Add maximized mode to markdown-textarea + CSS improvements (#2660)

* Add arrows-angle-contract/expand bootstrap icons

* Add grey textarea-background-color

* Add maximized support to markdown-textarea + improve column display

* Refactor CSS + add ResizeObservable

* Replace bootstrap icons with softies

* Add ResizeObserver typing definition

* Add focus on textarea + Fix Observables

* Propage component changes on markdown plugins

* Ignore ResizeObserver not implemented in typescript yet

* Move observers from constructor to click event

* Add scss and css variables

* Replace textareaWidth with textareaMaxWidth to fix others textareas

* Clean unused css rules

* Fix ResizeObserver unknown by TypeScript compiler

* Set max-width: 100% for small and mobile views

* Fix textarea/preview height on maximized mode

* Add common padding textarea/preview side-by-side

* Hide scrollbar sub-menu on small-views

* Add maximized mode for mobile views

* Fix sass calculate syntax

* Revert custom CSS variable for inputBorderRadius and inputBorderColor

* Remove unsued methods

* Fix missing implement method

Co-authored-by: kimsible <kimsible@users.noreply.github.com>

3 files changed, 266 insertions, 31 deletions

diff --git a/client/src/app/shared/forms/markdown-textarea.component.html b/client/src/app/shared/forms/markdown-textarea.component.html
index 3cadb3619..a519f3e0a 100644
--- a/client/src/app/shared/forms/markdown-textarea.component.html
+++ b/client/src/app/shared/forms/markdown-textarea.component.html
@@ -1,12 +1,12 @@
-<div class="root" [ngStyle]="{ 'flex-direction': flexDirection }">
-  <textarea
+<div class="root" [ngClass]="{ 'maximized': isMaximized }" [ngStyle]="{ 'max-width': textareaMaxWidth }">
+  <textarea #textarea
     [(ngModel)]="content" (ngModelChange)="onModelChange()"
     class="form-control" [ngClass]="classes"
-    [ngStyle]="{ width: textareaWidth, height: textareaHeight, 'margin-right': textareaMarginRight }"
+    [ngStyle]="{ height: textareaHeight }"
     [id]="name" [name]="name">
   </textarea>
 
-  <div ngbNav #nav="ngbNav" class="nav-pills previews">
+  <div ngbNav #nav="ngbNav" class="nav-pills nav-preview">
     <ng-container ngbNavItem *ngIf="truncate !== undefined">
       <a ngbNavLink i18n>Truncated preview</a>
 
@@ -22,6 +22,14 @@
         <div [innerHTML]="previewHTML"></div>
       </ng-template>
     </ng-container>
+
+    <my-button
+      *ngIf="!isMaximized" icon="fullscreen" (click)="onMaximizeClick()"
+    ></my-button>
+
+    <my-button
+      *ngIf="isMaximized" icon="exit-fullscreen" (click)="onMaximizeClick()"
+    ></my-button>
   </div>
 
   <div [ngbNavOutlet]="nav"></div>
diff --git a/client/src/app/shared/forms/markdown-textarea.component.scss b/client/src/app/shared/forms/markdown-textarea.component.scss
index bd02343de..065cd2dec 100644
--- a/client/src/app/shared/forms/markdown-textarea.component.scss
+++ b/client/src/app/shared/forms/markdown-textarea.component.scss
@@ -1,36 +1,250 @@
 @import '_variables';
 @import '_mixins';
 
-.root {
-  display: flex;
+$nav-preview-tab-height: 30px;
+$base-padding: 15px;
+$input-border-color: #C6C6C6;
+$input-border-radius: 3px;
+
+@mixin in-small-view {
+  .root {
+    display: flex;
+    flex-direction: column;
+
+    textarea {
+      @include peertube-textarea(100%, 150px);
+
+      background-color: var(--textareaBackgroundColor);
+      font-family: courier, monospace;
+      font-size: 13px;
+      border-bottom: none;
+      border-bottom-left-radius: unset;
+      border-bottom-right-radius: unset;
+    }
 
-  textarea {
-    @include peertube-textarea(100%, 150px);
+    .nav-preview {
+      display: block;
+      text-align: right;
+      padding-top: 10px;
+      padding-bottom: 10px;
+      padding-left: 10px;
+      padding-right: 10px;
+      border-top: 1px dashed $input-border-color;
+      border-left: 1px solid $input-border-color;
+      border-right: 1px solid $input-border-color;
+      border-bottom: 1px solid $input-border-color;
+      border-bottom-right-radius: $input-border-radius;
 
