import sizeOf from 'image-size'
import Util from './../common/Util.js'
import exif from 'exif'
import { Rng } from '../common/Rng.js'

// cut size of each puzzle tile in the
// final resized version of the puzzle image
const TILE_SIZE = 64

async function getDimensions(imagePath) {
  let dimensions = sizeOf(imagePath)
  try {
    const orientation = await getExifOrientation(imagePath)
    // when image is rotated to the left or right, switch width/height
    // https://jdhao.github.io/2019/07/31/image_rotation_exif_info/
    if (orientation === 6 || orientation === 8) {
      return {
        width: dimensions.height,
        height: dimensions.width,
      }
    }
  } catch {}
  return dimensions
}

async function getExifOrientation(imagePath) {
  return new Promise((resolve, reject) => {
    new exif.ExifImage({ image: imagePath }, function (error, exifData) {
      if (error) {
        reject(error)
      } else {
        resolve(exifData.image.Orientation)
      }
    })
  })
}

async function createPuzzle(
  /** @type Rng */ rng,
  targetTiles,
  image
) {
  const imagePath = image.file
  const imageUrl = image.url

  // load bitmap, to determine the original size of the image
  const dim = await getDimensions(imagePath)

  // determine puzzle information from the bitmap
  const info = determinePuzzleInfo(dim.width, dim.height, targetTiles)

  let tiles = new Array(info.tiles)
  for (let i = 0; i < tiles.length; i++) {
    tiles[i] = { idx: i }
  }
  const shapes = determinePuzzleTileShapes(rng, info)

  let positions = new Array(info.tiles)
  for (let tile of tiles) {
    let coord = Util.coordByTileIdx(info, tile.idx)
    positions[tile.idx] ={
      // instead of info.tileSize, we use info.tileDrawSize
      // to spread the tiles a bit
      x: coord.x * info.tileSize * 1.5,
      y: coord.y * info.tileSize * 1.5,
    }
  }

  const tableWidth = info.width * 3
  const tableHeight = info.height * 3

  const off = info.tileSize * 1.5
  let last = {
    x: info.width - (1 * off),
    y: info.height - (2 * off),
  }
  let countX = Math.ceil(info.width / off) + 2
  let countY = Math.ceil(info.height / off) + 2

  let diffX = off
  let diffY = 0
  let index = 0
  for (let pos of positions) {
    pos.x = last.x
    pos.y = last.y
    last.x+=diffX
    last.y+=diffY
    index++
    // did we move horizontally?
    if (diffX !== 0) {
      if (index === countX) {
        diffY = diffX
        countY++
        diffX = 0
        index = 0
      }
    } else {
      if (index === countY) {
        diffX = -diffY
        countX++
        diffY = 0
        index = 0
      }
    }
  }

  // then shuffle the positions
  positions = Util.shuffle(rng, positions)

  tiles = tiles.map(tile => {
    return Util.encodeTile({
      idx: tile.idx, // index of tile in the array
      group: 0, // if grouped with other tiles
      z: 0, // z index of the tile

      // who owns the tile
      // 0 = free for taking
      // -1 = finished
      // other values: id of player who has the tile
      owner: 0,

      // physical current position of the tile (x/y in pixels)
      // this position is the initial position only and is the
      // value that changes when moving a tile
      pos: positions[tile.idx],
    })
  })

  // Complete puzzle object
  return {
    // tiles array
    tiles,
    // game data for puzzle, data changes during the game
    data: {
      // TODO: maybe calculate this each time?
      maxZ: 0,     // max z of all pieces
      maxGroup: 0, // max group of all pieces
      started: Util.timestamp(), // start timestamp
      finished: 0, // finish timestamp
    },
    // static puzzle information. stays same for complete duration of
    // the game
    info: {
      table: {
        width: tableWidth,
        height: tableHeight,
      },
      // information that was used to create the puzzle
      targetTiles: targetTiles,
      imageUrl,

      width: info.width, // actual puzzle width (same as bitmap.width)
      height: info.height, // actual puzzle height (same as bitmap.height)
      tileSize: info.tileSize, // width/height of each tile (without tabs)
      tileDrawSize: info.tileDrawSize, // width/height of each tile (with tabs)
      tileMarginWidth: info.tileMarginWidth,
      // offset in x and y when drawing tiles, so that they appear to be at pos
      tileDrawOffset: (info.tileDrawSize - info.tileSize) / -2,
      // max distance between tile and destination that
      // makes the tile snap to destination
      snapDistance: info.tileSize / 2,
      tiles: info.tiles, // the final number of tiles in the puzzle
      tilesX: info.tilesX, // number of tiles each row
      tilesY: info.tilesY, // number of tiles each col
      // ( index => {x, y} )
      // this is not the physical coordinate, but
      // the tile_coordinate
      // this can be used to determine where the
      // final destination of a tile is
      shapes: shapes, // tile shapes
    },
  }
}

function determinePuzzleTileShapes(
  /** @type Rng */ rng,
  info
) {
  const tabs = [-1, 1]

  const shapes = new Array(info.tiles)
  for (let i = 0; i < info.tiles; i++) {
    let coord = Util.coordByTileIdx(info, i)
    shapes[i] = {
      top: coord.y === 0 ? 0 : shapes[i - info.tilesX].bottom * -1,
      right: coord.x === info.tilesX - 1 ? 0 : Util.choice(rng, tabs),
      left: coord.x === 0 ? 0 : shapes[i - 1].right * -1,
      bottom: coord.y === info.tilesY - 1 ? 0 : Util.choice(rng, tabs),
    }
  }
  return shapes.map(Util.encodeShape)
}

const determineTilesXY = (w, h, targetTiles) => {
  const w_ = w < h ? (w * h) : (w * w)
  const h_ = w < h ? (h * h) : (w * h)
  let size = 0
  let tiles = 0
  do {
    size++
    tiles = Math.floor(w_ / size) * Math.floor(h_ / size)
  } while (tiles >= targetTiles)
  size--
  return {
    tilesX: Math.round(w_ / size),
    tilesY: Math.round(h_ / size),
  }
}

const determinePuzzleInfo = (w, h, targetTiles) => {
  const {tilesX, tilesY} = determineTilesXY(w, h, targetTiles)
  const tiles = tilesX * tilesY
  const tileSize = TILE_SIZE
  const width = tilesX * tileSize
  const height = tilesY * tileSize

  const tileMarginWidth = tileSize * .5;
  const tileDrawSize = Math.round(tileSize + tileMarginWidth * 2)

  return {
    width,
    height,
    tileSize,
    tileMarginWidth,
    tileDrawSize,
    tiles,
    tilesX,
    tilesY,
  }
}

export {
  createPuzzle,
}