#include <graphics.h>
#include <stdio.h>

#define SCREEN_WIDTH 384
#define SCREEN_HEIGHT 224
#define MENU_HEIGHT 20

#define WINDOW_WIDTH SCREEN_WIDTH
#define WINDOW_HEIGHT (SCREEN_HEIGHT + MENU_HEIGHT)

static void setColorTable(struct nk_color *table) {
    table[NK_COLOR_TEXT] = nk_rgb(80, 80, 80);
    table[NK_COLOR_WINDOW] = nk_rgb(255, 255, 255);
    table[NK_COLOR_HEADER] = nk_rgb(40, 40, 40);
    table[NK_COLOR_BORDER] = nk_rgb(175, 175, 175);
    table[NK_COLOR_BUTTON] = nk_rgb(255, 255, 255);
    table[NK_COLOR_BUTTON_HOVER] = nk_rgb(215, 215, 215);
    table[NK_COLOR_BUTTON_ACTIVE] = nk_rgb(175, 175, 175);
    table[NK_COLOR_TOGGLE] = nk_rgb(100, 100, 100);
    table[NK_COLOR_TOGGLE_HOVER] = nk_rgb(120, 120, 120);
    table[NK_COLOR_TOGGLE_CURSOR] = nk_rgb(45, 45, 45);
    table[NK_COLOR_SELECT] = nk_rgb(45, 45, 45);
    table[NK_COLOR_SELECT_ACTIVE] = nk_rgb(35, 35, 35);
    table[NK_COLOR_SLIDER] = nk_rgb(38, 38, 38);
    table[NK_COLOR_SLIDER_CURSOR] = nk_rgb(100, 100, 100);
    table[NK_COLOR_SLIDER_CURSOR_HOVER] = nk_rgb(120, 120, 120);
    table[NK_COLOR_SLIDER_CURSOR_ACTIVE] = nk_rgb(150, 150, 150);
    table[NK_COLOR_PROPERTY] = nk_rgb(38, 38, 38);
    table[NK_COLOR_EDIT] = nk_rgb(38, 38, 38);
    table[NK_COLOR_EDIT_CURSOR] = nk_rgb(175, 175, 175);
    table[NK_COLOR_COMBO] = nk_rgb(45, 45, 45);
    table[NK_COLOR_CHART] = nk_rgb(120, 120, 120);
    table[NK_COLOR_CHART_COLOR] = nk_rgb(45, 45, 45);
    table[NK_COLOR_CHART_COLOR_HIGHLIGHT] = nk_rgb(255, 0, 0);
    table[NK_COLOR_SCROLLBAR] = nk_rgb(40, 40, 40);
    table[NK_COLOR_SCROLLBAR_CURSOR] = nk_rgb(100, 100, 100);
    table[NK_COLOR_SCROLLBAR_CURSOR_HOVER] = nk_rgb(120, 120, 120);
    table[NK_COLOR_SCROLLBAR_CURSOR_ACTIVE] = nk_rgb(150, 150, 150);
    table[NK_COLOR_TAB_HEADER] = nk_rgb(40, 40, 40);
    table[NK_COLOR_KNOB] = nk_rgb(38, 38, 38);
    table[NK_COLOR_KNOB_CURSOR] = nk_rgb(100, 100, 100);
    table[NK_COLOR_KNOB_CURSOR_HOVER] = nk_rgb(120, 120, 120);
    table[NK_COLOR_KNOB_CURSOR_ACTIVE] = nk_rgb(150, 150, 150);
}

static void applyStyles(struct nk_context *ctx) {
    struct nk_color table[NK_COLOR_COUNT];
    setColorTable(table);
    nk_style_from_table(ctx, table);
    ctx->style.window.padding = nk_vec2(0, 0);
    ctx->style.window.spacing = nk_vec2(0, 0);
    ctx->style.window.menu_padding = nk_vec2(0, 0);
    ctx->style.window.menu_border = 0;

