// https://stackoverflow.com/questions/21646738/convert-hex-to-rgba
// [
function hexToRGB(hex) {
  return [
    parseInt(hex.slice(1, 3), 16),
    parseInt(hex.slice(3, 5), 16),
    parseInt(hex.slice(5, 7), 16),
  ];
}

// https://stackoverflow.com/questions/4492385/convert-simple-array-into-two-dimensional-array-matrix
// convert a 1D array into a 2D matrix
export function toMatrix(array, width) {
  return array.reduce(
    (rows, key, index) =>
      (index % width == 0
        ? rows.push([key])
        : rows[rows.length - 1].push(key)) && rows,
    []
  );
}

// convert an image into a black and white image
export function picToBlackAndWhite(pixels, width, height) {
  return pixels.reduce((acc, pixel, index) => {
    if (index % 4 == 0) {
      const count = pixels[index] + pixels[index + 1] + pixels[index + 2];
      const colour = count >= 255 ? 255 : 1;
      acc.data[index] = colour;
      acc.data[index + 1] = colour;
      acc.data[index + 2] = colour;
      acc.data[index + 3] = 255;
    }
    return acc;
  }, new ImageData(width, height));
}

// convert an ImageData into a 2D array of boolean (0, 1) values
export function picToBoard(pixels, width, height) {
  const flat = pixels.reduce((acc, pixel, index) => {
    const i = index * 4;
    const count = pixels[i] + pixels[i + 1] + pixels[i + 2];
    const value = count >= 255 ? 1 : 0;
    acc[index] = value;
    return acc;
  }, []);

  return toMatrix(flat, width, height);
}

// convert board to ImageData
// TODO : different cell to color functions
// (binary, intermediate states, camaieux, etc)
export function boardToPic(board, width, height, cellProperties) {
  const live = cellProperties.liveColor;
  const dead = cellProperties.deadColor;
  const img = new ImageData(width, height);
  const colors = [hexToRGB(live), hexToRGB(dead)];
  board.flat().reduce((acc, cell, index) => {
    const color = cell === 1 ? colors[0] : colors[1];
    const i = index * 4;
    acc[i] = color[0];
    acc[i + 1] = color[1];
    acc[i + 2] = color[2];
    acc[i + 3] = 255;
    return acc;
  }, img.data);
  return img;
}