"""Extract best agentic upsampling images from an output directory."""

from __future__ import annotations

import argparse
import csv
import json
import shutil
from pathlib import Path
from typing import Any

from agentic_upsampling.io_utils import append_jsonl

IMAGE_SUFFIXES = {".jpg", ".jpeg", ".png", ".webp"}


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--output-dir", type=Path, required=True, help="Agentic upsampler run output directory.")
    parser.add_argument(
        "--export-dir",
        type=Path,
        default=None,
        help="Directory for copied best images and manifests. Defaults to OUTPUT_DIR/best_generations.",
    )
    parser.add_argument("--overwrite", action="store_true", help="Replace existing copied images/manifests.")
    return parser.parse_args()


def iter_best_jsons(output_dir: Path) -> list[Path]:
    """Return per-prompt best.json files in deterministic order."""
    return sorted(path for path in output_dir.glob("*/best.json") if path.parent.name != "best_generations")


def resolve_image_path(raw_path: str, *, output_dir: Path, best_json_path: Path) -> Path:
    """Resolve image paths written by runs launched with relative or absolute output dirs."""
    image_path = Path(raw_path)
    candidates = [image_path]
    if not image_path.is_absolute():
        candidates.extend(
            [
                output_dir / image_path,
                output_dir.parent / image_path,
                best_json_path.parent / image_path.name,
            ]
        )
    for candidate in candidates:
        if candidate.exists():
            return candidate
    raise FileNotFoundError(f"Best image does not exist: {raw_path}")


def copied_image_name(record: dict[str, Any], image_path: Path) -> str:
    """Build a simple copied image filename."""
    prompt_id = str(record["prompt_id"])
    suffix = image_path.suffix.lower()
    if suffix not in IMAGE_SUFFIXES:
        suffix = ".jpg"
    return f"{prompt_id}{suffix}"


def extract_record(best_json_path: Path, *, output_dir: Path, images_dir: Path, overwrite: bool) -> dict[str, Any]:
    """Copy one best image and return its export manifest record."""
    best_data = json.loads(best_json_path.read_text(encoding="utf-8"))
    if not isinstance(best_data, dict):
        raise ValueError(f"{best_json_path} must contain a JSON object.")
    best = best_data.get("best")
    if not isinstance(best, dict):
        raise ValueError(f"{best_json_path} is missing best candidate metadata.")
    raw_image_path = str(best.get("image_path") or "")
    if not raw_image_path:
        raise ValueError(f"{best_json_path} best candidate is missing image_path.")
    image_path = resolve_image_path(raw_image_path, output_dir=output_dir, best_json_path=best_json_path)
    record = {
        "prompt_id": str(best_data["prompt_id"]),
        "prompt": str(best_data.get("prompt") or ""),
        "best_score": best_data.get("best_score"),
        "best_iteration": best_data.get("best_iteration"),
        "selected_sample_index": best.get("selected_sample_index", best.get("sample_index")),
        "threshold_cleared_any": bool(best_data.get("threshold_cleared_any")),
        "source_image_path": str(image_path),
        "best_json_path": str(best_json_path),
        "analysis_path": str(best.get("analysis_path") or ""),
    }
    dest_path = images_dir / copied_image_name(record, image_path)
    if dest_path.exists() and not overwrite:
        raise FileExistsError(f"Refusing to overwrite existing image: {dest_path}")
    images_dir.mkdir(parents=True, exist_ok=True)
    shutil.copy2(image_path, dest_path)
    record["copied_image_path"] = str(dest_path)
    return record


def write_csv(path: Path, records: list[dict[str, Any]]) -> None:
    """Write a flat CSV summary for quick spreadsheet inspection."""
    fieldnames = [
        "prompt_id",
        "best_score",
        "best_iteration",
        "selected_sample_index",
        "threshold_cleared_any",
        "copied_image_path",
        "source_image_path",
        "best_json_path",
        "analysis_path",
        "prompt",
    ]
    with path.open("w", newline="", encoding="utf-8") as f:
        writer = csv.DictWriter(f, fieldnames=fieldnames)
        writer.writeheader()
        for record in records:
            writer.writerow({key: record.get(key, "") for key in fieldnames})


def extract_best_images(output_dir: Path, export_dir: Path, *, overwrite: bool = False) -> list[dict[str, Any]]:
    """Copy best images from a run and write JSONL/CSV manifests."""
    output_dir = output_dir.expanduser()
    export_dir = export_dir.expanduser()
    if not output_dir.exists():
        raise FileNotFoundError(f"Missing output directory: {output_dir}")
    best_jsons = iter_best_jsons(output_dir)
    if not best_jsons:
        raise RuntimeError(f"No per-prompt best.json files found under {output_dir}")

    images_dir = export_dir / "images"
    manifest_path = export_dir / "best_generations.jsonl"
    csv_path = export_dir / "best_generations.csv"
    if overwrite:
        manifest_path.unlink(missing_ok=True)
        csv_path.unlink(missing_ok=True)
    elif manifest_path.exists() or csv_path.exists():
        raise FileExistsError(f"Export manifests already exist in {export_dir}; pass --overwrite to replace them.")

    records: list[dict[str, Any]] = []
    for best_json_path in best_jsons:
        record = extract_record(best_json_path, output_dir=output_dir, images_dir=images_dir, overwrite=overwrite)
        records.append(record)
        append_jsonl(manifest_path, record)
    write_csv(csv_path, records)
    return records


def main() -> int:
    args = parse_args()
    export_dir = args.export_dir or (args.output_dir / "best_generations")
    records = extract_best_images(args.output_dir, export_dir, overwrite=args.overwrite)
    print(f"Exported {len(records)} best images to {export_dir}", flush=True)
    print(f"Images: {export_dir / 'images'}", flush=True)
    print(f"JSONL:  {export_dir / 'best_generations.jsonl'}", flush=True)
    print(f"CSV:    {export_dir / 'best_generations.csv'}", flush=True)
    return 0


if __name__ == "__main__":
    raise SystemExit(main())