    ctx->style.menu_button.hover = nk_style_item_color(table[NK_COLOR_BUTTON_HOVER]);
    ctx->style.menu_button.active = nk_style_item_color(table[NK_COLOR_BUTTON_ACTIVE]);
    ctx->style.contextual_button.padding = nk_vec2(20, 4);
}

static void copyScreenTexture(uint8_t *dst, const uint8_t *src, int pitch) {
    int x, y, i;
    uint8_t color;
    int delta = pitch / 384;
    for (y = 0; y < 224; ++y) {
        for (x = 0; x < 384; x += 1) {
            color = src[(y * 384) + x];
            for (i = 0; i < delta; ++i) {
                dst[(y * pitch) + (x * delta) + i] = color;
            }
        }
    }
}

int gfxInit(GraphicsContext *gfx) {
    float fontScale = 1;

    gfx->window = SDL_CreateWindow("Shrooms VB",
        SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
        WINDOW_WIDTH, WINDOW_HEIGHT, SDL_WINDOW_SHOWN | SDL_WINDOW_ALLOW_HIGHDPI);
    if (!gfx->window) {
        fprintf(stderr, "Error creating window: %s\n", SDL_GetError());
        return 1;
    }

    gfx->renderer = SDL_CreateRenderer(gfx->window, -1, 0);
    if (!gfx->renderer) {
        fprintf(stderr, "Error creating renderer: %s\n", SDL_GetError());
        goto cleanup_window;
    }

    /* scale the renderer output for High-DPI displays */
    {
        int renderW, renderH;
        int windowW, windowH;
        float scaleX, scaleY;
        SDL_GetRendererOutputSize(gfx->renderer, &renderW, &renderH);
        SDL_GetWindowSize(gfx->window, &windowW, &windowH);
        scaleX = (float)(renderW) / (float)(windowW);
        scaleY = (float)(renderH) / (float)(windowH);
        SDL_RenderSetScale(gfx->renderer, scaleX, scaleY);
    }

    gfx->nk = nk_sdl_init(gfx->window, gfx->renderer);
    applyStyles(gfx->nk);
    /* tell nuklear the mouse moved somewhere so it doesn't think we're hovering in the top left */
    nk_input_motion(gfx->nk, 1024, 1024);

    {
        struct nk_font_atlas *atlas;
        struct nk_font_config config = nk_font_config(0);
        
        nk_sdl_font_stash_begin(&atlas);
        gfx->font = nk_font_atlas_add_default(atlas, 13 * fontScale, &config);
        nk_sdl_font_stash_end();

        gfx->font->handle.height /= fontScale;
        nk_style_set_font(gfx->nk, &gfx->font->handle);
    }

    gfx->leftEye = SDL_CreateTexture(gfx->renderer, SDL_PIXELFORMAT_RGB24, SDL_TEXTUREACCESS_STREAMING, 384, 224);
    if (!gfx->leftEye) {
        fprintf(stderr, "Error creating left eye texture: %s\n", SDL_GetError());
        goto cleanup_window;
    }
    SDL_SetTextureColorMod(gfx->leftEye, 0xff, 0, 0);

    gfx->rightEye = SDL_CreateTexture(gfx->renderer, SDL_PIXELFORMAT_RGB24, SDL_TEXTUREACCESS_STREAMING, 384, 224);
    if (!gfx->rightEye) {
        fprintf(stderr, "Error creating left eye texture: %s\n", SDL_GetError());
        goto cleanup_left_eye;
    }
    SDL_SetTextureColorMod(gfx->rightEye, 0, 0xc6, 0xf0);
    SDL_SetTextureBlendMode(gfx->rightEye, SDL_BLENDMODE_ADD);

    return 0;

cleanup_left_eye:
    SDL_DestroyTexture(gfx->leftEye);
cleanup_window:
    SDL_DestroyWindow(gfx->window);
    return 1;
}

void gfxDestroy(GraphicsContext *gfx) {
    SDL_DestroyTexture(gfx->rightEye);
    SDL_DestroyTexture(gfx->leftEye);
    SDL_DestroyWindow(gfx->window);
}

