use serde_json::{json, Value};
use std::io::{BufRead, BufReader, Read, Write};
use std::process::{Command, Stdio};
use std::time::Duration;
use std::sync::Arc;
use tokio::sync::Mutex;

fn send_message(stdin: &mut std::process::ChildStdin, msg: Value) {
    let s = serde_json::to_string(&msg).unwrap();
    let payload = format!("Content-Length: {}\r\n\r\n{}", s.len(), s);
    stdin.write_all(payload.as_bytes()).unwrap();
    stdin.flush().unwrap();
}

fn read_message(stdout: &mut std::process::ChildStdout) -> Option<Value> {
    let mut reader = BufReader::new(stdout);
    let mut length = 0;
    
    loop {
        let mut line = String::new();
        if reader.read_line(&mut line).unwrap_or(0) == 0 {
            return None;
        }
        let line = line.trim_end();
        if line.is_empty() {
            break;
        }
        if let Some(len_str) = line.strip_prefix("Content-Length: ") {
            length = len_str.parse().unwrap_or(0);
        }
    }
    
    if length == 0 {
        return None;
    }
    
    let mut buf = vec![0u8; length];
    reader.read_exact(&mut buf).unwrap();
    let body_str = String::from_utf8_lossy(&buf);
    
    Some(serde_json::from_str(&body_str).unwrap())
}

#[tokio::test]
async fn test_full_system_e2e_performance() {
    let temp_dir = std::env::temp_dir().join(format!("mcp_e2e_{}", std::time::SystemTime::now().duration_since(std::time::UNIX_EPOCH).unwrap().as_secs()));
    std::fs::create_dir_all(&temp_dir).unwrap();

    let test_port = "3031"; // Use a distinct port
    
    let server_exe = env!("CARGO_BIN_EXE_mcp-memory-server");
    let nvim_exe = env!("CARGO_BIN_EXE_mcp-memory-win-nvim");

    // 1. Start Server
    let mut server = Command::new(server_exe)
        .env("MCP_PORT", test_port)
        .env("MCP_MEMORY_STORE_DIR", temp_dir.to_str().unwrap())
        .stdout(Stdio::null())
        .stderr(Stdio::null())
        .spawn()
        .expect("Failed to start server");
        
    tokio::time::sleep(Duration::from_secs(2)).await;
    
    // 2. Start Stub
    let stub_exe = env!("CARGO_BIN_EXE_mcp-memory-stub");
    let mut stub = Command::new(stub_exe)
        .arg("--target")
        .arg(format!("http://127.0.0.1:{}", test_port))
        .env("MCP_MEMORY_STORE_DIR", temp_dir.to_str().unwrap())
        .stdin(Stdio::piped())
        .stdout(Stdio::piped())
        .stderr(Stdio::null())
        .spawn()
        .expect("Failed to start stub");
        
    let mut stub_stdin = stub.stdin.take().unwrap();
    let mut stub_stdout = stub.stdout.take().unwrap();

    // 3. Start Win-Nvim
    let mut win_nvim = Command::new(&nvim_exe)
        .stdin(Stdio::piped())
        .stdout(Stdio::piped())
        .stderr(Stdio::null())
        .spawn()
        .expect("Failed to start win-nvim");

    let mut nvim_stdin = win_nvim.stdin.take().unwrap();
    let mut nvim_stdout = win_nvim.stdout.take().unwrap();

    // Send 100 concurrent-like sequential rapid requests to Stub
    let start_time = std::time::Instant::now();
    for i in 1..=100 {
        let tools_req = json!({
            "jsonrpc": "2.0",
            "method": "tools/list",
            "params": {},
            "id": i
        });
        send_message(&mut stub_stdin, tools_req);
        let resp = read_message(&mut stub_stdout).expect("Failed to read rapid response from stub");
        assert_eq!(resp["id"], i);
    }
    let stub_duration = start_time.elapsed();

    // Send 100 concurrent-like sequential rapid requests to Win-Nvim
    let start_time_nvim = std::time::Instant::now();
    for i in 1..=100 {
        let tools_req = json!({
            "jsonrpc": "2.0",
            "method": "tools/list",
            "params": {},
            "id": i
        });
        send_message(&mut nvim_stdin, tools_req);
        let resp = read_message(&mut nvim_stdout).expect("Failed to read rapid response from win-nvim");
        assert_eq!(resp["id"], i);
    }
    let nvim_duration = start_time_nvim.elapsed();

    println!("Stub 100 requests: {:?}", stub_duration);
    println!("Win-Nvim 100 requests: {:?}", nvim_duration);

    // Cleanup
    let _ = stub.kill();
    let _ = win_nvim.kill();
    let _ = server.kill();
}