#!/usr/bin/env python3
"""Convert APM prompt CSV files into JSONL examples for model inference."""

from __future__ import annotations

import argparse
import csv
import hashlib
import json
import re
from pathlib import Path
from typing import Any, Dict, Iterable, List


FILENAME_RE = re.compile(r"prompts_(?P<language>.+)_(?P<noise>N\d+)\.csv$")
ALPHA_RE = re.compile(r"alpha_(?P<value>\d+(?:\.\d+)?)$")
DEFAULT_INSTRUCTION = (
    "Rewrite the noisy user prompt into a clear prompt that preserves the user's "
    "intent. Return only the rewritten prompt; do not ask clarification questions "
    "or add explanations."
)


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument(
        "--dataset-dir",
        type=Path,
        default=Path("."),
        help="Directory containing prompts_<language>_<noise>.csv files.",
    )
    parser.add_argument(
        "--output-dir",
        type=Path,
        default=Path("benchmark_inputs"),
        help="Directory where JSONL inference inputs will be written.",
    )
    parser.add_argument(
        "--no-instruction",
        action="store_true",
        help="Do not include the default mediation instruction in each row.",
    )
    parser.add_argument(
        "--overwrite",
        action="store_true",
        help="Replace existing output files.",
    )
    return parser.parse_args()


def alpha_columns(fieldnames: Iterable[str]) -> List[str]:
    columns = [name for name in fieldnames if ALPHA_RE.fullmatch(name)]
    return sorted(columns, key=lambda name: float(ALPHA_RE.fullmatch(name).group("value")))


def example_id(payload: Dict[str, Any]) -> str:
    stable = json.dumps(payload, ensure_ascii=False, sort_keys=True, separators=(",", ":"))
    return hashlib.sha1(stable.encode("utf-8")).hexdigest()


def iter_examples(csv_path: Path, include_instruction: bool) -> Iterable[Dict[str, Any]]:
    match = FILENAME_RE.match(csv_path.name)
    if not match:
        return

    language = match.group("language")
    noise = match.group("noise")

    with csv_path.open("r", encoding="utf-8-sig", newline="") as f:
        reader = csv.DictReader(f)
        if reader.fieldnames is None:
            return
        alphas = alpha_columns(reader.fieldnames)

        for row_index, row in enumerate(reader):
            clean_text = row.get("Clean_text", "")
            category = row.get("Category", "")
            for alpha_col in alphas:
                alpha_value = float(ALPHA_RE.fullmatch(alpha_col).group("value"))
                noisy_prompt = row.get(alpha_col, "")
                identity = {
                    "language": language,
                    "noise": noise,
                    "row_index": row_index,
                    "alpha": alpha_value,
                    "clean_text": clean_text,
                    "noisy_prompt": noisy_prompt,
                }
                example = {
                    "example_id": example_id(identity),
                    "language": language,
                    "noise": noise,
                    "category": category,
                    "alpha": alpha_value,
                    "clean_text": clean_text,
                    "noisy_prompt": noisy_prompt,
                    "source_file": csv_path.name,
                    "row_index": row_index,
                }
                if include_instruction:
                    example["instruction"] = DEFAULT_INSTRUCTION
                yield example


def main() -> None:
    args = parse_args()
    csv_paths = sorted(args.dataset_dir.glob("prompts_*_N*.csv"))
    if not csv_paths:
        raise SystemExit(f"No prompt CSV files found in {args.dataset_dir}")

    total = 0
    args.output_dir.mkdir(parents=True, exist_ok=True)

    for csv_path in csv_paths:
        match = FILENAME_RE.match(csv_path.name)
        if not match:
            continue

        language = match.group("language")
        noise = match.group("noise")
        out_dir = args.output_dir / noise
        out_dir.mkdir(parents=True, exist_ok=True)
        out_path = out_dir / f"{language}.jsonl"

        if out_path.exists() and not args.overwrite:
            raise SystemExit(f"{out_path} already exists; pass --overwrite to replace it")

        count = 0
        with out_path.open("w", encoding="utf-8") as f:
            for example in iter_examples(csv_path, include_instruction=not args.no_instruction):
                f.write(json.dumps(example, ensure_ascii=False) + "\n")
                count += 1

        total += count
        print(f"Wrote {count:5d} examples -> {out_path}")

    print(f"Prepared {total} inference examples")


if __name__ == "__main__":
    main()