"""数据库治理能力的宿主组合根。"""

from __future__ import annotations

from dataclasses import dataclass

from app.adapters.system.backup.database import (
    PostgreSQLBackupBackend,
    SQLiteBackupBackend,
)
from app.adapters.system.backup.files import BackupFiles
from app.application.backup import BackupPolicy, DatabaseBackupService
from app.application.database import (
    DatabaseGovernance,
    DatabaseHealthService,
    configure_database_governance,
    reset_database_governance,
)
from app.application.maintenance import (
    DataCleanupService,
    read_cleanup_policy,
)
from app.application.plugin.runtime import get_existing_plugin_manager
from app.application.plugin.transaction import (
    PluginPersistenceService,
    configure_plugin_persistence,
    reset_plugin_persistence,
)
from app.application.query import (
    DataQueryService,
    configure_data_query_service,
    reset_data_query_service,
)
from app.application.workflow import (
    WorkflowQueryService,
    configure_workflow_execution,
    configure_workflow_query,
    reset_workflow_execution,
    reset_workflow_query,
)
from app.db.adapters.pluginidentity import TransactionalPluginIdentityStore
from app.db.adapters.plugininstallation import TransactionalPluginInstallationStore
from app.db.adapters.query import SqlAlchemyDataQueryAdapter
from app.db.adapters.transaction import TransactionalWriteRunner
from app.db.adapters.user import TransactionalUserRepository
from app.db.adapters.workflow import (
    TransactionalWorkflowExecutionService,
    TransactionalWorkflowQueryRepository,
)
from app.db.engine import get_engine
from app.db.health import probe_database
from app.db.maintenance import DatabaseCleanupRepository
from app.db.oper.systemconfig import SystemConfigOper
from app.db.plugin.registry import database_handles
from app.db.session import (
    SessionFactory,
    async_session_scope,
)
from app.db.uow import (
    configure_transaction_runners,
    reset_transaction_runners,
)
from app.db.worker import DatabaseWorker
from app.runtime.log import logger
from app.runtime.settings import get_runtime_setting


@dataclass(frozen=True, slots=True)
class DatabaseRuntime:
    """保存数据库 worker 与兼容写入口共享的事务执行器。"""

    worker: DatabaseWorker
    transaction: TransactionalWriteRunner


@dataclass(frozen=True, slots=True)
class DatabaseComposition:
    """保存初始化器后续装配所需的数据库查询能力。"""

    data_query: DataQueryService
    plugin_persistence: PluginPersistenceService
    workflow_query: WorkflowQueryService


_database_runtime: DatabaseRuntime | None = None
_database_runtime_starting = False


async def start_database_runtime() -> DatabaseRuntime:
    """启动进程唯一数据库 worker，并登记兼容写事务 runner。"""
    global _database_runtime, _database_runtime_starting
    if _database_runtime is not None or _database_runtime_starting:
        raise RuntimeError("数据库 runtime 已由当前进程持有")
    _database_runtime_starting = True
    try:
        transaction = TransactionalWriteRunner(
            sync_session=SessionFactory,
            async_session=async_session_scope,
        )
        worker = DatabaseWorker()
        await worker.start()
        configure_transaction_runners(
            sync=transaction.sync,
            async_=transaction.async_,
        )
        runtime = DatabaseRuntime(worker=worker, transaction=transaction)
        _database_runtime = runtime
        return runtime
    finally:
        _database_runtime_starting = False


async def stop_database_runtime() -> None:
    """关闭数据库 worker；失败时保留 owner 供诊断和重试。"""
    global _database_runtime
    runtime = _database_runtime
    if runtime is not None:
        await runtime.worker.shutdown()
        _database_runtime = None


def database_runtime_active() -> bool:
    """返回数据库 worker 是否仍由当前进程持有。"""
    return _database_runtime is not None


def build_transactional_user_repository() -> TransactionalUserRepository:
    """构造供 Chain、Agent 与进程级认证共享的短会话用户仓储。"""
    return TransactionalUserRepository(
        sync_session=SessionFactory,
        async_session=async_session_scope,
    )


