"""Consent/provenance sidecar field for voices (stored in <voice>.meta.json)."""
from __future__ import annotations

import re
from datetime import datetime, timezone
from urllib.parse import urlsplit

BASES = ("own_voice", "consented", "licensed", "public_domain", "unknown")
CONSENT_EXTS = {".webm", ".ogg", ".opus", ".wav", ".mp3", ".m4a"}
CONSENT_MIME = {".webm": "audio/webm", ".ogg": "audio/ogg", ".opus": "audio/ogg", ".wav": "audio/wav",
                ".mp3": "audio/mpeg", ".m4a": "audio/mp4"}
MAX_CONSENT_BYTES = 10 * 1024 * 1024
_LIMITS = {"source": 500, "licence": 300, "note": 1000}
_CTRL = re.compile(r"[\x00-\x08\x0b-\x1f\x7f]")


def _clean(value, limit: int) -> str:
    if value is None:
        return ""
    if not isinstance(value, str):
        raise ValueError("Provenance text fields must be strings")
    value = _CTRL.sub("", value).strip()
    if len(value) > limit:
        raise ValueError(f"Provenance text is too long (max {limit})")
    return value


def validate_provenance(data: dict, previous: dict | None = None) -> dict:
    """Return a clean provenance dict or raise ValueError (-> HTTP 400)."""
    if not isinstance(data, dict):
        raise ValueError("Provenance must be an object")
    basis = data.get("basis", "unknown")
    if basis not in BASES:
        raise ValueError("basis must be one of: " + ", ".join(BASES))
    out = {"basis": basis}
    for field, limit in _LIMITS.items():
        out[field] = _clean(data.get(field), limit)
    src = out["source"]
    if re.match(r"^[a-z][a-z0-9+.-]*:", src, re.I):  # looks like a URL: http(s) only, no credentials
        parts = urlsplit(src)
        if parts.scheme.lower() not in {"http", "https"} or not parts.hostname or parts.username or parts.password:
            raise ValueError("source URL must be http(s) without credentials")
    prev = previous or {}
    if prev.get("recorded_consent"):  # only the consent routes change the recording
        out["recorded_consent"] = prev["recorded_consent"]
    out["set_at"] = datetime.now(timezone.utc).isoformat(timespec="seconds")
    return out


def import_provenance(source_url: str) -> dict:
    """Prefill for imports from a known source; basis stays unknown until a human decides."""
    try:
        return validate_provenance({"basis": "unknown", "source": source_url})
    except ValueError:
        return {"basis": "unknown", "source": "", "licence": "", "note": ""}