"""项目/章节端点的依赖装配（运行时实现）。

- `get_project_repo` / `get_chapter_repo`：把请求 session 装配成 SQLAlchemy repo。
- `get_writer_gateway`：据 writer 档位路由从已存凭据解密 → 建 OpenAI 兼容适配器
  → `Gateway`（注入 `SqlAlchemyLedgerSink` + `resolve_route`）。这是 **draft SSE 的可注入缝**——
  测试经 `app.dependency_overrides[get_writer_gateway]` 注入 mock 网关（产 `Delta`，绝不联网）。
- `seed_stub_user`：幂等 seed 单用户 stub（owner_id FK 依赖它，见 memory/gotchas）。
"""

from __future__ import annotations

from typing import Annotated

from fastapi import Depends
from openai import AsyncOpenAI
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession
from ww_config import get_settings
from ww_core.domain import ForeshadowLedgerRepo, SqlForeshadowLedgerRepo
from ww_core.domain.chapter_repo import ChapterRepo, SqlChapterRepo
from ww_core.domain.digest_repo import DigestAppendRepo, SqlDigestAppendRepo
from ww_core.domain.outline_write_repo import OutlineWriteRepo, SqlOutlineWriteRepo
from ww_core.domain.project_repo import ProjectRepo, SqlProjectRepo
from ww_core.domain.repositories import MemoryRepos
from ww_core.domain.review_repo import ReviewRepo, SqlReviewRepo
from ww_core.memory.sql_repositories import sql_memory_repos
from ww_db import get_session, get_sessionmaker
from ww_db.models import User
from ww_llm_gateway import (
    Gateway,
    OpenAICompatAdapter,
    SqlAlchemyLedgerSink,
    resolve_route,
)
from ww_llm_gateway.types import Tier
from ww_shared import AppError, ErrorCode

from ww_api.security.credentials import (
    CredentialKeyError,
    decrypt_api_key,
)
from ww_api.services.credentials import (
    STUB_OWNER_ID,
    CredentialStore,
    SqlCredentialStore,
)
from ww_api.services.foreshadow_scan import SessionFactory
from ww_api.services.provider_deps import _PROVIDER_BASE_URLS

# 单用户 stub 的占位邮箱（多租户化时由真实主体替换）。
_STUB_USER_EMAIL = "stub@local"


async def seed_stub_user(session: AsyncSession) -> None:
    """幂等 seed 单用户 stub 行——所有 owner_id FK（projects/usage_ledger/...）依赖它。

    无该行时插入；已存在则跳过。在 app lifespan 启动时调用一次。
    """
    existing = (
        await session.execute(select(User).where(User.id == STUB_OWNER_ID))
    ).scalar_one_or_none()
    if existing is not None:
        return
    session.add(User(id=STUB_OWNER_ID, email=_STUB_USER_EMAIL, display_name="stub"))
    await session.commit()


def get_project_repo(
    session: Annotated[AsyncSession, Depends(get_session)],
) -> ProjectRepo:
    return SqlProjectRepo(session)


def get_chapter_repo(
    session: Annotated[AsyncSession, Depends(get_session)],
) -> ChapterRepo:
    return SqlChapterRepo(session)


def get_memory_repos(
    session: Annotated[AsyncSession, Depends(get_session)],
) -> MemoryRepos:
    """记忆组装的 7-repo 捆绑（draft SSE 用）。测试覆盖此依赖注入内存 fake。"""
    return sql_memory_repos(session)


def get_review_repo(
    session: Annotated[AsyncSession, Depends(get_session)],
) -> ReviewRepo:
    """审稿留痕 repo（review SSE collect / 历史 / accept 裁决）。"""
    return SqlReviewRepo(session)


def get_digest_append_repo(
    session: Annotated[AsyncSession, Depends(get_session)],
) -> DigestAppendRepo:
    """章节摘要写侧 repo（验收事务追加终稿 digest）。"""
    return SqlDigestAppendRepo(session)


def get_foreshadow_repo(
    session: Annotated[AsyncSession, Depends(get_session)],
) -> ForeshadowLedgerRepo:
    """伏笔账本写侧 repo（登记/状态变更端点；只 flush，端点提交）。测试经 override 注 fake。"""
    return SqlForeshadowLedgerRepo(session)


