import { Injectable, Inject, Injector } from '@angular/core';
import { Store, createFeatureSelector, createSelector, select } from '@ngrx/store';
import { BehaviorSubject, EMPTY, Observable, of as observableOf } from 'rxjs';
import { ThemeState } from './theme.reducer';
import { SetThemeAction, ThemeActionTypes } from './theme.actions';
import { expand, filter, map, switchMap, take, toArray } from 'rxjs/operators';
import { hasNoValue, hasValue, isNotEmpty } from '../empty.util';
import { RemoteData } from '../../core/data/remote-data';
import { DSpaceObject } from '../../core/shared/dspace-object.model';
import {
getFirstCompletedRemoteData,
getFirstSucceededRemoteData,
getRemoteDataPayload
} from '../../core/shared/operators';
import { HeadTagConfig, Theme, ThemeConfig, themeFactory } from '../../../config/theme.model';
import { NO_OP_ACTION_TYPE, NoOpAction } from '../ngrx/no-op.action';
import { followLink } from '../utils/follow-link-config.model';
import { LinkService } from '../../core/cache/builders/link.service';
import { environment } from '../../../environments/environment';
import { DSpaceObjectDataService } from '../../core/data/dspace-object-data.service';
import { ActivatedRouteSnapshot, ResolveEnd, Router } from '@angular/router';
import { GET_THEME_CONFIG_FOR_FACTORY } from '../object-collection/shared/listable-object/listable-object.decorator';
import { distinctNext } from 'src/app/core/shared/distinct-next';
import { DOCUMENT } from '@angular/common';
import { getDefaultThemeConfig } from '../../../config/config.util';
import { BASE_THEME_NAME } from './theme.constants';
export const themeStateSelector = createFeatureSelector<ThemeState>('theme');
export const currentThemeSelector = createSelector(
themeStateSelector,
(state: ThemeState): string => hasValue(state) ? state.currentTheme : undefined
);
@Injectable({
providedIn: 'root'
})
export class ThemeService {
/**
* The list of configured themes
*/
themes: Theme[];
/**
* True if at least one theme depends on the route
*/
hasDynamicTheme: boolean;
private _isThemeLoading$ = new BehaviorSubject<boolean>(false);
private _isThemeCSSLoading$ = new BehaviorSubject<boolean>(false);
constructor(
private store: Store<ThemeState>,
private linkService: LinkService,
private dSpaceObjectDataService: DSpaceObjectDataService,
protected injector: Injector,
@Inject(GET_THEME_CONFIG_FOR_FACTORY) private gtcf: (str) => ThemeConfig,
private router: Router,
@Inject(DOCUMENT) private document: any,
) {
// Create objects from the theme configs in the environment file
this.themes = environment.themes.map((themeConfig: ThemeConfig) => themeFactory(themeConfig, injector));
this.hasDynamicTheme = environment.themes.some((themeConfig: any) =>
hasValue(themeConfig.regex) ||
hasValue(themeConfig.handle) ||
hasValue(themeConfig.uuid)
);
}
/**
* Set the current theme
* @param newName
*/
setTheme(newName: string) {
this.store.dispatch(new SetThemeAction(newName));
}
/**
* The name of the current theme (synchronous)
*/
getThemeName(): string {
let currentTheme: string;
this.store.pipe(
select(currentThemeSelector),
take(1)
).subscribe((name: string) =>
currentTheme = name
);
return currentTheme;
}
/**
* The name of the current theme (asynchronous, tracks changes)
*/
getThemeName$(): Observable<string> {
return this.store.pipe(
select(currentThemeSelector)
);
}
/**
* Whether the theme is currently loading
*/
get isThemeLoading$(): Observable<boolean> {
return this._isThemeLoading$;
}
/**
* Every time the theme is changed
* - if the theme name is valid, load it (CSS + <head> tags)
* - otherwise fall back to {@link getDefaultThemeConfig} or {@link BASE_THEME_NAME}
* Should be called when initializing the app.
