"""
FastAPI Main Application
========================

Main entry point for the Autonomous Coding UI server.
Provides REST API, WebSocket, and static file serving.
"""

import shutil
from contextlib import asynccontextmanager
from pathlib import Path

from fastapi import FastAPI, HTTPException, Request, WebSocket
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import FileResponse
from fastapi.staticfiles import StaticFiles

from .routers import (
    agent_router,
    assistant_chat_router,
    features_router,
    filesystem_router,
    projects_router,
    spec_creation_router,
)
from .schemas import SetupStatus
from .services.assistant_chat_session import cleanup_all_sessions as cleanup_assistant_sessions
from .services.process_manager import cleanup_all_managers
from .websocket import project_websocket

# Paths
ROOT_DIR = Path(__file__).parent.parent
UI_DIST_DIR = ROOT_DIR / "ui" / "dist"


@asynccontextmanager
async def lifespan(app: FastAPI):
    """Lifespan context manager for startup and shutdown."""
    # Startup
    yield
    # Shutdown - cleanup all running agents and assistant sessions
    await cleanup_all_managers()
    await cleanup_assistant_sessions()


# Create FastAPI app
app = FastAPI(
    title="Autonomous Coding UI",
    description="Web UI for the Autonomous Coding Agent",
    version="1.0.0",
    lifespan=lifespan,
)

# CORS - allow only localhost origins for security
app.add_middleware(
    CORSMiddleware,
    allow_origins=[
        "http://localhost:5173",      # Vite dev server
        "http://127.0.0.1:5173",
        "http://localhost:8888",      # Production
        "http://127.0.0.1:8888",
    ],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)


# ============================================================================
# Security Middleware
# ============================================================================

@app.middleware("http")
async def require_localhost(request: Request, call_next):
    """Only allow requests from localhost."""
    client_host = request.client.host if request.client else None

    # Allow localhost connections
    if client_host not in ("127.0.0.1", "::1", "localhost", None):
        raise HTTPException(status_code=403, detail="Localhost access only")

    return await call_next(request)


# ============================================================================
# Include Routers
# ============================================================================

app.include_router(projects_router)
app.include_router(features_router)
app.include_router(agent_router)
app.include_router(spec_creation_router)
app.include_router(filesystem_router)
app.include_router(assistant_chat_router)


# ============================================================================
# WebSocket Endpoint
# ============================================================================

@app.websocket("/ws/projects/{project_name}")
async def websocket_endpoint(websocket: WebSocket, project_name: str):
    """WebSocket endpoint for real-time project updates."""
    await project_websocket(websocket, project_name)


# ============================================================================
# Setup & Health Endpoints
# ============================================================================

@app.get("/api/health")
async def health_check():
    """Health check endpoint."""
    return {"status": "healthy"}


@app.get("/api/setup/status", response_model=SetupStatus)
async def setup_status():
    """Check system setup status."""
    # Check for Claude CLI
    claude_cli = shutil.which("claude") is not None

    # Check for credentials file
    credentials_path = Path.home() / ".claude" / ".credentials.json"
    credentials = credentials_path.exists()

    # Check for Node.js and npm
    node = shutil.which("node") is not None
    npm = shutil.which("npm") is not None

    return SetupStatus(
        claude_cli=claude_cli,
        credentials=credentials,
        node=node,
        npm=npm,
    )


# ============================================================================
# Static File Serving (Production)
# ============================================================================

# Serve React build files if they exist
if UI_DIST_DIR.exists():
    # Mount static assets
    app.mount("/assets", StaticFiles(directory=UI_DIST_DIR / "assets"), name="assets")

    @app.get("/")
    async def serve_index():
        """Serve the React app index.html."""
        return FileResponse(UI_DIST_DIR / "index.html")

    @app.get("/{path:path}")
    async def serve_spa(path: str):
        """
        Serve static files or fall back to index.html for SPA routing.
        """
        # Check if the path is an API route (shouldn't hit this due to router ordering)
        if path.startswith("api/") or path.startswith("ws/"):
            raise HTTPException(status_code=404)

        # Try to serve the file directly
        file_path = UI_DIST_DIR / path
        if file_path.exists() and file_path.is_file():
            return FileResponse(file_path)

        # Fall back to index.html for SPA routing
        return FileResponse(UI_DIST_DIR / "index.html")


# ============================================================================
# Main Entry Point
# ============================================================================

if __name__ == "__main__":
    import uvicorn
    uvicorn.run(
        "server.main:app",
        host="127.0.0.1",  # Localhost only for security
        port=8888,
        reload=True,
    )