from __future__ import annotations

from contextlib import asynccontextmanager
from typing import Annotated

from fastapi import Depends, FastAPI
from pydantic_ai import Agent
from pydantic_ai.models.instrumented import InstrumentationSettings

from stirling.agents import ExecutionPlanningAgent, OrchestratorAgent, PdfEditAgent, PdfQuestionAgent, UserSpecAgent
from stirling.api.middleware import UserIdMiddleware
from stirling.api.routes import (
    agent_draft_router,
    execution_router,
    orchestrator_router,
    pdf_edit_router,
    pdf_question_router,
)
from stirling.config import AppSettings, load_settings
from stirling.contracts import HealthResponse
from stirling.services import build_runtime, setup_posthog_tracking


def _load_startup_settings(fast_api: FastAPI) -> AppSettings:
    override = fast_api.dependency_overrides.get(load_settings)
    if override is not None:
        return override()
    return load_settings()


@asynccontextmanager
async def lifespan(fast_api: FastAPI):
    # Load env vars on startup so we can immediately crash if required env vars aren't set
    settings = _load_startup_settings(fast_api)
    runtime = build_runtime(settings)
    fast_api.state.settings = settings
    fast_api.state.runtime = runtime
    fast_api.state.orchestrator_agent = OrchestratorAgent(runtime)
    fast_api.state.pdf_edit_agent = PdfEditAgent(runtime)
    fast_api.state.pdf_question_agent = PdfQuestionAgent(runtime)
    fast_api.state.user_spec_agent = UserSpecAgent(runtime)
    fast_api.state.execution_planning_agent = ExecutionPlanningAgent(runtime)
    tracer_provider = setup_posthog_tracking(settings)
    if tracer_provider:
        Agent.instrument_all(InstrumentationSettings(tracer_provider=tracer_provider))
    yield
    if tracer_provider:
        tracer_provider.shutdown()


app = FastAPI(title="Stirling AI Engine", lifespan=lifespan, version="0.1.0")
app.add_middleware(UserIdMiddleware)
app.include_router(orchestrator_router)
app.include_router(pdf_edit_router)
app.include_router(pdf_question_router)
app.include_router(agent_draft_router)
app.include_router(execution_router)


@app.get("/health", response_model=HealthResponse)
async def healthcheck(settings: Annotated[AppSettings, Depends(load_settings)]) -> HealthResponse:
    return HealthResponse(
        status="ok",
        smart_model=settings.smart_model_name,
        fast_model=settings.fast_model_name,
    )