Added args modifier dialog to custom args input in the subscribe dialog

src/app/dialogs/subscribe-dialog/subscribe-dialog.component.html

@@ -43,9 +43,10 @@
                     <mat-checkbox [disabled]="audioOnlyMode" [(ngModel)]="streamingOnlyMode"><ng-container i18n="Streaming-only mode">Streaming-only mode</ng-container></mat-checkbox>
                 </div>
             </div>
-            <div class="col-12 mb-2">
+            <div class="col-12 mb-3">
                 <mat-form-field color="accent">
                     <input [(ngModel)]="customArgs" matInput placeholder="Custom args" i18n-placeholder="Subscription custom args placeholder">
+                    <button class="args-edit-button" (click)="openArgsModifierDialog()" mat-icon-button><mat-icon>edit</mat-icon></button>
                     <mat-hint>
                         <ng-container i18n="Custom args hint">These are added after the standard args.</ng-container>
                     </mat-hint>

src/app/dialogs/subscribe-dialog/subscribe-dialog.component.scss

@@ -6,3 +6,8 @@
 .mat-spinner {
     margin-left: 5%;
 }
+
+.args-edit-button {
+    position: absolute;
+    margin-left: 10px;
+}

src/app/dialogs/subscribe-dialog/subscribe-dialog.component.ts

@@ -1,7 +1,8 @@
 import { Component, OnInit } from '@angular/core';
-import { MatDialogRef } from '@angular/material/dialog';
+import { MatDialogRef, MatDialog } from '@angular/material/dialog';
 import { MatSnackBar } from '@angular/material/snack-bar';
 import { PostsService } from 'app/posts.services';
+import { ArgModifierDialogComponent } from '../arg-modifier-dialog/arg-modifier-dialog.component';
 
 @Component({
   selector: 'app-subscribe-dialog',
@@ -25,8 +26,8 @@ export class SubscribeDialogComponent implements OnInit {
   // audio only mode
   audioOnlyMode = false;
 
-  customFileOutput = null;
-  customArgs = null;
+  customFileOutput = '';
+  customArgs = '';
 
   time_units = [
     'day',
@@ -37,6 +38,7 @@ export class SubscribeDialogComponent implements OnInit {
 
   constructor(private postsService: PostsService,
               private snackBar: MatSnackBar,
+              private dialog: MatDialog,
               public dialogRef: MatDialogRef<SubscribeDialogComponent>) { }
 
   ngOnInit() {
@@ -70,6 +72,20 @@ export class SubscribeDialogComponent implements OnInit {
     }
   }
 
+  // modify custom args
+  openArgsModifierDialog() {
+    const dialogRef = this.dialog.open(ArgModifierDialogComponent, {
+      data: {
+       initial_args: this.customArgs
+      }
+    });
+    dialogRef.afterClosed().subscribe(new_args => {
+      if (new_args !== null && new_args !== undefined) {
+        this.customArgs = new_args;
+      }
+    });
+  }
+
   public openSnackBar(message: string, action = '') {
     this.snackBar.open(message, action, {
       duration: 2000,