// widgetListBox.c — ListBox widget (single and multi-select)

#include "widgetInternal.h"

#include <stdlib.h>
#include <string.h>

#define LISTBOX_BORDER   2
#define LISTBOX_PAD      2
#define LISTBOX_MIN_ROWS 4
#define LISTBOX_SB_W     14


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

static void allocSelBits(WidgetT *w);
static void ensureScrollVisible(WidgetT *w, int32_t idx);
static void selectRange(WidgetT *w, int32_t from, int32_t to);


// ============================================================
// allocSelBits
// ============================================================

static void allocSelBits(WidgetT *w) {
    if (w->as.listBox.selBits) {
        free(w->as.listBox.selBits);
        w->as.listBox.selBits = NULL;
    }

    int32_t count = w->as.listBox.itemCount;

    if (count > 0 && w->as.listBox.multiSelect) {
        w->as.listBox.selBits = (uint8_t *)calloc(count, 1);
    }
}


// ============================================================
// ensureScrollVisible
// ============================================================

static void ensureScrollVisible(WidgetT *w, int32_t idx) {
    if (idx < 0) {
        return;
    }

    AppContextT       *ctx  = (AppContextT *)w->window->widgetRoot->userData;
    const BitmapFontT *font = &ctx->font;
    int32_t innerH      = w->h - LISTBOX_BORDER * 2;
    int32_t visibleRows = innerH / font->charHeight;

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

    if (idx < w->as.listBox.scrollPos) {
        w->as.listBox.scrollPos = idx;
    } else if (idx >= w->as.listBox.scrollPos + visibleRows) {
        w->as.listBox.scrollPos = idx - visibleRows + 1;
    }
}


// ============================================================
// selectRange
// ============================================================

static void selectRange(WidgetT *w, int32_t from, int32_t to) {
    if (!w->as.listBox.selBits) {
        return;
    }

    int32_t lo = from < to ? from : to;
    int32_t hi = from > to ? from : to;

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

    if (hi >= w->as.listBox.itemCount) {
        hi = w->as.listBox.itemCount - 1;
    }

    for (int32_t i = lo; i <= hi; i++) {
        w->as.listBox.selBits[i] = 1;
    }
}


// ============================================================
// widgetListBoxDestroy
// ============================================================

void widgetListBoxDestroy(WidgetT *w) {
    if (w->as.listBox.selBits) {
        free(w->as.listBox.selBits);
        w->as.listBox.selBits = NULL;
    }
}


// ============================================================
// wgtListBox
// ============================================================

WidgetT *wgtListBox(WidgetT *parent) {
    WidgetT *w = widgetAlloc(parent, WidgetListBoxE);

    if (w) {
        w->as.listBox.selectedIdx = -1;
        w->as.listBox.anchorIdx   = -1;
    }

    return w;
}


// ============================================================
// wgtListBoxClearSelection
// ============================================================

void wgtListBoxClearSelection(WidgetT *w) {
    if (!w || w->type != WidgetListBoxE || !w->as.listBox.selBits) {
        return;
    }

    memset(w->as.listBox.selBits, 0, w->as.listBox.itemCount);
}


// ============================================================
// wgtListBoxGetSelected
// ============================================================

int32_t wgtListBoxGetSelected(const WidgetT *w) {
    if (!w || w->type != WidgetListBoxE) {
        return -1;
    }

    return w->as.listBox.selectedIdx;
}


// ============================================================
// wgtListBoxIsItemSelected
// ============================================================

bool wgtListBoxIsItemSelected(const WidgetT *w, int32_t idx) {
    if (!w || w->type != WidgetListBoxE) {
        return false;
    }

    if (!w->as.listBox.multiSelect) {
        return idx == w->as.listBox.selectedIdx;
    }

    if (!w->as.listBox.selBits || idx < 0 || idx >= w->as.listBox.itemCount) {
        return false;
    }

    return w->as.listBox.selBits[idx] != 0;
}


// ============================================================
// wgtListBoxSelectAll
// ============================================================

void wgtListBoxSelectAll(WidgetT *w) {
    if (!w || w->type != WidgetListBoxE || !w->as.listBox.selBits) {
        return;
    }

    memset(w->as.listBox.selBits, 1, w->as.listBox.itemCount);
}


// ============================================================
// wgtListBoxSetItemSelected
// ============================================================

void wgtListBoxSetItemSelected(WidgetT *w, int32_t idx, bool selected) {
    if (!w || w->type != WidgetListBoxE) {
        return;
    }

    if (!w->as.listBox.selBits || idx < 0 || idx >= w->as.listBox.itemCount) {
        return;
    }

    w->as.listBox.selBits[idx] = selected ? 1 : 0;
}


// ============================================================
// wgtListBoxSetItems
// ============================================================

void wgtListBoxSetItems(WidgetT *w, const char **items, int32_t count) {
    if (!w || w->type != WidgetListBoxE) {
        return;
    }

    w->as.listBox.items     = items;
    w->as.listBox.itemCount = count;

