import contextlib
import io
import json
import os
import tempfile
import unittest
from pathlib import Path
from unittest.mock import patch

from sqlalchemy.sql.elements import TextClause
from sqlalchemy.exc import OperationalError

os.environ.setdefault("DATABASE_URL", "postgresql+psycopg://user:pass@localhost:5432/ai_ict_test")

from scripts import run_migrations as run_migrations_module
from scripts.run_migrations import apply_migration_file, run_migrations as run_migration_files, split_sql_statements


class MigrationRunnerTests(unittest.TestCase):
    def test_split_sql_statements_keeps_semicolon_inside_quotes(self) -> None:
        sql = """
        -- comment with ; should be ignored
        create table sample (id bigint);
        insert into sample (note) values ('semi;colon');
        """

        statements = split_sql_statements(sql)

        self.assertEqual(len(statements), 2)
        self.assertIn("create table sample", statements[0])
        self.assertIn("'semi;colon'", statements[1])

    def test_apply_migration_file_executes_each_statement(self) -> None:
        with tempfile.TemporaryDirectory() as tmpdir:
            path = Path(tmpdir) / "001_sample.sql"
            path.write_text("create table a (id bigint); create table b (id bigint);", encoding="utf-8")
            connection = FakeConnection()

            count = apply_migration_file(connection, path)

        self.assertEqual(count, 2)
        self.assertEqual(len(connection.statements), 2)
        self.assertTrue(all(isinstance(statement, TextClause) for statement in connection.statements))

    def test_run_migrations_reports_each_file(self) -> None:
        with tempfile.TemporaryDirectory() as tmpdir:
            first = Path(tmpdir) / "001_sample.sql"
            second = Path(tmpdir) / "002_sample.sql"
            first.write_text("create table a (id bigint);", encoding="utf-8")
            second.write_text("create table b (id bigint); create table c (id bigint);", encoding="utf-8")
            connection = FakeConnection()

            results = run_migration_files(connection=connection, files=[first, second])

        self.assertEqual(results, [{"file": "001_sample.sql", "statements": 1}, {"file": "002_sample.sql", "statements": 2}])

    def test_main_reports_database_unavailable(self) -> None:
        output = io.StringIO()

        with patch("scripts.run_migrations.engine.begin", side_effect=OperationalError("stmt", {}, Exception())), contextlib.redirect_stdout(output):
            exit_code = run_migrations_module.main()

        self.assertEqual(exit_code, 2)
        self.assertIn("Database unavailable for migrations: OperationalError", output.getvalue())

    def test_main_can_emit_json_failure(self) -> None:
        output = io.StringIO()

        with patch("scripts.run_migrations.engine.begin", side_effect=OperationalError("stmt", {}, Exception())), contextlib.redirect_stdout(output):
            exit_code = run_migrations_module.main(env={"MIGRATIONS_OUTPUT_JSON": "1"})

        payload = json.loads(output.getvalue())
        self.assertEqual(exit_code, 2)
        self.assertFalse(payload["passed"])
        self.assertEqual(payload["error_type"], "OperationalError")


class FakeConnection:
    def __init__(self) -> None:
        self.statements = []

    def execute(self, statement):
        self.statements.append(statement)
if __name__ == "__main__":
    unittest.main()