accepts any
// printable char. Literal characters in the mask are fixed and the
// cursor skips over them. This provides constrained input without
// needing a separate widget type.
//
// Password mode: renders bullets instead of characters (CP437 0xF9)
// and blocks copy/cut operations for security.

#include "widgetInternal.h"

#include <ctype.h>
#include <time.h>

#define TEXTAREA_BORDER    2
#define TEXTAREA_PAD       2
#define TEXTAREA_SB_W      14
#define TEXTAREA_MIN_ROWS  4
#define TEXTAREA_MIN_COLS  20
#define CLIPBOARD_MAX      4096
// Match the ANSI terminal cursor blink rate (CURSOR_MS in widgetAnsiTerm.c)
#define CURSOR_BLINK_MS    250

// ============================================================
// Prototypes
// ============================================================

static bool maskCharValid(char slot, char ch);
static int32_t maskFirstSlot(const char *mask);
static bool maskIsSlot(char ch);
static int32_t maskNextSlot(const char *mask, int32_t pos);
static int32_t maskPrevSlot(const char *mask, int32_t pos);
static void maskedInputOnKey(WidgetT *w, int32_t key, int32_t mod);
static int32_t textAreaCountLines(const char *buf, int32_t len);
static int32_t textAreaCursorToOff(const char *buf, int32_t len, int32_t row, int32_t col);
static inline void textAreaDirtyCache(WidgetT *w);
static void textAreaEnsureVisible(WidgetT *w, int32_t visRows, int32_t visCols);
static int32_t textAreaGetLineCount(WidgetT *w);
static int32_t textAreaGetMaxLineLen(WidgetT *w);
static int32_t textAreaLineLen(const char *buf, int32_t len, int32_t row);
static int32_t textAreaLineStart(const char *buf, int32_t len, int32_t row);
static int32_t textAreaMaxLineLen(const char *buf, int32_t len);
static void textAreaOffToRowCol(const char *buf, int32_t off, int32_t *row, int32_t *col);
static void textEditSaveUndo(char *buf, int32_t len, int32_t cursor, char *undoBuf, int32_t *pUndoLen, int32_t *pUndoCursor, int32_t bufSize);
static int32_t wordBoundaryLeft(const char *buf, int32_t pos);
static int32_t wordBoundaryRight(const char *buf, int32_t len, int32_t pos);

// ============================================================
// Cursor blink state
// ============================================================
// Shared across all text-editing widgets (TextInput, TextArea,
// ComboBox, Spinner). Matches the ANSI terminal's 250ms rate.

bool           sCursorBlinkOn   = true;
static clock_t sCursorBlinkTime = 0;


// ============================================================
// Cursor blink
// ============================================================

void wgtUpdateCursorBlink(void) {
    clock_t now      = clock();
    clock_t interval = (clock_t)CURSOR_BLINK_MS * CLOCKS_PER_SEC / 1000;

    if ((now - sCursorBlinkTime) >= interval) {
        sCursorBlinkTime = now;
        sCursorBlinkOn   = !sCursorBlinkOn;

        // Invalidate the focused widget so its cursor redraws
        if (sFocusedWidget) {
            wgtInvalidatePaint(sFocusedWidget);
        }
    }
}




// ============================================================
// Shared undo helpers
// ============================================================

static void textEditSaveUndo(char *buf, int32_t len, int32_t cursor, char *undoBuf, int32_t *pUndoLen, int32_t *pUndoCursor, int32_t bufSize) {
    if (!undoBuf) {
        return;
    }

    int32_t copyLen = len < bufSize ? len : bufSize - 1;
    memcpy(undoBuf, buf, copyLen);
    undoBuf[copyLen] = '\0';
    *pUndoLen    = copyLen;
    *pUndoCursor = cursor;
}


// ============================================================
// wordBoundaryLeft
// ============================================================
//
// From position pos, skip non-word chars left, then skip word chars left.
// Returns the position at the start of the word (or 0).

static int32_t wordBoundaryLeft(const char *buf, int32_t pos) {
    if (pos <= 0) {
        return 0;
    }

    // Skip non-word characters
    while (pos > 0 && !isalnum((unsigned char)buf[pos - 1]) && buf[pos - 1] != '_') {
        pos--;
    }

    // Skip word characters
    while (pos > 0 && (isalnum((unsigned char)buf[pos - 1]) || buf[pos - 1] == '_')) {
        pos--;
    }

    return pos;
}


// ============================================================
// wordBoundaryRight
// ============================================================
//
// From position pos, skip word chars right, then skip non-word chars right.
// Returns the position at the end of the word (or len).

static int32_t wordBoundaryRight(const char *buf, int32_t len, int32_t pos) {
    if (pos >= len) {
        return len;
    }

    // Skip word characters
    while (pos < len && (isalnum((unsigned char)buf[pos]) || buf[pos] == '_')) {
        pos++;
    }

    // Skip non-word characters
    while (pos < len && !isalnum((unsigned char)buf[pos]) && buf[pos] != '_') {
        pos++;
    }

    return pos;
}


// ============================================================
// wgtTextArea
// ============================================================

// TextArea allocates heap buffers for content and undo. maxLen controls
// the buffer size; 0 defaults to 256 bytes. The undo buffer is the
// same size as the content buffer to support full-buffer undo. Line
// count and max line length are cached (invalidated by textAreaDirtyCache)
// to avoid re-scanning the entire buffer on every paint/layout call.
WidgetT *wgtTextArea(WidgetT *parent, int32_t maxLen) {
    WidgetT *w = widgetAlloc(parent, WidgetTextAreaE);

    if (w) {
        int32_t bufSize = maxLen > 0 ? maxLen + 1 : 256;
        w->as.textArea.buf     = (char *)malloc(bufSize);
        w->as.textArea.undoBuf = (char *)malloc(bufSize);
        w->as.textArea.bufSize = bufSize;

        if (!w->as.textArea.buf || !w->as.textArea.undoBuf) {
            free(w->as.textArea.buf);
            free(w->as.textArea.undoBuf);
            w->as.textArea.buf     = NULL;
            w->as.textArea.undoBuf = NULL;
        } else {
            w->as.textArea.buf[0] = '\0';
        }

        w->as.textArea.selAnchor   = -1;
        w->as.textArea.selCursor   = -1;
        w->as.textArea.desiredCol  = 0;
        w->as.textArea.cachedLines = -1;
        w->as.textArea.cachedMaxLL = -1;
        w->weight = 100;
    }

    return w;
}


// ============================================================
// wgtTextInput
// ============================================================

// TextInput also heap-allocates buffers. The weight=100 default makes
// text inputs stretch to fill available width, which is the expected
// behavior in form layouts. Selection uses a start/end pair rather
// than anchor/cursor -- for single-line, the concepts are equivalent.
WidgetT *wgtTextInput(WidgetT *parent, int32_t maxLen) {
    WidgetT *w = widgetAlloc(parent, WidgetTextInputE);

    if (w) {
        int32_t bufSize = maxLen > 0 ? maxLen + 1 : 256;
        w->as.textInput.buf     = (char *)malloc(bufSize);
        w->as.textInput.bufSize = bufSize;

        if (w->as.textInput.buf) {
            w->as.textInput.buf[0] = '\0';
        }

        w->as.textInput.undoBuf  = (char *)malloc(bufSize);
        w->as.textInput.selStart = -1;
        w->as.textInput.selEnd   = -1;
        w->weight = 100;
    }

    return w;
}


WidgetT *wgtPasswordInput(WidgetT *parent, int32_t maxLen) {
    WidgetT *w = wgtTextInput(parent, maxLen);

    if (w) {
        w->as.textInput.inputMode = InputPasswordE;
    }

    return w;
}


// Masked input pre-fills the buffer from the mask pattern: literal
// characters are placed directly, editable slots get '_' placeholder.
// The cursor starts at the first editable slot. The mask string is
// NOT copied -- it must remain valid for the widget's lifetime (caller
// typically passes a string literal).
WidgetT *wgtMaskedInput(WidgetT *parent, const char *mask) {
    if (!mask) {
        return NULL;
    }

    int32_t maskLen = (int32_t)strlen(mask);
    WidgetT *w = wgtTextInput(parent, maskLen);

    if (w) {
        w->as.textInput.inputMode = InputMaskedE;
        w->as.textInput.mask      = mask;