    // Cache max item strlen to avoid recomputing in calcMinSize
    int32_t maxLen = 0;

    for (int32_t i = 0; i < count; i++) {
        int32_t slen = (int32_t)strlen(items[i]);

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

    w->as.listBox.maxItemLen = maxLen;

    if (w->as.listBox.selectedIdx >= count) {
        w->as.listBox.selectedIdx = count > 0 ? 0 : -1;
    }

    if (w->as.listBox.selectedIdx < 0 && count > 0) {
        w->as.listBox.selectedIdx = 0;
    }

    w->as.listBox.anchorIdx = w->as.listBox.selectedIdx;

    // Reallocate selection bits
    allocSelBits(w);

    // Pre-select the cursor item
    if (w->as.listBox.selBits && w->as.listBox.selectedIdx >= 0) {
        w->as.listBox.selBits[w->as.listBox.selectedIdx] = 1;
    }
}


// ============================================================
// wgtListBoxSetMultiSelect
// ============================================================

void wgtListBoxSetMultiSelect(WidgetT *w, bool multi) {
    if (!w || w->type != WidgetListBoxE) {
        return;
    }

    w->as.listBox.multiSelect = multi;
    allocSelBits(w);

    // Sync: mark current selection
    if (w->as.listBox.selBits && w->as.listBox.selectedIdx >= 0) {
        w->as.listBox.selBits[w->as.listBox.selectedIdx] = 1;
    }
}


// ============================================================
// wgtListBoxSetSelected
// ============================================================

void wgtListBoxSetSelected(WidgetT *w, int32_t idx) {
    if (!w || w->type != WidgetListBoxE) {
        return;
    }

    w->as.listBox.selectedIdx = idx;
    w->as.listBox.anchorIdx   = idx;

    // In multi-select, clear all then select just this one
    if (w->as.listBox.selBits) {
        memset(w->as.listBox.selBits, 0, w->as.listBox.itemCount);

        if (idx >= 0 && idx < w->as.listBox.itemCount) {
            w->as.listBox.selBits[idx] = 1;
        }
    }
}


// ============================================================
// widgetListBoxCalcMinSize
// ============================================================

void widgetListBoxCalcMinSize(WidgetT *w, const BitmapFontT *font) {
    int32_t maxItemW = w->as.listBox.maxItemLen * font->charWidth;
    int32_t minW     = font->charWidth * 8;

    if (maxItemW < minW) {
        maxItemW = minW;
    }

    w->calcMinW = maxItemW + LISTBOX_PAD * 2 + LISTBOX_BORDER * 2 + LISTBOX_SB_W;
    w->calcMinH = LISTBOX_MIN_ROWS * font->charHeight + LISTBOX_BORDER * 2;
}


// ============================================================
// widgetListBoxOnKey
// ============================================================

void widgetListBoxOnKey(WidgetT *w, int32_t key, int32_t mod) {
    if (!w || w->type != WidgetListBoxE || w->as.listBox.itemCount == 0) {
        return;
    }

    bool    multi = w->as.listBox.multiSelect;
    bool    shift = (mod & KEY_MOD_SHIFT) != 0;
    bool    ctrl  = (mod & KEY_MOD_CTRL) != 0;
    int32_t sel   = w->as.listBox.selectedIdx;

    // Ctrl+A — select all (multi-select only)
    if (multi && ctrl && (key == 'a' || key == 'A' || key == 1)) {
        wgtListBoxSelectAll(w);
        wgtInvalidatePaint(w);
        return;
    }

    // Space — toggle current item (multi-select only)
    if (multi && key == ' ') {
        if (sel >= 0 && w->as.listBox.selBits) {
            w->as.listBox.selBits[sel] ^= 1;
            w->as.listBox.anchorIdx = sel;
        }

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

        wgtInvalidatePaint(w);
        return;
    }

    int32_t newSel = sel;

    if (key == (0x50 | 0x100)) {
        // Down arrow
        if (newSel < w->as.listBox.itemCount - 1) {
            newSel++;
        } else if (newSel < 0) {
            newSel = 0;
        }
    } else if (key == (0x48 | 0x100)) {
        // Up arrow
        if (newSel > 0) {
            newSel--;
        } else if (newSel < 0) {
            newSel = 0;
        }
    } else if (key == (0x47 | 0x100)) {
        // Home
        newSel = 0;
    } else if (key == (0x4F | 0x100)) {
        // End
        newSel = w->as.listBox.itemCount - 1;
    } else if (key == (0x51 | 0x100)) {
        // Page Down
        AppContextT       *ctx  = (AppContextT *)w->window->widgetRoot->userData;
        const BitmapFontT *font = &ctx->font;
        int32_t visibleRows = (w->h - LISTBOX_BORDER * 2) / font->charHeight;