* @param isBrowser
*/
listenForThemeChanges(isBrowser: boolean): void {
this.getThemeName$().subscribe((themeName: string) => {
if (isBrowser) {
// the theme css will never download server side, so this should only happen on the browser
distinctNext(this._isThemeCSSLoading$, true);
}
if (hasValue(themeName)) {
this.loadGlobalThemeConfig(themeName);
} else {
const defaultThemeConfig = getDefaultThemeConfig();
if (hasValue(defaultThemeConfig)) {
this.loadGlobalThemeConfig(defaultThemeConfig.name);
} else {
this.loadGlobalThemeConfig(BASE_THEME_NAME);
}
}
});
}
/**
* For every resolved route, check if it matches a dynamic theme. If it does, load that theme.
* Should be called when initializing the app.
*/
listenForRouteChanges(): void {
this.router.events.pipe(
filter(event => event instanceof ResolveEnd),
switchMap((event: ResolveEnd) => this.updateThemeOnRouteChange$(event.urlAfterRedirects, event.state.root)),
switchMap((changed) => {
if (changed) {
return this._isThemeCSSLoading$;
} else {
return [false];
}
})
).subscribe((changed) => {
distinctNext(this._isThemeLoading$, changed);
});
}
/**
* Load a theme's configuration
* - CSS
* - <head> tags
* @param themeName
* @private
*/
private loadGlobalThemeConfig(themeName: string): void {
this.setThemeCss(themeName);
this.setHeadTags(themeName);
}
/**
* Update the theme css file in <head>
*
* @param themeName The name of the new theme
* @private
*/
private setThemeCss(themeName: string): void {
const head = this.document.getElementsByTagName('head')[0];
if (hasNoValue(head)) {
return;
}
// Array.from to ensure we end up with an array, not an HTMLCollection, which would be
// automatically updated if we add nodes later
const currentThemeLinks = Array.from(head.getElementsByClassName('theme-css'));
const link = this.document.createElement('link');
link.setAttribute('rel', 'stylesheet');
link.setAttribute('type', 'text/css');
link.setAttribute('class', 'theme-css');
link.setAttribute('href', `${encodeURIComponent(themeName)}-theme.css`);
// wait for the new css to download before removing the old one to prevent a
// flash of unstyled content
link.onload = () => {
if (isNotEmpty(currentThemeLinks)) {
currentThemeLinks.forEach((currentThemeLink: any) => {
if (hasValue(currentThemeLink)) {
currentThemeLink.remove();
}
});
}
// the fact that this callback is used, proves we're on the browser.
distinctNext(this._isThemeCSSLoading$, false);
};
head.appendChild(link);
}
/**
* Update the page to add a theme's <head> tags
* @param themeName the theme in question
* @private
*/
private setHeadTags(themeName: string): void {
const head = this.document.getElementsByTagName('head')[0];
if (hasNoValue(head)) {
return;
}
// clear head tags
const currentHeadTags = Array.from(head.getElementsByClassName('theme-head-tag'));
if (hasValue(currentHeadTags)) {
currentHeadTags.forEach((currentHeadTag: any) => currentHeadTag.remove());
}
// create new head tags (not yet added to DOM)
const headTagFragment = this.document.createDocumentFragment();
this.createHeadTags(themeName)
.forEach(newHeadTag => headTagFragment.appendChild(newHeadTag));
// add new head tags to DOM
head.appendChild(headTagFragment);
}
/**
* Create HTML elements for a theme's <head> tags
* (including those defined in the parent theme, if applicable)
* @param themeName the theme in question
* @private
*/
private createHeadTags(themeName: string): HTMLElement[] {
const themeConfig = this.getThemeConfigFor(themeName);
const headTagConfigs = themeConfig?.headTags;
if (hasNoValue(headTagConfigs)) {
const parentThemeName = themeConfig?.extends;
if (hasValue(parentThemeName)) {
