Start offline support

src/app/service/api.service.ts

@@ -1,8 +1,11 @@
-import { Injectable } from '@angular/core';
-import { environment } from '../../environments/environment';
+import {Injectable} from '@angular/core';
+import {environment} from '../../environments/environment';
 import {HttpClient} from '@angular/common/http';
-import {Observable} from 'rxjs';
+import {BehaviorSubject, Observable} from 'rxjs';
 import ApiResponse from '../structures/ApiResponse';
+import {MenuItem} from './db/MenuItem';
+import {DatabaseService} from './db/database.service';
+import {ConnectionService} from 'ng-connection-service';
 
 @Injectable({
   providedIn: 'root'
@@ -11,10 +14,36 @@ export class ApiService {
   protected baseEndpoint: string = environment.backendBase;
   protected statUrl: string = environment.statUrl;
   protected versionUrl: string = environment.versionUrl;
+  protected offline = false;
+  public readonly offline$: BehaviorSubject<boolean> = new BehaviorSubject<boolean>(false);
+
+  get isOffline() {
+    return this.offline;
+  }
 
   constructor(
       protected http: HttpClient,
-  ) { }
+      protected db: DatabaseService,
+      protected connection: ConnectionService,
+  ) {
+    connection.monitor().subscribe(isConnected => {
+      if ( !isConnected ) {
+        this.makeOffline();
+      } else {
+        this.makeOnline(); // TODO add checks for server.
+      }
+    });
+  }
+
+  public makeOffline() {
+    this.offline = true;
+    this.offline$.next(true);
+  }
+
+  public makeOnline() {
+    this.offline = false;
+    this.offline$.next(false);
+  }
 
   public get(endpoint, params = {}): Observable<ApiResponse> {
     return this.request(endpoint, params, 'get');
@@ -29,14 +58,55 @@ export class ApiService {
   }
 
   public stat(): Observable<ApiResponse> {
-    return this._request(this.statUrl);
+    return new Observable<ApiResponse>(sub => {
+      (async () => {
+        const statKV = await this.db.getKeyValue('host_stat');
+
+        // If offline, look up the last stored stat for information
+        if ( this.isOffline ) {
+          if ( typeof statKV !== 'object' ) {
+            throw new Error('No locally stored host stat found.');
+          }
+
+          sub.next(new ApiResponse(statKV.data));
+          sub.complete();
+        }
+
+        // Otherwise, fetch the stat and cache it locally
+        this._request(this.statUrl).subscribe(apiResponse => {
+          statKV.data = {status: apiResponse.status, message: apiResponse.message, data: apiResponse.data};
+          statKV.save().then(() => {
+            sub.next(statKV.data);
+            sub.complete();
+          });
+        });
+      })();
+
+    });
   }
 
   public version(): Promise<string> {
-    return new Promise((res, rej) => {
+    return new Promise(async (res, rej) => {
+      const versionKV = await this.db.getKeyValue('app_version');
+
+      // If offline, look up the local app version.
+      if ( this.isOffline ) {
+        if ( versionKV ) {
+          return res(versionKV.data);
+        } else {
+          return rej(new Error('No local app version found.'));
+        }
+      }
+
+      // Otherwise, look up the app version and store it locally
       this._request(this.versionUrl).subscribe({
-        next: result => {
-          res(result.data.text.trim());
+        next: async result => {
+          const version = result.data.text.trim();
+
+          versionKV.data = version;
+          await versionKV.save();
+
+          res(version);
         },
         error: rej,
       });
@@ -76,4 +146,79 @@ export class ApiService {
 