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

        newSel += visibleRows;

        if (newSel >= w->as.listBox.itemCount) {
            newSel = w->as.listBox.itemCount - 1;
        }
    } else if (key == (0x49 | 0x100)) {
        // Page Up
        AppContextT       *ctx  = (AppContextT *)w->window->widgetRoot->userData;
        const BitmapFontT *font = &ctx->font;
        int32_t visibleRows = (w->h - LISTBOX_BORDER * 2) / font->charHeight;

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

        newSel -= visibleRows;

        if (newSel < 0) {
            newSel = 0;
        }
    } else {
        return;
    }

    if (newSel == sel) {
        return;
    }

    w->as.listBox.selectedIdx = newSel;

    // Update selection
    if (multi && w->as.listBox.selBits) {
        if (shift) {
            // Shift+arrow: range from anchor to new cursor
            memset(w->as.listBox.selBits, 0, w->as.listBox.itemCount);
            selectRange(w, w->as.listBox.anchorIdx, newSel);
        }
        // Plain arrow: just move cursor, leave selections untouched
    }

    ensureScrollVisible(w, newSel);

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

    wgtInvalidatePaint(w);
}


// ============================================================
// widgetListBoxOnMouse
// ============================================================

void widgetListBoxOnMouse(WidgetT *hit, WidgetT *root, int32_t vx, int32_t vy) {
    AppContextT       *ctx  = (AppContextT *)root->userData;
    const BitmapFontT *font = &ctx->font;

    int32_t innerH      = hit->h - LISTBOX_BORDER * 2;
    int32_t visibleRows = innerH / font->charHeight;
    bool    needSb      = (hit->as.listBox.itemCount > visibleRows);

    // Clamp scroll
    int32_t maxScroll = hit->as.listBox.itemCount - visibleRows;

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

    hit->as.listBox.scrollPos = clampInt(hit->as.listBox.scrollPos, 0, maxScroll);

    // Check if click is on the scrollbar
    if (needSb) {
        int32_t sbX = hit->x + hit->w - LISTBOX_BORDER - LISTBOX_SB_W;

        if (vx >= sbX) {
            int32_t sbY      = hit->y + LISTBOX_BORDER;
            int32_t sbH      = innerH;
            int32_t relY     = vy - sbY;
            int32_t trackLen = sbH - LISTBOX_SB_W * 2;

            if (relY < LISTBOX_SB_W) {
                // Up arrow
                if (hit->as.listBox.scrollPos > 0) {
                    hit->as.listBox.scrollPos--;
                }
            } else if (relY >= sbH - LISTBOX_SB_W) {
                // Down arrow
                if (hit->as.listBox.scrollPos < maxScroll) {
                    hit->as.listBox.scrollPos++;
                }
            } else if (trackLen > 0) {
                // Track — page up/down
                int32_t thumbPos;
                int32_t thumbSize;
                widgetScrollbarThumb(trackLen, hit->as.listBox.itemCount, visibleRows, hit->as.listBox.scrollPos, &thumbPos, &thumbSize);

                int32_t trackRelY = relY - LISTBOX_SB_W;

                if (trackRelY < thumbPos) {
                    hit->as.listBox.scrollPos -= visibleRows;
                    hit->as.listBox.scrollPos = clampInt(hit->as.listBox.scrollPos, 0, maxScroll);
                } else if (trackRelY >= thumbPos + thumbSize) {
                    hit->as.listBox.scrollPos += visibleRows;
                    hit->as.listBox.scrollPos = clampInt(hit->as.listBox.scrollPos, 0, maxScroll);
                }
            }

            hit->focused = true;
            return;
        }
    }

    // Click on item area
    int32_t innerY = hit->y + LISTBOX_BORDER;
    int32_t relY   = vy - innerY;

    if (relY < 0) {
        return;
    }

    int32_t clickedRow = relY / font->charHeight;
    int32_t idx        = hit->as.listBox.scrollPos + clickedRow;

    if (idx < 0 || idx >= hit->as.listBox.itemCount) {
        return;
    }

    bool multi = hit->as.listBox.multiSelect;
    bool shift = (ctx->keyModifiers & KEY_MOD_SHIFT) != 0;
    bool ctrl  = (ctx->keyModifiers & KEY_MOD_CTRL) != 0;