// inherit the head tags of the parent theme
return this.createHeadTags(parentThemeName);
}
const defaultThemeConfig = getDefaultThemeConfig();
const defaultThemeName = defaultThemeConfig.name;
if (
hasNoValue(defaultThemeName) ||
themeName === defaultThemeName ||
themeName === BASE_THEME_NAME
) {
// last resort, use fallback favicon.ico
return [
this.createHeadTag({
'tagName': 'link',
'attributes': {
'rel': 'icon',
'href': 'assets/images/favicon.ico',
'sizes': 'any',
}
})
];
}
// inherit the head tags of the default theme
return this.createHeadTags(defaultThemeConfig.name);
}
return headTagConfigs.map(this.createHeadTag.bind(this));
}
/**
* Create a single <head> tag element
* @param headTagConfig the configuration for this <head> tag
* @private
*/
private createHeadTag(headTagConfig: HeadTagConfig): HTMLElement {
const tag = this.document.createElement(headTagConfig.tagName);
if (hasValue(headTagConfig.attributes)) {
Object.entries(headTagConfig.attributes)
.forEach(([key, value]) => tag.setAttribute(key, value));
}
// 'class' attribute should always be 'theme-head-tag' for removal
tag.setAttribute('class', 'theme-head-tag');
return tag;
}
/**
* Determine whether or not the theme needs to change depending on the current route's URL and snapshot data
* If the snapshot contains a dso, this will be used to match a theme
* If the snapshot contains a scope parameters, this will be used to match a theme
* Otherwise the URL is matched against
* If none of the above find a match, the theme doesn't change
* @param currentRouteUrl
* @param activatedRouteSnapshot
* @return Observable boolean emitting whether or not the theme has been changed
*/
updateThemeOnRouteChange$(currentRouteUrl: string, activatedRouteSnapshot: ActivatedRouteSnapshot): Observable<boolean> {
// and the current theme from the store
const currentTheme$: Observable<string> = this.store.pipe(select(currentThemeSelector));
const action$ = currentTheme$.pipe(
switchMap((currentTheme: string) => {
const snapshotWithData = this.findRouteData(activatedRouteSnapshot);
if (this.hasDynamicTheme === true && isNotEmpty(this.themes)) {
if (hasValue(snapshotWithData) && hasValue(snapshotWithData.data) && hasValue(snapshotWithData.data.dso)) {
const dsoRD: RemoteData<DSpaceObject> = snapshotWithData.data.dso;
if (dsoRD.hasSucceeded) {
// Start with the resolved dso and go recursively through its parents until you reach the top-level community
return observableOf(dsoRD.payload).pipe(
this.getAncestorDSOs(),
map((dsos: DSpaceObject[]) => {
const dsoMatch = this.matchThemeToDSOs(dsos, currentRouteUrl);
return this.getActionForMatch(dsoMatch, currentTheme);
})
);
}
}
if (hasValue(activatedRouteSnapshot.queryParams) && hasValue(activatedRouteSnapshot.queryParams.scope)) {
const dsoFromScope$: Observable<RemoteData<DSpaceObject>> = this.dSpaceObjectDataService.findById(activatedRouteSnapshot.queryParams.scope);
// Start with the resolved dso and go recursively through its parents until you reach the top-level community
return dsoFromScope$.pipe(
getFirstSucceededRemoteData(),
getRemoteDataPayload(),
this.getAncestorDSOs(),
map((dsos: DSpaceObject[]) => {
const dsoMatch = this.matchThemeToDSOs(dsos, currentRouteUrl);
return this.getActionForMatch(dsoMatch, currentTheme);
})
);
}
// check whether the route itself matches
const routeMatch = this.themes.find((theme: Theme) => theme.matches(currentRouteUrl, undefined));
return [this.getActionForMatch(routeMatch, currentTheme)];
}
// If there are no themes configured, do nothing
return [new NoOpAction()];
}),
take(1),
);
action$.pipe(