static void gfxUpdateEye(SDL_Texture *eye, const uint8_t *bytes) {
    void *target;
    int pitch;
    if (SDL_LockTexture(eye, NULL, &target, &pitch)) {
        fprintf(stderr, "Error locking buffer for eye: %s\n", SDL_GetError());
        return;
    }
    copyScreenTexture(target, bytes, pitch);
    SDL_UnlockTexture(eye);
}

void gfxUpdateEyes(GraphicsContext *gfx, const uint8_t *left, const uint8_t *right) {
    gfxUpdateEye(gfx->leftEye, left);
    gfxUpdateEye(gfx->rightEye, right);
}

void gfxMenuInputBegin(GraphicsContext *gfx) {
    nk_input_begin(gfx->nk);
}

void gfxMenuHandleEvent(GraphicsContext *gfx, SDL_Event *event) {
    (void) gfx;
    nk_sdl_handle_event(event);
}

void gfxMenuInputEnd(GraphicsContext *gfx) {
    nk_sdl_handle_grab();
    nk_input_end(gfx->nk);
}

static void pushMenubarSpace(GraphicsContext *gfx, const char *text) {
    struct nk_user_font *handle;
    int len;
    float width;
    handle = &gfx->font->handle;
    len = nk_strlen(text);
    width = handle->width(handle->userdata, handle->height, text, len) + 16;
    nk_layout_row_template_push_static(gfx->nk, width);
}

void gfxRender(GraphicsContext *gfx) {
    SDL_Rect dst;
    dst.x = 0;
    dst.y = MENU_HEIGHT;
    dst.w = SCREEN_WIDTH;
    dst.h = SCREEN_HEIGHT;

    SDL_RenderClear(gfx->renderer);
    SDL_RenderCopy(gfx->renderer, gfx->leftEye, NULL, &dst);
    SDL_RenderCopy(gfx->renderer, gfx->rightEye, NULL, &dst);

    /* GUI */
    if (nk_begin(gfx->nk, "Demo", nk_rect(0, 0, SCREEN_WIDTH, MENU_HEIGHT), NK_WINDOW_NO_SCROLLBAR | NK_WINDOW_BACKGROUND))
    {
        nk_menubar_begin(gfx->nk);
        nk_layout_row_template_begin(gfx->nk, 20);
            pushMenubarSpace(gfx, "File");
            pushMenubarSpace(gfx, "Emulation");
        nk_layout_row_template_end(gfx->nk);
        if (nk_menu_begin_label(gfx->nk, "File", NK_TEXT_ALIGN_CENTERED, nk_vec2(120, WINDOW_HEIGHT))) {
            nk_layout_row_dynamic(gfx->nk, 22, 1);
            if (nk_menu_item_label(gfx->nk, "Open ROM", NK_TEXT_ALIGN_LEFT)) {
                printf("Open ROM\n");
            }
            if (nk_menu_item_label(gfx->nk, "Quit", NK_TEXT_ALIGN_LEFT)) {
                SDL_Event QuitEvent;
                QuitEvent.type = SDL_QUIT;
                QuitEvent.quit.timestamp = SDL_GetTicks();
                SDL_PushEvent(&QuitEvent);
            }
            nk_menu_end(gfx->nk);
        }
        if (nk_menu_begin_label(gfx->nk, "Emulation", NK_TEXT_ALIGN_CENTERED, nk_vec2(120, WINDOW_HEIGHT))) {
            nk_layout_row_dynamic(gfx->nk, 22, 1);
            if (nk_menu_item_label(gfx->nk, "Pause", NK_TEXT_ALIGN_LEFT)) {
                printf("Pause\n");
            }
            if (nk_menu_item_label(gfx->nk, "Reset", NK_TEXT_ALIGN_LEFT)) {
                printf("Reset\n");
            }
            nk_menu_end(gfx->nk);
        }
        nk_menubar_end(gfx->nk);
    }
    nk_end(gfx->nk);

    nk_sdl_render(NK_ANTI_ALIASING_ON);

    SDL_RenderPresent(gfx->renderer);
}