From 934651ee8acdcb9b97618314618ccaa0a86ca52e Mon Sep 17 00:00:00 2001
From: Adam DeHaven <adam.dehaven@konghq.com>
Date: Sat, 6 Jan 2024 21:02:43 -0500
Subject: [PATCH] feat: download document

---
 README.md                     |  30 +++++++--
 sandbox/App.vue               |   1 +
 src/components/MarkdownUi.vue | 121 ++++++++++++++++++++++++++--------
 3 files changed, 120 insertions(+), 32 deletions(-)

diff --git a/README.md b/README.md
index cf7bc0dc..57be2d13 100644
--- a/README.md
+++ b/README.md
@@ -73,6 +73,20 @@ In order to utilize the `edit`, `split`, and `preview` modes, this `editable` pr
 > [!NOTE]
 > If the `editable` prop is set to `false`, it will override the `mode` and force into read-only mode.
 
+#### `downloadable`
+
+- type: `Boolean`
+- default: `false`
+
+Is the user allowed to download the document. Defaults to `false`.
+
+#### `filename`
+
+- type: `String`
+- default: `'document'`
+
+The markdown document filename used when downloaded.
+
 #### `mode`
 
 - type: `'read' | 'edit' | 'split' | 'preview'`
@@ -184,17 +198,23 @@ A slot for providing a custom element (i.e. `button`) that enables the `Edit` mo
 
 When the `edit` button (native, or custom) is clicked, the component will automatically determine whether to enable `edit` or `split` mode based on the browser's viewport width. On larger screens, the editor will launch in `split` mode.
 
+#### `download`
+
+A slot for providing a custom element (i.e. `button`) that triggers the `Download` functionality within the component. The slot exposes the `download` method to trigger the built-in function.
+
+When the `download` button (native, or custom) is clicked, the component will download the document to the user's computer.
+
 > [!NOTE]
-> The `editable` prop must be set to `true` to enable this slot.
+> The `downloadable` prop must be set to `true` to enable this slot.
 
 ```html
 <MarkdownUi
   v-model="content"
-  editable
+  downloadable
 >
-  <template #edit="{ edit }">
-    <!-- Call the provided `edit` method when custom button is clicked -->
-    <button @click="edit">Custom edit button</button>
+  <template #download="{ download }">
+    <!-- Call the provided `download` method when custom button is clicked -->
+    <button @click="download">Download the doc</button>
   </template>
 </MarkdownUi>
 ```
diff --git a/sandbox/App.vue b/sandbox/App.vue
index 2569fa97..0c7d91a1 100644
--- a/sandbox/App.vue
+++ b/sandbox/App.vue
@@ -6,6 +6,7 @@
       <p>Mollitia aspernatur itaque mollitia suscipit adipisci consectetur error quis. Pariatur et magni mollitia quia. Ut sit quos.</p>
       <MarkdownUi
         v-model="content"
+        downloadable
         :editable="editable"
         mode="split"
         @cancel="cancelEdit"
diff --git a/src/components/MarkdownUi.vue b/src/components/MarkdownUi.vue
index 12620c31..87d438b1 100644
--- a/src/components/MarkdownUi.vue
+++ b/src/components/MarkdownUi.vue
@@ -80,29 +80,55 @@
           class="markdown-content-container"
           data-testid="markdown-content-container"
         >
-          <div
-            v-if="editable && currentMode === 'read'"
-            class="edit-button"
-          >
-            <slot
-              :edit="edit"
-              name="edit"
+          <div class="content-buttons">
+            <div
+              v-if="currentMode === 'read' && downloadable"
+              class="download-button"
+            >
+              <slot
+                :download="download"
+                name="download"
+              >
+                <ToolbarButton
+                  appearance="primary"
+                  aria-label="Download markdown document"
+                  data-testid="download"
+                  :icon="false"
+                  :tabindex="0"
+                  @click="download"
+                >
+                  <ArrowDownIcon
+                    decorative
+                    :size="KUI_ICON_SIZE_30"
+                  />
+                  Download
+                </ToolbarButton>
+              </slot>
+            </div>
+            <div
+              v-if="currentMode === 'read' && editable"
+              class="edit-button"
             >
-              <ToolbarButton
-                appearance="primary"
-                aria-label="Edit markdown document"
-                data-testid="edit"
-                :icon="false"
-                :tabindex="0"
-                @click="edit"
+              <slot
+                :edit="edit"
+                name="edit"
               >
-                <EditIcon
-                  decorative
-                  :size="KUI_ICON_SIZE_30"
-                />
-                Edit
-              </ToolbarButton>
-            </slot>
+                <ToolbarButton
+                  appearance="primary"
+                  aria-label="Edit markdown document"
+                  data-testid="edit"
+                  :icon="false"
+                  :tabindex="0"
+                  @click="edit"
+                >
+                  <EditIcon
+                    decorative
+                    :size="KUI_ICON_SIZE_30"
+                  />
+                  Edit
+                </ToolbarButton>
+              </slot>
+            </div>
           </div>
           <MarkdownContent
             :class="{ 'html-preview': htmlPreview }"
@@ -128,7 +154,7 @@ import { v4 as uuidv4 } from 'uuid'
 import type { MarkdownMode, InlineFormat, MarkdownTemplate, TextAreaInputEvent, Theme } from '@/types'
 import formatHtml from 'html-format'
 import { KUI_FONT_FAMILY_TEXT, KUI_FONT_FAMILY_CODE, KUI_SPACE_60, KUI_BREAKPOINT_PHABLET, KUI_ICON_SIZE_30 } from '@kong/design-tokens'
-import { EditIcon } from '@kong/icons'
+import { EditIcon, ArrowDownIcon } from '@kong/icons'
 import MermaidJs from 'mermaid'
 
