from fastapi import APIRouter, Request
from fastapi.responses import HTMLResponse, FileResponse, JSONResponse
from pathlib import Path

router = APIRouter()

# Security: Define base directories for path traversal protection
DIST_DIR = Path("frontend/dist").resolve()
ASSETS_DIR = Path("frontend/dist/assets").resolve()


def is_safe_path(base_dir: Path, requested_path: Path) -> bool:
    """Check if the requested path is within the allowed base directory"""
    try:
        resolved = requested_path.resolve()
        return str(resolved).startswith(str(base_dir))
    except (OSError, ValueError):
        return False


@router.get("/agentgraph", response_class=HTMLResponse)
async def agentgraph_interface(request: Request):
    """Serve the React-based AgentGraph interface (requires authentication)"""
    # Serve the built React app from the new location
    dist_path = DIST_DIR / "index.html"
    if dist_path.exists():
        with open(dist_path, 'r') as f:
            content = f.read()
        return HTMLResponse(content=content)
    else:
        # Return error message if React app not built
        return JSONResponse(
            content={"error": "React app not built. Please run 'npm run build' in the frontend directory."},
            status_code=503
        )


@router.get("/agentgraph/{path:path}")
async def agentgraph_assets(path: str):
    """Serve static assets for the React app with path traversal protection"""
    requested_path = (DIST_DIR / path).resolve()

    # Security: Prevent path traversal attacks
    if not is_safe_path(DIST_DIR, requested_path):
        return JSONResponse(
            content={"error": "Access denied"},
            status_code=403
        )

    if requested_path.is_file():
        return FileResponse(requested_path)
    return JSONResponse(content={"error": "File not found"}, status_code=404)


@router.get("/assets/{path:path}")
async def serve_assets(path: str):
    """Serve React assets from /assets/ path with path traversal protection"""
    requested_path = (ASSETS_DIR / path).resolve()

    # Security: Prevent path traversal attacks
    if not is_safe_path(ASSETS_DIR, requested_path):
        return JSONResponse(
            content={"error": "Access denied"},
            status_code=403
        )

    if requested_path.is_file():
        return FileResponse(requested_path)
    return JSONResponse(content={"error": "Asset not found"}, status_code=404)


@router.get("/vite.svg")
async def serve_vite_svg():
    """Serve the vite.svg favicon"""
    file_path = DIST_DIR / "vite.svg"
    if file_path.exists():
        return FileResponse(file_path)
    return JSONResponse(content={"error": "Favicon not found"}, status_code=404)