    hit->as.listBox.selectedIdx = idx;
    hit->focused = true;

    if (multi && hit->as.listBox.selBits) {
        if (ctrl) {
            // Ctrl+click: toggle item, update anchor
            hit->as.listBox.selBits[idx] ^= 1;
            hit->as.listBox.anchorIdx = idx;
        } else if (shift) {
            // Shift+click: range from anchor to clicked
            memset(hit->as.listBox.selBits, 0, hit->as.listBox.itemCount);
            selectRange(hit, hit->as.listBox.anchorIdx, idx);
        } else {
            // Plain click: select only this item, update anchor
            memset(hit->as.listBox.selBits, 0, hit->as.listBox.itemCount);
            hit->as.listBox.selBits[idx] = 1;
            hit->as.listBox.anchorIdx = idx;
        }
    }

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

    if (hit->onDblClick && multiClickDetect(vx, vy) >= 2) {
        hit->onDblClick(hit);
    }
}


// ============================================================
// widgetListBoxPaint
// ============================================================

void widgetListBoxPaint(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;

    int32_t innerH      = w->h - LISTBOX_BORDER * 2;
    int32_t visibleRows = innerH / font->charHeight;
    bool    needSb      = (w->as.listBox.itemCount > visibleRows);
    int32_t contentW    = w->w - LISTBOX_BORDER * 2;

    if (needSb) {
        contentW -= LISTBOX_SB_W;
    }

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

    // Clamp scroll position
    int32_t maxScroll = w->as.listBox.itemCount - visibleRows;

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

    w->as.listBox.scrollPos = clampInt(w->as.listBox.scrollPos, 0, maxScroll);

    // Draw items
    int32_t  innerX    = w->x + LISTBOX_BORDER + LISTBOX_PAD;
    int32_t  innerY    = w->y + LISTBOX_BORDER;
    int32_t  scrollPos = w->as.listBox.scrollPos;
    bool     multi     = w->as.listBox.multiSelect;
    uint8_t *selBits   = w->as.listBox.selBits;

    for (int32_t i = 0; i < visibleRows && (scrollPos + i) < w->as.listBox.itemCount; i++) {
        int32_t  idx = scrollPos + i;
        int32_t  iy  = innerY + i * font->charHeight;
        uint32_t ifg = fg;
        uint32_t ibg = bg;

        bool isSelected;

        if (multi && selBits) {
            isSelected = selBits[idx] != 0;
        } else {
            isSelected = (idx == w->as.listBox.selectedIdx);
        }

        if (isSelected) {
            ifg = colors->menuHighlightFg;
            ibg = colors->menuHighlightBg;
            rectFill(d, ops, w->x + LISTBOX_BORDER, iy, contentW, font->charHeight, ibg);
        }

        drawText(d, ops, font, innerX, iy, w->as.listBox.items[idx], ifg, ibg, false);

        // Draw cursor indicator in multi-select (dotted focus rect on cursor item)
        if (multi && idx == w->as.listBox.selectedIdx && w->focused) {
            drawFocusRect(d, ops, w->x + LISTBOX_BORDER, iy, contentW, font->charHeight, fg);
        }
    }

    // Draw scrollbar
    if (needSb) {
        int32_t sbX = w->x + w->w - LISTBOX_BORDER - LISTBOX_SB_W;
        int32_t sbY = w->y + LISTBOX_BORDER;
        int32_t sbH = innerH;

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

        // Up arrow button
        BevelStyleT btnBevel = BEVEL_RAISED(colors, 1);
        drawBevel(d, ops, sbX, sbY, LISTBOX_SB_W, LISTBOX_SB_W, &btnBevel);

        // Up arrow triangle
        {
            int32_t  cx = sbX + LISTBOX_SB_W / 2;
            int32_t  cy = sbY + LISTBOX_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 - LISTBOX_SB_W;
        drawBevel(d, ops, sbX, downY, LISTBOX_SB_W, LISTBOX_SB_W, &btnBevel);

        // Down arrow triangle
        {
            int32_t  cx = sbX + LISTBOX_SB_W / 2;
            int32_t  cy = downY + LISTBOX_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 - LISTBOX_SB_W * 2;

        if (trackLen > 0) {
            int32_t thumbPos;
            int32_t thumbSize;
            widgetScrollbarThumb(trackLen, w->as.listBox.itemCount, visibleRows, w->as.listBox.scrollPos, &thumbPos, &thumbSize);

            drawBevel(d, ops, sbX, sbY + LISTBOX_SB_W + thumbPos, LISTBOX_SB_W, thumbSize, &btnBevel);
        }
    }

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