from __future__ import annotations

import tempfile
import unittest
from pathlib import Path
import shutil

from alembic.runtime.migration import MigrationContext
from sqlalchemy import create_engine, inspect

from govoplan_core.db.migrations import migrate_database
from dataclasses import replace

from govoplan_workflow_engine.backend.manifest import get_manifest


class WorkflowMigrationTests(unittest.TestCase):
    def test_migration_creates_definition_tables_and_head(self) -> None:
        with tempfile.TemporaryDirectory(
            prefix="govoplan-workflow-engine-migration-"
        ) as directory:
            url = f"sqlite:///{Path(directory) / 'workflow.db'}"
            migrate_database(
                database_url=url,
                enabled_modules=("workflow_engine",),
                manifest_factories=(get_manifest,),
            )
            engine = create_engine(url)
            try:
                with engine.connect() as connection:
                    self.assertIn(
                        "0b4e7c9a2d6f",
                        set(MigrationContext.configure(connection).get_current_heads()),
                    )
                    self.assertEqual(
                        {
                            "workflow_definition_revisions",
                            "workflow_definitions",
                            "workflow_instance_events",
                            "workflow_instance_steps",
                            "workflow_instances",
                        },
                        {
                            name
                            for name in inspect(connection).get_table_names()
                            if name.startswith("workflow_")
                        },
                    )
                    revision_columns = {
                        item["name"]
                        for item in inspect(connection).get_columns(
                            "workflow_definition_revisions"
                        )
                    }
                    self.assertTrue(
                        {
                            "bpmn_xml",
                            "bpmn_hash",
                            "bpmn_adapter_id",
                            "bpmn_adapter_version",
                            "bpmn_runtime_kind",
                            "bpmn_executable",
                            "execution_mode",
                            "view_id",
                            "view_revision_id",
                        }.issubset(revision_columns)
                    )
                    instance_columns = {
                        item["name"]
                        for item in inspect(connection).get_columns(
                            "workflow_instances"
                        )
                    }
                    self.assertIn("start_origin", instance_columns)
                    definition_columns = {
                        item["name"]
                        for item in inspect(connection).get_columns(
                            "workflow_definitions"
                        )
                    }
                    self.assertIn(
                        "standard_origin_module_id",
                        definition_columns,
                    )
            finally:
                engine.dispose()

    def test_existing_workflow_migration_head_transfers_without_replay(self) -> None:
        with tempfile.TemporaryDirectory(
            prefix="govoplan-workflow-engine-upgrade-"
        ) as directory:
            url = f"sqlite:///{Path(directory) / 'workflow.db'}"
            engine_manifest = get_manifest()
            assert engine_manifest.migration_spec is not None
            legacy_revisions = Path(directory) / "legacy-revisions"
            legacy_revisions.mkdir()
            current_revisions = Path(
                engine_manifest.migration_spec.script_location or ""
            )
            for path in current_revisions.glob("*.py"):
                if path.name.startswith("0b4e7c9a2d6f_"):
                    continue
                shutil.copy2(path, legacy_revisions / path.name)
            legacy_manifest = replace(
                engine_manifest,
                id="workflow",
                name="Workflow",
                permission_namespace=None,
                migration_spec=replace(
                    engine_manifest.migration_spec,
                    module_id="workflow",
                    script_location=str(legacy_revisions),
                ),
            )
            migrate_database(
                database_url=url,
                enabled_modules=("workflow",),
                manifest_factories=(lambda: legacy_manifest,),
            )
            engine = create_engine(url)
            try:
                first_tables = set(inspect(engine).get_table_names())
                with engine.connect() as connection:
                    self.assertIn(
                        "f1b7d3e5a9c2",
                        set(
                            MigrationContext.configure(
                                connection
                            ).get_current_heads()
                        ),
                    )
                self.assertNotIn(
                    "standard_origin_module_id",
                    {
                        item["name"]
                        for item in inspect(engine).get_columns(
                            "workflow_definitions"
                        )
                    },
                )
            finally:
                engine.dispose()

            result = migrate_database(
                database_url=url,
                enabled_modules=("workflow_engine",),
                manifest_factories=(get_manifest,),
            )

            self.assertIn("0b4e7c9a2d6f", result.current_revision or "")
            engine = create_engine(url)
            try:
                self.assertEqual(first_tables, set(inspect(engine).get_table_names()))
                self.assertIn(
                    "standard_origin_module_id",
                    {
                        item["name"]
                        for item in inspect(engine).get_columns(
                            "workflow_definitions"
                        )
                    },
                )
            finally:
                engine.dispose()


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