package logViewHandler

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"regexp"
	"strconv"
	"strings"
	"time"

	"gitee.com/zzoe/httplog/backend/fileConf"

	"golang.org/x/text/encoding"
	"golang.org/x/text/transform"
)

//Fenc file encoding
var Fenc encoding.Encoding

// Get 响应/logView Get请求,获取日志文件内容
func Get(w http.ResponseWriter, r *http.Request) {
	fmt.Println("Receive /logView")
	date := time.Now().Format("20060102")

	r.ParseForm()
	v, ok := fileConf.CurLogConfMap.Load(r.Form.Get("logType"))
	if !ok {
		fmt.Println(r.Form)
		w.Write([]byte("No log found!"))
		return
	}
	logConfInfo := v.(*fileConf.LogConfInfo)
	fileName := strings.Replace(logConfInfo.Path, "<date>", date, -1)

	f, err := os.Open(fileName)
	if err != nil {
		fmt.Println("Open log file error: ", err)
		w.Write([]byte("Open log file error: " + err.Error()))
		return
	}
	defer f.Close()

	logRows, err := strconv.Atoi(r.Form.Get("logRows"))
	if err != nil {
		logRows = (int)(logConfInfo.GetRows())
	}
	//这里埋了个坑，bp的日志是一行最多130个字符。假如日志每行都很长~ 那该如何是好？
	f.Seek(int64(-130*logRows), 2)

	fileBytes, _ := ioutil.ReadAll(transform.NewReader(f, Fenc.NewDecoder()))

	res, _ := splitLog(fileBytes, logRows)
	w.Write(res)
}

type logViewTemplate struct {
	TimeStamp  string `json:"timeStamp"`
	LogContent string `json:"logContent"`
}

func splitLog(fileBytes []byte, logRows int) ([]byte, error) {
	const patten string = `^(\[[^\]]+\]){4} ?`

	lineBytes := bytes.Split(fileBytes, []byte("\n"))

	lineNum := len(lineBytes) - logRows - 1
	if lineNum < 0 {
		lineNum = 0
	}

	timeStamp := strings.Builder{}
	logContent := strings.Builder{}
	for index := lineNum; index < len(lineBytes); index++ {
		lineStr := string(lineBytes[index])
		re, err := regexp.Compile(patten)
		if err != nil {
			log.Fatal("Error compiling regex", err)
		}
		res := re.FindString(lineStr)
		timeStamp.WriteString(res + "\n")
		logContent.WriteString(strings.TrimPrefix(string(lineBytes[index]), res) + "\n")
	}

	res := logViewTemplate{timeStamp.String(), logContent.String()}

	return json.Marshal(res)
}