"""Artifact manifest helpers."""

from __future__ import annotations

import hashlib
import mimetypes
from datetime import datetime, timezone
from pathlib import Path
from typing import Any

from guide_board.schema import assert_valid


def build_artifact_manifest(
    run_dir: Path,
    run_id: str,
    evidence: list[dict[str, Any]],
) -> list[dict[str, Any]]:
    artifacts: list[dict[str, Any]] = []
    seen: set[str] = set()
    for item in evidence:
        producer = item["check_id"]
        for artifact_ref in item.get("artifact_refs", []):
            if not isinstance(artifact_ref, str) or artifact_ref in seen:
                continue
            seen.add(artifact_ref)
            path = (run_dir / artifact_ref).resolve()
            try:
                path.relative_to(run_dir.resolve())
            except ValueError:
                continue
            if not path.exists() or not path.is_file():
                continue
            artifact = {
                "id": f"artifact:{_safe_id(artifact_ref)}",
                "run_id": run_id,
                "path": artifact_ref,
                "media_type": _media_type(path),
                "producer": producer,
                "checksum": f"sha256:{_sha256(path)}",
                "created_at": datetime.now(timezone.utc).isoformat(),
                "retention_class": "raw",
            }
            assert_valid(artifact, "raw-artifact")
            artifacts.append(artifact)
    return artifacts


def _sha256(path: Path) -> str:
    digest = hashlib.sha256()
    with path.open("rb") as handle:
        for chunk in iter(lambda: handle.read(1024 * 1024), b""):
            digest.update(chunk)
    return digest.hexdigest()


def _media_type(path: Path) -> str:
    guessed, _ = mimetypes.guess_type(path.name)
    if guessed:
        return guessed
    return "application/octet-stream"


def _safe_id(value: str) -> str:
    return "".join(char if char.isalnum() or char in {"-", "_"} else "_" for char in value)