codebase overhaul (#697)

1 files changed, 263 insertions, 0 deletions

diff --git a/apps/web/src/lib/commands/timeline/clipboard/paste.ts b/apps/web/src/lib/commands/timeline/clipboard/paste.ts
new file mode 100644
index 00000000..9c979790
--- /dev/null
+++ b/apps/web/src/lib/commands/timeline/clipboard/paste.ts
@@ -0,0 +1,263 @@
+import { Command } from "@/lib/commands/base-command";
+import { EditorCore } from "@/core";
+import type {
+	TimelineTrack,
+	TimelineElement,
+	ClipboardItem,
+} from "@/types/timeline";
+import { generateUUID } from "@/utils/id";
+import { wouldElementOverlap } from "@/lib/timeline/element-utils";
+import {
+	buildEmptyTrack,
+	getHighestInsertIndexForTrack,
+} from "@/lib/timeline/track-utils";
+
+export class PasteCommand extends Command {
+	private savedState: TimelineTrack[] | null = null;
+	private pastedElements: { trackId: string; elementId: string }[] = [];
+	private previousSelection: { trackId: string; elementId: string }[] = [];
+
+	constructor(
+		private time: number,
+		private clipboardItems: ClipboardItem[],
+	) {
+		super();
+	}
+
+	execute(): void {
+		if (this.clipboardItems.length === 0) return;
+
+		const editor = EditorCore.getInstance();
+		this.savedState = editor.timeline.getTracks();
+		this.previousSelection = editor.selection.getSelectedElements();
+		this.pastedElements = [];
+
+		const minStart = Math.min(
+			...this.clipboardItems.map((item) => item.element.startTime),
+		);
+
+		const updatedTracks = [...this.savedState];
+		const itemsByTrackId = groupClipboardItemsByTrackId({
+			clipboardItems: this.clipboardItems,
+		});
+
+		for (const [trackId, items] of itemsByTrackId) {
+			const elementsToAdd = buildPastedElements({
+				items,
+				minStart,
+				time: this.time,
+			});
+
+			if (elementsToAdd.length === 0) {
+				continue;
+			}
+
+			const trackType = items[0].trackType;
+			const sourceTrackIndex = updatedTracks.findIndex(
+				(track) => track.id === trackId,
+			);
+			const resolvedTargetIndex = resolveTargetTrackIndex({
+				tracks: updatedTracks,
+				sourceTrackIndex,
+				trackType,
+				elements: elementsToAdd,
+			});
+
+			if (resolvedTargetIndex >= 0) {
+				const targetTrack = updatedTracks[resolvedTargetIndex];
+				updatedTracks[resolvedTargetIndex] = {
+					...targetTrack,
+					elements: [...targetTrack.elements, ...elementsToAdd],
+				} as TimelineTrack;
+				for (const element of elementsToAdd) {
+					this.pastedElements.push({
+						trackId: targetTrack.id,
+						elementId: element.id,
+					});
+				}
+				continue;
+			}
+
+			const insertIndex = resolveInsertIndexForNewTrack({
+				tracks: updatedTracks,
+				sourceTrackIndex,
+				trackType,
+			});
+			const newTrack = buildTrackWithElements({
+				trackType,
+				elements: elementsToAdd,
+			});
+			updatedTracks.splice(insertIndex, 0, newTrack);
+			for (const element of elementsToAdd) {
+				this.pastedElements.push({
+					trackId: newTrack.id,
+					elementId: element.id,
+				});
+			}
+		}
+
+		editor.timeline.updateTracks(updatedTracks);
+
+		if (this.pastedElements.length > 0) {
+			editor.selection.setSelectedElements({ elements: this.pastedElements });
+		}
+	}
+
+	undo(): void {
+		if (this.savedState) {
+			const editor = EditorCore.getInstance();
+			editor.timeline.updateTracks(this.savedState);
