#!/usr/bin/env python3
"""
Build Hugging Face dataset artifacts from JSONL.

- Loads data/mux_assets.jsonl
- Runs a light validation (required fields + raw payload)
- Builds a datasets.Dataset
- Exports to Parquet at data/mux_assets.parquet

Usage:
  pip install -U datasets pyarrow
  python scripts/build_dataset.py
"""

from __future__ import annotations

import json
import os
from typing import Any, Dict, List

from datasets import Dataset

JSONL_PATH = os.path.join("data", "mux_assets.jsonl")
PARQUET_PATH = os.path.join("data", "mux_assets.parquet")

REQUIRED_FIELDS = [
    "asset_id",
    "upload_id",
    "title",
    "external_id",
    "creator_id",
    "status",
    "video_quality",
    "resolution_tier",
    "duration_seconds",
    "aspect_ratio",
    "max_width",
    "max_height",
    "max_frame_rate",
    "encoding_tier",
    "normalize_audio",
    "mp4_support",
    "playback_policy",
    "playback_id_public",
    "video_track_id",
    "audio_track_id",
    "audio_primary",
    "audio_channels",
    "audio_language_code",
    "created_at_unix",
    "raw_mux_json",
]


def load_jsonl(path: str) -> List[Dict[str, Any]]:
    rows: List[Dict[str, Any]] = []
    with open(path, "r", encoding="utf-8") as f:
        for i, line in enumerate(f, start=1):
            line = line.strip()
            if not line:
                continue
            try:
                rows.append(json.loads(line))
            except json.JSONDecodeError as e:
                raise SystemExit(f"[ERROR] Invalid JSON on line {i}: {e}") from e
    return rows


def light_validate(rows: List[Dict[str, Any]]) -> None:
    if not rows:
        raise SystemExit("[ERROR] No rows found in JSONL.")
    for idx, row in enumerate(rows):
        missing = [k for k in REQUIRED_FIELDS if k not in row]
        if missing:
            raise SystemExit(f"[ERROR] Row {idx} missing required fields: {missing}")
        if not isinstance(row["raw_mux_json"], dict):
            raise SystemExit(f"[ERROR] Row {idx} raw_mux_json must be an object/dict.")


def main() -> None:
    if not os.path.exists(JSONL_PATH):
        raise SystemExit(f"[ERROR] Missing file: {JSONL_PATH}")

    rows = load_jsonl(JSONL_PATH)
    light_validate(rows)

    ds = Dataset.from_list(rows)

    print("\n=== Dataset Preview ===")
    print(ds)
    print("\n=== Features ===")
    print(ds.features)

    ds.to_parquet(PARQUET_PATH)
    print(f"\n[OK] Wrote Parquet: {PARQUET_PATH}")


if __name__ == "__main__":
    main()