#include "Gbm.h"

#include <cstdio>

#include "Files.h"

#define GBM_SIGNATURE 0x204d4247

Bitmap Gbm::loadFromMemory(const void *data, size_t size) {
    // Check for minimum
    if (size < sizeof (uint32_t) + sizeof (uint16_t) + sizeof (uint16_t) + 16 * 3) return {};

    auto gbm = static_cast<const GbmHeader *>(data);

    if (gbm->signature != GBM_SIGNATURE) return {};
    if (gbm->width == 0 || gbm->height == 0) return {};

    Bitmap bitmap(gbm->width, gbm->height);
    for (auto i = 0; i < 16; i++) {
        bitmap.SetPaletteEntry(i, {gbm->palette[i].r, gbm->palette[i].g, gbm->palette[i].b});
    }

    for (auto y = 0; y < gbm->height; y++) {
        for (auto x = 0; x < gbm->width; x++) {
            auto pv = gbm->data[y * gbm->width + x];
            bitmap.SetPixel(x, y, pv);
        }
    }

    return bitmap;
}

Bitmap Gbm::loadFromFile(const char *path) {
    void *data;
    auto len = Files::allocateBufferAndLoadFromFile(path, &data);
    auto bitmap = loadFromMemory(data, len);
    Files::deleteBuffer(data);

    return bitmap;
}

void Gbm::writeToFile(const char *path, const Bitmap &bitmap) {
    auto fp = fopen(path, "wb");
    if (!fp) return;

    // Write signature
    uint32_t signature = GBM_SIGNATURE;
    fwrite(&signature, 4, 1, fp);
    uint16_t width = bitmap.GetWidth(), height = bitmap.GetHeight();
    fwrite(&width, 2, 1, fp);
    fwrite(&height, 2, 1, fp);
    for (auto i = 0; i < 16; i++) {
        auto entry = bitmap.GetPaletteEntry(i);
        auto r = entry.r, g = entry.g, b = entry.b;
        fwrite(&r, 1, 1, fp);
        fwrite(&g, 1, 1, fp);
        fwrite(&b, 1, 1, fp);
    }

    for (auto y = 0; y < height; y++) {
        for (auto x = 0; x < width; x++) {
            auto pv = bitmap.GetPixel(x, y);
            fwrite(&pv, 1, 1, fp);
        }
    }

    fclose(fp);
}