"""GFPAK archives (Game Freak), without game data: each entry's compression, Oodle through the game's own decoder."""
from pathlib import Path
import struct
import sys
import unittest
import zlib

import lz4.block

sys.path.insert(0, str(Path(__file__).resolve().parents[1] / 'tools'))
import shader_split


def gfpak(entries):
    """A GFPAK of (compression, raw length, stored bytes) entries: the 0x30-byte header, the file table, then the data"""
    table = 0x30
    data_at = table + 0x18 * len(entries)
    rows, data = b'', b''
    for ct, usz, stored in entries:
        rows += struct.pack('<HHII4xQ', 0, ct, usz, len(stored), data_at + len(data))
        data += stored
    return b'GFLXPACK' + struct.pack('<IIIIQQQ', 0x1000, 0, len(entries), 0, table, 0, 0) + rows + data


class GfpakTests(unittest.TestCase):
    def setUp(self):
        self.calls = []
        self.real_oodle = shader_split.oodle
        def fake_oodle(comp, n):   # stands in for the game's decoder in the Mac host (DM_OODLE_SERVE)
            self.calls.append((bytes(comp), n)); return b'K' * n
        shader_split.oodle = fake_oodle

    def tearDown(self):
        shader_split.oodle = self.real_oodle

    def test_entries_by_compression(self):
        # Sword's entries are LZ4; Pokémon Legends: Arceus's are Oodle Kraken (compression 3)
        raw = b'BNSH' + bytes(60)
        d = gfpak([(0, len(raw), raw), (1, len(raw), zlib.compress(raw)), (2, len(raw), lz4.block.compress(raw, store_size=False)),
                   (3, 0x40, b'kraken stream')])
        got = list(shader_split.gfpak_members(d, 'sample.gfpak'))
        self.assertEqual(got, [('#0', raw), ('#1', raw), ('#2', raw), ('#3', b'K' * 0x40)])
        self.assertEqual(self.calls, [(b'kraken stream', 0x40)])   # only the Oodle entry goes to the decoder

    def test_unknown_compression_stops(self):
        d = gfpak([(4, 8, b'????????')])
        with self.assertRaisesRegex(SystemExit, 'entry 0 has compression 4'):
            list(shader_split.gfpak_members(d, 'sample.gfpak'))


if __name__ == '__main__':
    unittest.main()