viewer: optional user-defined markdown splash screen

GitHub: closes #284

7 files changed, 205 insertions, 18 deletions

diff --git a/viewer/ldgallery-viewer.7.md b/viewer/ldgallery-viewer.7.md
index 96070dc..5012e3b 100644
--- a/viewer/ldgallery-viewer.7.md
+++ b/viewer/ldgallery-viewer.7.md
@@ -96,6 +96,53 @@ An alternative viewer configuration file located in the viewer's directory can b
 without the ".json" extension, as a query parameter given before the page anchor;
 for example, some alternative configuration named "config_2.json" can be loaded with "http://gallery/?config_2#".
 
+splashScreen
+: Displays an information notice before opening the gallery (see below).
+
+
+# SPLASH SCREEN CONFIGURATION
+
+splashScreen.resource
+: Absolute or relative path to the information notice. The user is prompted to explicitly acknowledge such notice before being allowed to browse the gallery.
+  Rich text formatting is possible through the use of the [GitHub Flavoured Markdown syntax][GFM].
+  Inline HTML and CSS are also supported.
+
+splashScreen.dontshowagainUID
+: Optional unique ID; when set, the information notice will appear only the first time it is proposed to the user. To display the notice again, change this UID.
+  When left empty, the notice will appear every time.
+
+splashScreen.buttonAcknowledgeLabel
+: Optional label for the acknowledge button shown below the notice.
+  *Defaults to "Acknowledge"*
+
+splashScreen.style
+: Optional CSS attributes for the information notice's container.
+  String or JSON formats are supported.
+
+  [GFM]: https://github.github.com/gfm/
+
+# CONFIGURATION EXAMPLE
+
+Viewer __config.json__:
+
+```json
+{
+  "galleryRoot": "./gallery/",
+  "galleryIndex": "index.json",
+  "initialItemSort": "date_desc",
+  "initialTagDisplayLimit": 10,
+  "splashScreen": {
+    "resource": "./splashscreen.md",
+    "dontshowagainUID": "v001",
+    "buttonAcknowledgeLabel": "I agree",
+    "style": {
+      "max-width": "45em",
+      "font-size": "20px",
+      "padding-top": "20vh"
+    }
+  }
+}
+```
 
 # PROGRESSIVE WEB APPLICATION
 
diff --git a/viewer/src/@types/gallery.d.ts b/viewer/src/@types/gallery.d.ts
index d9e7534..9011f19 100644
--- a/viewer/src/@types/gallery.d.ts
+++ b/viewer/src/@types/gallery.d.ts
@@ -18,6 +18,7 @@
 */
 
 import { ItemType } from "./ItemType";
+import { SplashScreenConfig } from "./splashscreen";
 
 export type ItemSortStr = "title_asc" | "date_asc" | "date_desc";
 
@@ -26,6 +27,7 @@ export interface Config {
   galleryIndex?: string;
   initialItemSort?: ItemSortStr;
   initialTagDisplayLimit?: number;
+  splashScreen?: SplashScreenConfig;
 }
 
 export interface Properties {
diff --git a/viewer/src/@types/splashscreen.d.ts b/viewer/src/@types/splashscreen.d.ts
new file mode 100644
index 0000000..bd79f80
--- /dev/null
+++ b/viewer/src/@types/splashscreen.d.ts
@@ -0,0 +1,25 @@
+/* ldgallery - A static generator which turns a collection of tagged
+--             pictures into a searchable web gallery.
+--
+-- Copyright (C) 2019-2021  Guillaume FOUET
+--
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU Affero General Public License as
+-- published by the Free Software Foundation, either version 3 of the
+-- License, or (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU Affero General Public License for more details.
+--
+-- You should have received a copy of the GNU Affero General Public License
+-- along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+export interface SplashScreenConfig {
+  resource?: string;
+  dontshowagainUID?: string;
+  buttonAcknowledgeLabel?: string;
+  style?: any;
+}
diff --git a/viewer/src/locales/en.json b/viewer/src/locales/en.json
index b21262a..d0a7a26 100644
--- a/viewer/src/locales/en.json
+++ b/viewer/src/locales/en.json
@@ -14,6 +14,8 @@
   "panelLeft.propositions": "Related filters",
   "panelLeft.propositions.other": "other filters",
   "search.no-result-fmt": "No result<br>({0} match in other folders) | No result<br>({0} matches in other folders)",
+  "snack.retry": "Retry",
+  "splashScreen.button.acknowledge": "Acknowledge",
   "tag-propositions.addition": "Include all items with this tag",
   "tag-propositions.intersection": "Search for this tag",
   "tag-propositions.item-count": "Item count",
diff --git a/viewer/src/store/uiStore.ts b/viewer/src/store/uiStore.ts
index f5bb898..2c45136 100644
--- a/viewer/src/store/uiStore.ts
+++ b/viewer/src/store/uiStore.ts
@@ -18,6 +18,7 @@
 */
 
