#!/bin/python3
import itertools
import io
from PIL import Image

from consts import *
from shared import main

palette_img = Image.new('P', (1, 1))
palette_img.putpalette(list(itertools.chain.from_iterable([
	*PICTOCHAT_PALETTE,
	*[PICTOCHAT_PALETTE[0] for x in range(256 - len(PICTOCHAT_PALETTE))],
])))

def convert_chunk(img, offset):
	palette_indices = []
	for y in range(DS_TILE_SIZE):
		for x in range(DS_TILE_SIZE):
			palette_indices.append(img.getpixel((x + offset[0], y + offset[1])))

	bytes = bytearray()
	for i in range(0, len(palette_indices), 2):
		bytes.append((palette_indices[i+0] << 0) | (palette_indices[i+1] << 4))
	
	return bytes

def png2pc(data):
	img = Image.open(io.BytesIO(data))
	if img.width != TILES_HORIZONTAL * DS_TILE_SIZE:
		print(f"error: input image is not {TILES_HORIZONTAL * DS_TILE_SIZE} pixels wide")
		exit(1)
	if img.height % DS_TILE_SIZE != 0:
		print(f"error: input image height not a muliple of {DS_TILE_SIZE}")
		exit(1)
	tile_count = (img.width * img.height) // (DS_TILE_SIZE ** 2)
	
	img = img.convert('RGB')
	img = img.quantize(palette=palette_img)

	output = b""
	for tile_idx in range(tile_count):
		tile = (
			tile_idx % TILES_HORIZONTAL,
			tile_idx // TILES_HORIZONTAL,
		)
		offset = (
			tile[0] * DS_TILE_SIZE,
			tile[1] * DS_TILE_SIZE,
		)
		output += convert_chunk(img, offset)

	return output

if __name__ == "__main__":
	main("png", "bin", png2pc)