#!/usr/bin/env python3
import sys
import json
import urllib.request
import argparse

def main():
    parser = argparse.ArgumentParser(description="MCP Stdio-to-HTTP Bridge for ESP32-S3-RLCD-4.2")
    parser.add_argument("--ip", required=True, help="IP address of the ESP32 board (e.g. 192.168.1.123)")
    parser.add_argument("--port", type=int, default=80, help="Port the MCP server is listening on (default 80)")
    args = parser.parse_args()
    
    url = f"http://{args.ip}:{args.port}/api/mcp"
    sys.stderr.write(f"ESP32 MCP Stdio-to-HTTP Bridge started. Routing stdio to {url}\n")
    sys.stderr.flush()
    
    # Sits in loop reading stdio requests from LLM client and routing them to ESP32
    while True:
        try:
            line = sys.stdin.readline()
            if not line:
                break
                
            # Parse request to ensure it's valid JSON
            req_data = json.loads(line.strip())
            
            # Forward the JSON-RPC request to the ESP32 board via HTTP POST
            req = urllib.request.Request(
                url,
                data=json.dumps(req_data).encode("utf-8"),
                headers={"Content-Type": "application/json"},
                method="POST"
            )
            
            with urllib.request.urlopen(req, timeout=10.0) as response:
                resp_data = response.read().decode("utf-8")
                # Write the response back to stdio for the LLM client
                sys.stdout.write(resp_data + "\n")
                sys.stdout.flush()
                
        except urllib.error.URLError as e:
            # Send standard JSON-RPC internal error response
            err_resp = {
                "jsonrpc": "2.0",
                "error": {
                    "code": -32000,
                    "message": f"Bridge failed to reach ESP32: {e.reason}"
                },
                "id": req_data.get("id") if "req_data" in locals() else None
            }
            sys.stdout.write(json.dumps(err_resp) + "\n")
            sys.stdout.flush()
            sys.stderr.write(f"Bridge error: Failed to connect to ESP32 at {url}: {e}\n")
            sys.stderr.flush()
            
        except Exception as e:
            err_resp = {
                "jsonrpc": "2.0",
                "error": {
                    "code": -32603,
                    "message": f"Bridge Internal Error: {str(e)}"
                },
                "id": req_data.get("id") if "req_data" in locals() else None
            }
            sys.stdout.write(json.dumps(err_resp) + "\n")
            sys.stdout.flush()
            sys.stderr.write(f"Bridge error: {e}\n")
            sys.stderr.flush()

if __name__ == "__main__":
    main()