Add draft restore prompt (#52)

apps/map/templates/map/form.html

@@ -13,6 +13,11 @@
 <style>
 .savebutton--icon { margin-left: 15px; margin-right: 2px; }
 .savebutton--icon-failed { color: #d9534f; }
+.savebutton--details { font-style: italic; }
+
+.draftprompt { display: none; }
+.draftprompt--delete { margin-left: 10px; }
+.draftprompt--details { margin-left: 10px; font-weight: bold; }
 </style>
 {% endblock %}
 
@@ -20,7 +25,18 @@
 {% block description %}{% trans "Here you can submit a case study for review and it will be added to the map." %}{% endblock %}
 
 {% block inner %}
+  <div class="draftprompt alert alert-info">
+    <div>
+      <b class="lead">You have a saved draft.</b>
+      <p>Do you want to restore it? Restoring the draft will overwrite any other data you have input into the form below.</p>
+    </div>
+    <button class="draftprompt--restore btn btn-success">Restore draft</button>
+    <button class="draftprompt--delete btn btn-default">Delete draft</button>
+    <span class="draftprompt--details"></span>
+  </div>
+
   <div class="savebutton"></div>
+
   {% crispy form %}
 {% endblock %}
 
@@ -189,13 +205,17 @@
 <script>
 "use strict";
 
+//
+// UI ELEMENTS
+//
+
 class SaveButton {
   constructor(div) {
     this.root = div
     this.root.className = "savebutton"
     this.root.innerHTML =
-      `<button class="savebutton--button btn btn-success">Save</button>
-       <i class="savebutton--icon"></i><i><span class="savebutton--details"></span></i>`
+      '<button class="savebutton--button btn btn-success">Save</button>' +
+      '<i class="savebutton--icon"></i> <span class="savebutton--details"></span>'
 
     this.element = {
       root: this.root,
@@ -208,7 +228,7 @@ class SaveButton {
   }
 
   changeState(data) {
-    data = data || {}
+    var data = data || {}
     this.element.button.innerText = data.buttonText || "Save"
     this.element.button.disabled = data.buttonClickable === false ? true : false
     this.element.icon.className = 'savebutton--icon ' + (data.iconClasses || "")
@@ -251,24 +271,93 @@ class SaveButton {
   }
 }
 
-function initDrafts() {
-  var button = new SaveButton(document.querySelector('.savebutton'))
 
-  $('#case-study-form').dirtyForms()
-  $('#case-study-form').on('dirty.dirtyforms', ev => {
-    button.switchStateUnsaved()
-  })
+class DraftPrompt {
+  constructor(opts) {
+    this.restoreDraft = opts.restoreFn
+    this.deleteDraft = opts.deleteFn
 
-  button.element.button.addEventListener('click', evt => {
-    button.switchStateSaving()
+    this.root = opts.root
+    this.element = {
+      root: this.root,
+      restore: this.root.querySelector('.draftprompt--restore'),
+      delete: this.root.querySelector('.draftprompt--delete'),
+      details: this.root.querySelector('.draftprompt--details')
+    }
 
-    var fs = new FormSaver({
-      formId: 'case-study-form',
-      except: [ 'csrfmiddlewaretoken' ]
+    // Restore should restore, then hide the prompt
+    this.element.restore.addEventListener('click', () => {
+      this.restoreDraft()
+      this.switchStateHidden()
     })
-    var s = fs.serialise();
 
-    fetch('/en-gb/case-study/draft', {
+    // Delete button will delete the draft
+    this.element.delete.addEventListener('click', () => {
+      if (window.confirm('Are you sure you want to delete your draft?')) {
+        this.switchStateDeleting()
+        this.deleteDraft().then(ok => ok ?
+                                          this.switchStateHidden() :
+                                          this.switchStateDeleteFailed()
+        )
+      }
+    })
+
+    this.switchStateShown()
+  }
+
+  changeState(data) {
+    var data = data || {}
+    this.element.root.style.display = data.visible ? "block" : "none"
+    this.element.details.innerHTML = data.detailsText || ""
+  }
+
+  switchStateHidden() {
+    this.changeState({
+      visible: false
+    })
+  }
+
+  switchStateShown() {
+    this.changeState({
+      visible: true
+    })
+  }
+
+  switchStateDeleting() {
+    this.changeState({
+      visible: true,
+      details: '<i classs="fa fa-spinner fa-spin"></i>'
+    })
+  }
+
+  switchStateDeleteFailed() {
+    this.changeState({
+      details: 'Delete failed!'
+    })
+  }
+}
+
+
+//
+// API UTILITIES
+//
+
+function apiGetDraft() {
+  return fetch('/en-gb/case-study/draft', {
+    method: 'GET',
+    credentials: "same-origin",
+    headers: {
+        "X-CSRFToken": jQuery("[name=csrfmiddlewaretoken]").val(),
+    }
+  })
+}
+
+function apiPutDraft(formSaver) {
+  if (!formSaver) {
+    throw new Error("apiPutDraft: parameter not provided")
+  }
+
+  return fetch('/en-gb/case-study/draft', {
       method: 'PUT',
       credentials: "same-origin",
       headers: {
@@ -276,9 +365,69 @@ function initDrafts() {
           "Accept": "application/json",
           "Content-Type": "application/json"
       },
-      body: JSON.stringify({ data: s.form, version: 1 })
-    }).then(response => {
-      console.log(response);
+      body: JSON.stringify({ version: 1, data: formSaver.serialise() })
+    })
+}
+
+function apiDeleteDraft() {
+  return fetch('/en-gb/case-study/draft', {
+      method: 'DELETE',
+      credentials: "same-origin",
+      headers: {
+          "X-CSRFToken": jQuery("[name=csrfmiddlewaretoken]").val(),
+      }
+    })
+}
+
+
+//
+// GNARLY BITS TYING API & UI STUFF TOGETHER
+//
+
+function showDraftPrompt(formSaver, serialisedForm) {
+  let prompt = new DraftPrompt({
+    root: document.querySelector('.draftprompt'),
+    restoreFn: () => formSaver.deserialise(serialisedForm),
+    deleteFn: () => apiDeleteDraft().then(response => response.ok)
+  })
+}
+
+function initDrafts() {
+  var formSaver = new FormSaver({
+    formId: 'case-study-form',
+    except: [ 'csrfmiddlewaretoken' ]
+  })
+
+  // Get the previous draft, if any
+  apiGetDraft()
+    .then(response => response.json())
+    .then(json => {
+      // Handle the case where we didn't get a response
+      if (!json) return
+
+      if (json.version !== 1) {
+        throw new Error("Bad JSON response version")
+      }
+
+      showDraftPrompt(formSaver, json.data.form)
+    }).catch(err => {
+      console.error(err);
+    })
+
+  // Init the button controller
+  var button = new SaveButton(document.querySelector('.savebutton'))
+
+  // Dirty forms set up
+  $('#case-study-form').dirtyForms()
+  $('#case-study-form').on('dirty.dirtyforms', ev => {
+    button.switchStateUnsaved()
+  })
+
+  // Save button
+  button.element.button.addEventListener('click', evt => {
+    button.switchStateSaving()
+
+    apiPutDraft(formSaver).then(response => {
       if (response.ok) {
         button.switchStateSaveSuccess();
         $('#case-study-form').dirtyForms('setClean');
@@ -292,7 +441,7 @@ function initDrafts() {
   })
 
   document.forms['case-study-form'].addEventListener('submit', () => {
-    // We're submitting, so kosh the saved data
+    // XXX We're submitting, so kosh the saved data
   })
 }