-    margin-bottom: 15px;
+      border-bottom-left-radius: $input-border-radius;
+      ::ng-deep {
+        .nav-link {
+          display: none !important;
+        }
+
+        .grey-button {
+          padding: 0 12px 0 12px;
+        }
+      }
+    }
+
+    ::ng-deep {
+      .tab-content {
+        display: none;
+      }
+    }
   }
+}
+
+@mixin nav-preview-medium {
+  display: flex;
+  flex-grow: 1;
+  border-bottom-left-radius: unset;
+  border-bottom-right-radius: unset;
+  border-bottom: 2px solid var(--mainColor);
 
-  .previews {
-    max-height: 150px;
-    overflow-y: auto;
-    flex-grow: 1;
+  :first-child {
+    margin-left: auto;
   }
 
   ::ng-deep {
     .nav-link {
       display: flex !important;
       align-items: center;
-      height: 30px !important;
+      height: $nav-preview-tab-height !important;
       padding: 0 15px !important;
       font-size: 85% !important;
       opacity: .7;
     }
 
-    .tab-content {
-      min-height: 75px;
-      padding: 15px;
-      font-size: 15px;
-      word-wrap: break-word;
+    .grey-button {
+      margin-left: 5px;
+    }
+  }
+}
+
+@mixin content-preview-base {
+  display: block;
+  min-height: 75px;
+  padding: $base-padding;
+  overflow-y: auto;
+  font-size: 15px;
+  word-wrap: break-word;
+}
+
+@mixin maximized-base {
+  flex-direction: row;
+  z-index: #{z(header) - 1};
+  position: fixed;
+  top: $header-height;
+  left: $menu-width;
+  max-height: none !important;
+  max-width: none !important;
+  width: calc(100% - #{$menu-width});
+  height: calc(100vh - #{$header-height}) !important;
+
+  $nav-preview-vertical-padding: 40px;
+
+  .nav-preview {
+    @include nav-preview-medium();
+    padding-top: #{$nav-preview-vertical-padding / 2};
+    padding-bottom: #{$nav-preview-vertical-padding / 2};
+    padding-left: 0px;
+    padding-right: 0px;
+    position: absolute;
+    background-color: var(--mainBackgroundColor);
+    width: 100% !important;
+    border-top: none;
+    border-left: none;
+    border-right: none;
+
+    :last-child {
+      margin-right: $not-expanded-horizontal-margins;
+    }
+  }
+
+  ::ng-deep .tab-content {
+    @include content-preview-base();
+    background-color: var(--mainBackgroundColor);
+    scrollbar-color: var(--actionButtonColor) var(--mainBackgroundColor);
+  }
+
+  textarea,
+  ::ng-deep .tab-content {
+    max-height: none !important;
+    max-width: none !important;
+    margin-top: #{$nav-preview-tab-height + $nav-preview-vertical-padding} !important;
+    height: calc(100vh - #{$header-height + $nav-preview-tab-height + $nav-preview-vertical-padding}) !important;
+    width: 50% !important;
+    border: none !important;
+    border-radius: unset !important;
+  }
+
+  :host-context(.expanded) {
+    .root.maximized {
+      left: 0;
+      width: 100%;
+    }
+  }
+}
+
+@mixin maximized-in-small-view {
+  .root.maximized {
+    @include maximized-base();
+
+    textarea {
+      display: none;
     }
+
+    ::ng-deep .tab-content {
+      width: 100% !important;
+    }
+  }
+}
+
+@mixin maximized-tabs-in-mobile-view {
+  // Ellipsis on tabs for mobile view
+  .root.maximized {
+    .nav-preview {
+      ::ng-deep .nav-link {
+        @include ellipsis();
+
+        display: block !important;
+        max-width: 45% !important;
+        padding: 5px 0 !important;
+        margin-right: 10px !important;
+        text-align: center;
+
+        &:not(.active) {
+          max-width: 15% !important;
+        }
+
+        &.active {
+          padding: 5px 15px !important;
+        }
+      }
+    }
+  }
+}
+
+@mixin in-medium-view {
+  .root {
+    .nav-preview {
+      @include nav-preview-medium();
+    }
+
+    ::ng-deep .tab-content {
+      @include content-preview-base();
+      max-height: 210px;
+      border-bottom: 1px solid $input-border-color;
+      border-left: 1px solid $input-border-color;
+      border-right: 1px solid $input-border-color;
+      border-bottom-left-radius: $input-border-radius;
+      border-bottom-right-radius: $input-border-radius;
+    }
+  }
+}
+
+@mixin maximized-in-medium-view {
+  .root.maximized {
+    @include maximized-base();
+
+    textarea {
+      display: block;
+      padding: $base-padding;
+      border-right: 1px dashed $input-border-color !important;
+      resize: none;
+      scrollbar-color: var(--actionButtonColor) var(--textareaBackgroundColor);
+
+      &:focus {
+        box-shadow: none;
+      }
+    }
+  }
+}
+
+@include in-small-view();
+@include maximized-in-small-view();
+
+@media only screen and (max-width: $mobile-view) {
+  @include maximized-tabs-in-mobile-view();
+}
+
+@media only screen and (max-width: #{$mobile-view + $menu-width}) {
+  :host-context(.main-col:not(.expanded)) {
+    @include maximized-tabs-in-mobile-view();
+  }
+}
+
+@media only screen and (min-width: $small-view) {
+  :host-context(.expanded) {
+    @include in-medium-view();
+  }
+
+  @include maximized-in-medium-view();
+}
+
+@media only screen and (min-width: #{$small-view + $menu-width}) {
+  :host-context(.main-col:not(.expanded)) {
+    @include in-medium-view();
   }
 }
diff --git a/client/src/app/shared/forms/markdown-textarea.component.ts b/client/src/app/shared/forms/markdown-textarea.component.ts
index cbcfdfe78..dde7b4d98 100644
--- a/client/src/app/shared/forms/markdown-textarea.component.ts
+++ b/client/src/app/shared/forms/markdown-textarea.component.ts
@@ -1,5 +1,5 @@
 import { debounceTime, distinctUntilChanged } from 'rxjs/operators'
-import { Component, forwardRef, Input, OnInit } from '@angular/core'
+import { Component, forwardRef, Input, OnInit, ViewChild, ElementRef } from '@angular/core'
 import { ControlValueAccessor, NG_VALUE_ACCESSOR } from '@angular/forms'
 import { Subject } from 'rxjs'
 import truncate from 'lodash-es/truncate'
@@ -22,18 +22,18 @@ import { MarkdownService } from '@app/shared/renderer'
 export class MarkdownTextareaComponent implements ControlValueAccessor, OnInit {
   @Input() content = ''
   @Input() classes: string[] | { [klass: string]: any[] | any } = []
-  @Input() textareaWidth = '100%'
+  @Input() textareaMaxWidth = '100%'
   @Input() textareaHeight = '150px'
-  @Input() previewColumn = false
   @Input() truncate: number
   @Input() markdownType: 'text' | 'enhanced' = 'text'
   @Input() markdownVideo = false
   @Input() name = 'description'
 
