package lsp

import (
	"encoding/json"
	"fmt"
	"net"
	"os"
	"os/exec"
	"strconv"
	"syscall"
	"time"
)

// ClientRequest sends a request to the bridge daemon, starting it if needed.
// Returns the raw JSON result.
func ClientRequest(req *BridgeRequest) (json.RawMessage, error) {
	if !bridgeRunning() {
		if err := startBridge(); err != nil {
			return nil, fmt.Errorf("start bridge: %w", err)
		}
	}

	resp, err := sendRequest(req)
	if err != nil {
		// Stale socket — restart
		os.Remove(SockPath())
		if err := startBridge(); err != nil {
			return nil, fmt.Errorf("restart bridge: %w", err)
		}
		resp, err = sendRequest(req)
		if err != nil {
			return nil, err
		}
	}

	if resp.Error != "" {
		return nil, fmt.Errorf("%s", resp.Error)
	}
	return resp.Result, nil
}

func bridgeRunning() bool {
	data, err := os.ReadFile(PidPath())
	if err != nil {
		return false
	}
	pid, err := strconv.Atoi(string(data))
	if err != nil {
		return false
	}
	// Check if process exists
	proc, err := os.FindProcess(pid)
	if err != nil {
		return false
	}
	return proc.Signal(syscall.Signal(0)) == nil
}

func startBridge() error {
	exe, err := os.Executable()
	if err != nil {
		return err
	}
	cmd := exec.Command(exe, "--bridge")
	cmd.Stdin = nil
	cmd.Stdout = nil
	cmd.Stderr = nil
	cmd.SysProcAttr = &syscall.SysProcAttr{Setsid: true}
	if err := cmd.Start(); err != nil {
		return err
	}
	cmd.Process.Release()

	// Wait for socket
	sock := SockPath()
	for i := 0; i < 50; i++ {
		if _, err := os.Stat(sock); err == nil {
			return nil
		}
		time.Sleep(100 * time.Millisecond)
	}
	return fmt.Errorf("bridge did not start within 5s")
}

func sendRequest(req *BridgeRequest) (*BridgeResponse, error) {
	conn, err := net.DialTimeout("unix", SockPath(), 5*time.Second)
	if err != nil {
		return nil, err
	}
	defer conn.Close()

	conn.SetDeadline(time.Now().Add(60 * time.Second))

	if err := json.NewEncoder(conn).Encode(req); err != nil {
		return nil, err
	}

	var resp BridgeResponse
	if err := json.NewDecoder(conn).Decode(&resp); err != nil {
		return nil, err
	}
	return &resp, nil
}