feat: add new global state service

src/app/projects/states/index/global-state.service.ts

@@ -1,20 +1,85 @@
-import { Injectable } from '@angular/core';
-import { Observable, Observer, Subject } from 'rxjs';
+import { Inject, Injectable } from '@angular/core';
+import { ReplaySubject } from 'rxjs';
+import { projectService, unitService } from 'src/app/ajs-upgraded-providers';
 
+export class DoubtfireViewState {
+  public EntityObject: any; // Unit | Project | undefined
+  public EntityType: 'unit' | 'project' | 'other' = 'other';
+}
+
+export enum ViewType {
+  UNIT = 'UNIT',
+  PROJECT = 'PROJECT',
+  OTHER = 'OTHER',
+}
 @Injectable({
   providedIn: 'root',
 })
+/**
+ * The global state for the current user. This uses replay subjects, which acts as subjects, but allow
+ * for subscribers to request the previously emitted value.
+ *
+ * This maintains two sets of values:
+ * - Units taught and subjects studied
+ * - Current view and selected entity
+ */
 export class GlobalStateService {
-  public unitRole: Subject<any> = new Subject<any>();
-  public project: Subject<any> = new Subject<any>();
+  /**
+   * The current view and entity, indicating what kind of page is being shown.
+   */
+  public currentViewAndEntitySubject: ReplaySubject<{ viewType: ViewType; entity: {} }> = new ReplaySubject<{
+    viewType: ViewType;
+    entity: {};
+  }>();
+
+  /**
+   * A Unit Role for when a tutor is viewing a Project.
+   */
+  public unitRoleSubject: ReplaySubject<any> = new ReplaySubject<any>();
+
+  /**
+   * The list of all of the units taught by the current user
+   */
+  public unitRolesSubject: ReplaySubject<any> = new ReplaySubject<any>();
 
-  constructor() {}
+  /**
+   * The list of all of the units studied by the current user
+   */
+  public projectsSubject: ReplaySubject<any> = new ReplaySubject<any>();
+
+  constructor(
+    @Inject(unitService) private UnitService: any,
+    @Inject(projectService) private ProjectService: any
+  ) {
+    this.loadUnitsAndProjects();
+  }
+
+  /**
+   * Query the API for the units taught and studied by the current user.
+   */
+  public loadUnitsAndProjects() {
+    //TODO: Consider sequence here? Can we adjust to fail once.
+    this.UnitService.getUnitRoles((roles: any) => {
+      this.unitRolesSubject.next(roles);
+    });
+
+    this.ProjectService.getProjects(false, (projects: any) => {
+      this.projectsSubject.next(projects);
+    });
+  }
 
-  public setUnitRole(unitRole: any) {
-    this.unitRole.next(unitRole);
+  /**
+   * Clear all of the project and unit role data on sign out
+   */
+  public clearUnitsAndProjects() {
+    this.unitRolesSubject.next(null);
+    this.projectsSubject.next(null);
   }
 
-  public setProject(project: any) {
-    this.project.next(project);
+  /**
+   * Switch to a new view, and its associated entity object
+   */
+  public setView(kind: ViewType, entity?: any) {
+    this.currentViewAndEntitySubject.next({ viewType: kind, entity: entity });
   }
 }