def compose_database_services(
    *,
    runtime: DatabaseRuntime,
    system_config: SystemConfigOper,
) -> DatabaseComposition:
    """组合查询、插件持久化与工作流查询所需实现。"""
    data_query_adapter = SqlAlchemyDataQueryAdapter(SessionFactory)
    data_query = DataQueryService(
        subscriptions=data_query_adapter,
        histories=data_query_adapter,
        async_executor=runtime.worker,
    )
    plugin_persistence = PluginPersistenceService(
        executor=runtime.worker,
        identities=TransactionalPluginIdentityStore(SessionFactory),
        installations=TransactionalPluginInstallationStore(
            SessionFactory,
            system_config.update_atomically,
        ),
    )
    workflow_query = WorkflowQueryService(
        repository=TransactionalWorkflowQueryRepository(
            sync_session=SessionFactory,
            async_session=async_session_scope,
        )
    )
    return DatabaseComposition(
        data_query=data_query,
        plugin_persistence=plugin_persistence,
        workflow_query=workflow_query,
    )


def publish_database_services(composition: DatabaseComposition) -> None:
    """一次性发布当前 lifespan 的查询与插件持久化服务。"""
    configure_data_query_service(composition.data_query)
    configure_plugin_persistence(composition.plugin_persistence)
    configure_workflow_query(composition.workflow_query)


def configure_workflow_execution_composition() -> None:
    """构造并发布使用短事务会话的工作流执行服务。"""
    configure_workflow_execution(TransactionalWorkflowExecutionService(SessionFactory))


def reset_workflow_execution_composition() -> None:
    """撤销当前 lifespan 发布的工作流执行服务。"""
    reset_workflow_execution()


def reset_database_services() -> None:
    """撤销当前 lifespan 发布的全部数据库派生服务。"""
    reset_database_governance()
    reset_transaction_runners()
    reset_workflow_query()
    reset_plugin_persistence()
    reset_data_query_service()


def build_database_governance() -> DatabaseGovernance:
    """以缓存同步引擎为事实源构造一个完整数据库治理门面。"""
    engine = get_engine()
    dialect = engine.dialect.name
    if dialect == "sqlite":
        backup_backend = SQLiteBackupBackend(engine)
    elif dialect == "postgresql":
        backup_backend = PostgreSQLBackupBackend(engine)
    else:
        raise RuntimeError(f"不支持的数据库类型：{dialect}")

    def backup_plugin_databases() -> None:
        """为当前已建立的 SQLite 插件库创建独立制品。"""
        if dialect != "sqlite":
            return
        manager = get_existing_plugin_manager()
        if manager is None:
            return
        for handle in database_handles():
            if handle.db_path is None:
                continue
            version = manager.get_local_plugin_version(handle.plugin_id)
            if not version:
                logger.warning(
                    "插件 %s 未找到版本，将使用无版本文件名继续备份数据库",
                    handle.plugin_id,
                )
            plugin_service = DatabaseBackupService(
                backend=SQLiteBackupBackend(handle.engine),
                artifact_store_factory=BackupFiles,
                policy_reader=lambda: BackupPolicy(
                    root=get_runtime_setting("DATABASE_BACKUP_PATH") / "plugins" / handle.plugin_id,
                    retention_days=get_runtime_setting("DB_BACKUP_RETENTION_DAYS"),
                    max_count=get_runtime_setting("DB_BACKUP_MAX_COUNT"),
                ),
                target=handle.plugin_id,
                version=version,
            )
            plugin_service.create()

    return DatabaseGovernance(
        health=DatabaseHealthService(probe_database),
        cleanup=DataCleanupService(
            repository=DatabaseCleanupRepository(session_factory=SessionFactory),
            policy_reader=read_cleanup_policy,
        ),
        backup=DatabaseBackupService(
            backend=backup_backend,
            artifact_store_factory=BackupFiles,
            policy_reader=read_backup_policy,
        ),
        plugin_backup=backup_plugin_databases,
    )


def configure_database() -> None:
    """构造并登记宿主进程唯一的数据库治理门面。"""
    configure_database_governance(build_database_governance())


def read_backup_policy() -> BackupPolicy:
    """读取一次可热更新的数据库备份目录与保留策略。"""
    return BackupPolicy(
        root=get_runtime_setting("DATABASE_BACKUP_PATH"),
        retention_days=get_runtime_setting("DB_BACKUP_RETENTION_DAYS"),
        max_count=get_runtime_setting("DB_BACKUP_MAX_COUNT"),
    )