        // Pre-fill buffer: literals copied as-is, slots filled with '_'
        for (int32_t i = 0; i < maskLen; i++) {
            if (maskIsSlot(mask[i])) {
                w->as.textInput.buf[i] = '_';
            } else {
                w->as.textInput.buf[i] = mask[i];
            }
        }

        w->as.textInput.buf[maskLen] = '\0';
        w->as.textInput.len          = maskLen;
        w->as.textInput.cursorPos    = maskFirstSlot(mask);
    }

    return w;
}


// ============================================================
// Mask helpers
// ============================================================

static bool maskIsSlot(char ch) {
    return ch == '#' || ch == 'A' || ch == '*';
}


static bool maskCharValid(char slot, char ch) {
    switch (slot) {
        case '#':
            return ch >= '0' && ch <= '9';
        case 'A':
            return isalpha((unsigned char)ch);
        case '*':
            return ch >= 32 && ch < 127;
        default:
            return false;
    }
}


static int32_t maskFirstSlot(const char *mask) {
    for (int32_t i = 0; mask[i]; i++) {
        if (maskIsSlot(mask[i])) {
            return i;
        }
    }

    return 0;
}


static int32_t maskNextSlot(const char *mask, int32_t pos) {
    for (int32_t i = pos + 1; mask[i]; i++) {
        if (maskIsSlot(mask[i])) {
            return i;
        }
    }

    return (int32_t)strlen(mask);
}


static int32_t maskPrevSlot(const char *mask, int32_t pos) {
    for (int32_t i = pos - 1; i >= 0; i--) {
        if (maskIsSlot(mask[i])) {
            return i;
        }
    }

    return pos;
}


// Masked input key handling is entirely separate from the shared
// text editor because the editing semantics are fundamentally different:
// the buffer length is fixed (it's always maskLen), characters can
// only be placed in slot positions, and backspace clears a slot rather
// than removing a character. The cursor skips over literal characters
// when moving left/right. Cut clears slots to '_' rather than removing
// text. Paste fills consecutive slots, skipping non-matching clipboard
// characters.
static void maskedInputOnKey(WidgetT *w, int32_t key, int32_t mod) {
    char       *buf    = w->as.textInput.buf;
    const char *mask   = w->as.textInput.mask;
    int32_t    *pCur   = &w->as.textInput.cursorPos;
    int32_t     maskLen = w->as.textInput.len;
    bool        shift  = (mod & KEY_MOD_SHIFT) != 0;

    (void)shift;

    // Ctrl+A  -- select all
    if (key == 1) {
        w->as.textInput.selStart = 0;
        w->as.textInput.selEnd   = maskLen;
        *pCur = maskLen;
        goto done;
    }

    // Ctrl+C  -- copy formatted text
    if (key == 3) {
        if (w->as.textInput.selStart >= 0 && w->as.textInput.selEnd >= 0 && w->as.textInput.selStart != w->as.textInput.selEnd) {
            int32_t selLo = w->as.textInput.selStart < w->as.textInput.selEnd ? w->as.textInput.selStart : w->as.textInput.selEnd;
            int32_t selHi = w->as.textInput.selStart < w->as.textInput.selEnd ? w->as.textInput.selEnd : w->as.textInput.selStart;

            if (selLo < 0) {
                selLo = 0;
            }

            if (selHi > maskLen) {
                selHi = maskLen;
            }

            if (selHi > selLo) {
                clipboardCopy(buf + selLo, selHi - selLo);
            }
        }

        return;
    }

    // Ctrl+V  -- paste valid chars into slots
    if (key == 22) {
        int32_t clipLen;
        const char *clip = clipboardGet(&clipLen);

        if (clipLen > 0) {
            if (w->as.textInput.undoBuf) {
                textEditSaveUndo(buf, maskLen, *pCur, w->as.textInput.undoBuf, &w->as.textInput.undoLen, &w->as.textInput.undoCursor, w->as.textInput.bufSize);
            }

            int32_t slotPos = *pCur;
            bool changed = false;

            for (int32_t i = 0; i < clipLen && slotPos < maskLen; i++) {
                // Skip to next slot if not on one
                while (slotPos < maskLen && !maskIsSlot(mask[slotPos])) {
                    slotPos++;
                }

                if (slotPos >= maskLen) {
                    break;
                }

                // Skip non-matching clipboard chars
                if (maskCharValid(mask[slotPos], clip[i])) {
                    buf[slotPos] = clip[i];
                    slotPos = maskNextSlot(mask, slotPos);
                    changed = true;
                }
            }

            if (changed) {
                *pCur = slotPos <= maskLen ? slotPos : maskLen;
                w->as.textInput.selStart = -1;
                w->as.textInput.selEnd   = -1;

                if (w->onChange) {
                    w->onChange(w);
                }
            }
        }

        goto done;
    }

    // Ctrl+X  -- copy and clear selected slots
    if (key == 24) {
        if (w->as.textInput.selStart >= 0 && w->as.textInput.selEnd >= 0 && w->as.textInput.selStart != w->as.textInput.selEnd) {
            int32_t selLo = w->as.textInput.selStart < w->as.textInput.selEnd ? w->as.textInput.selStart : w->as.textInput.selEnd;
            int32_t selHi = w->as.textInput.selStart < w->as.textInput.selEnd ? w->as.textInput.selEnd : w->as.textInput.selStart;

            if (selLo < 0) {
                selLo = 0;
            }

            if (selHi > maskLen) {
                selHi = maskLen;
            }

            clipboardCopy(buf + selLo, selHi - selLo);

            if (w->as.textInput.undoBuf) {
                textEditSaveUndo(buf, maskLen, *pCur, w->as.textInput.undoBuf, &w->as.textInput.undoLen, &w->as.textInput.undoCursor, w->as.textInput.bufSize);
            }

            for (int32_t i = selLo; i < selHi; i++) {
                if (maskIsSlot(mask[i])) {
                    buf[i] = '_';
                }
            }

            *pCur = selLo;
            w->as.textInput.selStart = -1;
            w->as.textInput.selEnd   = -1;

            if (w->onChange) {
                w->onChange(w);
            }
        }

        goto done;
    }

    // Ctrl+Z  -- undo
    if (key == 26 && w->as.textInput.undoBuf) {
        char tmpBuf[256];
        int32_t tmpLen = maskLen + 1 < (int32_t)sizeof(tmpBuf) ? maskLen + 1 : (int32_t)sizeof(tmpBuf);
        int32_t tmpCursor = *pCur;
        memcpy(tmpBuf, buf, tmpLen);

        memcpy(buf, w->as.textInput.undoBuf, maskLen + 1);
        *pCur = w->as.textInput.undoCursor < maskLen ? w->as.textInput.undoCursor : maskLen;

        memcpy(w->as.textInput.undoBuf, tmpBuf, tmpLen);
        w->as.textInput.undoCursor = tmpCursor;

        w->as.textInput.selStart = -1;
        w->as.textInput.selEnd   = -1;

        if (w->onChange) {
            w->onChange(w);
        }

        goto done;
    }

    if (key >= 32 && key < 127) {
        // Printable character  -- place at current slot if valid
        if (*pCur < maskLen && maskIsSlot(mask[*pCur]) && maskCharValid(mask[*pCur], (char)key)) {
            if (w->as.textInput.undoBuf) {
                textEditSaveUndo(buf, maskLen, *pCur, w->as.textInput.undoBuf, &w->as.textInput.undoLen, &w->as.textInput.undoCursor, w->as.textInput.bufSize);
            }

            buf[*pCur] = (char)key;
            *pCur = maskNextSlot(mask, *pCur);

            w->as.textInput.selStart = -1;
            w->as.textInput.selEnd   = -1;

            if (w->onChange) {
                w->onChange(w);
            }
        }
    } else if (key == 8) {
        // Backspace  -- clear previous slot
        int32_t prev = maskPrevSlot(mask, *pCur);

        if (prev != *pCur) {
            if (w->as.textInput.undoBuf) {
                textEditSaveUndo(buf, maskLen, *pCur, w->as.textInput.undoBuf, &w->as.textInput.undoLen, &w->as.textInput.undoCursor, w->as.textInput.bufSize);
            }

            buf[prev] = '_';
            *pCur = prev;

            w->as.textInput.selStart = -1;
            w->as.textInput.selEnd   = -1;

            if (w->onChange) {
                w->onChange(w);
            }
        }
    } else if (key == (0x53 | 0x100)) {
        // Delete  -- clear current slot
        if (*pCur < maskLen && maskIsSlot(mask[*pCur])) {
            if (w->as.textInput.undoBuf) {
                textEditSaveUndo(buf, maskLen, *pCur, w->as.textInput.undoBuf, &w->as.textInput.undoLen, &w->as.textInput.undoCursor, w->as.textInput.bufSize);
            }

            buf[*pCur] = '_';

            w->as.textInput.selStart = -1;
            w->as.textInput.selEnd   = -1;

            if (w->onChange) {
                w->onChange(w);
            }
        }
    } else if (key == (0x4B | 0x100)) {
        // Left arrow  -- move to previous slot
        int32_t prev = maskPrevSlot(mask, *pCur);

        if (shift) {
            if (w->as.textInput.selStart < 0) {
                w->as.textInput.selStart = *pCur;
                w->as.textInput.selEnd   = *pCur;
            }

            *pCur = prev;
            w->as.textInput.selEnd = *pCur;
        } else {
            w->as.textInput.selStart = -1;
            w->as.textInput.selEnd   = -1;
            *pCur = prev;
        }
    } else if (key == (0x4D | 0x100)) {
        // Right arrow  -- move to next slot
        int32_t next = maskNextSlot(mask, *pCur);

        if (shift) {
            if (w->as.textInput.selStart < 0) {
                w->as.textInput.selStart = *pCur;
                w->as.textInput.selEnd   = *pCur;
            }

