suaveplan/packages/ui/react/react-audio/src/hooks/use-analyser/use-analyser.test.ts

import { describe, expect, it, vi } from "@suaveplan/testing/runner";
import { act, renderHook } from "@testing-library/react";
import { useAnalyser } from "./use-analyser.js";
import type { AnalyserLike } from "./use-analyser.types.js";

function makeFakeAnalyser(bins = 16): AnalyserLike & {
    freqCalls: number;
    waveCalls: number;
} {
    const state = {
        fftSize: 2048,
        frequencyBinCount: bins,
        minDecibels: -100,
        maxDecibels: -30,
        smoothingTimeConstant: 0.8,
        freqCalls: 0,
        waveCalls: 0,
        getByteFrequencyData(out: Uint8Array) {
            state.freqCalls += 1;
            out[0] = (state.freqCalls % 250) + 1;
        },
        getByteTimeDomainData(out: Uint8Array) {
            state.waveCalls += 1;
            out[0] = ((state.waveCalls * 2) % 250) + 1;
        },
    };
    Object.defineProperty(state, "frequencyBinCount", {
        get: () => Math.max(1, Math.floor(state.fftSize / 2)),
    });
    return state as unknown as AnalyserLike & {
        freqCalls: number;
        waveCalls: number;
    };
}

describe("useAnalyser", () => {
    it("returns null analyser + empty buffers when no source provided", {
        timeout: 5000,
    }, () => {
        const { result, unmount } = renderHook(() => useAnalyser());
        expect(result.current.analyser).toBeNull();
        expect(result.current.frequency.length).toBe(0);
        expect(result.current.waveform.length).toBe(0);
        unmount();
    });

    it("polls the explicit analyser and writes into the shared buffer", {
        timeout: 5000,
    }, () => {
        vi.useFakeTimers();
        try {
            const a = makeFakeAnalyser(8);
            const { result, unmount } = renderHook(() =>
                useAnalyser({ analyser: a, intervalMs: 5, fftSize: 16 })
            );
            expect(result.current.analyser).toBe(a);
            expect(result.current.frequency.length).toBe(8);
            act(() => {
                vi.advanceTimersByTime(20);
            });
            expect(a.freqCalls).toBeGreaterThan(0);
            expect(a.waveCalls).toBeGreaterThan(0);
            expect(result.current.frequency[0]).toBeGreaterThan(0);
            unmount();
        } finally {
            vi.useRealTimers();
        }
    });

    it("applies fftSize/smoothing/min-max on the analyser", {
        timeout: 5000,
    }, () => {
        const a = makeFakeAnalyser();
        renderHook(() =>
            useAnalyser({
                analyser: a,
                fftSize: 512,
                smoothingTimeConstant: 0.3,
                minDecibels: -120,
                maxDecibels: -20,
            })
        );
        expect(a.fftSize).toBe(512);
        expect(a.smoothingTimeConstant).toBe(0.3);
        expect(a.minDecibels).toBe(-120);
        expect(a.maxDecibels).toBe(-20);
    });

    it("resolves via factory on tick, then stops re-resolving", {
        timeout: 5000,
    }, () => {
        vi.useFakeTimers();
        try {
            let calls = 0;
            const a = makeFakeAnalyser();
            const factory = () => {
                calls += 1;
                return calls >= 2 ? a : null;
            };
            const { result } = renderHook(() =>
                useAnalyser({ factory, intervalMs: 5 })
            );
            expect(result.current.analyser).toBeNull();
            act(() => {
                vi.advanceTimersByTime(6);
            });
            // First tick: factory returns null; resolved still null.
            act(() => {
                vi.advanceTimersByTime(6);
            });
            expect(result.current.analyser).toBe(a);
            // Once resolved, factory should not be called again.
            const beforeCalls = calls;
            act(() => {
                vi.advanceTimersByTime(20);
            });
            expect(calls).toBe(beforeCalls);
        } finally {
            vi.useRealTimers();
        }
    });

