feat: Initial clean release of CHM

packages/lib/services/NotePositionService.ts

@@ -0,0 +1,66 @@
+
+export interface EditorCursorLocations {
+	readonly richText?: unknown; // Depends on the editor implementation
+	readonly markdown?: number;
+}
+
+type NoteIdAndWindowKey = `note-window:${string}`;
+type NoteIdKey = `note:${string}`;
+
+export default class NotePositionService {
+	private constructor() {}
+
+	private static instance_: NotePositionService;
+	public static instance() {
+		this.instance_ ??= new NotePositionService();
+		return this.instance_;
+	}
+
+	private toFallbackKey_(noteId: string): NoteIdKey {
+		return `note:${noteId}`;
+	}
+
+	private toKey_(noteId: string, windowId?: string): NoteIdAndWindowKey {
+		return `note-window:${windowId}--${noteId}`;
+	}
+
+	private cursorFallback_: Map<NoteIdKey, EditorCursorLocations> = new Map();
+	private cursorLocations_: Map<NoteIdAndWindowKey, EditorCursorLocations> = new Map();
+
+	public getCursorPosition(noteId: string, windowId: string) {
+		// If available, use the cursor position for the current window
+		return this.cursorLocations_.get(this.toKey_(noteId, windowId))
+			// Fall back to the last-set cursor location for all windows
+			?? this.cursorFallback_.get(this.toFallbackKey_(noteId))
+			?? { };
+	}
+
+	public updateCursorPosition(noteId: string, windowId: string, position: EditorCursorLocations) {
+		const key = this.toKey_(noteId, windowId);
+		this.cursorLocations_.set(key, {
+			...this.cursorLocations_.get(key),
+			...position,
+		});
+
+		const fallbackKey = this.toFallbackKey_(noteId);
+		this.cursorFallback_.set(fallbackKey, {
+			...this.cursorFallback_.get(fallbackKey),
+			...position,
+		});
+	}
+
+	private scrollFallback_: Map<NoteIdKey, number> = new Map();
+	private scrollLocations_: Map<NoteIdAndWindowKey, number> = new Map();
+
+	public getScrollPercent(noteId: string, windowId: string) {
+		return this.scrollLocations_.get(this.toKey_(noteId, windowId))
+			?? this.scrollFallback_.get(this.toFallbackKey_(noteId))
+			?? 0;
+	}
+
+	public updateScrollPosition(noteId: string, windowId: string, percent: number) {
+		const key = this.toKey_(noteId, windowId);
+		this.scrollLocations_.set(key, percent);
+		this.scrollFallback_.set(this.toFallbackKey_(noteId), percent);
+	}
+}