from pathlib import Path

from fastapi import FastAPI, Request
from fastapi.responses import JSONResponse
from fastapi.staticfiles import StaticFiles

from app.api.controllers.admin import router as admin_router
from app.api.controllers.agent_runs import router as agent_runs_router
from app.api.controllers.conversations import router as conversations_router
from app.api.controllers.health import router as health_router
from app.api.controllers.knowledge import router as knowledge_router
from app.api.controllers.offsite_fund import operation_router as offsite_operation_router
from app.api.controllers.offsite_fund import router as offsite_fund_router
from app.api.controllers.public_platform import router as public_platform_router
from app.api.controllers.risk import router as risk_router
from app.api.controllers.visitor_tokens import router as visitor_tokens_router
from app.api.middleware import attach_trace_id
from app.core.config import get_settings
from app.core.errors import AgentError


def create_app() -> FastAPI:
    settings = get_settings()
    application = FastAPI(title=settings.app_name, version="0.1.0")
    # 接口文档承诺的 X-Trace-ID 此前完全没实现；中间件对成功与错误响应都生效。
    application.middleware("http")(attach_trace_id)

    @application.exception_handler(AgentError)
    async def agent_error_handler(request: Request, exc: AgentError) -> JSONResponse:
        context = getattr(request.state, "request_context", None)
        # 认证失败时请求上下文尚未建立（`build_request_context` 不会写 request_context），
        # 按文档 §3.4 优先复用请求头里客户端带来的 `X-Trace-ID`；都没有就是空字符串，
        # 绝不凭空生成 id——会让排障时把两个请求认成同一个。
        trace_id = (getattr(context, "trace_id", None)
                    or getattr(request.state, "trace_id", None)
                    or request.headers.get("X-Trace-ID") or "")
        # retryable 按文档 §3.6 逐码标注，不再简单按 5xx 推导
        # （例如 RESOURCE_VERSION_CONFLICT 是 409 但文档标注可重试）。
        headers: dict[str, str] = {}
        retry_after = getattr(exc, "retry_after_seconds", None)
        if isinstance(retry_after, int):
            # 文档 §3.6 把 RATE_LIMITED 标注为可重试：只给 retryable=true 而不给
            # Retry-After，客户端只能自己猜退避时长（或立刻重试再被拒）。
            headers["Retry-After"] = str(retry_after)
        return JSONResponse(status_code=exc.status_code, content={
            "error": {"code": exc.code, "message": exc.message,
                      "retryable": exc.is_retryable, "field_errors": []},
            "meta": {"trace_id": trace_id},
        }, headers=headers or None)
    application.include_router(agent_runs_router)
    application.include_router(conversations_router)
    application.include_router(public_platform_router)
    application.include_router(risk_router)
    application.include_router(visitor_tokens_router)
    application.include_router(offsite_fund_router)
    application.include_router(offsite_operation_router)
    application.include_router(knowledge_router)
    application.include_router(health_router)
    application.include_router(admin_router)
    application.mount(
        "/customer-service-test",
        StaticFiles(directory=Path(__file__).resolve().parent / "static", html=True),
        name="customer-service-test",
    )
    return application


app = create_app()