from fastapi import FastAPI, Request, status
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse
from fastapi.exceptions import RequestValidationError
from starlette.exceptions import HTTPException as StarletteHTTPException
import time

from app.config import settings
from app.api.v1.api import api_router
from app.core.exceptions import PrepMindException

# Create FastAPI app
app = FastAPI(
    title=settings.APP_NAME,
    description="AI-powered placement preparation platform API",
    version=settings.API_VERSION,
    debug=settings.DEBUG,
    docs_url=f"/api/{settings.API_VERSION}/docs",
    redoc_url=f"/api/{settings.API_VERSION}/redoc",
    openapi_url=f"/api/{settings.API_VERSION}/openapi.json",
)

# CORS Middleware
app.add_middleware(
    CORSMiddleware,
    allow_origins=settings.CORS_ORIGINS,
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)


# Request timing middleware
@app.middleware("http")
async def add_process_time_header(request: Request, call_next):
    start_time = time.time()
    response = await call_next(request)
    process_time = time.time() - start_time
    response.headers["X-Process-Time"] = str(process_time)
    return response


# Exception handlers
@app.exception_handler(PrepMindException)
async def prepmind_exception_handler(request: Request, exc: PrepMindException):
    return JSONResponse(
        status_code=exc.status_code,
        content={"detail": exc.detail},
    )


@app.exception_handler(StarletteHTTPException)
async def http_exception_handler(request: Request, exc: StarletteHTTPException):
    return JSONResponse(
        status_code=exc.status_code,
        content={"detail": exc.detail},
    )


@app.exception_handler(RequestValidationError)
async def validation_exception_handler(request: Request, exc: RequestValidationError):
    return JSONResponse(
        status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
        content={"detail": exc.errors()},
    )


# Root endpoint
@app.get("/")
async def root():
    return {
        "message": "Welcome to PrepMind API",
        "version": settings.API_VERSION,
        "docs": f"/api/{settings.API_VERSION}/docs",
    }


# Health check
@app.get("/health")
async def health_check():
    return {
        "status": "healthy",
        "environment": settings.ENVIRONMENT,
    }


# Include API router
app.include_router(api_router, prefix=f"/api/{settings.API_VERSION}")


if __name__ == "__main__":
    import uvicorn
    uvicorn.run(
        "app.main:app",
        host=settings.HOST,
        port=settings.PORT,
        reload=settings.DEBUG,
    )