            *pCur = next;
            w->as.textInput.selEnd = *pCur;
        } else {
            w->as.textInput.selStart = -1;
            w->as.textInput.selEnd   = -1;
            *pCur = next;
        }
    } else if (key == (0x47 | 0x100)) {
        // Home  -- first slot
        if (shift) {
            if (w->as.textInput.selStart < 0) {
                w->as.textInput.selStart = *pCur;
                w->as.textInput.selEnd   = *pCur;
            }

            *pCur = maskFirstSlot(mask);
            w->as.textInput.selEnd = *pCur;
        } else {
            w->as.textInput.selStart = -1;
            w->as.textInput.selEnd   = -1;
            *pCur = maskFirstSlot(mask);
        }
    } else if (key == (0x4F | 0x100)) {
        // End  -- past last slot
        int32_t last = maskLen;

        if (shift) {
            if (w->as.textInput.selStart < 0) {
                w->as.textInput.selStart = *pCur;
                w->as.textInput.selEnd   = *pCur;
            }

            *pCur = last;
            w->as.textInput.selEnd = *pCur;
        } else {
            w->as.textInput.selStart = -1;
            w->as.textInput.selEnd   = -1;
            *pCur = last;
        }
    } else {
        return;
    }

done:
    // Adjust scroll
    {
        AppContextT *ctx = wgtGetContext(w);
        const BitmapFontT *font = &ctx->font;
        int32_t visibleChars = (w->w - TEXT_INPUT_PAD * 2) / font->charWidth;

        if (*pCur < w->as.textInput.scrollOff) {
            w->as.textInput.scrollOff = *pCur;
        }

        if (*pCur >= w->as.textInput.scrollOff + visibleChars) {
            w->as.textInput.scrollOff = *pCur - visibleChars + 1;
        }
    }

    wgtInvalidatePaint(w);
}


// ============================================================
// TextArea line helpers
// ============================================================

static int32_t textAreaCountLines(const char *buf, int32_t len) {
    int32_t lines = 1;

    for (int32_t i = 0; i < len; i++) {
        if (buf[i] == '\n') {
            lines++;
        }
    }

    return lines;
}


// Cached line count -- sentinel value -1 means "dirty, recompute".
// This avoids O(N) buffer scans on every paint frame. The cache is
// invalidated (set to -1) by textAreaDirtyCache() after any buffer
// mutation. The same pattern is used for max line length.
static int32_t textAreaGetLineCount(WidgetT *w) {
    if (w->as.textArea.cachedLines < 0) {
        w->as.textArea.cachedLines = textAreaCountLines(w->as.textArea.buf, w->as.textArea.len);
    }

    return w->as.textArea.cachedLines;
}


static int32_t textAreaLineStart(const char *buf, int32_t len, int32_t row) {
    (void)len;
    int32_t off = 0;

    for (int32_t r = 0; r < row; r++) {
        while (off < len && buf[off] != '\n') {
            off++;
        }

        if (off < len) {
            off++;
        }
    }

    return off;
}


static int32_t textAreaLineLen(const char *buf, int32_t len, int32_t row) {
    int32_t start = textAreaLineStart(buf, len, row);
    int32_t end   = start;

    while (end < len && buf[end] != '\n') {
        end++;
    }

    return end - start;
}


static int32_t textAreaMaxLineLen(const char *buf, int32_t len) {
    int32_t maxLen = 0;
    int32_t curLen = 0;

    for (int32_t i = 0; i < len; i++) {
        if (buf[i] == '\n') {
            if (curLen > maxLen) {
                maxLen = curLen;
            }
            curLen = 0;
        } else {
            curLen++;
        }
    }

    if (curLen > maxLen) {
        maxLen = curLen;
    }

    return maxLen;
}


static int32_t textAreaGetMaxLineLen(WidgetT *w) {
    if (w->as.textArea.cachedMaxLL < 0) {
        w->as.textArea.cachedMaxLL = textAreaMaxLineLen(w->as.textArea.buf, w->as.textArea.len);
    }

    return w->as.textArea.cachedMaxLL;
}


static inline void textAreaDirtyCache(WidgetT *w) {
    w->as.textArea.cachedLines = -1;
    w->as.textArea.cachedMaxLL = -1;
}


static int32_t textAreaCursorToOff(const char *buf, int32_t len, int32_t row, int32_t col) {
    int32_t start  = textAreaLineStart(buf, len, row);
    int32_t lineL  = textAreaLineLen(buf, len, row);
    int32_t clampC = col < lineL ? col : lineL;

    return start + clampC;
}


static void textAreaOffToRowCol(const char *buf, int32_t off, int32_t *row, int32_t *col) {
    int32_t r = 0;
    int32_t c = 0;

    for (int32_t i = 0; i < off; i++) {
        if (buf[i] == '\n') {
            r++;
            c = 0;
        } else {
            c++;
        }
    }

    *row = r;
    *col = c;
}


static void textAreaEnsureVisible(WidgetT *w, int32_t visRows, int32_t visCols) {
    int32_t row = w->as.textArea.cursorRow;
    int32_t col = w->as.textArea.cursorCol;

    if (row < w->as.textArea.scrollRow) {
        w->as.textArea.scrollRow = row;
    }

    if (row >= w->as.textArea.scrollRow + visRows) {
        w->as.textArea.scrollRow = row - visRows + 1;
    }

    if (col < w->as.textArea.scrollCol) {
        w->as.textArea.scrollCol = col;
    }

    if (col >= w->as.textArea.scrollCol + visCols) {
        w->as.textArea.scrollCol = col - visCols + 1;
    }
}


// ============================================================
// widgetTextAreaCalcMinSize
// ============================================================

void widgetTextAreaCalcMinSize(WidgetT *w, const BitmapFontT *font) {
    w->calcMinW = font->charWidth * TEXTAREA_MIN_COLS + TEXTAREA_PAD * 2 + TEXTAREA_BORDER * 2 + TEXTAREA_SB_W;
    w->calcMinH = font->charHeight * TEXTAREA_MIN_ROWS + TEXTAREA_BORDER * 2;
}


// ============================================================
// widgetTextAreaDestroy
// ============================================================

void widgetTextAreaDestroy(WidgetT *w) {
    free(w->as.textArea.buf);
    free(w->as.textArea.undoBuf);
}


// ============================================================
// widgetTextAreaGetText
// ============================================================

const char *widgetTextAreaGetText(const WidgetT *w) {
    return w->as.textArea.buf ? w->as.textArea.buf : "";
}


// ============================================================
// widgetTextAreaOnKey
// ============================================================

// TextArea key handling is inline (not using widgetTextEditOnKey)
// because multi-line editing has fundamentally different cursor
// semantics: row/col instead of linear offset, desiredCol for
// vertical movement (so moving down from a long line to a short
// line remembers the original column), and Enter inserts newlines.
//
// The SEL_BEGIN/SEL_END/HAS_SEL macros factor out the repetitive
// selection-start/selection-extend pattern: SEL_BEGIN initializes
// the anchor at the current offset if Shift is held and no selection
// exists yet. SEL_END updates the selection cursor to the new
// position (or clears selection if Shift isn't held). This keeps
// the per-key handler code manageable despite the large number of
// key combinations.
//
// textAreaEnsureVisible() is called after every cursor movement to
// auto-scroll the viewport. It adjusts scrollRow/scrollCol so the
// cursor is within the visible range.
void widgetTextAreaOnKey(WidgetT *w, int32_t key, int32_t mod) {
    if (!w->as.textArea.buf) {
        return;
    }

    clearOtherSelections(w);

    char    *buf     = w->as.textArea.buf;
    int32_t  bufSize = w->as.textArea.bufSize;
    int32_t *pLen    = &w->as.textArea.len;
    int32_t *pRow    = &w->as.textArea.cursorRow;
    int32_t *pCol    = &w->as.textArea.cursorCol;
    int32_t *pSA     = &w->as.textArea.selAnchor;
    int32_t *pSC     = &w->as.textArea.selCursor;
    bool     shift   = (mod & KEY_MOD_SHIFT) != 0;

    AppContextT *ctx = wgtGetContext(w);
    const BitmapFontT *font = &ctx->font;
    int32_t innerW   = w->w - TEXTAREA_BORDER * 2 - TEXTAREA_PAD * 2 - TEXTAREA_SB_W;
    int32_t visCols  = innerW / font->charWidth;
    int32_t maxLL    = textAreaGetMaxLineLen(w);
    bool    needHSb  = (maxLL > visCols);
    int32_t innerH   = w->h - TEXTAREA_BORDER * 2 - (needHSb ? TEXTAREA_SB_W : 0);
    int32_t visRows  = innerH / font->charHeight;

    if (visRows < 1) {
        visRows = 1;
    }

    if (visCols < 1) {
        visCols = 1;
    }

    int32_t totalLines = textAreaGetLineCount(w);

    // Helper macros for cursor offset
    #define CUR_OFF() textAreaCursorToOff(buf, *pLen, *pRow, *pCol)

    // Start/extend selection
    #define SEL_BEGIN() do { \
        if (shift && *pSA < 0) { *pSA = CUR_OFF(); *pSC = *pSA; } \
    } while (0)

