from __future__ import annotations

import json
import shutil
from pathlib import Path


def load_records(path: str | Path) -> list[dict]:
    value = json.loads(Path(path).read_text(encoding="utf-8"))
    if not isinstance(value, list):
        raise ValueError("External benchmark metadata must be a JSON array")
    return value


def prepare_ruler(
    metadata_json: str | Path,
    videos_dir: str | Path,
    output_dir: str | Path,
    seeds: list[int],
    filename_template: str,
) -> dict:
    rows = load_records(metadata_json)
    source_root = Path(videos_dir)
    target_root = Path(output_dir)
    copied = 0
    missing = []
    for row in rows:
        source_id = Path(row["image_path"]).stem
        for seed in seeds:
            source = source_root / filename_template.format(
                id=row["id"], id06=f"{row['id']:06d}", seed=seed
            )
            if not source.is_file():
                missing.append(str(source))
                continue
            target = target_root / f"seed_{seed}" / row["task_name"] / f"{source_id}.mp4"
            target.parent.mkdir(parents=True, exist_ok=True)
            shutil.copy2(source, target)
            copied += 1
    return {"copied": copied, "missing": len(missing), "missing_examples": missing[:10]}


def prepare_vreason(
    metadata_json: str | Path,
    videos_dir: str | Path,
    output_dir: str | Path,
    seeds: list[int],
    model_name: str,
    filename_template: str,
) -> dict:
    rows = load_records(metadata_json)
    source_root = Path(videos_dir)
    target_root = Path(output_dir)
    copied = 0
    missing = []
    for row in rows:
        original_stem = Path(row["image_path"]).stem
        task = row["task_name"]
        prefix = f"{task}_"
        ground_truth_id = (
            original_stem[len(prefix) :] if original_stem.startswith(prefix) else original_stem
        )
        for seed in seeds:
            source = source_root / filename_template.format(
                id=row["id"], id06=f"{row['id']:06d}", seed=seed
            )
            if not source.is_file():
                missing.append(str(source))
                continue
            target = (
                target_root
                / f"{task}_{model_name}_{ground_truth_id}_{seed}.mp4"
            )
            target.parent.mkdir(parents=True, exist_ok=True)
            shutil.copy2(source, target)
            copied += 1
    return {"copied": copied, "missing": len(missing), "missing_examples": missing[:10]}