from django.db import migrations


# Before the submissions -> opus_magnum rename, this app owned the opus magnum
# tables and its 0001_initial was already applied. The new 0001_initial has the
# same name, so on those databases Django skipped it and kept the legacy
# submissions_submission / submissions_submissionfile layout (is_validated NOT
# NULL, response_id, ...) and never created submissions_imagecrop.
LEGACY_TABLES = [
    "submissions_imagecrop",
    "submissions_submissionfile",
    "submissions_puzzleresponse",
    "submissions_submission",
    "submissions_steamcollectionitem",
    "submissions_steamcollection",
    "submissions_steamapikey",
]


def repair_legacy_tables(apps, schema_editor):
    connection = schema_editor.connection

    with connection.cursor() as cursor:
        columns = {
            col.name
            for col in connection.introspection.get_table_description(
                cursor, "submissions_submission"
            )
        }

        if "is_validated" not in columns:
            return

        # Data was copied to opus_magnum (0015) and 0007 wiped submissions, so
        # this should be empty: refuse to drop anything otherwise.
        cursor.execute("SELECT COUNT(*) FROM submissions_submission")
        if cursor.fetchone()[0]:
            raise RuntimeError(
                "submissions_submission has the legacy layout but is not empty"
            )

    existing_tables = set(connection.introspection.table_names())
    for table in LEGACY_TABLES:
        if table in existing_tables:
            schema_editor.execute(f"DROP TABLE {schema_editor.quote_name(table)}")

    for model_name in ["Submission", "SubmissionFile", "ImageCrop"]:
        schema_editor.create_model(apps.get_model("submissions", model_name))


class Migration(migrations.Migration):
    dependencies = [
        ("submissions", "0008_remove_submission_game"),
    ]

    operations = [
        migrations.RunPython(repair_legacy_tables, migrations.RunPython.noop),
    ]