package main

import (
	"bufio"
	"embed"
	"encoding/csv"
	"encoding/json"
	"flag"
	"fmt"
	"io"
	"io/fs"
	"log"
	"net"
	"net/http"
	"os"
	"os/exec"
	"runtime"
	"time"
)

//go:embed web/*
var webFS embed.FS

var collector *Collector

// waitExit keeps the console window open on Windows so the user can read errors.
func waitExit() {
	if runtime.GOOS == "windows" {
		fmt.Println("\n按回车键退出...")
		bufio.NewReader(os.Stdin).ReadBytes('\n')
	}
}

func main() {
	// Log to file so crashes are diagnosable even if console closes.
	lf, lfErr := os.OpenFile("bypos-collector.log", os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0644)
	if lfErr == nil {
		log.SetOutput(io.MultiWriter(os.Stderr, lf))
		defer lf.Close()
	}

	defer func() {
		if r := recover(); r != nil {
			log.Printf("程序崩溃: %v", r)
			waitExit()
		}
	}()

	log.Println("bypos-collector 启动中...")

	addr := flag.String("addr", "127.0.0.1:8765", "本地监听地址")
	noOpen := flag.Bool("no-open", false, "不自动打开浏览器")
	sdog := flag.String("sdogid", "", "中心库账号 id（优先读 $BYPOS_SDOGID 环境变量）")
	flag.Parse()
	collector = NewCollector(*sdog)
	if collector.sdogID == "" {
		log.Println("警告: 未配置 sdogid，请通过 $BYPOS_SDOGID 环境变量、-sdogid 参数或控制台输入框指定")
	}

	sub, err := fs.Sub(webFS, "web")
	if err != nil {
		log.Printf("错误: 无法加载内嵌 web 资源: %v", err)
		waitExit()
		return
	}
	mux := http.NewServeMux()
	mux.Handle("/", http.FileServer(http.FS(sub)))
	mux.HandleFunc("/api/start", handleStart)
	mux.HandleFunc("/api/stop", handleStop)
	mux.HandleFunc("/api/stats", handleStats)
	mux.HandleFunc("/api/download", handleDownload)
	mux.HandleFunc("/api/export.csv", handleExportCSV)

	ln, err := net.Listen("tcp", *addr)
	if err != nil {
		log.Printf("端口 %s 被占用，自动选择可用端口...", *addr)
		ln, err = net.Listen("tcp", "127.0.0.1:0")
		if err != nil {
			log.Printf("错误: 无法监听: %v", err)
			waitExit()
			return
		}
	}
	realAddr := ln.Addr().String()
	urlStr := "http://" + realAddr + "/"
	fmt.Println("==============================================")
	fmt.Println(" 中心库商品采集器  bypos-collector")
	fmt.Println(" 控制台: " + urlStr)
	fmt.Println(" 关闭本窗口即停止程序")
	fmt.Println("==============================================")
	log.Printf("监听地址: %s", realAddr)
	if !*noOpen {
		go openBrowser(urlStr)
	}
	if err := http.Serve(ln, mux); err != nil {
		log.Printf("HTTP 服务异常退出: %v", err)
		waitExit()
	}
}

func openBrowser(url string) {
	time.Sleep(600 * time.Millisecond)
	var cmd string
	var args []string
	switch runtime.GOOS {
	case "windows":
		cmd = "rundll32"
		args = []string{"url.dll,FileProtocolHandler", url}
	case "darwin":
		cmd = "open"
		args = []string{url}
	default:
		cmd = "xdg-open"
		args = []string{url}
	}
	_ = exec.Command(cmd, args...).Start()
}

func writeJSON(w http.ResponseWriter, code int, v interface{}) {
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	w.WriteHeader(code)
	json.NewEncoder(w).Encode(v)
}

func handleStart(w http.ResponseWriter, r *http.Request) {
	if r.Method != "POST" {
		http.Error(w, "method", 405)
		return
	}
	var req JobReq
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeJSON(w, 400, map[string]string{"error": "请求格式错误"})
		return
	}
	if err := collector.Start(req); err != nil {
		writeJSON(w, 400, map[string]string{"error": err.Error()})
		return
	}
	writeJSON(w, 200, map[string]string{"ok": "started"})
}

func handleStop(w http.ResponseWriter, r *http.Request) {
	collector.Stop()
	writeJSON(w, 200, map[string]string{"ok": "stopping"})
}

func handleStats(w http.ResponseWriter, r *http.Request) {
	writeJSON(w, 200, map[string]interface{}{
		"stats":  collector.snapshot(),
		"recent": collector.recentResults(),
	})
}

func handleDownload(w http.ResponseWriter, r *http.Request) {
	s := collector.snapshot()
	if s.OutFile == "" {
		http.Error(w, "no output yet", 404)
		return
	}
	f, err := os.Open(s.OutFile)
	if err != nil {
		http.Error(w, err.Error(), 404)
		return
	}
	defer f.Close()
	w.Header().Set("Content-Type", "application/x-ndjson; charset=utf-8")
	w.Header().Set("Content-Disposition", "attachment; filename=products.jsonl")
	io.Copy(w, f)
}

func handleExportCSV(w http.ResponseWriter, r *http.Request) {
	s := collector.snapshot()
	if s.OutFile == "" {
		http.Error(w, "no output yet", 404)
		return
	}
	f, err := os.Open(s.OutFile)
	if err != nil {
		http.Error(w, err.Error(), 404)
		return
	}
	defer f.Close()
	w.Header().Set("Content-Type", "text/csv; charset=utf-8")
	w.Header().Set("Content-Disposition", "attachment; filename=products.csv")
	w.Write([]byte{0xEF, 0xBB, 0xBF}) // UTF-8 BOM so Excel reads Chinese correctly
	cw := csv.NewWriter(w)
	cw.Write([]string{"barcode", "name", "spec", "unit", "area", "manufacturer", "license", "in_price", "sell_price", "status", "retmsg", "fetched_at", "source"})
	dec := json.NewDecoder(f)
	for {
		var p Product
		if err := dec.Decode(&p); err != nil {
			break
		}
		cw.Write([]string{p.Barcode, p.Name, p.Spec, p.Unit, p.Area, p.Manufacturer, p.License, p.InPrice, p.SellPrice, p.Status, p.RetMsg, p.FetchedAt, p.Source})
	}
	cw.Flush()
}