#!/bin/python3

import sys
import re
import math
import io

from PIL import Image

from consts import PICTOCHAT_PALETTE

DS_TILE_SIZE = 8
TILE_BYTES = 32 # tiles are stored in 32 bytes chunks

TILES_HORIZONTAL = 32

# convert a single DS tile (8x8) from packed palette index format to RGB colors
def convert_chunk(img, chunk, offset):
	palette_indices = []
	for byte in chunk:
		palette_indices += [
			(byte >> 0) & 0x0f,
			(byte >> 4) & 0x0f,
		]

	for i, palette_idx in enumerate(palette_indices):
		color = PICTOCHAT_PALETTE[palette_idx]
		location = (
			i % DS_TILE_SIZE + offset[0],
			i // DS_TILE_SIZE + offset[1],
		)
		img.putpixel(location, color)

# convert a string of tiles into a PNG image
def pc2png(data):
	tile_count = math.floor(len(data) / TILE_BYTES)
	size = (
		TILES_HORIZONTAL * DS_TILE_SIZE,
		math.ceil(tile_count / TILES_HORIZONTAL) * DS_TILE_SIZE,
	)
	img = Image.new(mode="RGB", size=size)

	for tile in range(tile_count):
		chunk_idx = tile * TILE_BYTES
		chunk = data[chunk_idx:chunk_idx+TILE_BYTES]
		tile_offset = (
			tile % TILES_HORIZONTAL,
			tile // TILES_HORIZONTAL,
		)
		convert_chunk(img, chunk, [x * DS_TILE_SIZE for x in tile_offset])

	output = io.BytesIO()
	img.save(output, format='PNG')
	return output.getvalue()

def convert_file(input_filename, output_filename):
	with open(input_filename, 'rb') as input_file:
		content = input_file.read()
		output = pc2png(content)
		with open(output_filename, 'wb+') as output_file:
			output_file.write(output)

if __name__ == "__main__":
	del sys.argv[0]
	for input_filename in sys.argv:
		output_filename = re.sub('.bin$', '.png', input_filename)
		if not output_filename.endswith('.png'):
			output_filename += '.png'
		convert_file(input_filename, output_filename)