main.go

package main

import (
	"flag"
	"fmt"
	"net/http"
	"io/ioutil"
	"strconv"
	"strings"
)

var (
	httpPort = flag.Int("http_port", 80, "HTTP port to serve on (defaults to 80)")
)

func main() {
	// Parse the flags
	flag.Parse()
	mux := http.NewServeMux()
	mux.HandleFunc("/auth", func(w http.ResponseWriter, r *http.Request) {
		query := r.URL.Query()
		fmt.Println(query)
		// host := strings.Split(query.Get("state"), "-")[1]
		clientId := query.Get("client_id")
		cozyOrigin := query.Get("redirect_uri") // here we use the redirect_uri param to transmit our stack url
		state := query.Get("state")
		authReq := "https://gw.hml.api.enedis.fr/group/espace-particuliers/consentement-linky/oauth2/authorize?client_id="+ clientId +"&duration=P6M&redirect_uri=https://oauth-proxy.wf.alpha.grandlyon.com/&response_type=code&state="+ state +"-"+ cozyOrigin
		fmt.Println(authReq)
		response, err := http.Get(authReq)
		if err != nil {
			fmt.Println(err)
		} else {
			defer response.Body.Close()
			contents, err := ioutil.ReadAll(response.Body)
			if err != nil {
				fmt.Println(err)
			}
			// Get the response body as a string
			pageContent := string(contents)
		
			// Find a substr
			codeStartIndex := strings.Index(pageContent, "?code=")
			if codeStartIndex == -1 {
				fmt.Println("No code found")
			}
			codeStartIndex += 6
		
			// Find the index of the closing tag
			codeEndIndex := strings.Index(pageContent, "&state=")
			if codeEndIndex == -1 {
				fmt.Println("No closing tag for code found.")
			}

			stateStartIndex := strings.Index(pageContent, "&state=")
			if stateStartIndex == -1 {
				fmt.Println("No state found")
			}
			stateStartIndex += 7
		
			stateEndIndex := strings.Index(pageContent, "&usage_point_id=")
			if stateEndIndex == -1 {
				fmt.Println("No closing tag for state found.")
			}


			usageStartIndex := strings.Index(pageContent, "&usage_point_id=")
			if usageStartIndex == -1 {
				fmt.Println("No usage found")
			}
			usageStartIndex += 16
		
			usageEndIndex := strings.Index(pageContent, "&usage_point_id=")
			if usageEndIndex == -1 {
				fmt.Println("No closing tag for usage found.")
			}
			usageEndIndex += 30

			pageCode := []byte(pageContent[codeStartIndex:codeEndIndex])
			pageState := []byte(pageContent[stateStartIndex:stateEndIndex])
			pageUsage := []byte(pageContent[usageStartIndex:usageEndIndex])

			// Print out the result
			fmt.Printf("Page code: %s\n", pageCode)
			fmt.Printf("Page state: %s\n", pageState)
			fmt.Printf("Page usage: %s\n", pageUsage)

			state := strings.Split(pageState, "-")[0]
			host := strings.Split(pageState, "-")[1]

			redir := "https://" + host + "/accounts/enedisoauth/redirect?code=" + pageCode + "&state="+ state +"&usage_point_id=" + pageUsage
			fmt.Println(redir)
			http.Redirect(w, r, redir, 302)
		}
	
	})

	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		query := r.URL.Query()
		fmt.Println(query)
		state := strings.Split(query.Get("state"), "-")[0]
		host := strings.Split(query.Get("state"), "-")[1]
		fmt.Println(host)
		fmt.Println(state)
		usagePointId := query.Get("usage_point_id")
		code := query.Get("code")
		redir := "https://" + host + "/accounts/enedisoauth/redirect?code=" + code + "&state="+ state +"&usage_point_id=" + usagePointId
		fmt.Println(redir)
		http.Redirect(w, r, redir, 302)
	})

	http.ListenAndServe(":"+strconv.Itoa(*httpPort), mux)
}