    #define SEL_END() do { \
        if (shift) { *pSC = CUR_OFF(); } \
        else { *pSA = -1; *pSC = -1; } \
    } while (0)

    #define HAS_SEL() (*pSA >= 0 && *pSC >= 0 && *pSA != *pSC)

    #define SEL_LO() (*pSA < *pSC ? *pSA : *pSC)
    #define SEL_HI() (*pSA < *pSC ? *pSC : *pSA)

    // Clamp selection to buffer bounds
    if (HAS_SEL()) {
        if (*pSA > *pLen) {
            *pSA = *pLen;
        }

        if (*pSC > *pLen) {
            *pSC = *pLen;
        }
    }

    // Ctrl+A  -- select all
    if (key == 1) {
        *pSA = 0;
        *pSC = *pLen;
        textAreaOffToRowCol(buf, *pLen, pRow, pCol);
        w->as.textArea.desiredCol = *pCol;
        textAreaEnsureVisible(w, visRows, visCols);
        wgtInvalidatePaint(w);
        return;
    }

    // Ctrl+C  -- copy
    if (key == 3) {
        if (HAS_SEL()) {
            clipboardCopy(buf + SEL_LO(), SEL_HI() - SEL_LO());
        }

        return;
    }

    // Read-only: allow select-all, copy, and navigation but block editing
    if (w->readOnly) {
        goto navigation;
    }

    // Ctrl+V  -- paste
    if (key == 22) {
        int32_t clipLen = 0;
        const char *clip = clipboardGet(&clipLen);

        if (clipLen > 0) {
            textEditSaveUndo(buf, *pLen, CUR_OFF(), w->as.textArea.undoBuf, &w->as.textArea.undoLen, &w->as.textArea.undoCursor, bufSize);

            if (HAS_SEL()) {
                int32_t lo = SEL_LO();
                int32_t hi = SEL_HI();
                memmove(buf + lo, buf + hi, *pLen - hi + 1);
                *pLen -= (hi - lo);
                textAreaOffToRowCol(buf, lo, pRow, pCol);
                *pSA = -1;
                *pSC = -1;
            }

            int32_t off    = CUR_OFF();
            int32_t canFit = bufSize - 1 - *pLen;
            int32_t paste  = clipLen < canFit ? clipLen : canFit;

            if (paste > 0) {
                memmove(buf + off + paste, buf + off, *pLen - off + 1);
                memcpy(buf + off, clip, paste);
                *pLen += paste;
                textAreaOffToRowCol(buf, off + paste, pRow, pCol);
                w->as.textArea.desiredCol = *pCol;
            }

            if (w->onChange) {
                w->onChange(w);
            }

            textAreaDirtyCache(w);
        }

        textAreaEnsureVisible(w, visRows, visCols);
        wgtInvalidatePaint(w);
        return;
    }

    // Ctrl+X  -- cut
    if (key == 24) {
        if (HAS_SEL()) {
            clipboardCopy(buf + SEL_LO(), SEL_HI() - SEL_LO());
            textEditSaveUndo(buf, *pLen, CUR_OFF(), w->as.textArea.undoBuf, &w->as.textArea.undoLen, &w->as.textArea.undoCursor, bufSize);

            int32_t lo = SEL_LO();
            int32_t hi = SEL_HI();
            memmove(buf + lo, buf + hi, *pLen - hi + 1);
            *pLen -= (hi - lo);
            textAreaOffToRowCol(buf, lo, pRow, pCol);
            *pSA = -1;
            *pSC = -1;
            w->as.textArea.desiredCol = *pCol;

            if (w->onChange) {
                w->onChange(w);
            }

            textAreaDirtyCache(w);
        }

        textAreaEnsureVisible(w, visRows, visCols);
        wgtInvalidatePaint(w);
        return;
    }

    // Ctrl+Z  -- undo
    if (key == 26) {
        if (w->as.textArea.undoBuf && w->as.textArea.undoLen >= 0) {
            // Swap current and undo
            char tmpBuf[CLIPBOARD_MAX];
            int32_t tmpLen    = *pLen;
            int32_t tmpCursor = CUR_OFF();
            int32_t copyLen   = tmpLen < (int32_t)sizeof(tmpBuf) - 1 ? tmpLen : (int32_t)sizeof(tmpBuf) - 1;

            memcpy(tmpBuf, buf, copyLen);
            tmpBuf[copyLen] = '\0';

            int32_t restLen = w->as.textArea.undoLen < bufSize - 1 ? w->as.textArea.undoLen : bufSize - 1;
            memcpy(buf, w->as.textArea.undoBuf, restLen);
            buf[restLen] = '\0';
            *pLen = restLen;

            // Save current as new undo
            int32_t saveLen = copyLen < bufSize - 1 ? copyLen : bufSize - 1;
            memcpy(w->as.textArea.undoBuf, tmpBuf, saveLen);
            w->as.textArea.undoBuf[saveLen] = '\0';
            w->as.textArea.undoLen    = saveLen;
            w->as.textArea.undoCursor = tmpCursor;

            // Restore cursor
            int32_t restoreOff = w->as.textArea.undoCursor < *pLen ? w->as.textArea.undoCursor : *pLen;
            w->as.textArea.undoCursor = tmpCursor;
            textAreaOffToRowCol(buf, restoreOff, pRow, pCol);
            w->as.textArea.desiredCol = *pCol;
            *pSA = -1;
            *pSC = -1;

            if (w->onChange) {
                w->onChange(w);
            }

            textAreaDirtyCache(w);
        }

        textAreaEnsureVisible(w, visRows, visCols);
        wgtInvalidatePaint(w);
        return;
    }

    // Enter  -- insert newline
    if (key == 0x0D) {
        if (*pLen < bufSize - 1) {
            textEditSaveUndo(buf, *pLen, CUR_OFF(), w->as.textArea.undoBuf, &w->as.textArea.undoLen, &w->as.textArea.undoCursor, bufSize);

            if (HAS_SEL()) {
                int32_t lo = SEL_LO();
                int32_t hi = SEL_HI();
                memmove(buf + lo, buf + hi, *pLen - hi + 1);
                *pLen -= (hi - lo);
                textAreaOffToRowCol(buf, lo, pRow, pCol);
                *pSA = -1;
                *pSC = -1;
            }

            int32_t off = CUR_OFF();

            if (*pLen < bufSize - 1) {
                memmove(buf + off + 1, buf + off, *pLen - off + 1);
                buf[off] = '\n';
                (*pLen)++;
                (*pRow)++;
                *pCol = 0;
                w->as.textArea.desiredCol = 0;
            }

            if (w->onChange) {
                w->onChange(w);
            }

            textAreaDirtyCache(w);
        }

        textAreaEnsureVisible(w, visRows, visCols);
        wgtInvalidatePaint(w);
        return;
    }

    // Backspace
    if (key == 8) {
        if (HAS_SEL()) {
            textEditSaveUndo(buf, *pLen, CUR_OFF(), w->as.textArea.undoBuf, &w->as.textArea.undoLen, &w->as.textArea.undoCursor, bufSize);
            int32_t lo = SEL_LO();
            int32_t hi = SEL_HI();
            memmove(buf + lo, buf + hi, *pLen - hi + 1);
            *pLen -= (hi - lo);
            textAreaOffToRowCol(buf, lo, pRow, pCol);
            *pSA = -1;
            *pSC = -1;
            w->as.textArea.desiredCol = *pCol;
            textAreaDirtyCache(w);

            if (w->onChange) {
                w->onChange(w);
            }
        } else {
            int32_t off = CUR_OFF();

            if (off > 0) {
                textEditSaveUndo(buf, *pLen, off, w->as.textArea.undoBuf, &w->as.textArea.undoLen, &w->as.textArea.undoCursor, bufSize);
                memmove(buf + off - 1, buf + off, *pLen - off + 1);
                (*pLen)--;
                textAreaOffToRowCol(buf, off - 1, pRow, pCol);
                w->as.textArea.desiredCol = *pCol;
                textAreaDirtyCache(w);

                if (w->onChange) {
                    w->onChange(w);
                }
            }
        }

        textAreaEnsureVisible(w, visRows, visCols);
        wgtInvalidatePaint(w);
        return;
    }

    // Delete
    if (key == (0x53 | 0x100)) {
        if (HAS_SEL()) {
            textEditSaveUndo(buf, *pLen, CUR_OFF(), w->as.textArea.undoBuf, &w->as.textArea.undoLen, &w->as.textArea.undoCursor, bufSize);
            int32_t lo = SEL_LO();
            int32_t hi = SEL_HI();
            memmove(buf + lo, buf + hi, *pLen - hi + 1);
            *pLen -= (hi - lo);
            textAreaOffToRowCol(buf, lo, pRow, pCol);
            *pSA = -1;
            *pSC = -1;
            w->as.textArea.desiredCol = *pCol;
            textAreaDirtyCache(w);

            if (w->onChange) {
                w->onChange(w);
            }
        } else {
            int32_t off = CUR_OFF();

            if (off < *pLen) {
                textEditSaveUndo(buf, *pLen, off, w->as.textArea.undoBuf, &w->as.textArea.undoLen, &w->as.textArea.undoCursor, bufSize);
                memmove(buf + off, buf + off + 1, *pLen - off);
                (*pLen)--;
                textAreaDirtyCache(w);

                if (w->onChange) {
                    w->onChange(w);
                }
            }
        }

        textAreaEnsureVisible(w, visRows, visCols);
        wgtInvalidatePaint(w);
        return;
    }

navigation:
    // Left arrow
    if (key == (0x4B | 0x100)) {
        SEL_BEGIN();
        int32_t off = CUR_OFF();

        if (off > 0) {
            textAreaOffToRowCol(buf, off - 1, pRow, pCol);
        }

        w->as.textArea.desiredCol = *pCol;
        SEL_END();
        textAreaEnsureVisible(w, visRows, visCols);
        wgtInvalidatePaint(w);
        return;
    }

