package main

import (
	"bufio"
	"encoding/json"
	"fmt"
	"io"
	"log"
	"net"
	"net/http"
	"strings"
)

// Configuration
const (
	TargetTCPAddr = "127.0.0.1:9011"
	WebPort       = ":8088"
)

type APIRequest struct {
	Command string   `json:"command"`
	Args    []string `json:"args"`
}

type APIResponse struct {
	Status string `json:"status"`
	Data   any    `json:"data,omitempty"`
	Error  string `json:"error,omitempty"`
}

func main() {
	// Serve static files (HTML)
	http.HandleFunc("/", handleIndex)

	// API Endpoint
	http.HandleFunc("/api/proxy", handleAPI)

	fmt.Printf("Web Admin started at http://localhost%s\n", WebPort)
	log.Fatal(http.ListenAndServe(WebPort, nil))
}

func handleIndex(w http.ResponseWriter, r *http.Request) {
	if r.URL.Path != "/" {
		http.NotFound(w, r)
		return
	}
	// Serve the embedded HTML directly
	http.ServeFile(w, r, "example/web_admin/index.html")
}

func handleAPI(w http.ResponseWriter, r *http.Request) {
	if r.Method != "POST" {
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
		return
	}

	// 1. Parse Request
	body, _ := io.ReadAll(r.Body)
	var req APIRequest
	if err := json.Unmarshal(body, &req); err != nil {
		jsonResponse(w, APIResponse{Status: "error", Error: "Invalid JSON"})
		return
	}

	// 2. Get Token from Header
	token := r.Header.Get("X-Session-Token")

	// 3. Connect to TCP
	conn, err := net.Dial("tcp", TargetTCPAddr)
	if err != nil {
		jsonResponse(w, APIResponse{Status: "error", Error: "Connection failed: " + err.Error()})
		return
	}
	defer conn.Close()
	reader := bufio.NewReader(conn)

	// 4. Authenticate if token present (Except for LOGIN command itself)
	if req.Command != "LOGIN" && token != "" {
		fmt.Fprintf(conn, "AUTH %s\n", token)
		authResp, _ := reader.ReadString('\n')
		if !strings.HasPrefix(authResp, "OK") {
			jsonResponse(w, APIResponse{Status: "error", Error: "Session Expired"})
			return
		}
	}

	// 5. Construct TCP Command
	// Escape args if necessary (simple space joining for now)
	cmdStr := req.Command
	if len(req.Args) > 0 {
		cmdStr += " " + strings.Join(req.Args, " ")
	}
	fmt.Fprintf(conn, "%s\n", cmdStr)

	// 6. Read TCP Response
	respStr, _ := reader.ReadString('\n')
	respStr = strings.TrimSpace(respStr)

	// 7. Parse Response
	if strings.HasPrefix(respStr, "OK") {
		// Extract potential data payload
		payload := strings.TrimPrefix(respStr, "OK ")

		// If payload looks like JSON, try to parse it
		var jsonData any
		if strings.HasPrefix(payload, "[") || strings.HasPrefix(payload, "{") {
			if err := json.Unmarshal([]byte(payload), &jsonData); err == nil {
				jsonResponse(w, APIResponse{Status: "ok", Data: jsonData})
				return
			}
		}

		// Otherwise return as string
		jsonResponse(w, APIResponse{Status: "ok", Data: payload})
	} else if strings.HasPrefix(respStr, "ERR") {
		errMsg := strings.TrimPrefix(respStr, "ERR ")
		jsonResponse(w, APIResponse{Status: "error", Error: errMsg})
	} else {
		jsonResponse(w, APIResponse{Status: "error", Error: "Unknown response: " + respStr})
	}
}

func jsonResponse(w http.ResponseWriter, resp APIResponse) {
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(resp)
}