"""Bounded source acquisition and lossless metadata stress variants; no inference."""
import argparse
import hashlib
import json
from pathlib import Path
import subprocess
import struct
import urllib.request


def sha(data):
    return hashlib.sha256(data).hexdigest()


def execute(args):
    return subprocess.run(args, check=True, capture_output=True, timeout=60).stdout


def probe(path, ffprobe):
    value = json.loads(execute([str(ffprobe), "-v", "error", "-show_format", "-show_streams", "-of", "json", str(path)]))
    tags = {k.lower(): v for k, v in value.get("format", {}).get("tags", {}).items()}
    for stream in value["streams"]:
        tags.update({k.lower(): v for k, v in stream.get("tags", {}).items()})
    return tags


def pcm(path, ffmpeg, ffprobe):
    metadata = json.loads(execute([str(ffprobe), "-v", "error", "-show_format", "-of", "json", str(path)]))
    duration_ms = min(30000, int(float(metadata["format"]["duration"]) * 1000 + 0.5))
    data = execute([str(ffmpeg), "-v", "error", "-nostdin", "-threads", "1", "-ss", "0.000", "-t", f"{duration_ms / 1000:.3f}", "-i", str(path), "-af", f"aresample=16000,atrim=end_sample={duration_ms * 16},asetpts=PTS-STARTPTS", "-ac", "1", "-ar", "16000", "-threads", "1", "-f", "s16le", "pipe:1"])
    if not data or len(data) > 480000 * 2 or len(data) % 2:
        raise ValueError("Invalid bounded PCM")
    return sha(b"".join(struct.pack("<f", value[0] / 32768) for value in struct.iter_unpack("<h", data)))


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("fixture", type=Path)
    parser.add_argument("output", type=Path)
    parser.add_argument("ffmpeg", type=Path)
    parser.add_argument("ffprobe", type=Path)
    args = parser.parse_args()
    raw = args.fixture.read_bytes()
    fixture = json.loads(raw)
    lock = json.loads(args.fixture.with_name("labels.lock.json").read_text())
    if sha(raw) != lock["fixture_sha256"]:
        raise ValueError("Frozen fixture changed")
    args.output.mkdir(parents=True, exist_ok=True)
    plan_path = args.output / "prepared.json"
    if plan_path.exists():
        raise ValueError("Preserve existing prepared plan; use a fresh output directory")
    sources = []
    for asset in fixture["assets"]:
        destination = args.output / (asset["id"] + "-source.ogg")
        if destination.exists():
            data = destination.read_bytes()
        else:
            request = urllib.request.Request(asset["url"] + "?download=1", headers={"User-Agent": "SearchiMediaEvaluation/1.0"})
            with urllib.request.urlopen(request, timeout=60) as response:
                data = response.read(asset["bytes"] + 1)
            if len(data) != asset["bytes"] or hashlib.sha1(data).hexdigest() != asset["sha1"]:
                raise ValueError("Publisher bytes changed")
            destination.write_bytes(data)
        if len(data) != asset["bytes"] or hashlib.sha1(data).hexdigest() != asset["sha1"]:
            raise ValueError("Existing source changed")
        sources.append({"asset": asset, "path": destination.resolve(), "sha256": sha(data), "tags": probe(destination, args.ffprobe)})
    prepared = []
    whitelist = ["artist", "title", "album", "genre", "composer"]
    for i, source in enumerate(sources):
        original_pcm = None
        for variant in fixture["variants"]:
            path = args.output / (source["asset"]["id"] + "-" + variant + ".flac")
            tags = source["tags"] if variant == "original" else (sources[(i + 1) % len(sources)]["tags"] if variant == "misleading_metadata" else {})
            command = [str(args.ffmpeg), "-v", "error", "-nostdin", "-n", "-threads", "1", "-i", str(source["path"]), "-t", "30", "-ac", "1", "-ar", "16000", "-map_metadata", "-1", "-c:a", "flac"]
            for key in whitelist:
                if key in tags:
                    command.extend(["-metadata", f"{key}={tags[key]}"])
            command.append(str(path))
            execute(command)
            pcm_hash = pcm(path, args.ffmpeg, args.ffprobe)
            if original_pcm is None:
                original_pcm = pcm_hash
            if pcm_hash != original_pcm:
                raise ValueError("Metadata variant changed decoded audio")
            prepared.append({"id": source["asset"]["id"], "variant": variant, "kind": "audio", "path": str(path.resolve()), "sha256": sha(path.read_bytes()), "pcm_sha256": pcm_hash, "actual_tags": probe(path, args.ffprobe), "source_sha256": source["sha256"], "source_page": source["asset"]["source_page"], "license": source["asset"]["license"]})
    # Previously evaluated assets are distractors only, never new positive evidence.
    legacy_root = Path("fixtures/media")
    legacy_raw = (legacy_root / "fixture.json").read_bytes()
    legacy = json.loads(legacy_raw)
    legacy_lock = json.loads((legacy_root / "labels.lock.json").read_text())
    if sha(legacy_raw) != legacy_lock["fixture_sha256"]:
        raise ValueError("Legacy distractor fixture changed")
    for asset in legacy["assets"]:
        if asset["id"] not in fixture["legacy_distractors"]:
            continue
        path = (legacy_root / asset["path"]).resolve()
        if sha(path.read_bytes()) != asset["sha256"]:
            raise ValueError("Legacy distractor changed")
        prepared.append({"id": asset["id"], "variant": "fixed", "kind": "image" if asset["kind"] == "image" else "audio", "path": str(path), "sha256": asset["sha256"], "actual_tags": {} if asset["kind"] == "image" else probe(path, args.ffprobe), "legacy_distractor": True})
    result = {"fixture_sha256": sha(raw), "fixture": fixture, "candidates": prepared, "ffmpeg_sha256": sha(args.ffmpeg.read_bytes()), "ffprobe_sha256": sha(args.ffprobe.read_bytes()), "source_info": [{**s, "path": str(s["path"])} for s in sources]}
    with plan_path.open("x", encoding="utf-8") as output:
        json.dump(result, output, ensure_ascii=False, indent=2)
    print("Prepared", len(prepared), "containers; no inference. Plan SHA256", sha(plan_path.read_bytes()))


if __name__ == "__main__":
    main()