import { describe, expect, test } from "bun:test";
import {
	applyVisualTransition,
	buildTransitionFromParams,
} from "@/rendering/transition";
import type { Transform } from "@/rendering";
import { TICKS_PER_SECOND } from "@/wasm";

const baseTransform: Transform = {
	scaleX: 1,
	scaleY: 1,
	position: { x: 0, y: 0 },
	rotate: 0,
};

describe("visual transitions", () => {
	test("fade ramps opacity at clip edges", () => {
		const transition = buildTransitionFromParams({
			params: {
				"transition.kind": "fade",
				"transition.inDuration": 1,
				"transition.outDuration": 1,
			},
		});

		expect(
			applyVisualTransition({
				baseTransform,
				transition,
				localTime: 0,
				duration: 4 * TICKS_PER_SECOND,
				canvasWidth: 100,
			}).opacityMultiplier,
		).toBe(0);
		expect(
			applyVisualTransition({
				baseTransform,
				transition,
				localTime: 2 * TICKS_PER_SECOND,
				duration: 4 * TICKS_PER_SECOND,
				canvasWidth: 100,
			}).opacityMultiplier,
		).toBe(1);
		expect(
			applyVisualTransition({
				baseTransform,
				transition,
				localTime: 4 * TICKS_PER_SECOND,
				duration: 4 * TICKS_PER_SECOND,
				canvasWidth: 100,
			}).opacityMultiplier,
		).toBe(0);
	});

	test("slide left moves in and out across canvas", () => {
		const transition = buildTransitionFromParams({
			params: {
				"transition.kind": "push-left",
				"transition.inDuration": 1,
				"transition.outDuration": 1,
			},
		});

		const enter = applyVisualTransition({
			baseTransform,
			transition,
			localTime: 0,
			duration: 4 * TICKS_PER_SECOND,
			canvasWidth: 100,
		});
		const middle = applyVisualTransition({
			baseTransform,
			transition,
			localTime: 2 * TICKS_PER_SECOND,
			duration: 4 * TICKS_PER_SECOND,
			canvasWidth: 100,
		});
		const leave = applyVisualTransition({
			baseTransform,
			transition,
			localTime: 4 * TICKS_PER_SECOND,
			duration: 4 * TICKS_PER_SECOND,
			canvasWidth: 100,
		});

		expect(enter.transform.position.x).toBe(100);
		expect(middle.transform.position.x).toBe(0);
		expect(leave.transform.position.x).toBe(-100);
		expect(leave.opacityMultiplier).toBe(1);
	});

	test("slide right mirrors horizontal entry and exit", () => {
		const transition = buildTransitionFromParams({
			params: {
				"transition.kind": "push-right",
				"transition.inDuration": 1,
				"transition.outDuration": 1,
			},
		});

		const enter = applyVisualTransition({
			baseTransform,
			transition,
			localTime: 0,
			duration: 4 * TICKS_PER_SECOND,
			canvasWidth: 100,
		});
		const middle = applyVisualTransition({
			baseTransform,
			transition,
			localTime: 2 * TICKS_PER_SECOND,
			duration: 4 * TICKS_PER_SECOND,
			canvasWidth: 100,
		});
		const leave = applyVisualTransition({
			baseTransform,
			transition,
			localTime: 4 * TICKS_PER_SECOND,
			duration: 4 * TICKS_PER_SECOND,
			canvasWidth: 100,
		});

		expect(enter.transform.position.x).toBe(-100);
		expect(middle.transform.position.x).toBe(0);
		expect(leave.transform.position.x).toBe(100);
		expect(enter.opacityMultiplier).toBe(1);
	});

	test("zoom and spin variants converge on the base transform", () => {
		const applyKind = ({
			kind,
			localTime,
		}: {
			kind: "zoom" | "zoom-out" | "spin";
			localTime: number;
		}) =>
			applyVisualTransition({
				baseTransform,
				transition: buildTransitionFromParams({
					params: {
						"transition.kind": kind,
						"transition.inDuration": 1,
						"transition.outDuration": 0,
					},
				}),
				localTime,
				duration: 4 * TICKS_PER_SECOND,
				canvasWidth: 100,
			});

		expect(applyKind({ kind: "zoom", localTime: 0 }).transform.scaleX).toBe(
			0.96,
		);
		expect(applyKind({ kind: "zoom-out", localTime: 0 }).transform.scaleX).toBe(
			1.04,
		);
		expect(applyKind({ kind: "spin", localTime: 0 }).transform.rotate).toBe(-6);

		const settledSpin = applyKind({
			kind: "spin",
			localTime: 2 * TICKS_PER_SECOND,
		});
		expect(settledSpin.transform.scaleX).toBe(1);
		expect(settledSpin.transform.rotate).toBe(0);
	});
});