from migrations.fixtures.delphi_tables.v8.triggers.base_trigger import TriggerType


class TriggerMigrator:
    def __init__(self, bind, target):
        self.bind = bind
        self.target = target

    def upgrade(self):
        if hasattr(self.target, "type") and self.target.type == TriggerType.STATEMENT.value:
            self.bind.execute(
                f"""
                    CREATE OR REPLACE FUNCTION {self.target.function_name}()
                    RETURNS TRIGGER
                    LANGUAGE  PLPGSQL
                    AS
                    $$
                        BEGIN
                            IF (TG_OP = 'DELETE') THEN
                                {self.target.on_delete()}
                            ELSIF (TG_OP = 'UPDATE') THEN
                                {self.target.on_update()}
                            ELSIF (TG_OP = 'INSERT') THEN
                                {self.target.on_insert()}
                            END IF;
                            RETURN NULL;
                        END
                    $$;
                """
            )

            self.bind.execute(
                f"""
                    CREATE TRIGGER {self.target.function_name}_insert_trigger
                    AFTER INSERT ON "{self.target.table}"
                    REFERENCING NEW TABLE AS new_table
                    FOR EACH STATEMENT
                    EXECUTE FUNCTION {self.target.function_name}();

                    CREATE TRIGGER {self.target.function_name}_delete_trigger
                    AFTER DELETE ON "{self.target.table}"
                    REFERENCING OLD TABLE AS old_table
                    FOR EACH STATEMENT
                    EXECUTE FUNCTION {self.target.function_name}();
                """
            )
        else:
            self.bind.execute(
                f"""
                    CREATE OR REPLACE FUNCTION {self.target.function_name}()
                    RETURNS TRIGGER
                    LANGUAGE  PLPGSQL
                    AS
                    $$
                        BEGIN
                            IF (TG_OP = 'DELETE') THEN
                                {self.target.on_delete()}
                            RETURN OLD;
                            ELSIF (TG_OP = 'UPDATE') THEN
                                {self.target.on_update()}
                            RETURN NEW;
                            ELSIF (TG_OP = 'INSERT') THEN
                                {self.target.on_insert()}
                            RETURN NEW;
                            END IF;
                        END
                    $$;
                """
            )

            self.bind.execute(
                f"""
                    CREATE TRIGGER {self.target.function_name}_trigger
                    AFTER INSERT OR UPDATE OR DELETE
                    ON "{self.target.table}"
                    FOR EACH ROW
                    EXECUTE PROCEDURE {self.target.function_name}();
                """
            )


    def rollback(self):
        if hasattr(self.target, "type") and self.target.type == TriggerType.STATEMENT.value:
            self.bind.execute(
                f"""
                    DROP TRIGGER IF EXISTS {self.target.function_name}_insert_trigger ON "{self.target.table}";
                    DROP TRIGGER IF EXISTS {self.target.function_name}_delete_trigger ON "{self.target.table}";
                    DROP TRIGGER IF EXISTS {self.target.function_name}_trigger ON "{self.target.table}";
                    DROP FUNCTION IF EXISTS {self.target.function_name}();
                """
            )
        else:
            self.bind.execute(
                f"""
                    DROP TRIGGER IF EXISTS {self.target.function_name}_trigger ON "{self.target.table}";
                    DROP FUNCTION IF EXISTS {self.target.function_name}();
                """
            )