def get_outline_write_repo(
    session: Annotated[AsyncSession, Depends(get_session)],
) -> OutlineWriteRepo:
    """大纲写侧 repo（大纲生成端点逐章 upsert；只 flush，端点提交）。测试经 override 注 fake。"""
    return SqlOutlineWriteRepo(session)


def get_session_factory() -> SessionFactory:
    """验收后到期扫描的**独立 session 工厂**缝。

    BackgroundTask 在请求 session 关闭后才跑，必须自建 session（不复用 `get_session`）。
    返回的工厂 `()` → `async with` 得一个新 `AsyncSession`。测试经 `app.dependency_overrides`
    注入 fake 工厂（避免真起后台线程/真连 DB）。
    """
    return get_sessionmaker()


async def build_gateway_for_tier(
    session: AsyncSession, store: CredentialStore, tier: Tier
) -> Gateway:
    """据指定档位路由解密对应 provider 凭据 → 建网关（解析器仍为全局 `resolve_route`）。

    无凭据/未知 provider → `LLM_UNAVAILABLE`（友好提示，前端引导去配置）。
    解析器用 `resolve_route`（按 tier 路由）；这里只决定**要预备哪个 provider 的适配器**。
    """
    settings = get_settings()
    route = resolve_route(tier)
    base_url = _PROVIDER_BASE_URLS.get(route.provider)
    if base_url is None:
        raise AppError(
            ErrorCode.LLM_UNAVAILABLE,
            f"{tier} 档位 provider {route.provider} 暂不支持",
            {"provider": route.provider, "tier": tier},
        )
    cred = await store.get_credential(STUB_OWNER_ID, route.provider)
    if cred is None:
        raise AppError(
            ErrorCode.LLM_UNAVAILABLE,
            f"{tier} 档位 provider {route.provider} 未配置凭据，请先在设置中配置",
            {"provider": route.provider, "tier": tier},
        )
    try:
        api_key = decrypt_api_key(cred.api_key_enc, key=settings.credential_enc_key)
    except CredentialKeyError as exc:
        raise AppError(ErrorCode.INTERNAL, str(exc)) from exc

    client = AsyncOpenAI(api_key=api_key, base_url=base_url)
    adapter = OpenAICompatAdapter(provider=route.provider, client=client)
    return Gateway(
        adapters={route.provider: adapter},
        ledger=SqlAlchemyLedgerSink(session),
        resolver=resolve_route,
    )


async def build_writer_gateway(session: AsyncSession, store: CredentialStore) -> Gateway:
    """据 writer 档位路由解密对应 provider 凭据 → 建网关。"""
    return await build_gateway_for_tier(session, store, "writer")


async def get_writer_gateway(
    session: Annotated[AsyncSession, Depends(get_session)],
) -> Gateway:
    """draft SSE 的可注入网关缝。测试覆盖此依赖注入 mock（产 `Delta`，绝不联网）。"""
    store = SqlCredentialStore(session)
    return await build_writer_gateway(session, store)


async def get_review_gateway(
    session: Annotated[AsyncSession, Depends(get_session)],
) -> Gateway:
    """续审（analyst 档位）的可注入网关缝。测试经 override 注 mock（产 `parsed`，绝不联网）。"""
    store = SqlCredentialStore(session)
    return await build_gateway_for_tier(session, store, "analyst")


async def get_digest_gateway(
    session: Annotated[AsyncSession, Depends(get_session)],
) -> Gateway:
    """验收终稿 digest 提炼（light 档位）的可注入网关缝。测试经 override 注 mock。"""
    store = SqlCredentialStore(session)
    return await build_gateway_for_tier(session, store, "light")


async def get_outline_gateway(
    session: Annotated[AsyncSession, Depends(get_session)],
) -> Gateway:
    """大纲生成（analyst 档位）的可注入网关缝。测试经 override 注 mock（产 OutlineResult）。"""
    store = SqlCredentialStore(session)
    return await build_gateway_for_tier(session, store, "analyst")