window.customElements.define('d4s-boot-2', class extends HTMLElement {

    #keycloak = null
    #authorization = null
    #url = null
    #realm = "d4science"
    #clientId = null
    #redirectUrl = null
    #audience = null

    // loading attempts nr and timer between attempts
    //#attempts = 6
    //#timer = 500
    
    #locked = true
    #queue = []
    #interval = null
     
    constructor() {
        super()
    }
   
    unlock(){
      this.#locked = false
    }

    connectedCallback(){
      
      this.startStateChecker()
      
      this.loadKeycloak().then(()=>{
      
        console.log("Keycloak loaded")
        return this.initKeycloak()
      
      }).then((authenticated)=>{
      
        if(!authenticated) throw "Failed to authenticate";
         
        console.log("Keycloak initialized and user authenticated")
        return this.loadKeycloakAuthorization()
        
      }).then(()=>{
       
        this.#authorization = new KeycloakAuthorization(this.#keycloak)
        console.log("Keycloak authorization loaded and initialized", this.#authorization)
        this.unlock()  
        
      }).catch(err=>{
        console.error("Unable to initialize Keycloak",err)
      })
    }

    loadKeycloak(){
      return new Promise((resolve, reject)=>{
        if (typeof Keycloak === 'undefined') {
            const script = document.createElement('script')
            script.src = this.#url + '/js/keycloak.js'
            script.type = 'text/javascript'
            script.addEventListener('load', resolve)
            document.head.appendChild(script)
        } else {
            resolve()
        }
      })
    }
    
    initKeycloak(){
      this.#keycloak = new Keycloak({
          url: this.#url,
          realm: this.#realm,
          clientId: this.#clientId
      })
      
      return this.#keycloak.init({onLoad: 'login-required', checkLoginIframe: false })
    }
    
    loadKeycloakAuthorization(){
      return new Promise((resolve, reject)=>{
        if (typeof KeycloakAuthorization === 'undefined') {
          const authz = document.createElement('script')
          authz.src = this.#url + '/js/keycloak-authz.js'
          authz.type = 'text/javascript'
          authz.addEventListener('load', resolve)
          document.head.appendChild(authz)
        } else {
          resolve()
        }
      })
    }

    startStateChecker(){
      this.#interval = window.setInterval(()=>{
        if(this.#locked){
          console.log("Still locked. Currently has " + this.#queue.length + " pending requests.")
        }else{
          if(this.#queue.length > 0){
            const audience = encodeURIComponent(this.#audience)
            console.log("Updating token")
            this.#keycloak.updateToken(30).then(()=>{
              console.log("Checking entitlement")
              return this.#authorization.entitlement(audience)
            }).then(
              rpt => {
                console.log("Authorized")
                //transform all queued requests to fetches
                console.log("All pending requests to promises")
                let promises = this.#queue.map(r => {
                  r.request.headers["Authorization"] = "Bearer " + rpt
                  return r.resolve( fetch(r.url, r.request) )
                })
                //clear queue
                this.#queue = []
                console.log("Resolving all fetches")
                return Promise.all(promises)
              }
            ).catch(err => alert("Unable to make calls: " + err))
          }
        } 
      }, 300)
    }

    parseJwt(token) {
        var base64Url = token.split('.')[1]
        var base64 = base64Url.replace(/-/g, '+').replace(/_/g, '/')
        var jsonPayload = decodeURIComponent(atob(base64).split('').map(function(c) {
            return '%' + ('00' + c.charCodeAt(0).toString(16)).slice(-2)
        }).join(''))
    
        return JSON.parse(jsonPayload);
    }

    expirationDate(utc) {
        let d = new Date(0)
        d.setUTCSeconds(utc)
        return d
    }

    checkContext() {
        const parseJwt = this.parseJwt
        const expDt = this.expirationDate
        const audience = encodeURIComponent(this.#audience)
        this.#authorization.entitlement(audience).then(function (rpt) {
          // onGrant callback function.
          // If authorization was successful you'll receive an RPT
          // with the necessary permissions to access the resource server
          console.log(rpt)
          //console.log("rpt expires: " + expDt(parseJwt(rpt).exp))
        })
    }

    secureFetch(url, request){
      const p = new Promise((resolve, reject)=>{
        let req = request ? request : {}
        if("headers" in req){
          req.headers["Authorization"] = null
        } else {
          req.headers = { "Authorization" : null}
        }
        console.log("Queued request to url ", url)
        this.#queue.push({ url : url, request : req, resolve : resolve, reject : reject})
      })
      return p
    }

