# Apaga o texto "POed" do item de mesmo nome (nome de um jogo comercial) na folha de imagens do Go-inovation
# (ino/internal/assets/images/{color,mono}/ino.png, tile de 16x16 em x=240, y=64) e poe no lugar um icone neutro (um quadrado de
# cantos cortados). So biblioteca padrao; deterministico. Aceita PNG RGBA de 8 bits (color) e PNG de paleta de 4 bits (mono) e grava
# os dois como RGBA de 8 bits, sem entrelacamento, com zlib nivel 9.
import struct, sys, zlib

def read(p):
    d = open(p, 'rb').read()
    assert d[:8] == b'\x89PNG\r\n\x1a\n'
    pos, idat, plte, trns = 8, b'', b'', b''
    while pos < len(d):
        n, t = struct.unpack('>I4s', d[pos:pos + 8])
        body = d[pos + 8:pos + 8 + n]
        if t == b'IHDR':
            w, h, bd, ct, _, _, il = struct.unpack('>IIBBBBB', body)
            assert (bd, ct, il) in ((8, 6, 0), (4, 3, 0)), (bd, ct, il)
        elif t == b'PLTE': plte = body
        elif t == b'tRNS': trns = body
        elif t == b'IDAT': idat += body
        pos += 12 + n
    raw = zlib.decompress(idat)
    bpp = 4 if ct == 6 else 1
    stride = w * 4 if ct == 6 else (w + 1) // 2
    lines, prev = [], bytearray(stride)
    for y in range(h):
        f = raw[y * (stride + 1)]
        cur = bytearray(raw[y * (stride + 1) + 1:(y + 1) * (stride + 1)])
        for i in range(stride):
            a = cur[i - bpp] if i >= bpp else 0
            b = prev[i]
            c = prev[i - bpp] if i >= bpp else 0
            if f == 1: cur[i] = (cur[i] + a) & 255
            elif f == 2: cur[i] = (cur[i] + b) & 255
            elif f == 3: cur[i] = (cur[i] + ((a + b) >> 1)) & 255
            elif f == 4:
                pa, pb, pc = abs(b - c), abs(a - c), abs(a + b - 2 * c)
                pr = a if pa <= pb and pa <= pc else (b if pb <= pc else c)
                cur[i] = (cur[i] + pr) & 255
        lines.append(cur)
        prev = cur
    if ct == 6:
        return w, h, lines
    rows = []
    for cur in lines:
        r = bytearray()
        for x in range(w):
            v = cur[x // 2]
            idx = (v >> 4) if x % 2 == 0 else (v & 15)
            r += plte[idx * 3:idx * 3 + 3] + bytes((trns[idx] if idx < len(trns) else 255,))
        rows.append(r)
    return w, h, rows

def write(p, w, h, rows):
    def chunk(t, b): return struct.pack('>I', len(b)) + t + b + struct.pack('>I', zlib.crc32(t + b))
    raw = b''.join(b'\0' + bytes(r) for r in rows)
    open(p, 'wb').write(b'\x89PNG\r\n\x1a\n' + chunk(b'IHDR', struct.pack('>IIBBBBB', w, h, 8, 6, 0, 0, 0))
                        + chunk(b'IDAT', zlib.compress(raw, 9)) + chunk(b'IEND', b''))

for path, fill in ((sys.argv[1], (232, 51, 93, 255)), (sys.argv[2], (255, 255, 255, 255))):
    w, h, rows = read(path)
    for y in range(64, 80):
        for x in range(240, 256):
            rows[y][x * 4:x * 4 + 4] = b'\0\0\0\0'
    for y in range(66, 78):
        for x in range(242, 254):
            if x in (242, 253) and y in (66, 77): continue
            edge = x in (242, 253) or y in (66, 77)
            rows[y][x * 4:x * 4 + 4] = bytes((0, 0, 0, 255) if edge else fill)
    write(path, w, h, rows)