    // Right arrow
    if (key == (0x4D | 0x100)) {
        SEL_BEGIN();
        int32_t off = CUR_OFF();

        if (off < *pLen) {
            textAreaOffToRowCol(buf, off + 1, pRow, pCol);
        }

        w->as.textArea.desiredCol = *pCol;
        SEL_END();
        textAreaEnsureVisible(w, visRows, visCols);
        wgtInvalidatePaint(w);
        return;
    }

    // Ctrl+Left  -- word left
    if (key == (0x73 | 0x100)) {
        SEL_BEGIN();
        int32_t off    = CUR_OFF();
        int32_t newOff = wordBoundaryLeft(buf, off);
        textAreaOffToRowCol(buf, newOff, pRow, pCol);
        w->as.textArea.desiredCol = *pCol;
        SEL_END();
        textAreaEnsureVisible(w, visRows, visCols);
        wgtInvalidatePaint(w);
        return;
    }

    // Ctrl+Right  -- word right
    if (key == (0x74 | 0x100)) {
        SEL_BEGIN();
        int32_t off    = CUR_OFF();
        int32_t newOff = wordBoundaryRight(buf, *pLen, off);
        textAreaOffToRowCol(buf, newOff, pRow, pCol);
        w->as.textArea.desiredCol = *pCol;
        SEL_END();
        textAreaEnsureVisible(w, visRows, visCols);
        wgtInvalidatePaint(w);
        return;
    }

    // Up arrow
    if (key == (0x48 | 0x100)) {
        SEL_BEGIN();

        if (*pRow > 0) {
            (*pRow)--;
            int32_t lineL = textAreaLineLen(buf, *pLen, *pRow);
            *pCol = w->as.textArea.desiredCol < lineL ? w->as.textArea.desiredCol : lineL;
        }

        SEL_END();
        textAreaEnsureVisible(w, visRows, visCols);
        wgtInvalidatePaint(w);
        return;
    }

    // Down arrow
    if (key == (0x50 | 0x100)) {
        SEL_BEGIN();

        if (*pRow < totalLines - 1) {
            (*pRow)++;
            int32_t lineL = textAreaLineLen(buf, *pLen, *pRow);
            *pCol = w->as.textArea.desiredCol < lineL ? w->as.textArea.desiredCol : lineL;
        }

        SEL_END();
        textAreaEnsureVisible(w, visRows, visCols);
        wgtInvalidatePaint(w);
        return;
    }

    // Home
    if (key == (0x47 | 0x100)) {
        SEL_BEGIN();
        *pCol = 0;
        w->as.textArea.desiredCol = 0;
        SEL_END();
        textAreaEnsureVisible(w, visRows, visCols);
        wgtInvalidatePaint(w);
        return;
    }

    // End
    if (key == (0x4F | 0x100)) {
        SEL_BEGIN();
        *pCol = textAreaLineLen(buf, *pLen, *pRow);
        w->as.textArea.desiredCol = *pCol;
        SEL_END();
        textAreaEnsureVisible(w, visRows, visCols);
        wgtInvalidatePaint(w);
        return;
    }

    // Page Up
    if (key == (0x49 | 0x100)) {
        SEL_BEGIN();
        *pRow -= visRows;

        if (*pRow < 0) {
            *pRow = 0;
        }

        int32_t lineL = textAreaLineLen(buf, *pLen, *pRow);
        *pCol = w->as.textArea.desiredCol < lineL ? w->as.textArea.desiredCol : lineL;
        SEL_END();
        textAreaEnsureVisible(w, visRows, visCols);
        wgtInvalidatePaint(w);
        return;
    }

    // Page Down
    if (key == (0x51 | 0x100)) {
        SEL_BEGIN();
        *pRow += visRows;

        if (*pRow >= totalLines) {
            *pRow = totalLines - 1;
        }

        int32_t lineL = textAreaLineLen(buf, *pLen, *pRow);
        *pCol = w->as.textArea.desiredCol < lineL ? w->as.textArea.desiredCol : lineL;
        SEL_END();
        textAreaEnsureVisible(w, visRows, visCols);
        wgtInvalidatePaint(w);
        return;
    }

    // Ctrl+Home (scancode 0x77)
    if (key == (0x77 | 0x100)) {
        SEL_BEGIN();
        *pRow = 0;
        *pCol = 0;
        w->as.textArea.desiredCol = 0;
        SEL_END();
        textAreaEnsureVisible(w, visRows, visCols);
        wgtInvalidatePaint(w);
        return;
    }

    // Ctrl+End (scancode 0x75)
    if (key == (0x75 | 0x100)) {
        SEL_BEGIN();
        textAreaOffToRowCol(buf, *pLen, pRow, pCol);
        w->as.textArea.desiredCol = *pCol;
        SEL_END();
        textAreaEnsureVisible(w, visRows, visCols);
        wgtInvalidatePaint(w);
        return;
    }

    // Printable character (blocked in read-only mode)
    if (key >= 32 && key < 127 && !w->readOnly) {
        if (*pLen < bufSize - 1) {
            textEditSaveUndo(buf, *pLen, CUR_OFF(), w->as.textArea.undoBuf, &w->as.textArea.undoLen, &w->as.textArea.undoCursor, bufSize);

            if (HAS_SEL()) {
                int32_t lo = SEL_LO();
                int32_t hi = SEL_HI();
                memmove(buf + lo, buf + hi, *pLen - hi + 1);
                *pLen -= (hi - lo);
                textAreaOffToRowCol(buf, lo, pRow, pCol);
                *pSA = -1;
                *pSC = -1;
            }

            int32_t off = CUR_OFF();

            if (*pLen < bufSize - 1) {
                memmove(buf + off + 1, buf + off, *pLen - off + 1);
                buf[off] = (char)key;
                (*pLen)++;
                (*pCol)++;
                w->as.textArea.desiredCol = *pCol;
            }

            textAreaDirtyCache(w);

            if (w->onChange) {
                w->onChange(w);
            }
        }

        textAreaEnsureVisible(w, visRows, visCols);
        wgtInvalidatePaint(w);
        return;
    }

    #undef CUR_OFF
    #undef SEL_BEGIN
    #undef SEL_END
    #undef HAS_SEL
    #undef SEL_LO
    #undef SEL_HI
}


// ============================================================
// widgetTextAreaOnMouse
// ============================================================

// Mouse handling: scrollbar clicks (both V and H), then content area
// clicks. Content clicks convert pixel coordinates to row/col using
// font metrics and scroll offset. Multi-click: double-click selects
// word, triple-click selects entire line. Single click starts a
// drag-select (sets sDragTextSelect which the event loop monitors
// on mouse-move to extend the selection). The drag-select global
// is cleared on double/triple click since the selection is already
// complete.
void widgetTextAreaOnMouse(WidgetT *w, WidgetT *root, int32_t vx, int32_t vy) {
    w->focused = true;
    clearOtherSelections(w);

    AppContextT *ctx = (AppContextT *)root->userData;
    const BitmapFontT *font = &ctx->font;

    int32_t innerX  = w->x + TEXTAREA_BORDER + TEXTAREA_PAD;
    int32_t innerY  = w->y + TEXTAREA_BORDER;
    int32_t innerW  = w->w - TEXTAREA_BORDER * 2 - TEXTAREA_PAD * 2 - TEXTAREA_SB_W;
    int32_t visCols = innerW / font->charWidth;
    int32_t maxLL   = textAreaGetMaxLineLen(w);
    bool    needHSb = (maxLL > visCols);
    int32_t innerH  = w->h - TEXTAREA_BORDER * 2 - (needHSb ? TEXTAREA_SB_W : 0);
    int32_t visRows = innerH / font->charHeight;

    if (visRows < 1) {
        visRows = 1;
    }

    if (visCols < 1) {
        visCols = 1;
    }

    int32_t totalLines = textAreaCountLines(w->as.textArea.buf, w->as.textArea.len);
    int32_t maxScroll  = totalLines - visRows;

    if (maxScroll < 0) {
        maxScroll = 0;
    }

    w->as.textArea.scrollRow = clampInt(w->as.textArea.scrollRow, 0, maxScroll);

    int32_t maxHScroll = maxLL - visCols;

    if (maxHScroll < 0) {
        maxHScroll = 0;
    }

    w->as.textArea.scrollCol = clampInt(w->as.textArea.scrollCol, 0, maxHScroll);