    download(url, name) {
      this.secureFetch(url).then(reply=>{
	if(reply.status !== 200) throw "Unable to download";
	return reply.blob()
      }).then(blob=>{
	const objectURL = URL.createObjectURL(blob)
        var tmplnk = document.createElement("a")
        tmplnk.download = name
        tmplnk.href = objectURL
        document.body.appendChild(tmplnk)
        tmplnk.click()      
        document.body.removeChild(tmplnk)
      }).catch(err=>alert(err)
    }

    logout() {
        if (this.#keycloak) {
            if (!this.#redirectUrl) {
                console.error("Missing required @redirectUrl attribute in d4s-boot")
            } else {
                this.#keycloak.logout({
                    redirectUri: this.#redirectUrl
                })
            }
        }
    }

    static get observedAttributes() {
        return ["url", "realm", "gateway", "redirect-url", "context"];
    }

    attributeChangedCallback(name, oldValue, newValue) {
        if (oldValue !== newValue) {
            switch (name) {
                case "url":
                    this.#url = newValue
                    break
                case "realm":
                    this.#realm = newValue
                    break
                case "gateway":
                    this.#clientId = newValue
                    break
                case "redirect-url":
                    this.#redirectUrl = newValue
                    break
                case "context":
                    this.#audience = newValue
                    break
            }
        }
    }
    
    get url() {
        return this.#url
    }

    set url(url) {
        this.#url = url
        this.setAttribute("url", url)
    }

    get realm() {
        return this.#realm
    }

    set realm(realm) {
        this.#realm = realm
        this.setAttribute("realm", realm)
    }

    get clientId() {
        return this.#clientId
    }

    set clientId(clientId) {
        this.#clientId = clientId
        this.setAttribute("gateway", clientId)
    }

    get redirectUrl() {
        return this.#redirectUrl
    }

    set redirectUrl(redirectUrl) {
        this.#redirectUrl = redirectUrl
        this.setAttribute("redirect-url", redirectUrl)
    }

    get context() {
        return this.#audience
    }

    set context(context) {
        this.#audience = context
        this.setAttribute("context", context)
    }
})

 /*connectedCallback() {
        if (typeof Keycloak === 'undefined') {
            const script = document.createElement('script')
            script.src = this.#url + '/js/keycloak.js'
            script.type = 'text/javascript'
            script.addEventListener('load', () => {
                this.initKeycloak()
            })
            document.head.appendChild(script)
        } else {
            this.initKeycloak()
        }
    }*/
    
        /*initKeycloak() {
        this.#keycloak = new Keycloak({
            url: this.#url,
            realm: this.#realm,
            clientId: this.#clientId
        })

        const keycloak = this.#keycloak
        const url = this.#url

        keycloak.init({
            onLoad: 'login-required'
            , checkLoginIframe: false

        }).then((authenticated) => {
            console.log(authenticated ? 'Authenticated in ' + this.#realm : 'Not authenticated')
            if (typeof KeycloakAuthorization === 'undefined') {
                const authz = document.createElement('script')
                authz.src = url + '/js/keycloak-authz.js'
                authz.type = 'text/javascript'
                authz.addEventListener('load', () => {
                    this.#authorization = new KeycloakAuthorization(keycloak)
                })
                document.head.appendChild(authz)
            } else {
                this.#authorization = new KeycloakAuthorization(keycloak)
            }
            //console.log("expires: " + this.expirationDate(keycloak.tokenParsed.exp))

        }).catch(function(err) {
            console.error("Failed to initialize d4science boot component")

        })
    }*/
    
        /*service(endpoint, method, params, onSuccess, onForbidden) {
        if (this.#authorization == null) {
            if (this.#attempts-- > 0) {
                setTimeout(() => this.service(endpoint, method, params, onSuccess, onForbidden), this.#timer)
                return
            } else {
                console.error("Impossible to initialize D4Science authorization component")
                throw "Fatal error"
            }
        }
        this.#keycloak.updateToken(30).then(() => {
            const audience = encodeURIComponent(this.#audience)
            this.#authorization.entitlement(audience).then(function (rpt) {
                var req = new XMLHttpRequest()
                req.open(method, endpoint, true)
                req.setRequestHeader('Accept', 'application/json')
                req.setRequestHeader('Authorization', 'Bearer ' + rpt)
    
                req.onreadystatechange = function () {
                    if (req.readyState == 4) {
                        if (req.status == 200) {
                            onSuccess(req.response)
                        } else if (req.status == 403) {
                            onForbidden(req.statusText)
                        }
                    }
                }
                req.send(params)
            })
        }).catch(function() {
            onForbidden('Failed to refresh token')
        })
    }*/