-  textareaMarginRight = '0'
-  flexDirection = 'column'
+  @ViewChild('textarea') textareaElement: ElementRef
+
   truncatedPreviewHTML = ''
   previewHTML = ''
+  isMaximized = false
 
   private contentChanged = new Subject<string>()
 
@@ -51,11 +51,6 @@ export class MarkdownTextareaComponent implements ControlValueAccessor, OnInit {
         .subscribe(() => this.updatePreviews())
 
     this.contentChanged.next(this.content)
-
-    if (this.previewColumn) {
-      this.flexDirection = 'row'
-      this.textareaMarginRight = '15px'
-    }
   }
 
   propagateChange = (_: any) => { /* empty */ }
@@ -80,8 +75,26 @@ export class MarkdownTextareaComponent implements ControlValueAccessor, OnInit {
     this.contentChanged.next(this.content)
   }
 
-  arePreviewsDisplayed () {
-    return this.screenService.isInSmallView() === false
+  onMaximizeClick () {
+    this.isMaximized = !this.isMaximized
+
+    // Make sure textarea have the focus
+    this.textareaElement.nativeElement.focus()
+
+    // Make sure the window has no scrollbars
+    if (!this.isMaximized) {
+      this.unlockBodyScroll()
+    } else {
+      this.lockBodyScroll()
+    }
+  }
+
+  private lockBodyScroll () {
+    document.getElementById('content').classList.add('lock-scroll')
+  }
+
+  private unlockBodyScroll () {
+    document.getElementById('content').classList.remove('lock-scroll')
   }
 
   private async updatePreviews () {