from pathlib import Path
import tempfile
import unittest

from engine.task_loader import TaskValidationError, load_task


VALID_TASK = """
id: demo
description: Demo task
artifacts:
  include:
    - tasks/demo/sample.txt
  exclude: []
  max_files_per_iteration: 1
mutation:
  mode: direct_edit
  allowed_file_types: [".txt"]
  max_changed_lines: 10
runner:
  command: "python -c \\\"print('run')\\\""
  cwd: "."
  timeout_seconds: 10
scorer:
  type: command
  command: "python -c \\\"import json; print(json.dumps({'score': 1, 'metrics': {'violation_count': 0}}))\\\""
  parse:
    format: json
    score_field: "score"
    metrics_field: "metrics"
objective:
  primary_metric: score
  direction: maximize
constraints:
  - metric: violation_count
    op: "<="
    value: 0
policy:
  keep_if: better_primary
  tie_breakers: []
  on_failure: discard
budget:
  max_iterations: 3
  max_failures: 1
logging:
  results_file: work/results.jsonl
  candidate_dir: work/candidates
"""


class TaskLoaderTest(unittest.TestCase):
    def write_task(self, content: str) -> Path:
        temp_dir = tempfile.TemporaryDirectory()
        self.addCleanup(temp_dir.cleanup)
        task_path = Path(temp_dir.name) / "task.yaml"
        task_path.write_text(content, encoding="utf-8")
        return task_path

    def test_loads_minimal_task(self) -> None:
        task = load_task(self.write_task(VALID_TASK))
        self.assertEqual(task.id, "demo")
        self.assertEqual(task.artifacts.max_files_per_iteration, 1)
        self.assertEqual(task.constraints[0].metric, "violation_count")

    def test_rejects_missing_required_section(self) -> None:
        content = VALID_TASK.replace("objective:\n  primary_metric: score\n  direction: maximize\n", "")
        with self.assertRaises(TaskValidationError) as ctx:
            load_task(self.write_task(content))
        self.assertIn("objective", str(ctx.exception))

    def test_rejects_invalid_direction(self) -> None:
        content = VALID_TASK.replace("direction: maximize", "direction: sideways")
        with self.assertRaises(TaskValidationError) as ctx:
            load_task(self.write_task(content))
        self.assertIn("direction", str(ctx.exception))

    def test_rejects_malformed_yaml(self) -> None:
        content = VALID_TASK + "  bad_indent: [\n"
        with self.assertRaises(TaskValidationError):
            load_task(self.write_task(content))

    def test_rejects_invalid_enum_value(self) -> None:
        content = VALID_TASK.replace("mode: direct_edit", "mode: patch")
        with self.assertRaises(TaskValidationError) as ctx:
            load_task(self.write_task(content))
        self.assertIn("mutation.mode", str(ctx.exception))


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