package main

import (
	"crypto/md5"
	"encoding/hex"
	"fmt"
	"log"
	"net/http"
	"os"
	"strconv"
	"time"

	"strings"

	"github.com/aliyun/aliyun-tablestore-go-sdk/tablestore"
)

var (
	alphabet = []byte("abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ")
	l        = &Log{}
)

func ShortUrl(url string) string {
	md5Str := getMd5Str(url)
	var tempVal int64
	var result [4]string
	for i := 0; i < 4; i++ {
		tempSubStr := md5Str[i*8 : (i+1)*8]
		hexVal, _ := strconv.ParseInt(tempSubStr, 16, 64)
		tempVal = 0x3FFFFFFF & hexVal
		var index int64
		tempUri := []byte{}
		for i := 0; i < 6; i++ {
			index = 0x0000003D & tempVal
			tempUri = append(tempUri, alphabet[index])
			tempVal = tempVal >> 5
		}
		result[i] = string(tempUri)
	}
	return result[0]
}

func getMd5Str(str string) string {
	m := md5.New()
	m.Write([]byte(str))
	c := m.Sum(nil)
	return hex.EncodeToString(c)
}

type Log struct {
}

func (log *Log) Infof(format string, a ...interface{}) {
	log.log("INFO", format, a...)
}

func (log *Log) Info(msg string) {
	log.log("INFO", "%s", msg)
}

func (log *Log) Errorf(format string, a ...interface{}) {
	log.log("ERROR", format, a...)
}

func (log *Log) Error(msg string) {
	log.log("ERROR", "%s", msg)
}

func (log *Log) Fatalf(format string, a ...interface{}) {
	log.log("FATAL", format, a...)
}

func (log *Log) Fatal(msg string) {
	log.log("FATAL", "%s", msg)
}

func (log *Log) log(level, format string, a ...interface{}) {
	var cstSh, _ = time.LoadLocation("Asia/Shanghai")
	ft := fmt.Sprintf("%s %s %s\n", time.Now().In(cstSh).Format("2006-01-02 15:04:05"), level, format)
	fmt.Printf(ft, a...)
}

func handler(w http.ResponseWriter, r *http.Request) {
	l := &Log{}
	l.Infof("Hello world received a request, url: %s", r.URL.Path)
	l.Infof("url:%s ", r.URL)
	//if r.URL.Path == "/favicon.ico" {
	//	http.NotFound(w, r)
	//	return
	//}

	urls := strings.Split(r.URL.Path, "/")
	originUrl := getOriginUrl(urls[len(urls)-1])
	http.Redirect(w, r, originUrl, http.StatusMovedPermanently)
}

func new(w http.ResponseWriter, r *http.Request) {
	l.Infof("Hello world received a request, url: %s", r.URL)
	l.Infof("url:%s ", r.URL)
	originUrl, ok := r.URL.Query()["origin-url"]
	if !ok {
		l.Errorf("no origin-url params found")
		w.WriteHeader(http.StatusBadRequest)
		w.Write([]byte("Bad request!"))
		return
	}

	surl := ShortUrl(originUrl[0])
	save(surl, originUrl[0])
	fmt.Fprint(w, surl)

}

func getOriginUrl(surl string) string {
	endpoint := os.Getenv("OTS_TEST_ENDPOINT")
	tableName := os.Getenv("TABLE_NAME")
	instanceName := os.Getenv("OTS_TEST_INSTANCENAME")
	accessKeyId := os.Getenv("OTS_TEST_KEYID")
	accessKeySecret := os.Getenv("OTS_TEST_SECRET")
	client := tablestore.NewClient(endpoint, instanceName, accessKeyId, accessKeySecret)

	getRowRequest := &tablestore.GetRowRequest{}
	criteria := &tablestore.SingleRowQueryCriteria{}

	putPk := &tablestore.PrimaryKey{}
	putPk.AddPrimaryKeyColumn("id", surl)
	criteria.PrimaryKey = putPk

	getRowRequest.SingleRowQueryCriteria = criteria
	getRowRequest.SingleRowQueryCriteria.TableName = tableName
	getRowRequest.SingleRowQueryCriteria.MaxVersion = 1

	getResp, _ := client.GetRow(getRowRequest)
	colmap := getResp.GetColumnMap()
	return fmt.Sprintf("%s", colmap.Columns["originUrl"][0].Value)
}

func save(surl, originUrl string) {
	endpoint := os.Getenv("OTS_TEST_ENDPOINT")
	tableName := os.Getenv("TABLE_NAME")
	instanceName := os.Getenv("OTS_TEST_INSTANCENAME")
	accessKeyId := os.Getenv("OTS_TEST_KEYID")
	accessKeySecret := os.Getenv("OTS_TEST_SECRET")
	client := tablestore.NewClient(endpoint, instanceName, accessKeyId, accessKeySecret)

	putRowRequest := &tablestore.PutRowRequest{}
	putRowChange := &tablestore.PutRowChange{}
	putRowChange.TableName = tableName

	putPk := &tablestore.PrimaryKey{}
	putPk.AddPrimaryKeyColumn("id", surl)
	putRowChange.PrimaryKey = putPk

	putRowChange.AddColumn("originUrl", originUrl)
	putRowChange.SetCondition(tablestore.RowExistenceExpectation_IGNORE)
	putRowRequest.PutRowChange = putRowChange

	if _, err := client.PutRow(putRowRequest); err != nil {
		l.Errorf("putrow failed with error: %s", err)
	}
}

func main() {
	http.HandleFunc("/", handler)
	http.HandleFunc("/new", new)
	port := os.Getenv("PORT")
	if port == "" {
		port = "9090"
	}

	if err := http.ListenAndServe(fmt.Sprintf(":%s", port), nil); err != nil {
		log.Fatalf("ListenAndServe error:%s ", err.Error())
	}

}

apiVersion: serving.knative.dev/v1
kind: Service
metadata:
  name: short-url
  namespace: default
spec:
  template:
    metadata:
      labels:
        app: short-url
      annotations:
        autoscaling.knative.dev/maxScale: "20"
        autoscaling.knative.dev/minScale: "0"
        autoscaling.knative.dev/target: "100"
    spec:
      containers:
        - image: registry.cn-hangzhou.aliyuncs.com/knative-sample/shorturl:v1
          ports:
            - name: http1
              containerPort: 8080
          env:
          - name: OTS_TEST_ENDPOINT
            value: http://t.cn-hangzhou.ots.aliyuncs.com
          - name: TABLE_NAME
            value: ${TABLE_NAME}
          - name: OTS_TEST_INSTANCENAME
            value: ${OTS_TEST_INSTANCENAME}
          - name: OTS_TEST_KEYID
            value: ${OTS_TEST_KEYID}
          - name: OTS_TEST_SECRET
            value: ${OTS_TEST_SECRET}