import { EditorCore } from "@/core";
import {
	getKeyframeAtTime,
	updateScalarKeyframeCurve,
	upsertPathKeyframe,
} from "@/animation";
import { Command, type CommandResult } from "@/commands/base-command";
import type { KeyframeClipboardItem } from "@/clipboard";
import type { SceneTracks, TimelineElement } from "@/timeline";
import { updateElementInSceneTracks } from "@/timeline";
import { resolveAnimationTarget } from "@/timeline/animation-targets";
import { generateUUID } from "@/utils/id";

function pasteKeyframesIntoElement({
	element,
	time,
	clipboardItems,
}: {
	element: TimelineElement;
	time: number;
	clipboardItems: KeyframeClipboardItem[];
}): TimelineElement {
	let nextElement = element;

	for (const item of clipboardItems) {
		const target = resolveAnimationTarget({
			element: nextElement,
			path: item.propertyPath,
		});
		if (!target) {
			continue;
		}

		const keyframeTime = Math.max(
			0,
			Math.min(time + item.timeOffset, nextElement.duration),
		);
		const nextAnimations = upsertPathKeyframe({
			animations: nextElement.animations,
			propertyPath: item.propertyPath,
			time: keyframeTime,
			value: item.value,
			interpolation: item.interpolation,
			keyframeId: generateUUID(),
			kind: target.kind,
			defaultInterpolation: target.defaultInterpolation,
			coerceValue: target.coerceValue,
		});
		const pastedKeyframe = getKeyframeAtTime({
			animations: nextAnimations,
			propertyPath: item.propertyPath,
			time: keyframeTime,
		});

		let patchedAnimations = nextAnimations;
		if (pastedKeyframe) {
			for (const curvePatch of item.curvePatches) {
				const nextPatchedAnimations = updateScalarKeyframeCurve({
					animations: patchedAnimations,
					propertyPath: item.propertyPath,
					componentKey: curvePatch.componentKey,
					keyframeId: pastedKeyframe.id,
					patch: curvePatch.patch,
				});
				patchedAnimations = nextPatchedAnimations ?? patchedAnimations;
			}
		}

		nextElement = {
			...nextElement,
			animations: patchedAnimations,
		};
	}

	return nextElement;
}

export class PasteKeyframesCommand extends Command {
	private savedState: SceneTracks | null = null;
	private readonly trackId: string;
	private readonly elementId: string;
	private readonly time: number;
	private readonly clipboardItems: KeyframeClipboardItem[];

	constructor({
		trackId,
		elementId,
		time,
		clipboardItems,
	}: {
		trackId: string;
		elementId: string;
		time: number;
		clipboardItems: KeyframeClipboardItem[];
	}) {
		super();
		this.trackId = trackId;
		this.elementId = elementId;
		this.time = time;
		this.clipboardItems = clipboardItems;
	}

	execute(): CommandResult | undefined {
		if (this.clipboardItems.length === 0) {
			return undefined;
		}

		const editor = EditorCore.getInstance();
		this.savedState = editor.scenes.getActiveScene().tracks;

		const updatedTracks = updateElementInSceneTracks({
			tracks: this.savedState,
			trackId: this.trackId,
			elementId: this.elementId,
			update: (element) =>
				pasteKeyframesIntoElement({
					element,
					time: this.time,
					clipboardItems: this.clipboardItems,
				}),
		});

		editor.timeline.updateTracks(updatedTracks);
		return undefined;
	}

	undo(): void {
		if (!this.savedState) {
			return;
		}

		const editor = EditorCore.getInstance();
		editor.timeline.updateTracks(this.savedState);
	}
}