#!/usr/bin/env python3
import tempfile
import unittest
import json
from pathlib import Path

from validate_task_pointer import PointerError, validate_pointer


VALID = """# pointer
## Current
context_id: c1
## Read
read paths only; coverage/report.json
## Task
one result
## Next
one next
## Verify
one test
## Stop
stop on drift
"""


class TaskPointerTests(unittest.TestCase):
    def write(self, text: str) -> Path:
        directory = tempfile.TemporaryDirectory()
        self.addCleanup(directory.cleanup)
        path = Path(directory.name) / "nextTask.md"
        path.write_text(text, encoding="utf-8")
        return path

    def test_valid_pointer_reports_bounded_size(self):
        result = validate_pointer(self.write(VALID))
        self.assertLessEqual(result["bytes"], 8192)

    def test_context_id_must_match_lock_when_supplied(self):
        directory = tempfile.TemporaryDirectory()
        self.addCleanup(directory.cleanup)
        root = Path(directory.name)
        pointer = root / "nextTask.md"
        pointer.write_text(VALID, encoding="utf-8")
        lock = root / "context-lock.json"
        lock.write_text(json.dumps({"context_id": "other"}), encoding="utf-8")
        with self.assertRaisesRegex(PointerError, "does not match lock"):
            validate_pointer(pointer, lock_path=lock)

    def test_history_heading_is_rejected(self):
        with self.assertRaisesRegex(PointerError, "history section"):
            validate_pointer(self.write(VALID + "\n## History\nold log\n"))

    def test_evidence_heading_is_rejected(self):
        with self.assertRaisesRegex(PointerError, "history section"):
            validate_pointer(self.write(VALID + "\n## Evidence\nold evidence\n"))

    def test_large_pointer_is_rejected(self):
        with self.assertRaisesRegex(PointerError, "byte budget"):
            validate_pointer(self.write(VALID + "x" * 9000))


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