#define STB_TRUETYPE_IMPLEMENTATION
#define STB_IMAGE_WRITE_IMPLEMENTATION
#define STB_RECT_PACK_IMPLEMENTATION

#include "stb_rect_pack.h"
#include "stb_truetype.h"
#include "stb_image_write.h"
#include "load_entire_file.h"
#include "log.h"
#include "defer.h"
#include "glyphs.h"

struct Glyph {
    int x_off;
    int y_off;
    char* data;
};

Glyph_Coord glyph_coords[512];

int main() {
    stbtt_fontinfo font_info;
    stbrp_context packer_context;
    stbrp_node packer_nodes[600];
    stbrp_rect packer_rects[100];

    Glyph glyphs[512];

    String font_file = load_entire_file("../assets/fonts/Lexend-Regular.ttf");

    if (!font_file.length) {
        log_error("Loading font file has failed.");
        return 1;
    }
    
    if (!stbtt_InitFont(&font_info, (unsigned char*)font_file.data, 0)) {
        log_error("Init Font has failed.");
        return 1;
    }

    float font_scale = stbtt_ScaleForPixelHeight(&font_info, 48);

    stbrp_init_target(&packer_context, 512, 512, packer_nodes, sizeof(packer_nodes) / sizeof(*packer_nodes));
    int rect_number = 0;
    for (int i = ' '; i <= '~'; i++) {
        int glyph_width;
        int glyph_height;
        int glyph_offset_x;
        int glyph_offset_y;
        glyphs[rect_number].data = (char*) stbtt_GetCodepointBitmap(&font_info, font_scale, font_scale, i, &glyph_width, &glyph_height, &glyph_offset_x, &glyph_offset_y);
        glyphs[rect_number].x_off = glyph_offset_x;
        glyphs[rect_number].y_off = glyph_offset_y;
        
        packer_rects[rect_number].id = i;
        packer_rects[rect_number].w = glyph_width;
        packer_rects[rect_number].h = glyph_height;
        rect_number++;
    }

    stbrp_pack_rects(&packer_context, packer_rects, rect_number);
    char* glyph_atlas = (char*) malloc(512 * 512);
    for (int x = 0; x < 512; x++) {
        for (int y = 0; y < 512; y++) {
            glyph_atlas[y * 512 + x] = 0;
        }
    }


    for (int i = 0; i < rect_number; i++) {
        glyph_coords[i].x = packer_rects[i].x / 512.0f;
        glyph_coords[i].y = packer_rects[i].y / 512.0f;
        glyph_coords[i].width = packer_rects[i].w / 512.0f;
        glyph_coords[i].height = packer_rects[i].h / 512.0f;
        for (int x = 0; x < packer_rects[i].w; x++) {
            for (int y = 0; y < packer_rects[i].h; y++) {
                glyph_atlas[(y + packer_rects[i].y) * 512 + x + packer_rects[i].x] = glyphs[i].data[y * packer_rects[i].w + x];
            }
        }
    }

    FILE* file = fopen("../assets/fonts/glyph_coords_lexend.co", "wb");

    if (!file) {
        log_error("Glyph coords file creation has failed.");
        return 1;
    }
    defer(fclose(file));

    if (fwrite(glyph_coords, sizeof(*glyph_coords) * rect_number, 1, file) != 1) {
        log_error("fwrite for glyph_coords has failed.");
        return 1;
    }
    
    if (!stbi_write_bmp("../assets/fonts/glyph_atlas_lexend.bmp", 512, 512, 1, glyph_atlas)) {
        log_error("stbi_write_bmp has failed.");
        return 1;
    }

    return 0;
}