Refactoring of image detection, fix loading wikimedia images

Logic/ImageProviders/ImageProvider.ts

@@ -0,0 +1,64 @@
+import {UIEventSource} from "../UIEventSource";
+import BaseUIElement from "../../UI/BaseUIElement";
+import {LicenseInfo} from "./LicenseInfo";
+
+export interface ProvidedImage {
+    url: string, key: string, provider: ImageProvider
+}
+
+export default abstract class ImageProvider {
+    
+    protected abstract readonly defaultKeyPrefixes : string[]
+    
+    private _cache = new Map<string, UIEventSource<LicenseInfo>>()
+    
+    GetAttributionFor(url: string): UIEventSource<LicenseInfo> {
+        const cached = this._cache.get(url);
+        if (cached !== undefined) {
+            return cached;
+        }
+        const src =UIEventSource.FromPromise(this.DownloadAttribution(url))
+        this._cache.set(url, src)
+        return src;
+    }
+
+    public abstract SourceIcon(backlinkSource?: string): BaseUIElement;
+
+    protected abstract DownloadAttribution(url: string): Promise<LicenseInfo>;
+
+    /**
+     * Given a properies object, maps it onto _all_ the available pictures for this imageProvider
+     */
+    public GetRelevantUrls(allTags: UIEventSource<any>, options?: {
+        prefixes?: string[]
+    }):UIEventSource<ProvidedImage[]> {
+        const prefixes = options?.prefixes ?? this.defaultKeyPrefixes
+        const relevantUrls = new UIEventSource<{ url: string; key: string; provider: ImageProvider }[]>([])
+        const seenValues = new Set<string>()
+        allTags.addCallbackAndRunD(tags => {
+            for (const key in tags) {
+                if(!prefixes.some(prefix => key.startsWith(prefix))){
+                    continue
+                }
+                const value = tags[key]
+                if(seenValues.has(value)){
+                    continue
+                }
+                seenValues.add(value)
+
+                this.ExtractUrls(key, value).then(promises => {
+                    for (const promise of promises) {
+                        promise.then(providedImage => {
+                            relevantUrls.data.push(providedImage)
+                            relevantUrls.ping()
+                        })
+                    }
+                })
+            }
+        })
+        return relevantUrls
+    }
+
+    public abstract ExtractUrls(key: string, value: string) : Promise<Promise<ProvidedImage>[]>;
+    
+}