    it("swapping the analyser prop reconfigures buffers", {
        timeout: 5000,
    }, () => {
        const a1 = makeFakeAnalyser(8);
        const a2 = makeFakeAnalyser(16);
        const { result, rerender } = renderHook(
            ({ a }: { a: typeof a1 }) =>
                useAnalyser({ analyser: a, fftSize: 32 }),
            { initialProps: { a: a1 } }
        );
        expect(result.current.frequency.length).toBeGreaterThan(0);
        const first = result.current.frequency;
        rerender({ a: a2 });
        // Buffer identity may change; instance must be a2.
        expect(result.current.analyser).toBe(a2);
        // Different fftSize bin count → different length.
        expect(result.current.frequency.length).toBe(Math.floor(32 / 2));
        expect(first).not.toBe(result.current.frequency);
    });

    it("setting analyser to null disables polling", { timeout: 5000 }, () => {
        vi.useFakeTimers();
        try {
            const a = makeFakeAnalyser();
            const { rerender } = renderHook(
                ({ x }: { x: typeof a | null }) =>
                    useAnalyser({ analyser: x, intervalMs: 5 }),
                { initialProps: { x: a as typeof a | null } }
            );
            act(() => {
                vi.advanceTimersByTime(20);
            });
            const before = a.freqCalls;
            rerender({ x: null });
            act(() => {
                vi.advanceTimersByTime(20);
            });
            // After null, no new poll calls land on `a`.
            expect(a.freqCalls).toBe(before);
        } finally {
            vi.useRealTimers();
        }
    });

    it("cleans up the interval on unmount", { timeout: 5000 }, () => {
        vi.useFakeTimers();
        try {
            const a = makeFakeAnalyser();
            const { unmount } = renderHook(() =>
                useAnalyser({ analyser: a, intervalMs: 5 })
            );
            act(() => {
                vi.advanceTimersByTime(10);
            });
            const before = a.freqCalls;
            unmount();
            act(() => {
                vi.advanceTimersByTime(50);
            });
            expect(a.freqCalls).toBe(before);
        } finally {
            vi.useRealTimers();
        }
    });

    it("factory returning null indefinitely keeps analyser null", {
        timeout: 5000,
    }, () => {
        vi.useFakeTimers();
        try {
            const { result } = renderHook(() =>
                useAnalyser({ factory: () => null, intervalMs: 5 })
            );
            act(() => {
                vi.advanceTimersByTime(30);
            });
            expect(result.current.analyser).toBeNull();
        } finally {
            vi.useRealTimers();
        }
    });

    it("no factory, no analyser → tick is a no-op", { timeout: 5000 }, () => {
        vi.useFakeTimers();
        try {
            const { result } = renderHook(() => useAnalyser({ intervalMs: 5 }));
            act(() => {
                vi.advanceTimersByTime(20);
            });
            expect(result.current.analyser).toBeNull();
        } finally {
            vi.useRealTimers();
        }
    });

    it("changing fftSize after mount reallocates buffers", {
        timeout: 5000,
    }, () => {
        const a = makeFakeAnalyser();
        const { result, rerender } = renderHook(
            ({ size }: { size: number }) =>
                useAnalyser({ analyser: a, fftSize: size }),
            { initialProps: { size: 32 } }
        );
        expect(result.current.frequency.length).toBe(16);
        rerender({ size: 64 });
        expect(result.current.frequency.length).toBe(32);
        expect(a.fftSize).toBe(64);
    });

    it("intervalMs <= 0 is clamped to 1", { timeout: 5000 }, () => {
        vi.useFakeTimers();
        try {
            const a = makeFakeAnalyser();
            renderHook(() => useAnalyser({ analyser: a, intervalMs: 0 }));
            act(() => {
                vi.advanceTimersByTime(5);
            });
            expect(a.freqCalls).toBeGreaterThan(0);
        } finally {
            vi.useRealTimers();
        }
    });
});