from pathlib import Path
from hashlib import sha256
import tempfile
import unittest

from engine.artifact_manager import ArtifactManager
from engine.models import ArtifactSpec, BaselineSnapshot, TaskSpec
from engine.models import BudgetSpec, ConstraintSpec, LoggingSpec, MutationSpec, ObjectiveSpec, PolicySpec, RunnerSpec, ScorerParseSpec, ScorerSpec


def make_task(root_dir: Path) -> TaskSpec:
    return TaskSpec(
        id="demo",
        description="Demo",
        artifacts=ArtifactSpec(include=["artifacts/*.md"], exclude=["artifacts/ignore.md"], max_files_per_iteration=1),
        mutation=MutationSpec(mode="direct_edit", allowed_file_types=[".md"], max_changed_lines=20),
        runner=RunnerSpec(command="python -c \"print('run')\"", cwd=".", timeout_seconds=10),
        scorer=ScorerSpec(
            type="command",
            command="python -c \"import json; print(json.dumps({'score': 1, 'metrics': {'violation_count': 0}}))\"",
            parse=ScorerParseSpec(format="json", score_field="score", metrics_field="metrics"),
        ),
        objective=ObjectiveSpec(primary_metric="score", direction="maximize"),
        constraints=[ConstraintSpec(metric="violation_count", op="<=", value=0)],
        policy=PolicySpec(keep_if="better_primary", tie_breakers=[], on_failure="discard"),
        budget=BudgetSpec(max_iterations=1, max_failures=1),
        logging=LoggingSpec(results_file="work/results.jsonl", candidate_dir="work/candidates"),
        root_dir=root_dir,
    )


class ArtifactManagerTest(unittest.TestCase):
    def test_snapshot_and_restore(self) -> None:
        with tempfile.TemporaryDirectory() as tmp:
            root = Path(tmp)
            artifact_dir = root / "artifacts"
            artifact_dir.mkdir()
            target = artifact_dir / "sample.md"
            target.write_text("hello\n", encoding="utf-8")
            manager = ArtifactManager(make_task(root))
            snapshot = manager.snapshot()
            target.write_text("changed\n", encoding="utf-8")
            manager.restore(snapshot)
            self.assertEqual(target.read_text(encoding="utf-8"), "hello\n")

    def test_restore_removes_newly_created_included_artifact(self) -> None:
        with tempfile.TemporaryDirectory() as tmp:
            root = Path(tmp)
            artifact_dir = root / "artifacts"
            artifact_dir.mkdir()
            target = artifact_dir / "sample.md"
            target.write_text("hello\n", encoding="utf-8")
            manager = ArtifactManager(make_task(root))
            snapshot = manager.snapshot()
            extra = artifact_dir / "new.md"
            extra.write_text("new\n", encoding="utf-8")
            manager.restore(snapshot)
            self.assertFalse(extra.exists())
            self.assertEqual(target.read_text(encoding="utf-8"), "hello\n")

    def test_snapshot_and_restore_preserve_crlf_content(self) -> None:
        with tempfile.TemporaryDirectory() as tmp:
            root = Path(tmp)
            artifact_dir = root / "artifacts"
            artifact_dir.mkdir()
            target = artifact_dir / "sample.md"
            original = "line1\r\nline2\r\n"
            with target.open("w", encoding="utf-8", newline="") as handle:
                handle.write(original)
            manager = ArtifactManager(make_task(root))
            snapshot = manager.snapshot()
            self.assertEqual(snapshot.file_contents[target], original)
            self.assertEqual(
                snapshot.file_hashes[target],
                sha256(original.encode("utf-8")).hexdigest(),
            )
            with target.open("w", encoding="utf-8", newline="") as handle:
                handle.write("changed\r\n")
            manager.restore(snapshot)
            with target.open("r", encoding="utf-8", newline="") as handle:
                restored = handle.read()
            self.assertEqual(restored, original)

    def test_resolve_paths_is_deterministic_and_respects_excludes(self) -> None:
        with tempfile.TemporaryDirectory() as tmp:
            root = Path(tmp)
            artifact_dir = root / "artifacts"
            artifact_dir.mkdir()
            (artifact_dir / "b.md").write_text("b\n", encoding="utf-8")
            (artifact_dir / "ignore.md").write_text("ignore\n", encoding="utf-8")
            (artifact_dir / "a.md").write_text("a\n", encoding="utf-8")
            manager = ArtifactManager(make_task(root))
            paths = manager.resolve_paths()
            self.assertEqual(paths, [artifact_dir / "a.md", artifact_dir / "b.md"])

    def test_diff_summary_contains_changed_line(self) -> None:
        with tempfile.TemporaryDirectory() as tmp:
            root = Path(tmp)
            artifact_dir = root / "artifacts"
            artifact_dir.mkdir()
            target = artifact_dir / "sample.md"
            target.write_text("before\n", encoding="utf-8")
            manager = ArtifactManager(make_task(root))
            snapshot = manager.snapshot()
            target.write_text("after\n", encoding="utf-8")
            summary = manager.diff_summary(snapshot)
            self.assertIn("-before", summary)
            self.assertIn("+after", summary)


if __name__ == "__main__":
    unittest.main()