"""从 FastAPI AppState 读取类型化宿主能力。"""

from collections.abc import AsyncGenerator
from typing import cast

from fastapi import Depends, Request

from app.application.messaging.chat import AsyncAgentChatRepository, AsyncUnitOfWork
from app.application.outbox import AsyncOutboxTransaction
from app.application.subscription.delete import SubscribeDeletionRepository
from app.application.subscription.identity import SubscribeIdentityDeletionRepository
from app.application.subscription.mutation import (
    SubscriptionHistoryMutationRepository,
    SubscriptionMutationRepository,
)
from app.startup.context import (
    AgentChatRuntime,
    HostRuntime,
    SubscriptionRuntime,
)


def get_host_runtime(request: Request) -> HostRuntime:
    """返回当前 lifespan 挂载的宿主运行时。"""
    runtime = getattr(request.app.state, "host_runtime", None)
    if not isinstance(runtime, HostRuntime):
        raise RuntimeError("HostRuntime 尚未由启动组合根装配")
    return runtime


def get_agent_chat_runtime(
    runtime: HostRuntime = Depends(get_host_runtime),
) -> AgentChatRuntime:
    """从完整宿主运行时收窄到 Agent 会话能力。"""
    return runtime.agent_chat


async def get_agent_chat_session(
    runtime: AgentChatRuntime = Depends(get_agent_chat_runtime),
) -> AsyncGenerator[object, None]:
    """从类型化 Agent 会话运行时生成请求独占会话。"""
    async for session in runtime.async_session():
        yield session


def get_agent_chat_repository(
    session: object = Depends(get_agent_chat_session),
    runtime: AgentChatRuntime = Depends(get_agent_chat_runtime),
) -> AsyncAgentChatRepository:
    """构造绑定当前请求会话的 Agent 会话仓储。"""
    return cast(AsyncAgentChatRepository, runtime.repository(session))


def get_agent_chat_transaction(
    session: object = Depends(get_agent_chat_session),
    runtime: AgentChatRuntime = Depends(get_agent_chat_runtime),
) -> AsyncUnitOfWork:
    """构造绑定当前请求会话的 Agent 会话事务端口。"""
    return cast(AsyncUnitOfWork, runtime.transaction(session))


def get_subscription_runtime(
    runtime: HostRuntime = Depends(get_host_runtime),
) -> SubscriptionRuntime:
    """从完整宿主运行时收窄到订阅写事务能力。"""
    return runtime.subscription


async def get_subscription_session(
    runtime: SubscriptionRuntime = Depends(get_subscription_runtime),
) -> AsyncGenerator[object, None]:
    """从订阅运行时生成请求独占的异步会话。"""
    async for session in runtime.async_session():
        yield session


def get_subscription_repository(
    session: object = Depends(get_subscription_session),
    runtime: SubscriptionRuntime = Depends(get_subscription_runtime),
) -> (
    SubscriptionMutationRepository
    | SubscribeDeletionRepository
    | SubscribeIdentityDeletionRepository
):
    """构造绑定当前请求会话的订阅仓储。"""
    return runtime.repository(session)


def get_subscription_history_repository(
    session: object = Depends(get_subscription_session),
    runtime: SubscriptionRuntime = Depends(get_subscription_runtime),
) -> SubscriptionHistoryMutationRepository:
    """构造绑定当前请求会话的订阅历史仓储。"""
    return runtime.history_repository(session)


def get_subscription_transaction(
    session: object = Depends(get_subscription_session),
    runtime: SubscriptionRuntime = Depends(get_subscription_runtime),
) -> AsyncUnitOfWork:
    """构造绑定当前订阅请求会话的异步事务端口。"""
    return cast(AsyncUnitOfWork, runtime.transaction(session))


def get_subscription_outbox(
    session: object = Depends(get_subscription_session),
    runtime: SubscriptionRuntime = Depends(get_subscription_runtime),
) -> AsyncOutboxTransaction:
    """构造与订阅写入共享请求会话的 outbox 端口。"""
    return runtime.outbox(session)