 import { Config } from "@/@types/gallery";
+import { SplashScreenConfig } from "@/@types/splashscreen";
 import ItemComparators, { ItemSort } from "@/services/itemComparators";
 import { action, createModule, mutation } from "vuex-class-component";
 
@@ -26,12 +27,17 @@ const VuexModule = createModule({
   strict: true,
 });
 
+const STORAGE_SPLASHSCREEN_VALIDATION = "splashScreenValidation";
+
 export default class UIStore extends VuexModule {
   fullscreen: boolean = false;
   fullWidth: boolean = window.innerWidth < Number(process.env.VUE_APP_FULLWIDTH_LIMIT);
   searchMode: boolean = false;
   sort: ItemSort = ItemComparators.DEFAULT;
 
+  splashScreenConfig: SplashScreenConfig | null = null;
+  splashScreenEnabled: boolean = false;
+
   // ---
 
   @mutation toggleFullscreen(value?: boolean) {
@@ -50,11 +56,34 @@ export default class UIStore extends VuexModule {
     this.sort = sort;
   }
 
+  @mutation setSplashScreenConfig(splashScreenConfig: SplashScreenConfig) {
+    this.splashScreenConfig = splashScreenConfig;
+  }
+
+  @mutation setSplashScreenEnabled(enabled: boolean) {
+    this.splashScreenEnabled = enabled;
+  }
+
+  // ---
+
   @action async initFromConfig(config: Config) {
     if (config.initialItemSort) {
       const itemSort = ItemComparators.ITEM_SORTS[config.initialItemSort];
       if (itemSort) this.setSort(itemSort);
       else throw new Error("Unknown sort type: " + config.initialItemSort);
     }
+    if (config.splashScreen) {
+      this.setSplashScreenConfig(config.splashScreen);
+      const uid = config.splashScreen.dontshowagainUID;
+      this.setSplashScreenEnabled(!uid || localStorage.getItem(STORAGE_SPLASHSCREEN_VALIDATION) !== uid);
+    }
+  }
+
+  // ---
+
+  @action async validateSpashScreen() {
+    this.setSplashScreenEnabled(false);
+    const uid = this.splashScreenConfig?.dontshowagainUID;
+    if (uid) localStorage.setItem(STORAGE_SPLASHSCREEN_VALIDATION, String(uid));
   }
 }
diff --git a/viewer/src/views/MainLayout.vue b/viewer/src/views/MainLayout.vue
index c54f183..2347ba7 100644
--- a/viewer/src/views/MainLayout.vue
+++ b/viewer/src/views/MainLayout.vue
@@ -22,14 +22,13 @@
     <ld-title :gallery-title="$galleryStore.galleryTitle" :current-item="$galleryStore.currentItem" />
     <PanelTop v-if="isReady" :class="[$style.layout, $style.layoutTop]" />
     <PanelLeft v-if="isReady" :class="[$style.layout, $style.layoutLeft]" />
-    <router-view
-      v-if="!isLoading"
-      ref="content"
-      :class="[$style.layout, $style.layoutContent]"
-      class="scrollbar"
-      tabindex="01"
+    <b-loading v-if="isLoading" active />
+    <SplashScreen
+      v-else-if="$uiStore.splashScreenEnabled"
+      :class="$style.layout"
+      @validation="$uiStore.validateSpashScreen()"
     />
-    <b-loading :active="isLoading" is-full-page />
+    <router-view v-else ref="content" :class="[$style.layout, $style.layoutContent]" class="scrollbar" tabindex="01" />
     <ld-key-press :keycode="27" @action="$uiStore.toggleFullscreen(false)" />
   </div>
 </template>
@@ -40,18 +39,32 @@ import { Component, Ref, Vue, Watch } from "vue-property-decorator";