from __future__ import annotations

import os
from logging.config import fileConfig

from alembic import context
from sqlalchemy import engine_from_config, pool, text

from iaai_sync_service.models import Base

config = context.config

if config.config_file_name is not None:
    fileConfig(config.config_file_name)

target_metadata = Base.metadata
SYNC_VERSION_TABLE = "iaai_sync_alembic_version"
LEGACY_VERSION_TABLE = "alembic_version"
SYNC_REVISIONS = {
    "0001_ensure_sync_schema",
    "0002_extend_origin_enum_for_iaai",
    "0003_create_iaai_source_tables",
}


def _normalize_database_url(url: str) -> str:
    normalized = url.strip()
    if normalized.startswith("jdbc:"):
        normalized = normalized[len("jdbc:") :]
    if normalized.startswith("postgres://"):
        normalized = "postgresql+psycopg://" + normalized[len("postgres://") :]
    elif normalized.startswith("postgresql://"):
        normalized = "postgresql+psycopg://" + normalized[len("postgresql://") :]
    return normalized


def _database_url() -> str:
    raw_url = os.getenv("DATABASE_URL", config.get_main_option("sqlalchemy.url"))
    return _normalize_database_url(raw_url)


def _select_version_table(connection) -> str:  # noqa: ANN001
    inspector = connection.dialect
    if inspector.has_table(connection, SYNC_VERSION_TABLE):
        return SYNC_VERSION_TABLE
    if inspector.has_table(connection, LEGACY_VERSION_TABLE):
        version_num = connection.execute(text(f"SELECT version_num FROM {LEGACY_VERSION_TABLE} LIMIT 1")).scalar()
        if version_num in SYNC_REVISIONS:
            return LEGACY_VERSION_TABLE
    return SYNC_VERSION_TABLE


def run_migrations_offline() -> None:
    url = _database_url()
    context.configure(
        url=url,
        target_metadata=target_metadata,
        version_table=SYNC_VERSION_TABLE,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
    )
    with context.begin_transaction():
        context.run_migrations()


def run_migrations_online() -> None:
    configuration = config.get_section(config.config_ini_section) or {}
    configuration["sqlalchemy.url"] = _database_url()
    connectable = engine_from_config(configuration, prefix="sqlalchemy.", poolclass=pool.NullPool)

    with connectable.connect() as connection:
        version_table = _select_version_table(connection)
        context.configure(
            connection=connection,
            target_metadata=target_metadata,
            version_table=version_table,
        )
        with context.begin_transaction():
            context.run_migrations()


if context.is_offline_mode():
    run_migrations_offline()
else:
    run_migrations_online()