    // Check horizontal scrollbar click
    if (needHSb) {
        int32_t hsbY = w->y + w->h - TEXTAREA_BORDER - TEXTAREA_SB_W;

        if (vy >= hsbY && vx < w->x + w->w - TEXTAREA_BORDER - TEXTAREA_SB_W) {
            int32_t hsbX     = w->x + TEXTAREA_BORDER;
            int32_t hsbW     = w->w - TEXTAREA_BORDER * 2 - TEXTAREA_SB_W;
            int32_t relX     = vx - hsbX;
            int32_t trackLen = hsbW - TEXTAREA_SB_W * 2;

            if (relX < TEXTAREA_SB_W) {
                // Left arrow
                if (w->as.textArea.scrollCol > 0) {
                    w->as.textArea.scrollCol--;
                }
            } else if (relX >= hsbW - TEXTAREA_SB_W) {
                // Right arrow
                if (w->as.textArea.scrollCol < maxHScroll) {
                    w->as.textArea.scrollCol++;
                }
            } else if (trackLen > 0) {
                int32_t thumbPos;
                int32_t thumbSize;
                widgetScrollbarThumb(trackLen, maxLL, visCols, w->as.textArea.scrollCol, &thumbPos, &thumbSize);

                int32_t trackRelX = relX - TEXTAREA_SB_W;

                if (trackRelX < thumbPos) {
                    w->as.textArea.scrollCol -= visCols;
                    w->as.textArea.scrollCol = clampInt(w->as.textArea.scrollCol, 0, maxHScroll);
                } else if (trackRelX >= thumbPos + thumbSize) {
                    w->as.textArea.scrollCol += visCols;
                    w->as.textArea.scrollCol = clampInt(w->as.textArea.scrollCol, 0, maxHScroll);
                } else {
                    sDragScrollbar       = w;
                    sDragScrollbarOrient = 1;
                    sDragScrollbarOff    = trackRelX - thumbPos;
                    return;
                }
            }

            return;
        }
    }

    // Check vertical scrollbar click
    int32_t sbX = w->x + w->w - TEXTAREA_BORDER - TEXTAREA_SB_W;

    if (vx >= sbX) {
        int32_t sbY      = w->y + TEXTAREA_BORDER;
        int32_t sbH      = innerH;
        int32_t relY     = vy - sbY;
        int32_t trackLen = sbH - TEXTAREA_SB_W * 2;

        if (relY < TEXTAREA_SB_W) {
            // Up arrow
            if (w->as.textArea.scrollRow > 0) {
                w->as.textArea.scrollRow--;
            }
        } else if (relY >= sbH - TEXTAREA_SB_W) {
            // Down arrow
            if (w->as.textArea.scrollRow < maxScroll) {
                w->as.textArea.scrollRow++;
            }
        } else if (trackLen > 0) {
            int32_t thumbPos;
            int32_t thumbSize;
            widgetScrollbarThumb(trackLen, totalLines, visRows, w->as.textArea.scrollRow, &thumbPos, &thumbSize);

            int32_t trackRelY = relY - TEXTAREA_SB_W;

            if (trackRelY < thumbPos) {
                w->as.textArea.scrollRow -= visRows;
                w->as.textArea.scrollRow = clampInt(w->as.textArea.scrollRow, 0, maxScroll);
            } else if (trackRelY >= thumbPos + thumbSize) {
                w->as.textArea.scrollRow += visRows;
                w->as.textArea.scrollRow = clampInt(w->as.textArea.scrollRow, 0, maxScroll);
            } else {
                sDragScrollbar       = w;
                sDragScrollbarOrient = 0;
                sDragScrollbarOff    = trackRelY - thumbPos;
                return;
            }
        }

        return;
    }

    // Click on text area  -- place cursor
    int32_t relX = vx - innerX;
    int32_t relY = vy - innerY;

    int32_t clickRow = w->as.textArea.scrollRow + relY / font->charHeight;
    int32_t clickCol = w->as.textArea.scrollCol + relX / font->charWidth;

    if (clickRow < 0) {
        clickRow = 0;
    }

    if (clickRow >= totalLines) {
        clickRow = totalLines - 1;
    }

    if (clickCol < 0) {
        clickCol = 0;
    }

    int32_t lineL = textAreaLineLen(w->as.textArea.buf, w->as.textArea.len, clickRow);

    if (clickCol > lineL) {
        clickCol = lineL;
    }

    int32_t clicks = multiClickDetect(vx, vy);

    if (clicks >= 3) {
        // Triple-click: select entire line
        int32_t lineStart = textAreaCursorToOff(w->as.textArea.buf, w->as.textArea.len, clickRow, 0);
        int32_t lineEnd   = textAreaCursorToOff(w->as.textArea.buf, w->as.textArea.len, clickRow, lineL);

        w->as.textArea.cursorRow  = clickRow;
        w->as.textArea.cursorCol  = lineL;
        w->as.textArea.desiredCol = lineL;
        w->as.textArea.selAnchor  = lineStart;
        w->as.textArea.selCursor  = lineEnd;
        sDragTextSelect = NULL;
        return;
    }

    if (clicks == 2 && w->as.textArea.buf) {
        // Double-click: select word
        int32_t off = textAreaCursorToOff(w->as.textArea.buf, w->as.textArea.len, clickRow, clickCol);
        int32_t ws  = wordStart(w->as.textArea.buf, off);
        int32_t we  = wordEnd(w->as.textArea.buf, w->as.textArea.len, off);

        int32_t weRow;
        int32_t weCol;
        textAreaOffToRowCol(w->as.textArea.buf, we, &weRow, &weCol);

        w->as.textArea.cursorRow  = weRow;
        w->as.textArea.cursorCol  = weCol;
        w->as.textArea.desiredCol = weCol;
        w->as.textArea.selAnchor  = ws;
        w->as.textArea.selCursor  = we;
        sDragTextSelect = NULL;
        return;
    }

    // Single click: place cursor + start drag-select
    w->as.textArea.cursorRow  = clickRow;
    w->as.textArea.cursorCol  = clickCol;
    w->as.textArea.desiredCol = clickCol;

    int32_t anchorOff = textAreaCursorToOff(w->as.textArea.buf, w->as.textArea.len, clickRow, clickCol);
    w->as.textArea.selAnchor = anchorOff;
    w->as.textArea.selCursor = anchorOff;
    sDragTextSelect = w;
}


// ============================================================
// widgetTextAreaPaint
// ============================================================

// TextArea paint uses an optimized incremental line-offset approach:
// instead of calling textAreaLineStart() for each visible row (which
// would re-scan from the buffer start each time), we compute the
// starting offset of the first visible line once, then advance it
// line by line. This makes the paint cost O(visRows * maxLineLen)
// rather than O(visRows * totalLines).
//
// Each line is drawn in up to 3 runs (before-selection, selection,
// after-selection) to avoid overdraw. Selection highlighting that
// extends past the end of a line (the newline itself is "selected")
// is rendered as a highlight-colored rectFill past the text.
//
// Scrollbars are drawn inline (not using the shared scrollbar
// functions) because TextArea scrolling is in rows/cols (logical
// units) rather than pixels, so the thumb calculation parameters
// differ. The dead corner between scrollbars is filled with
// windowFace color.
void widgetTextAreaPaint(WidgetT *w, DisplayT *d, const BlitOpsT *ops, const BitmapFontT *font, const ColorSchemeT *colors) {
    uint32_t fg = w->fgColor ? w->fgColor : colors->contentFg;
    uint32_t bg = w->bgColor ? w->bgColor : colors->contentBg;

    char   *buf      = w->as.textArea.buf;
    int32_t len      = w->as.textArea.len;
    int32_t innerW   = w->w - TEXTAREA_BORDER * 2 - TEXTAREA_PAD * 2 - TEXTAREA_SB_W;
    int32_t visCols  = innerW / font->charWidth;
    int32_t maxLL    = textAreaGetMaxLineLen(w);
    bool    needHSb  = (maxLL > visCols);
    int32_t innerH   = w->h - TEXTAREA_BORDER * 2 - (needHSb ? TEXTAREA_SB_W : 0);
    int32_t visRows  = innerH / font->charHeight;
    int32_t totalLines = textAreaGetLineCount(w);
    bool    needVSb    = (totalLines > visRows);

    // Sunken border
    BevelStyleT bevel = BEVEL_SUNKEN(colors, bg, 2);
    drawBevel(d, ops, w->x, w->y, w->w, w->h, &bevel);

    // Clamp vertical scroll
    int32_t maxScroll = totalLines - visRows;

    if (maxScroll < 0) {
        maxScroll = 0;
    }

    w->as.textArea.scrollRow = clampInt(w->as.textArea.scrollRow, 0, maxScroll);

    // Clamp horizontal scroll
    int32_t maxHScroll = maxLL - visCols;

    if (maxHScroll < 0) {
        maxHScroll = 0;
    }

    w->as.textArea.scrollCol = clampInt(w->as.textArea.scrollCol, 0, maxHScroll);