+			editor.selection.setSelectedElements({ elements: this.previousSelection });
+		}
+	}
+
+	getPastedElements(): { trackId: string; elementId: string }[] {
+		return this.pastedElements;
+	}
+}
+
+function groupClipboardItemsByTrackId({
+	clipboardItems,
+}: {
+	clipboardItems: ClipboardItem[];
+}): Map<string, ClipboardItem[]> {
+	const groupedItems = new Map<string, ClipboardItem[]>();
+
+	for (const item of clipboardItems) {
+		const existingItems = groupedItems.get(item.trackId) ?? [];
+		groupedItems.set(item.trackId, [...existingItems, item]);
+	}
+
+	return groupedItems;
+}
+
+function buildPastedElements({
+	items,
+	minStart,
+	time,
+}: {
+	items: ClipboardItem[];
+	minStart: number;
+	time: number;
+}): TimelineElement[] {
+	const elementsToAdd: TimelineElement[] = [];
+
+	for (const item of items) {
+		const relativeOffset = item.element.startTime - minStart;
+		const startTime = Math.max(0, time + relativeOffset);
+		const newElementId = generateUUID();
+
+		elementsToAdd.push({
+			...item.element,
+			id: newElementId,
+			startTime,
+		} as TimelineElement);
+	}
+
+	return elementsToAdd;
+}
+
+function resolveTargetTrackIndex({
+	tracks,
+	sourceTrackIndex,
+	trackType,
+	elements,
+}: {
+	tracks: TimelineTrack[];
+	sourceTrackIndex: number;
+	trackType: ClipboardItem["trackType"];
+	elements: TimelineElement[];
+}): number {
+	if (sourceTrackIndex >= 0) {
+		const aboveIndex = sourceTrackIndex - 1;
+		if (aboveIndex < 0) {
+			return -1;
+		}
+
+		const aboveTrack = tracks[aboveIndex];
+		if (aboveTrack.type !== trackType) {
+			return -1;
+		}
+
+		const canPlaceOnAbove = canPlaceElementsOnTrack({
+			track: aboveTrack,
+			elements,
+		});
+		return canPlaceOnAbove ? aboveIndex : -1;
+	}
+
+	const highestCompatibleIndex = tracks.findIndex(
+		(track) => track.type === trackType,
+	);
+	if (highestCompatibleIndex < 0) {
+		return -1;
+	}
+
+	const highestCompatibleTrack = tracks[highestCompatibleIndex];
+	const canPlaceOnHighest = canPlaceElementsOnTrack({
+		track: highestCompatibleTrack,
+		elements,
+	});
+
+	return canPlaceOnHighest ? highestCompatibleIndex : -1;
+}
+
+function resolveInsertIndexForNewTrack({
+	tracks,
+	sourceTrackIndex,
+	trackType,
+}: {
+	tracks: TimelineTrack[];
+	sourceTrackIndex: number;
+	trackType: ClipboardItem["trackType"];
+}): number {
+	if (sourceTrackIndex >= 0) {
+		return sourceTrackIndex;
+	}
+
+	const highestCompatibleIndex = tracks.findIndex(
+		(track) => track.type === trackType,
+	);
+	if (highestCompatibleIndex >= 0) {
+		return highestCompatibleIndex;
+	}
+
+	return getHighestInsertIndexForTrack({ tracks, trackType });
+}
+
+function canPlaceElementsOnTrack({
+	track,
+	elements,
+}: {
+	track: TimelineTrack;
+	elements: TimelineElement[];
+}): boolean {
+	for (const element of elements) {
+		const endTime = element.startTime + element.duration;
+		const hasOverlap = wouldElementOverlap({
+			elements: track.elements,
+			startTime: element.startTime,
+			endTime,
+		});
+		if (hasOverlap) {
+			return false;
+		}
+	}
+
+	return true;
+}
+
+function buildTrackWithElements({
+	trackType,
+	elements,
+}: {
+	trackType: ClipboardItem["trackType"];
+	elements: TimelineElement[];
+}): TimelineTrack {
+	const newTrackId = generateUUID();
+	const newTrackBase = buildEmptyTrack({ id: newTrackId, type: trackType });
+	return {
+		...newTrackBase,
+		elements,
+	} as TimelineTrack;
+}