filter((action) => action.type !== NO_OP_ACTION_TYPE),
).subscribe((action) => {
this.store.dispatch(action);
});
return action$.pipe(
map((action) => action.type === ThemeActionTypes.SET),
);
}
/**
* Find a DSpaceObject in one of the provided route snapshots their data
* Recursively looks for the dso in the routes their child routes until it reaches a dead end or finds one
* @param routes
*/
findRouteData(...routes: ActivatedRouteSnapshot[]) {
const result = routes.find((route) => hasValue(route.data) && hasValue(route.data.dso));
if (hasValue(result)) {
return result;
} else {
const nextLevelRoutes = routes
.map((route: ActivatedRouteSnapshot) => route.children)
.reduce((combined: ActivatedRouteSnapshot[], current: ActivatedRouteSnapshot[]) => [...combined, ...current]);
if (isNotEmpty(nextLevelRoutes)) {
return this.findRouteData(...nextLevelRoutes);
} else {
return undefined;
}
}
}
/**
* An rxjs operator that will return an array of all the ancestors of the DSpaceObject used as
* input. The initial DSpaceObject will be the first element of the output array, followed by
* its parent, its grandparent etc
*
* @private
*/
private getAncestorDSOs() {
return (source: Observable<DSpaceObject>): Observable<DSpaceObject[]> =>
source.pipe(
expand((dso: DSpaceObject) => {
// Check if the dso exists and has a parent link
if (hasValue(dso) && typeof (dso as any).getParentLinkKey === 'function') {
const linkName = (dso as any).getParentLinkKey();
// If it does, retrieve it.
return this.linkService.resolveLinkWithoutAttaching<DSpaceObject, DSpaceObject>(dso, followLink(linkName)).pipe(
getFirstCompletedRemoteData(),
map((rd: RemoteData<DSpaceObject>) => {
if (hasValue(rd.payload)) {
// If there's a parent, use it for the next iteration
return rd.payload;
} else {
// If there's no parent, or an error, return null, which will stop recursion
// in the next iteration
return null;
}
}),
);
}
// The current dso has no value, or no parent. Return EMPTY to stop recursion
return EMPTY;
}),
// only allow through DSOs that have a value
filter((dso: DSpaceObject) => hasValue(dso)),
// Wait for recursion to complete, and emit all results at once, in an array
toArray()
);
}
/**
* return the action to dispatch based on the given matching theme
*
* @param newTheme The theme to create an action for
* @param currentThemeName The name of the currently active theme
* @private
*/
private getActionForMatch(newTheme: Theme, currentThemeName: string): SetThemeAction | NoOpAction {
if (hasValue(newTheme) && newTheme.config.name !== currentThemeName) {
// If we have a match, and it isn't already the active theme, set it as the new theme
return new SetThemeAction(newTheme.config.name);
} else {
// Otherwise, do nothing
return new NoOpAction();
}
}
/**
* Check the given DSpaceObjects in order to see if they match the configured themes in order.
* If a match is found, the matching theme is returned
*
* @param dsos The DSpaceObjects to check
* @param currentRouteUrl The url for the current route
* @private
*/
private matchThemeToDSOs(dsos: DSpaceObject[], currentRouteUrl: string): Theme {
// iterate over the themes in order, and return the first one that matches
return this.themes.find((theme: Theme) => {
// iterate over the dsos's in order (most specific one first, so Item, Collection,
// Community), and return the first one that matches the current theme
const match = dsos.find((dso: DSpaceObject) => theme.matches(currentRouteUrl, dso));
return hasValue(match);
});
}
/**
* Searches for a ThemeConfig by its name;
*/
getThemeConfigFor(themeName: string): ThemeConfig {
return this.gtcf(themeName);
}
}