 const props = defineProps({
@@ -142,6 +168,16 @@ const props = defineProps({
     type: Boolean,
     default: false,
   },
+  /** Is the markdown document able to be edited by the user. Defaults to `false`. */
+  downloadable: {
+    type: Boolean,
+    default: false,
+  },
+  /** The markdown document filename used when downloaded. */
+  filename: {
+    type: String,
+    default: 'document',
+  },
   /** The mode used when the component initializes, one of 'read', 'edit', 'split', 'preview' */
   mode: {
     type: String as PropType<MarkdownMode>,
@@ -287,13 +323,13 @@ const insertTemplate = (template: MarkdownTemplate): void => {
 const htmlPreview = ref<boolean>(false)
 
 // If the htmlPreview is enabled, pass the generated HTML through the markdown renderer and output the syntax-highlighted result
-watchEffect(() => {
+watchEffect((): void => {
   if (htmlPreview.value) {
     markdownPreviewHtml.value = md.value?.render('```html' + NEW_LINE_CHARACTER + formatHtml(markdownHtml.value, ' '.repeat(tabSize.value)) + NEW_LINE_CHARACTER + '```')
   }
 })
 
-const updateMermaid = async () => {
+const updateMermaid = async (): Promise<void> => {
   if (props.mermaid) {
     // Scope the query selector to this instance of the markdown component (unique container id)
     const mermaidNodes = `#${componentContainerId.value} .markdown-content-container .mermaid`
@@ -306,6 +342,33 @@ const updateMermaid = async () => {
   }
 }
 
+const download = (): void => {
+  try {
+    const blob = new Blob([rawMarkdown.value], { type: 'text/markdown;charset=utf-8' })
+    const data = URL.createObjectURL(blob)
+    const link = document.createElement('a')
+    link.href = data
+    link.download = `${props.filename.replace(/(\.md)+$/g, '')}.md`
+
+    // link.click() doesn't work in Firefox
+    link.dispatchEvent(
+      new MouseEvent('click', {
+        bubbles: true,
+        cancelable: true,
+        view: window,
+      }),
+    )
+    // For Firefox it is necessary to delay revoking the ObjectURL
+    setTimeout(() => {
+      window.URL.revokeObjectURL(data)
+      link.remove()
+    }, 100)
+
+  } catch (err) {
+    console.warn('download', err)
+  }
+}
+
 // When the textarea `input` event is triggered, or "faked" by other editor methods, update the Vue refs and rendered markdown
 const onContentEdit = (event: TextAreaInputEvent, emitEvent = true): void => {
   // Update the ref immediately
@@ -601,10 +664,14 @@ const markdownPanesMaxHeight = computed((): string => `${props.maxHeight}px`)
     box-sizing: border-box; // Ensure the padding is calculated in the element's width
     position: relative;
 
-    .edit-button {
+    .content-buttons {
+      align-items: center;
+      display: flex;
+      gap: var(--kui-space-20, $kui-space-20);
+      justify-content: flex-end;
       position: absolute;
-      right: 4px;
-      top: 4px;
+      right: 6px;
+      top: 6px;
     }
   }