"""Prepare original Alien Grunt / hornet assets, without changing Steam files.

Embed the companion texture MDL; keep only self-contained sequence-group-zero
animations. External group 1 contains cinematic sequences, not the combat set.
"""
import hashlib
import json
import shutil
import struct
from pathlib import Path

ROOT = Path(__file__).resolve().parents[1]
SOURCE = Path.home() / '.steam/steam/steamapps/common/Half-Life/valve'
DEST = ROOT / 'assets/boss'


def digest(path):
    return hashlib.sha256(path.read_bytes()).hexdigest()


def prepare_model(name, companion=None):
    src = SOURCE / 'models' / (name + '.mdl')
    body = bytearray(src.read_bytes())
    assert body[:4] == b'IDST' and struct.unpack_from('<i', body, 4)[0] == 10
    sources = [{'path': 'models/' + src.name, 'sha256': digest(src)}]
    if companion:
        texpath = SOURCE / 'models' / companion
        tex = bytearray(texpath.read_bytes())
        base = len(body)
        count, records, data, refs, families, skins = struct.unpack_from('<6i', tex, 180)
        assert count > 0
        for i in range(count):
            pos = records + i * 80
            pixel = struct.unpack_from('<i', tex, pos + 76)[0]
            struct.pack_into('<i', tex, pos + 76, pixel + base)
        struct.pack_into('<6i', body, 180, count, records + base, data + base,
                         refs, families, skins + base)
        body.extend(tex)
        sources.append({'path': 'models/' + companion, 'sha256': digest(texpath)})
    count, offset = struct.unpack_from('<2i', body, 164)
    sequences, omitted, used = [], [], set()
    for i in range(count):
        record = bytearray(body[offset + 176 * i:offset + 176 * (i + 1)])
        label = bytes(record[:32]).split(b'\0')[0].decode('ascii')
        group = struct.unpack_from('<i', record, 156)[0]
        if group:
            omitted.append({'index': i, 'label': label, 'external_group': group})
            continue
        unique = label
        suffix = 2
        while unique in used:
            unique = label + '_' + str(suffix)
            suffix += 1
        used.add(unique)
        record[:32] = unique.encode().ljust(32, b'\0')
        sequences.append(record)
    # All sequence offsets still address the original, unchanged body data.
    struct.pack_into('<2i', body, 164, len(sequences), len(body))
    body.extend(b''.join(sequences))
    struct.pack_into('<i', body, 172, 1)
    struct.pack_into('<i', body, 72, len(body))
    out = DEST / (name + '_textured.mdl')
    out.write_bytes(body)
    return {'sources': sources, 'destination': str(out.relative_to(ROOT)),
            'sha256': digest(out), 'animations': sorted(used), 'omitted_sequences': omitted}


def main():
    DEST.mkdir(parents=True, exist_ok=True)
    records = [prepare_model('agrunt', 'agruntt.mdl'), prepare_model('hornet')]
    sounds = ['agrunt/ag_alert1.wav', 'agrunt/ag_attack1.wav', 'agrunt/ag_fire1.wav',
              'agrunt/ag_idle1.wav', 'agrunt/ag_pain1.wav', 'agrunt/ag_die1.wav',
              'ambience/port_suckin1.wav', 'ambience/port_suckout1.wav']
    for relative in sounds:
        src = SOURCE / 'sound' / relative
        out = ROOT / 'assets/audio' / relative
        out.parent.mkdir(parents=True, exist_ok=True)
        shutil.copyfile(src, out)
        assert digest(src) == digest(out)
        records.append({'source': 'sound/' + relative,
                        'destination': str(out.relative_to(ROOT)), 'sha256': digest(src)})
    (DEST / 'source_manifest.json').write_text(json.dumps(records, indent=2) + '\n')
    for r in records:
        print(r.get('destination'), r['sha256'])


if __name__ == '__main__':
    main()