// The mouse (PLAN.md decision 4). Sierra's DOS interpreters had none; its
// Amiga, ST, IIgs, and Macintosh ones did, and this follows them as
// ScummVM describes them:
//
// - A pointer is drawn over the screen at every present while the machine
//   has a mouse and the game has not hidden it (hide.mouse), kept to the
//   box fence.mouse gives.
// - A left click on the menu bar opens the menus (as menu.input would);
//   in the picture, with the player in control, ego walks to it: its
//   baseline's middle to the click (objMouseWalk). A direction key, or in
//   AGI 3 a new room, stops the walk.
// - In the menus the pointer picks the menu and the item, and in a message
//   window a click is Enter (agiText.c, agiInput.c).

#include "agi.h"

#include "joey/core.h"
#include "joey/input.h"
#include "joey/sprite.h"
#include "joey/tile.h"


// The pointer: a 16x16 arrow, its point the hot spot. '.' is
// transparent, 'k' its outline (dark grey: color 0, black, is the
// sprite's transparent one), 'w' its white.
#define POINTER_TILES       2u
#define POINTER_PX          (POINTER_TILES * JL_TILE_PIXELS_PER_SIDE)
#define POINTER_OUTLINE     8u
#define POINTER_FILL        15u
#define PIXELS_PER_BYTE     2u
#define NIBBLE_BITS         4u
#define FENCE_X1            0u
#define FENCE_Y1            1u
#define FENCE_X2            2u
#define FENCE_Y2            3u


// ----- Prototypes -----

static void  pointerAt(int16_t *x, int16_t *y);
static bool  pointerShown(void);


// ----- Tables -----

static const char *const kPointerArt[POINTER_PX] = {
    "k...............",
    "kk..............",
    "kwk.............",
    "kwwk............",
    "kwwwk...........",
    "kwwwwk..........",
    "kwwwwwk.........",
    "kwwwwwwk........",
    "kwwwwwwwk.......",
    "kwwwwwkkkk......",
    "kwwkwwk.........",
    "kwk.kwwk........",
    "kk..kwwk........",
    "k....kwwk.......",
    ".....kwwk.......",
    "......kk........"
};


// ----- Module state -----

static uint8_t          gPointerTiles[POINTER_TILES * POINTER_TILES * JL_TILE_BYTES];
static jlSpriteT       *gPointer;
static uint16_t         gPointerUnder[jlSpriteBackupLength(POINTER_TILES, POINTER_TILES)];
static jlSpriteBackupT  gPointerSaved;
static bool             gPointerDrawn;


// ----- Internal helpers (alphabetical) -----

// Where the pointer is on the screen, kept inside fence.mouse's box (in
// picture coordinates; all zero is no fence).
static void pointerAt(int16_t *x, int16_t *y) {
    const uint8_t  *f;
    int16_t         left;
    int16_t         top;
    int16_t         right;
    int16_t         bottom;

    *x = jlMouseX();
    *y = jlMouseY();
    f  = gAgi->mouseFence;
    if (f[FENCE_X1] == 0u && f[FENCE_Y1] == 0u && f[FENCE_X2] == 0u && f[FENCE_Y2] == 0u) {
        return;
    }
    left   = (int16_t)(f[FENCE_X1] * AGI_SCREEN_PX_PER_AGI);
    right  = (int16_t)(f[FENCE_X2] * AGI_SCREEN_PX_PER_AGI);
    top    = (int16_t)(f[FENCE_Y1] + gAgi->picRow * AGI_CELL_PX);
    bottom = (int16_t)(f[FENCE_Y2] + gAgi->picRow * AGI_CELL_PX);
    if (*x < left) {
        *x = left;
    } else if (*x > right) {
        *x = right;
    }
    if (*y < top) {
        *y = top;
    } else if (*y > bottom) {
        *y = bottom;
    }
}


static bool pointerShown(void) {
    return gPointer != NULL && jlMousePresent() && !gAgi->mouseHidden;
}