     return `${this.baseEndpoint.endsWith('/') ? this.baseEndpoint.slice(0, -1) : this.baseEndpoint}${endpoint}`;
   }
+
+  public getMenuItems(): Promise<any[]> {
+    return new Promise(async (res, rej) => {
+      await this.db.createSchemata();
+
+      // If offline, fetch the menu from the database
+      if ( this.isOffline ) {
+        const items = await this.db.menuItems.toArray();
+        const nodes = MenuItem.inflateTree(items as MenuItem[]);
+        return res(nodes);
+      }
+
+      // Download the latest menu items
+      const tree: any[] = await new Promise(res2 => {
+        this.get('/menu/items').subscribe({
+          next: async result => {
+            const nodes = result.data as any[];
+            const items = MenuItem.deflateTree(nodes);
+
+            // Update the locally stored nodes
+            await this.db.menuItems.clear();
+            await Promise.all(items.map(item => item.save()));
+
+            res2(nodes);
+          },
+          error: rej,
+        });
+      });
+
+      res(tree);
+    });
+  }
+
+  public getSessionData(): Promise<any> {
+    return new Promise(async (res, rej) => {
+      const sessionKV = await this.db.getKeyValue('session_data');
+
+      // If offline, just return the locally cached session data
+      if ( this.isOffline ) {
+        if ( typeof sessionKV.data !== 'object' ) {
+          return rej(new Error('No locally cached session data found.'));
+        }
+
+        return res(sessionKV.data);
+      }
+
+      // Otherwise, fetch the session data from the server and cache it locally
+      this.get('/session').subscribe(async result => {
+        sessionKV.data = result.data;
+        await sessionKV.save();
+        res(sessionKV.data);
+      });
+    });
+  }
+
+  public saveSessionData(data: any): Promise<void> {
+    return new Promise(async (res, rej) => {
+      // Update the local session data
+      const sessionKV = await this.db.getKeyValue('session_data');
+      sessionKV.data = data;
+      await sessionKV.save();
+
+      // If we're not offline, then update the data on the server
+      if ( !this.isOffline ) {
+        await new Promise(res2 => {
+          this.post('/session', data || {}).subscribe({
+            next: res2,
+            error: rej,
+          });
+        });
+      }
+
+      res();
+    });
+  }
 }

src/app/service/db/KeyValue.ts

@@ -0,0 +1,65 @@
+import {Model} from './Model';
+
+export interface IKeyValue {
+    id?: number;
+    key: string;
+    value: string;
+    json: boolean;
+}
+
+export class KeyValue extends Model<IKeyValue> implements IKeyValue {
+    id?: number;
+    key: string;
+    value: string;
+    json: boolean;
+
+    public static getTableName() {
+        return 'keyValues';
+    }
+
+    public static getSchema() {
+        return '++id, key, value, json';
+    }
+
+    constructor(key: string, value: string, json: boolean, id?: number) {
+        super();
+
+        this.key = key;
+        this.value = value;
+        this.json = json;
+        if ( id ) {
+            this.id = id;
+        }
+    }
+
+    get data(): any {
+        if ( this.json ) {
+            return JSON.parse(this.value);
+        }
+
+        return this.value;
+    }
+
+    set data(val: any) {
+        if ( typeof val === 'string' ) {
+            this.json = false;
+            this.value = val;
+        } else {
+            this.json = true;
+            this.value = JSON.stringify(val);
+        }
+    }
+
+    public getSaveRecord(): any {
+        return {
+            ...(this.id ? { id: this.id } : {}),
+            key: this.key,
+            value: this.value,
+            json: this.json,
+        };
+    }
+
+    public getDatabase(): Dexie.Table<IKeyValue, number> {
+        return this.staticClass().dbService.table('keyValues') as Dexie.Table<IKeyValue, number>;
+    }
+}

