package main

import (
    "fmt"
    "time"
    "github.com/gorilla/mux"
    "net/http"
    "github.com/gorilla/sessions"
    "strings"
    "encoding/json"
    "io/ioutil"
    "github.com/gorilla/handlers"
)

const sessionobjectname = "mysessionobject"
var store = sessions.NewCookieStore([]byte("this-is-the-secret"))

func MySessionMW(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        session, err := store.Get(r, sessionobjectname)
        if err != nil {
            w.Write([]byte("ERROR: Cannot read session object?n"))
            return
        }

        if session.IsNew {
            session.Values["loggedin"] = "0"
        }

        loggedIn := session.Values["loggedin"]
        session.Save(r, w)

        // If this is for an API request then we will always return JSON and no page content is needed
        if strings.Contains(r.RequestURI, "/api/") {
            next.ServeHTTP(w, r)
            return
        }

        w.Header().Set("Content-Type","text/html; charset=utf-8")

        if loggedIn == "0" {
            // Not logged in
            w.Write([]byte("<div>User <b>NOT</b> logged in.</div>"))
        } else {
            // Logged in
            w.Write([]byte("<div>User logged in.</div>"))
        }
        w.Write([]byte("<br/>"))

        t := time.Now()
        s := fmt.Sprintf("<div>[MySessionMW] - %s</div>",t.Format("2006-01-02@15:04:05"))
        w.Write([]byte(s))


        s = `
            <script
              src="https://code.jquery.com/jquery-3.3.1.min.js"
              integrity="sha256-FgpCb/KJQlLNfOu91ta32o/NMZxltwRo8QtmkMRdAu8="
              crossorigin="anonymous">
            </script>

            <div>
                <div>Username <input id='username' /></div>
                <div>Password <input id='password' /></div>
                <div><button onclick='doLogin()'>Login</button></div>
            </div>

            <script>
                function doLogin() {
                    var username = $('#username').val();
                    var password = $('#password').val();
                    console.log("Perform login with: Username [" + username + "] Password [" + password + "]");
                    var theData = JSON.stringify({ username:'John', password:'123456' });
                    $.ajax({
                        type: "POST",
                        crossOrigin: true,
                        url: 'http://localhost:5000//api//login',
                        //headers: {"Access-Control-Allow-Origin": "*", "Access-Control-Allow-Headers": "access-control-allow-origin, access-control-allow-headers"},
                        dataType: 'json',
                        data: theData,
                        contentType: 'application/json; charset=UTF-8',
                        success: function(a, b, c) {
                                    console.log("Success values returned");
                                    console.dir(a);
                                    },
                        error: function(a, b, c) {
                                    console.log("ERROR returned from AJAX");
                                    console.dir(a);
                                    console.dir(b);
                                    console.dir(c);
                                    }
                    })
                }
            </script>
`
        w.Write([]byte(s))


        next.ServeHTTP(w, r)
    })
}

type loginPOCO struct {
    username string `json:"username"`
    password string `json:"password"`
}

func main() {

    router := mux.NewRouter()


    router.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        fmt.Fprintf(w, "<div>Home page requested!</div>")
    })

    router.HandleFunc("/api/login", func(w http.ResponseWriter, r *http.Request) {


        a := r.FormValue("username")
        b := r.FormValue("password")
        fmt.Printf("a=%s b=%s",a,b)

        var err error

        loginAttempt2 := loginPOCO{}
        err = json.NewDecoder(r.Body).Decode(&loginAttempt2)


        body, err := ioutil.ReadAll(r.Body)
        if err != nil {
            panic(err)
        }
        loginAttempt := loginPOCO{}
        err = json.Unmarshal(body, &loginAttempt)



        returnJSON := []byte(`{ "error": "Hello" }`)
        w.Write(returnJSON)
    })


    router.Use(MySessionMW)

    corsObj := handlers.AllowedOrigins([]string{"*"})

    http.ListenAndServe(":5000", handlers.CORS(corsObj)(router))

    fmt.Printf("nCompleted...")
}