const PNG = require('pngjs').PNG;
const fs = require('fs');
const {
  TILE_WIDTH,
  TILE_HEIGHT
} = require('./common');

const colorPixel = (id) => {
  if(id === undefined) id = 3;
  if(id === 3) return { r: 8, g: 24, b: 32 };
  if(id === 2) return { r: 52, g: 104, b: 86 };
  if(id === 1) return { r: 136, g: 192, b: 112 };
  if(id === 0) return { r: 224, g: 248, b: 208 };
  throw new Error();
}

const gb2png = (DATA, fileOut) => {
  // Begin
  const PIXELS = DATA.length / 2 * TILE_WIDTH;
  const DATA_WIDTH = TILE_WIDTH;
  const DATA_HEIGHT = PIXELS / DATA_WIDTH;

  // Create output image
  const imageData = new PNG({
    width: DATA_WIDTH,
    height: DATA_HEIGHT
  });

  // Convert data into pixels
  const pixelsOut = [];
  for(let i = 0; i < DATA.length; i += 2) {
    const low = DATA[i];
    const high = DATA[i+1];

    for(let j = 0; j < 8; j++) {
      const mask = 0x80 >> j;
      const pixel = (low & mask ? 1 : 0) + (high & mask ? 2 : 0);
      pixelsOut.push(pixel);
    }
  }

  // Buffer data output
  for(let y = 0; y < DATA_HEIGHT; y++) {
    for(let x = 0; x < DATA_WIDTH; x++) {
      const id = (DATA_WIDTH * y + x);
      const color = colorPixel(pixelsOut[id]);
      const idx = id << 2;

      imageData.data[idx] = color.r;
      imageData.data[idx+1] = color.g;
      imageData.data[idx+2] = color.b;
      imageData.data[idx+3] = 0xFF;
    }
  }
  const buffer = PNG.sync.write(imageData, {  });
  fs.writeFileSync(fileOut, buffer);
}

// // Now work out tile data
// if(TILEMAP.length) {
//   for(let i = 0; i < TILEMAP.length; i++) {
//     const tileX = i % TILEMAP_WIDTH;
//     const tileY = Math.floor(i / TILEMAP_WIDTH);
//     const tile = TILEMAP[i];

//     for(let j = 0; j < TILE_WIDTH*TILE_HEIGHT; j++) {
//       const outI = (
//         (tileX * TILE_WIDTH) + (tileY * TILE_HEIGHT * TILEMAP_PIXEL_WIDTH) +
//         ((j % TILE_WIDTH) + (Math.floor(j / TILE_WIDTH) * TILEMAP_PIXEL_WIDTH))
//       );
//       const idx = outI << 2;
//       const pixelI = (tile * TILE_WIDTH * TILE_HEIGHT) + j;
//       const color = colorPixel(pixelsOut[pixelI]);

//       tileData.data[idx] = color.r;
//       tileData.data[idx+1] = color.g;
//       tileData.data[idx+2] = color.b;
//       tileData.data[idx+3] = 0xFF;
//     }
//   }

//   const buffer2 = PNG.sync.write(tileData, {  });
//   fs.writeFileSync('out.png', buffer2);
// }

module.exports = {
  gb2png
};