package logger

import (
	"os"
	"strconv"
	"strings"
	"time"

	"github.com/gin-gonic/gin"
	"go.uber.org/zap"
)

const (
	unKnowHostName   = "unkonw"
	bufferDefaultLen = 4 * 2000
)

func GinLoggerMiddleware(logger *zap.SugaredLogger) gin.HandlerFunc {
	hostName, err := os.Hostname()
	if err != nil {
		hostName = unKnowHostName
	}

	return func(c *gin.Context) {
		info := requestInfo{
			Host:            hostName,
			Path:            c.Request.URL.Path,
			Method:          c.Request.Method,
			Start:           time.Now(),
			ClientIP:        c.ClientIP(),
			ClientUserAgent: c.Request.UserAgent(),
			Referer:         c.Request.Referer(),
			DataLen:         c.Writer.Size(),
		}

		c.Next()

		info.End = time.Now()
		info.Status = c.Writer.Status()

		if len(c.Errors) > 0 {
			logger.Error(info.String(c.Errors.Last()))
		} else {
			logger.Info(info.String(nil))
		}
	}
}

type requestInfo struct {
	ClientIP        string
	Host            string
	Method          string
	Path            string
	Referer         string
	ClientUserAgent string
	Start           time.Time
	End             time.Time
	Status          int
	DataLen         int
}

func (i *requestInfo) String(err error) string {
	infoBuffer := strings.Builder{}
	infoBuffer.Grow(bufferDefaultLen)

	infoBuffer.WriteString("clientIP:")
	infoBuffer.WriteString(i.ClientIP)
	infoBuffer.WriteString("-host:")
	infoBuffer.WriteString(i.Host)

	infoBuffer.WriteString(" method:")
	infoBuffer.WriteString(i.Method)
	infoBuffer.WriteString(" path:")
	infoBuffer.WriteString(i.Path)

	infoBuffer.WriteString(" status:")
	infoBuffer.WriteString(strconv.Itoa(i.Status))

	infoBuffer.WriteString(" start:")
	infoBuffer.WriteString(i.Start.Format(time.StampMicro))
	infoBuffer.WriteString(" end:")
	infoBuffer.WriteString(i.End.Format(time.StampMicro))

	infoBuffer.WriteString(" cost:")
	infoBuffer.WriteString(strconv.FormatInt(i.End.Sub(i.Start).Microseconds(), 10))
	infoBuffer.WriteString("ms ")

	infoBuffer.WriteString(" dataLen:")
	infoBuffer.WriteString(strconv.Itoa(i.DataLen))
	infoBuffer.WriteString(" referer:")
	infoBuffer.WriteString(i.Referer)

	infoBuffer.WriteString(" clientUserAgent:")
	infoBuffer.WriteString(i.ClientUserAgent)

	if err != nil {
		infoBuffer.WriteString(" errMsg:")
		infoBuffer.WriteString(err.Error())
	}

	return infoBuffer.String()
}