src/app/service/db/MenuItem.ts

@@ -0,0 +1,171 @@
+import {Model} from './Model';
+import Dexie from 'dexie';
+
+export interface IMenuItem {
+    id?: number;
+    serverId: string;
+    name: string;
+    childIds?: string[];
+    noDelete?: boolean;
+    noChildren?: boolean;
+    virtual?: boolean;
+    type?: string;
+    shared?: boolean;
+    needsServerUpdate?: boolean;
+}
+
+export class MenuItem extends Model<IMenuItem> implements IMenuItem {
+    id?: number;
+    serverId: string;
+    name: string;
+    childIds?: string[];
+    noDelete?: boolean;
+    noChildren?: boolean;
+    virtual?: boolean;
+    type?: string;
+    shared?: boolean;
+    needsServerUpdate?: boolean;
+
+    public static getTableName() {
+        return 'menuItems';
+    }
+
+    public static getSchema() {
+        return '++id, serverId, name, childIds, noDelete, noChildren, virtual, type, shared, needsServerUpdate';
+    }
+
+    public static deflateTree(nodes: any[]): MenuItem[] {
+        let items = [];
+
+        for ( const node of nodes ) {
+            const childIds = node.children ? node.children.map(x => x.id) : [];
+            const item = new MenuItem(node.name, node.id, childIds, node.noDelete, node.noChildren, node.virtual, node.type, node.shared);
+
+            items.push(item);
+            if ( node.children ) {
+                items = items.concat(...this.deflateTree(node.children));
+            }
+        }
+
+        return items;
+    }
+
+    public static inflateTree(items: MenuItem[]) {
+        const serverIdXItems: { [key: string]: MenuItem[] } = {};
+
+        for ( const item of items ) {
+            if ( !serverIdXItems[item.serverId] ) {
+                serverIdXItems[item.serverId] = [];
+            }
+
+            serverIdXItems[item.serverId].push(item);
+        }
+
+        const inflateNode = (item, alreadyChildren = [], seen = []) => {
+            const node: any = item.getSaveRecord();
+            seen.push(item);
+            node.id = node.serverId;
+
+            node.children = [];
+            if ( item.childIds ) {
+                for ( const childId of item.childIds ) {
+                    if ( serverIdXItems[childId] ) {
+                        const children = serverIdXItems[childId].filter(x => {
+                            if ( x.type !== 'page' && item.serverId !== x.serverId ) {
+                                return false;
+                            }
+
+                            return x !== item && !alreadyChildren.includes(x) && !seen.includes(x);
+                        });
+
+                        node.children = node.children.concat(...children.map(x => inflateNode(x, children, seen)));
+                    }
+                }
+            }
+
+            const pageChildren = [];
+            const otherChildren = [];
+            for ( const child of node.children ) {
+                if ( child.type === 'page' ) {
+                    pageChildren.push(child);
+                } else {
+                    otherChildren.push(child);
+                }
+            }
+
+            node.children = [...otherChildren, ...pageChildren];
+            return node;
+        };
+
+        const topLevelItems = items.filter(x => String(x.serverId) === '0');
+        return topLevelItems.map(x => inflateNode(x));
+    }
+
+    constructor(
+        name: string,
+        serverId: string,
+        childIds?: string[],
+        noDelete?: boolean,
+        noChildren?: boolean,
+        virtual?: boolean,
+        type?: string,
+        shared?: boolean,
+        needsServerUpdate?: boolean,
+        id?: number
+    ) {
+        super();
+
+        this.name = name;
+        this.serverId = serverId;
+        if ( childIds ) {
+            this.childIds = childIds;
+        }
+
+        if ( typeof noDelete !== 'undefined' ) {
+            this.noDelete = noDelete;
+        }
+
+        if ( typeof noChildren !== 'undefined' ) {
+            this.noChildren = noChildren;
+        }
+
+        if ( typeof virtual !== 'undefined' ) {
+            this.virtual = virtual;
+        }
+
+        if ( type ) {
+            this.type = type;
+        }
+
+        if ( typeof shared !== 'undefined' ) {
+            this.shared = shared;
+        }
+
+        if ( typeof needsServerUpdate !== 'undefined' ) {
+            this.needsServerUpdate = needsServerUpdate;
+        }
+
+        if ( id ) {
+            this.id = id;
+        }
+    }
+
+    public getDatabase(): Dexie.Table<IMenuItem, number> {
+        return this.staticClass().dbService.table('menuItems') as Dexie.Table<IMenuItem, number>;
+    }
+
+    public getSaveRecord(): any {
+        return {
+            ...(this.id ? { id: this.id } : {}),
+            serverId: this.serverId,
+            name: this.name,
+            ...(typeof this.childIds !== 'undefined' ? { childIds: this.childIds } : {}),
+            ...(typeof this.noDelete !== 'undefined' ? { noDelete: this.noDelete } : {}),
+            ...(typeof this.noChildren !== 'undefined' ? { noChildren: this.noChildren } : {}),
+            ...(typeof this.virtual !== 'undefined' ? { virtual: this.virtual } : {}),
+            ...(typeof this.type !== 'undefined' ? { type: this.type } : {}),
+            ...(typeof this.shared !== 'undefined' ? { shared: this.shared } : {}),
+            ...(typeof this.needsServerUpdate !== 'undefined' ? { needsServerUpdate: this.needsServerUpdate } : {}),
+        };
+    }
+}

