"""Tests for webapp.services.advisor_comparison: same-scenario run comparison."""
from __future__ import annotations

import json
from pathlib import Path

import pandas as pd

from webapp.services.advisor_comparison import find_previous_run


def _write_fake_run(
    root: Path,
    run_id: str,
    scenario_name: str,
    finished_at: str,
    judge_model: str,
    rows: list[dict],
) -> Path:
    """Write a minimal run directory discoverable by run_reader.list_run_summaries()."""
    run_dir = root / run_id
    run_dir.mkdir(parents=True, exist_ok=True)
    pd.DataFrame(rows).to_csv(run_dir / "scores.csv", index=False)
    metadata = {
        "run_id": run_id,
        "scenario_name": scenario_name,
        "judge_model": judge_model,
        "embedding_model": "embed-model",
        "finished_at": finished_at,
        "started_at": finished_at,
        "valid_samples": len(rows),
        "invalid_samples": 0,
    }
    (run_dir / "metadata.json").write_text(json.dumps(metadata), encoding="utf-8")
    return run_dir


class TestFindPreviousRun:
    def test_finds_most_recent_prior_run_with_same_scenario(self, tmp_path: Path) -> None:
        _write_fake_run(tmp_path, "r1", "scn-a", "2026-01-01T00:00:00+00:00", "gpt-5",
                         [{"sample_id": "s1", "faithfulness": 0.5}])
        _write_fake_run(tmp_path, "r2", "scn-a", "2026-01-02T00:00:00+00:00", "gpt-5",
                         [{"sample_id": "s1", "faithfulness": 0.6}])
        _write_fake_run(tmp_path, "r3", "scn-a", "2026-01-03T00:00:00+00:00", "gpt-5",
                         [{"sample_id": "s1", "faithfulness": 0.9}])

        previous = find_previous_run(
            "scn-a", "r3", "2026-01-03T00:00:00+00:00", extra_roots=[tmp_path]
        )

        assert previous is not None
        assert previous.run_id == "r2"

    def test_excludes_runs_with_different_scenario_name(self, tmp_path: Path) -> None:
        _write_fake_run(tmp_path, "r1", "scn-other", "2026-01-01T00:00:00+00:00", "gpt-5",
                         [{"sample_id": "s1", "faithfulness": 0.5}])
        _write_fake_run(tmp_path, "r2", "scn-a", "2026-01-02T00:00:00+00:00", "gpt-5",
                         [{"sample_id": "s1", "faithfulness": 0.6}])

        previous = find_previous_run(
            "scn-a", "r2", "2026-01-02T00:00:00+00:00", extra_roots=[tmp_path]
        )

        assert previous is None

    def test_returns_none_when_no_history(self, tmp_path: Path) -> None:
        _write_fake_run(tmp_path, "r1", "scn-a", "2026-01-01T00:00:00+00:00", "gpt-5",
                         [{"sample_id": "s1", "faithfulness": 0.5}])

        previous = find_previous_run(
            "scn-a", "r1", "2026-01-01T00:00:00+00:00", extra_roots=[tmp_path]
        )

        assert previous is None

    def test_ignores_runs_at_or_after_current_time(self, tmp_path: Path) -> None:
        _write_fake_run(tmp_path, "r1", "scn-a", "2026-01-01T00:00:00+00:00", "gpt-5",
                         [{"sample_id": "s1", "faithfulness": 0.5}])
        _write_fake_run(tmp_path, "r2", "scn-a", "2026-01-05T00:00:00+00:00", "gpt-5",
                         [{"sample_id": "s1", "faithfulness": 0.6}])

        # Current run finished at 2026-01-02, i.e. AFTER r1 but BEFORE r2.
        previous = find_previous_run(
            "scn-a", "r-current", "2026-01-02T00:00:00+00:00", extra_roots=[tmp_path]
        )

        assert previous is not None
        assert previous.run_id == "r1"