import datetime
import io
import json
import os
import tempfile
import unittest

from werkrevisor import protection

ARGS = ["https://git.example.org/mi/werkator", "main", "--contexts", "werkator,ai-review/gate",
        "--approvers", "ai-reviewer,mi"]


class FakeProtectionClient:
    def __init__(self, existing=None):
        self.existing = existing
        self.saved = []

    def get_protection(self, branch):
        return self.existing

    def save_protection(self, branch, fields, exists):
        self.saved.append((branch, fields, exists))


def run(client, *extra):
    out = io.StringIO()
    cwd = os.getcwd()
    with tempfile.TemporaryDirectory() as tmp:
        os.chdir(tmp)
        try:
            code = protection.main(ARGS + list(extra), {}, out, client, lambda: datetime.datetime(2026, 10, 6, 9, 0, 0))
            files = {name: json.load(open(name)) for name in os.listdir(tmp)}
        finally:
            os.chdir(cwd)
    return code, out.getvalue(), files


class BranchProtectionTest(unittest.TestCase):
    def test_existing_rule_is_saved_first_and_its_contexts_stay(self):
        existing = {"rule_name": "main", "enable_status_check": True, "status_check_contexts": ["werkator", "lint"],
                    "required_approvals": 0}
        client = FakeProtectionClient(existing)
        code, out, files = run(client)
        self.assertEqual(code, 0)
        self.assertEqual(files, {"branch-protection-mi-werkator-main-20261006-090000.json": existing})
        branch, fields, exists = client.saved[0]
        self.assertEqual((branch, exists), ("main", True))
        self.assertEqual(fields["status_check_contexts"], ["werkator", "lint", "ai-review/gate"])
        self.assertEqual((fields["required_approvals"], fields["approvals_whitelist_username"]), (1, ["ai-reviewer", "mi"]))
        self.assertNotIn("block_admin_merge_override", fields)
        self.assertIn('required_approvals: 0 -> 1', out)

    def test_missing_rule_is_created(self):
        client = FakeProtectionClient(None)
        run(client, "--block-admin-override")
        branch, fields, exists = client.saved[0]
        self.assertEqual((fields["rule_name"], exists, fields["block_admin_merge_override"]), ("main", False, True))

    def test_dry_run_and_unchanged_rule_write_nothing(self):
        client = FakeProtectionClient({"status_check_contexts": []})
        code, out, files = run(client, "--dry-run")
        self.assertEqual((code, client.saved, files), (0, [], {}))
        self.assertIn("dry run: nothing written", out)
        done = protection.wanted({"status_check_contexts": ["werkator", "ai-review/gate"]}, "main",
                                 ["werkator", "ai-review/gate"], ["ai-reviewer", "mi"], False)
        client = FakeProtectionClient(done)
        code, out, files = run(client)
        self.assertEqual((client.saved, files, out), ([], {}, "branch protection is already as wanted\n"))


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