    // Selection range
    int32_t selLo = -1;
    int32_t selHi = -1;

    if (w->as.textArea.selAnchor >= 0 && w->as.textArea.selCursor >= 0 && w->as.textArea.selAnchor != w->as.textArea.selCursor) {
        selLo = w->as.textArea.selAnchor < w->as.textArea.selCursor ? w->as.textArea.selAnchor : w->as.textArea.selCursor;
        selHi = w->as.textArea.selAnchor < w->as.textArea.selCursor ? w->as.textArea.selCursor : w->as.textArea.selAnchor;
    }

    // Draw lines  -- compute first visible line offset once, then advance incrementally
    int32_t textX = w->x + TEXTAREA_BORDER + TEXTAREA_PAD;
    int32_t textY = w->y + TEXTAREA_BORDER;
    int32_t lineOff = textAreaLineStart(buf, len, w->as.textArea.scrollRow);

    for (int32_t i = 0; i < visRows; i++) {
        int32_t row = w->as.textArea.scrollRow + i;

        if (row >= totalLines) {
            break;
        }

        // Compute line length by scanning from lineOff (not from buffer start)
        int32_t lineL = 0;
        while (lineOff + lineL < len && buf[lineOff + lineL] != '\n') {
            lineL++;
        }
        int32_t drawY = textY + i * font->charHeight;

        // Visible range within line
        int32_t scrollCol = w->as.textArea.scrollCol;
        int32_t visStart  = scrollCol;
        int32_t visEnd    = scrollCol + visCols;
        int32_t textEnd   = lineL; // chars in this line

        // Clamp visible range to actual line content for text drawing
        int32_t drawStart = visStart < textEnd ? visStart : textEnd;
        int32_t drawEnd   = visEnd < textEnd ? visEnd : textEnd;

        // Determine selection intersection with this line
        int32_t lineSelLo = -1;
        int32_t lineSelHi = -1;

        if (selLo >= 0) {
            // Selection range in column-space for this line
            if (selLo < lineOff + lineL + 1 && selHi > lineOff) {
                lineSelLo = selLo - lineOff;
                lineSelHi = selHi - lineOff;
                if (lineSelLo < 0) { lineSelLo = 0; }
                // selHi can extend past line (newline selected)
            }
        }

        if (lineSelLo >= 0 && lineSelLo < lineSelHi) {
            // Clamp selection to visible columns for text runs
            int32_t vSelLo = lineSelLo < drawStart ? drawStart : lineSelLo;
            int32_t vSelHi = lineSelHi < drawEnd ? lineSelHi : drawEnd;

            if (vSelLo > vSelHi) { vSelLo = vSelHi; }

            // Before selection
            if (drawStart < vSelLo) {
                drawTextN(d, ops, font, textX + (drawStart - scrollCol) * font->charWidth, drawY, buf + lineOff + drawStart, vSelLo - drawStart, fg, bg, true);
            }

            // Selection (text portion)
            if (vSelLo < vSelHi) {
                drawTextN(d, ops, font, textX + (vSelLo - scrollCol) * font->charWidth, drawY, buf + lineOff + vSelLo, vSelHi - vSelLo, colors->menuHighlightFg, colors->menuHighlightBg, true);
            }

            // After selection
            if (vSelHi < drawEnd) {
                drawTextN(d, ops, font, textX + (vSelHi - scrollCol) * font->charWidth, drawY, buf + lineOff + vSelHi, drawEnd - vSelHi, fg, bg, true);
            }

            // Past end of text: fill selected area with highlight bg
            int32_t nlOff = lineOff + lineL;
            bool pastEolSelected = (nlOff >= selLo && nlOff < selHi);

            if (pastEolSelected && drawEnd < visEnd) {
                int32_t selPastStart = drawEnd < lineSelLo ? lineSelLo : drawEnd;
                int32_t selPastEnd   = visEnd;

                if (selPastStart < visStart) { selPastStart = visStart; }

                if (selPastStart < selPastEnd) {
                    rectFill(d, ops, textX + (selPastStart - scrollCol) * font->charWidth, drawY, (selPastEnd - selPastStart) * font->charWidth, font->charHeight, colors->menuHighlightBg);
                }
            }
        } else {
            // No selection on this line  -- single run
            if (drawStart < drawEnd) {
                drawTextN(d, ops, font, textX + (drawStart - scrollCol) * font->charWidth, drawY, buf + lineOff + drawStart, drawEnd - drawStart, fg, bg, true);
            }
        }

        // Advance lineOff to the next line
        lineOff += lineL;
        if (lineOff < len && buf[lineOff] == '\n') {
            lineOff++;
        }
    }

    // Draw cursor (blinks at same rate as terminal cursor)
    if (w->focused && sCursorBlinkOn) {
        int32_t curDrawCol = w->as.textArea.cursorCol - w->as.textArea.scrollCol;
        int32_t curDrawRow = w->as.textArea.cursorRow - w->as.textArea.scrollRow;

        if (curDrawCol >= 0 && curDrawCol <= visCols && curDrawRow >= 0 && curDrawRow < visRows) {
            int32_t cursorX = textX + curDrawCol * font->charWidth;
            int32_t cursorY = textY + curDrawRow * font->charHeight;
            drawVLine(d, ops, cursorX, cursorY, font->charHeight, fg);
        }
    }

    BevelStyleT btnBevel = BEVEL_RAISED(colors, 1);

    // Draw vertical scrollbar
    if (needVSb) {
        int32_t sbX = w->x + w->w - TEXTAREA_BORDER - TEXTAREA_SB_W;
        int32_t sbY = w->y + TEXTAREA_BORDER;
        int32_t sbH = innerH;

        // Trough
        BevelStyleT troughBevel = BEVEL_TROUGH(colors);
        drawBevel(d, ops, sbX, sbY, TEXTAREA_SB_W, sbH, &troughBevel);

        // Up arrow button
        drawBevel(d, ops, sbX, sbY, TEXTAREA_SB_W, TEXTAREA_SB_W, &btnBevel);

        // Up arrow triangle
        {
            int32_t cx = sbX + TEXTAREA_SB_W / 2;
            int32_t cy = sbY + TEXTAREA_SB_W / 2;

            for (int32_t i = 0; i < 4; i++) {
                drawHLine(d, ops, cx - i, cy - 2 + i, 1 + i * 2, colors->contentFg);
            }
        }

        // Down arrow button
        int32_t downY = sbY + sbH - TEXTAREA_SB_W;
        drawBevel(d, ops, sbX, downY, TEXTAREA_SB_W, TEXTAREA_SB_W, &btnBevel);

        // Down arrow triangle
        {
            int32_t cx = sbX + TEXTAREA_SB_W / 2;
            int32_t cy = downY + TEXTAREA_SB_W / 2;

            for (int32_t i = 0; i < 4; i++) {
                drawHLine(d, ops, cx - i, cy + 2 - i, 1 + i * 2, colors->contentFg);
            }
        }

        // Thumb
        int32_t trackLen = sbH - TEXTAREA_SB_W * 2;

        if (trackLen > 0) {
            int32_t thumbPos;
            int32_t thumbSize;
            widgetScrollbarThumb(trackLen, totalLines, visRows, w->as.textArea.scrollRow, &thumbPos, &thumbSize);
            drawBevel(d, ops, sbX, sbY + TEXTAREA_SB_W + thumbPos, TEXTAREA_SB_W, thumbSize, &btnBevel);
        }
    }

    // Draw horizontal scrollbar
    if (needHSb) {
        int32_t hsbX = w->x + TEXTAREA_BORDER;
        int32_t hsbY = w->y + w->h - TEXTAREA_BORDER - TEXTAREA_SB_W;
        int32_t hsbW = w->w - TEXTAREA_BORDER * 2 - TEXTAREA_SB_W;

        // Trough
        BevelStyleT troughBevel = BEVEL_TROUGH(colors);
        drawBevel(d, ops, hsbX, hsbY, hsbW, TEXTAREA_SB_W, &troughBevel);

        // Left arrow button
        drawBevel(d, ops, hsbX, hsbY, TEXTAREA_SB_W, TEXTAREA_SB_W, &btnBevel);

        // Left arrow triangle
        {
            int32_t cx = hsbX + TEXTAREA_SB_W / 2;
            int32_t cy = hsbY + TEXTAREA_SB_W / 2;

            for (int32_t i = 0; i < 4; i++) {
                drawVLine(d, ops, cx - 2 + i, cy - i, 1 + i * 2, colors->contentFg);
            }
        }

        // Right arrow button
        int32_t rightX = hsbX + hsbW - TEXTAREA_SB_W;
        drawBevel(d, ops, rightX, hsbY, TEXTAREA_SB_W, TEXTAREA_SB_W, &btnBevel);

        // Right arrow triangle
        {
            int32_t cx = rightX + TEXTAREA_SB_W / 2;
            int32_t cy = hsbY + TEXTAREA_SB_W / 2;

            for (int32_t i = 0; i < 4; i++) {
                drawVLine(d, ops, cx + 2 - i, cy - i, 1 + i * 2, colors->contentFg);
            }
        }

