from __future__ import annotations

import argparse
import json
import sys
from pathlib import Path

ROOT_DIR = Path(__file__).resolve().parents[1]
if str(ROOT_DIR) not in sys.path:
    sys.path.insert(0, str(ROOT_DIR))

from engine.artifact_manager import ArtifactManager
from engine.decision_engine import decide_candidate
from engine.runner import run_command
from engine.scorer import parse_score_output
from engine.task_loader import load_task


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser()
    parser.add_argument("--task", required=True)
    return parser.parse_args()


def main() -> int:
    args = parse_args()
    root_dir = Path.cwd()
    task_path = (root_dir / args.task).resolve()
    task = load_task(task_path)

    artifact_manager = ArtifactManager(task)
    snapshot = artifact_manager.snapshot()

    run_result = run_command(
        task.runner.command,
        (root_dir / task.runner.cwd).resolve(),
        task.runner.timeout_seconds,
    )
    scorer_result = run_command(
        task.scorer.command,
        root_dir.resolve(),
        task.runner.timeout_seconds,
    )
    score_result = parse_score_output(
        scorer_result.stdout,
        score_field=task.scorer.parse.score_field,
        metrics_field=task.scorer.parse.metrics_field,
    )
    decision = decide_candidate(
        baseline=None,
        candidate=score_result,
        objective=task.objective,
        constraints=task.constraints,
        tie_breakers=task.policy.tie_breakers,
        run_result=run_result,
    )

    record = {
        "task_id": task.id,
        "status": decision.status,
        "reason": decision.reason,
        "candidate_score": decision.candidate_score,
        "diff_summary": artifact_manager.diff_summary(snapshot),
    }

    results_path = (root_dir / task.logging.results_file).resolve()
    results_path.parent.mkdir(parents=True, exist_ok=True)
    with results_path.open("a", encoding="utf-8", newline="") as handle:
        handle.write(json.dumps(record, ensure_ascii=False) + "\n")

    print(json.dumps(record, ensure_ascii=False))
    return 0


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