# ============================================================================
# agent verf - FastAPI Application
# Version: 0.1.0
# Last Updated: 2026-01-13
#
# Main FastAPI application entry point.
#
# Usage:
#   uvicorn src.main:app --reload --port 8000
#
# Endpoints:
#   POST /api/v1/verify     - Submit URL for verification
#   GET  /api/v1/status/:id - Check verification status
#   GET  /api/v1/receipt/:id - Get verification receipt
#   GET  /health            - Health check
# ============================================================================

import os
import structlog
from contextlib import asynccontextmanager
from dotenv import load_dotenv

from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware

from src.routes import verify, health, receipts, user

# Load environment variables
load_dotenv()

# Configure structured logging
structlog.configure(
    processors=[
        structlog.stdlib.filter_by_level,
        structlog.stdlib.add_logger_name,
        structlog.stdlib.add_log_level,
        structlog.stdlib.PositionalArgumentsFormatter(),
        structlog.processors.TimeStamper(fmt="iso"),
        structlog.processors.StackInfoRenderer(),
        structlog.processors.format_exc_info,
        structlog.processors.UnicodeDecoder(),
        structlog.processors.JSONRenderer(),
    ],
    wrapper_class=structlog.stdlib.BoundLogger,
    context_class=dict,
    logger_factory=structlog.stdlib.LoggerFactory(),
    cache_logger_on_first_use=True,
)

logger = structlog.get_logger()


# ============================================================================
# Lifespan Events
# ============================================================================

@asynccontextmanager
async def lifespan(app: FastAPI):
    """
    Startup and shutdown events for the application.

    Startup:
        - Initialize Redis connection pool
        - Warm up LLM client
        - Log startup

    Shutdown:
        - Close Redis connections
        - Log shutdown
    """
    # Startup
    logger.info(
        "Starting agent verf API",
        version="0.1.0",
        environment=os.getenv("ENVIRONMENT", "development"),
    )

    # TODO: Initialize Redis pool
    # TODO: Warm up LLM client

    yield

    # Shutdown
    logger.info("Shutting down agent verf API")


# ============================================================================
# Application Factory
# ============================================================================

def create_app() -> FastAPI:
    """
    Create and configure the FastAPI application.

    Returns:
        Configured FastAPI app instance
    """
    app = FastAPI(
        title="agent verf API",
        description="Social media fact-checking and verification API",
        version="0.1.0",
        docs_url="/docs",
        redoc_url="/redoc",
        lifespan=lifespan,
    )

    # Configure CORS
    # In production, restrict origins to your frontend domain
    allowed_origins = os.getenv("CORS_ORIGINS", "http://localhost:3000").split(",")

    app.add_middleware(
        CORSMiddleware,
        allow_origins=allowed_origins,
        allow_credentials=True,
        allow_methods=["GET", "POST", "PATCH", "OPTIONS"],
        allow_headers=["*"],
    )

    # Register routes
    app.include_router(health.router, tags=["Health"])
    app.include_router(verify.router, prefix="/api/v1", tags=["Verification"])
    app.include_router(receipts.router, prefix="/api/v1", tags=["Receipts"])
    app.include_router(user.router, prefix="/api/v1/user", tags=["User"])

    return app


# ============================================================================
# App Instance
# ============================================================================

app = create_app()


# ============================================================================
# Root Route
# ============================================================================

@app.get("/")
async def root():
    """
    Root endpoint - API info.
    """
    return {
        "name": "agent verf API",
        "version": "0.1.0",
        "docs": "/docs",
        "health": "/health",
    }