        // Thumb
        int32_t trackLen = hsbW - TEXTAREA_SB_W * 2;

        if (trackLen > 0) {
            int32_t thumbPos;
            int32_t thumbSize;
            widgetScrollbarThumb(trackLen, maxLL, visCols, w->as.textArea.scrollCol, &thumbPos, &thumbSize);
            drawBevel(d, ops, hsbX + TEXTAREA_SB_W + thumbPos, hsbY, thumbSize, TEXTAREA_SB_W, &btnBevel);
        }

        // Dead corner between scrollbars
        if (needVSb) {
            int32_t cornerX = w->x + w->w - TEXTAREA_BORDER - TEXTAREA_SB_W;
            rectFill(d, ops, cornerX, hsbY, TEXTAREA_SB_W, TEXTAREA_SB_W, colors->windowFace);
        }
    }

    // Focus rect
    if (w->focused) {
        drawFocusRect(d, ops, w->x + 1, w->y + 1, w->w - 2, w->h - 2, fg);
    }
}


// ============================================================
// widgetTextAreaSetText
// ============================================================

void widgetTextAreaSetText(WidgetT *w, const char *text) {
    if (w->as.textArea.buf) {
        strncpy(w->as.textArea.buf, text, w->as.textArea.bufSize - 1);
        w->as.textArea.buf[w->as.textArea.bufSize - 1] = '\0';
        w->as.textArea.len        = (int32_t)strlen(w->as.textArea.buf);
        w->as.textArea.cursorRow  = 0;
        w->as.textArea.cursorCol  = 0;
        w->as.textArea.scrollRow  = 0;
        w->as.textArea.scrollCol  = 0;
        w->as.textArea.desiredCol = 0;
        w->as.textArea.selAnchor  = -1;
        w->as.textArea.selCursor  = -1;
        w->as.textArea.cachedLines = -1;
        w->as.textArea.cachedMaxLL = -1;
    }
}


// ============================================================
// widgetTextInputCalcMinSize
// ============================================================

void widgetTextInputCalcMinSize(WidgetT *w, const BitmapFontT *font) {
    w->calcMinW = font->charWidth * 8 + TEXT_INPUT_PAD * 2;
    w->calcMinH = font->charHeight + TEXT_INPUT_PAD * 2;
}


// ============================================================
// widgetTextInputDestroy
// ============================================================

void widgetTextInputDestroy(WidgetT *w) {
    free(w->as.textInput.buf);
    free(w->as.textInput.undoBuf);
}


// ============================================================
// widgetTextInputGetText
// ============================================================

const char *widgetTextInputGetText(const WidgetT *w) {
    return w->as.textInput.buf ? w->as.textInput.buf : "";
}


// ============================================================
// widgetTextInputOnKey
// ============================================================

// TextInput key handling delegates to the shared widgetTextEditOnKey
// engine, passing pointers to its state fields. Masked input mode
// gets its own handler since the editing semantics are completely
// different. Password mode blocks copy/cut at this level before
// reaching the shared engine.
void widgetTextInputOnKey(WidgetT *w, int32_t key, int32_t mod) {
    if (!w->as.textInput.buf) {
        return;
    }

    clearOtherSelections(w);

    if (w->as.textInput.inputMode == InputMaskedE) {
        maskedInputOnKey(w, key, mod);
        return;
    }

    // Password mode: block copy (Ctrl+C) and cut (Ctrl+X)
    if (w->as.textInput.inputMode == InputPasswordE) {
        if (key == 3 || key == 24) {
            return;
        }
    }

    widgetTextEditOnKey(w, key, mod, w->as.textInput.buf, w->as.textInput.bufSize,
                        &w->as.textInput.len, &w->as.textInput.cursorPos,
                        &w->as.textInput.scrollOff,
                        &w->as.textInput.selStart, &w->as.textInput.selEnd,
                        w->as.textInput.undoBuf, &w->as.textInput.undoLen,
                        &w->as.textInput.undoCursor);
}


// ============================================================
// widgetTextInputOnMouse
// ============================================================

// Mouse handling for single-line input. Cursor position is computed
// from pixel offset using the fixed-width font (relX / charWidth +
// scrollOff). Multi-click: double-click selects word (using
// wordStart/wordEnd), triple-click selects all. Single click starts
// drag-select by setting both selStart and selEnd to the click
// position and registering sDragTextSelect.
void widgetTextInputOnMouse(WidgetT *w, WidgetT *root, int32_t vx, int32_t vy) {
    w->focused = true;
    clearOtherSelections(w);

    AppContextT *ctx = (AppContextT *)root->userData;
    widgetTextEditMouseClick(w, vx, vy, w->x + TEXT_INPUT_PAD, &ctx->font, w->as.textInput.buf, w->as.textInput.len, w->as.textInput.scrollOff, &w->as.textInput.cursorPos, &w->as.textInput.selStart, &w->as.textInput.selEnd, true, true);
}


// ============================================================
// widgetTextInputPaint
// ============================================================

// TextInput paint: sunken 2px bevel, then text with optional selection
// highlighting, then cursor line. Text is drawn from a display buffer
// that may be either the actual text or bullets (password mode, using
// CP437 character 0xF9 which renders as a small centered dot).
//
// The 3-run approach (before/during/after selection) draws text in a
// single pass without overdraw. The scroll offset ensures only the
// visible portion of the text is drawn. The cursor is a 1px-wide
// vertical line drawn at the character boundary.
void widgetTextInputPaint(WidgetT *w, DisplayT *d, const BlitOpsT *ops, const BitmapFontT *font, const ColorSchemeT *colors) {
    uint32_t fg = w->enabled ? (w->fgColor ? w->fgColor : colors->contentFg) : colors->windowShadow;
    uint32_t bg = w->bgColor ? w->bgColor : colors->contentBg;

    // Sunken border
    BevelStyleT bevel;
    bevel.highlight = colors->windowShadow;
    bevel.shadow    = colors->windowHighlight;
    bevel.face      = bg;
    bevel.width     = 2;
    drawBevel(d, ops, w->x, w->y, w->w, w->h, &bevel);

    // Draw text
    if (w->as.textInput.buf) {
        int32_t textX    = w->x + TEXT_INPUT_PAD;
        int32_t textY    = w->y + (w->h - font->charHeight) / 2;
        int32_t maxChars = (w->w - TEXT_INPUT_PAD * 2) / font->charWidth;
        int32_t off      = w->as.textInput.scrollOff;
        int32_t len      = w->as.textInput.len - off;

        if (len > maxChars) {
            len = maxChars;
        }

        bool isPassword = (w->as.textInput.inputMode == InputPasswordE);

        // Build display buffer (password masking)
        char dispBuf[256];
        int32_t dispLen = len > 255 ? 255 : len;

        if (isPassword) {
            memset(dispBuf, '\xF9', dispLen); // CP437 bullet
        } else {
            memcpy(dispBuf, w->as.textInput.buf + off, dispLen);
        }

        widgetTextEditPaintLine(d, ops, font, colors, textX, textY, dispBuf, dispLen, off, w->as.textInput.cursorPos, w->as.textInput.selStart, w->as.textInput.selEnd, fg, bg, w->focused && w->enabled, w->x + TEXT_INPUT_PAD, w->x + w->w - TEXT_INPUT_PAD);
    }
}


// ============================================================
// widgetTextInputSetText
// ============================================================

void widgetTextInputSetText(WidgetT *w, const char *text) {
    if (w->as.textInput.buf) {
        strncpy(w->as.textInput.buf, text, w->as.textInput.bufSize - 1);
        w->as.textInput.buf[w->as.textInput.bufSize - 1] = '\0';
        w->as.textInput.len       = (int32_t)strlen(w->as.textInput.buf);
        w->as.textInput.cursorPos = w->as.textInput.len;
        w->as.textInput.scrollOff = 0;
        w->as.textInput.selStart  = -1;
        w->as.textInput.selEnd    = -1;
    }
}


// ============================================================
// DXE registration
// ============================================================


static const WidgetClassT sClassTextInput = {
    .flags       = WCLASS_FOCUSABLE,
    .paint       = widgetTextInputPaint,
    .paintOverlay = NULL,
    .calcMinSize = widgetTextInputCalcMinSize,
    .layout      = NULL,
    .onMouse     = widgetTextInputOnMouse,
    .onKey       = widgetTextInputOnKey,
    .destroy     = widgetTextInputDestroy,
    .getText     = widgetTextInputGetText,
    .setText     = widgetTextInputSetText
};

static const WidgetClassT sClassTextArea = {
    .flags       = WCLASS_FOCUSABLE,
    .paint       = widgetTextAreaPaint,
    .paintOverlay = NULL,
    .calcMinSize = widgetTextAreaCalcMinSize,
    .layout      = NULL,
    .onMouse     = widgetTextAreaOnMouse,
    .onKey       = widgetTextAreaOnKey,
    .destroy     = widgetTextAreaDestroy,
    .getText     = widgetTextAreaGetText,
    .setText     = widgetTextAreaSetText
};

void wgtRegister(void) {
    widgetClassTable[WidgetTextInputE] = &sClassTextInput;
    widgetClassTable[WidgetTextAreaE]  = &sClassTextArea;
}