// ----- Public API (alphabetical) -----

// A left click in a cycle (inputProcess): the menus on the menu bar, else
// a walk for ego.
void mouseClick(void) {
    int16_t  x;
    int16_t  y;
    uint8_t  ax;
    uint8_t  ay;

    if (!pointerShown()) {
        return;
    }
    pointerAt(&x, &y);
    if (y < (int16_t)AGI_CELL_PX) {
        if (gAgi->flags[FLAG_MENU] != 0u) {
            gAgi->menuRequested = true;
        }
        return;
    }
    if (gAgi->playerControl && !gAgi->textMode) {
        mousePosition(&ax, &ay);
        objMouseWalk(ax, ay);
    }
}


// The pointer onto the stage just before a present, what it covers kept.
void mouseDrawPointer(void) {
    int16_t  x;
    int16_t  y;

    if (!pointerShown()) {
        return;
    }
    pointerAt(&x, &y);
    jlSpriteSaveAndDraw(jlStageGet(), gPointer, x, y, &gPointerSaved);
    gPointerDrawn = true;
}


// And off again just after, so nothing else ever draws under it.
void mouseErasePointer(void) {
    if (!gPointerDrawn) {
        return;
    }
    jlSpriteRestoreUnder(jlStageGet(), &gPointerSaved);
    gPointerDrawn = false;
}


void mouseInit(void) {
    uint8_t  tx;
    uint8_t  ty;
    uint8_t  r;
    uint8_t  b;
    uint8_t  pixel[PIXELS_PER_BYTE];
    uint8_t  p;
    char     c;

    for (ty = 0u; ty < POINTER_TILES; ty++) {
        for (tx = 0u; tx < POINTER_TILES; tx++) {
            uint8_t  *tile = &gPointerTiles[(ty * POINTER_TILES + tx) * JL_TILE_BYTES];

            for (r = 0u; r < JL_TILE_PIXELS_PER_SIDE; r++) {
                for (b = 0u; b < JL_TILE_BYTES_PER_ROW; b++) {
                    for (p = 0u; p < PIXELS_PER_BYTE; p++) {
                        c        = kPointerArt[ty * JL_TILE_PIXELS_PER_SIDE + r][tx * JL_TILE_PIXELS_PER_SIDE + b * PIXELS_PER_BYTE + p];
                        pixel[p] = (c == 'k') ? POINTER_OUTLINE : ((c == 'w') ? POINTER_FILL : 0u);
                    }
                    tile[r * JL_TILE_BYTES_PER_ROW + b] = (uint8_t)((pixel[0] << NIBBLE_BITS) | pixel[1]);
                }
            }
        }
    }
    gPointerSaved.bytes = (uint8_t *)gPointerUnder;
    gPointer            = jlSpriteCreate(gPointerTiles, POINTER_TILES, POINTER_TILES);
    if (gPointer != NULL) {
        (void)jlSpriteCompile(gPointer);
    }
}


// The text cell under the pointer, when one is shown.
bool mouseOver(int16_t *col, int16_t *row) {
    int16_t  x;
    int16_t  y;

    if (!pointerShown()) {
        return false;
    }
    pointerAt(&x, &y);
    *col = (int16_t)(x / AGI_CELL_PX);
    *row = (int16_t)(y / AGI_CELL_PX);
    return true;
}


// get.mse.posn: the pointer in picture coordinates, kept to the picture.
void mousePosition(uint8_t *x, uint8_t *y) {
    int16_t  sx;
    int16_t  sy;
    int16_t  mx;
    int16_t  my;

    pointerAt(&sx, &sy);
    mx = (int16_t)(sx / AGI_SCREEN_PX_PER_AGI);
    my = (int16_t)(sy - (int16_t)gAgi->picRow * AGI_CELL_PX);
    *x = (uint8_t)(mx < 0 ? 0 : (mx > AGI_WIDTH - 1 ? AGI_WIDTH - 1 : mx));
    *y = (uint8_t)(my < 0 ? 0 : (my > AGI_MAX_Y ? AGI_MAX_Y : my));
}


void mouseShutdown(void) {
    if (gPointer != NULL) {
        jlSpriteDestroy(gPointer);
        gPointer = NULL;
    }
}