src/app/service/db/Migration.ts

@@ -0,0 +1,43 @@
+import {Model} from './Model';
+
+export interface IMigration {
+    id?: number;
+    uuid: string;
+    applied: boolean;
+}
+
+export class Migration extends Model<IMigration> implements IMigration {
+    id?: number;
+    uuid: string;
+    applied: boolean;
+
+    public static getTableName() {
+        return 'migrations';
+    }
+
+    public static getSchema() {
+        return '++id, uuid, applied';
+    }
+
+    constructor(uuid: string, applied: boolean, id?: number) {
+        super();
+
+        this.uuid = uuid;
+        this.applied = applied;
+        if ( id ) {
+            this.id = id;
+        }
+    }
+
+    public getSaveRecord(): any {
+        return {
+            ...(this.id ? { id: this.id } : {}),
+            uuid: this.uuid,
+            applied: this.applied,
+        };
+    }
+
+    public getDatabase(): Dexie.Table<IMigration, number> {
+        return this.staticClass().dbService.table('migrations') as Dexie.Table<IMigration, number>;
+    }
+}

src/app/service/db/Model.ts

@@ -0,0 +1,31 @@
+import Dexie from 'dexie';
+import {DatabaseService} from './database.service';
+
+export abstract class Model<InterfaceType> {
+    public static dbService?: DatabaseService;
+
+    public id?: number;
+
+    public static getSchema(): string {
+        throw new TypeError('Child class must implement.');
+    }
+
+    public static getTableName(): string {
+        throw new TypeError('Child class must implement.');
+    }
+
+    public abstract getDatabase(): Dexie.Table<InterfaceType, number>;
+    public abstract getSaveRecord(): any;
+
+    public staticClass() {
+        return (this.constructor as typeof Model);
+    }
+
+    public exists() {
+        return !!this.id;
+    }
+
+    public async save() {
+        this.id = await this.getDatabase().put(this.getSaveRecord());
+    }
+}

src/app/service/db/database.service.ts

@@ -0,0 +1,67 @@
+import { Injectable } from '@angular/core';
+import Dexie from 'dexie';
+import {IMigration, Migration} from './Migration';
+import {IMenuItem, MenuItem} from './MenuItem';
+import {KeyValue, IKeyValue} from './KeyValue';
+
+@Injectable({
+    providedIn: 'root'
+})
+export class DatabaseService extends Dexie {
+    protected static registeredModels = [Migration, MenuItem, KeyValue];
+    protected initialized = false;
+
+    migrations!: Dexie.Table<IMigration, number>;
+    menuItems!: Dexie.Table<IMenuItem, number>;
+    keyValues!: Dexie.Table<IKeyValue, number>;
+
+    constructor(
+    ) {
+        super('NodedLocalDatabase');
+    }
+
+    public async getKeyValue(key: string): Promise<KeyValue> {
+        const matches = await this.keyValues.where({ key }).toArray();
+
+        if ( matches.length > 0 ) {
+            return matches[0] as KeyValue;
+        }
+
+        return new KeyValue(key, '', false);
+    }
+
+    public async createSchemata() {
+        if ( this.initialized ) {
+            return;
+        }
+        this.initialized = true;
+
+        console.log('db', this);
+
+        const staticClass = this.constructor as typeof DatabaseService;
+        const schema: any = {};
+
+        for ( const ModelClass of staticClass.registeredModels ) {
+            ModelClass.dbService = this;
+            schema[ModelClass.getTableName()] = ModelClass.getSchema();
+        }
+
+        await this.version(3).stores(schema);
+        await this.open();
+
+        this.migrations = this.table('migrations');
+        this.migrations.mapToClass(Migration);
+
+        this.menuItems = this.table('menuItems');
+        this.menuItems.mapToClass(MenuItem);
+
+        this.keyValues = this.table('keyValues');
+        this.keyValues.mapToClass(KeyValue);
+
+        // await new Promise(res => {
+        //     setTimeout(() => {
+        //         res();
+        //     }, 1000);
+        // });
+    }
+}

src/app/service/session.service.ts

@@ -50,28 +50,13 @@ export class SessionService {
     }
 
     async initialize() {
-        return new Promise((res, rej) => {
-            this.api.get('/session').subscribe(response => {
-                this.data = response.data;
-                res();
-            });
-        });
+        this.data = await this.api.getSessionData();
     }
 
     async save() {
         this.saving = true;
-        return new Promise((res, rej) => {
-            this.api.post('/session', this.data || {}).subscribe({
-                next: result => {
-                    res();
-                    this.saving = false;
-                },
-                error: (e) => {
-                    this.saving = false;
-                    rej(e);
-                },
-            });
-        });
+        await this.api.saveSessionData(this.data);
+        this.saving = false;
     }
 
     buildAppUrl(...parts: string[]): string {