import { describe, expect, it } from "@suaveplan/testing/runner";
import { constantTimeEqual } from "./constant-time-equal.js";

describe("constantTimeEqual", () => {
    it("returns true for identical buffers", { timeout: 5000 }, () => {
        const a = new Uint8Array([1, 2, 3]);
        const b = new Uint8Array([1, 2, 3]);
        expect(constantTimeEqual(a, b)).toBe(true);
    });

    it("returns true for empty buffers", { timeout: 5000 }, () => {
        expect(constantTimeEqual(new Uint8Array(), new Uint8Array())).toBe(
            true
        );
    });

    it("returns false when contents differ at end", { timeout: 5000 }, () => {
        expect(
            constantTimeEqual(
                new Uint8Array([1, 2, 3]),
                new Uint8Array([1, 2, 4])
            )
        ).toBe(false);
    });

    it("returns false when contents differ at start", { timeout: 5000 }, () => {
        expect(
            constantTimeEqual(
                new Uint8Array([0, 2, 3]),
                new Uint8Array([1, 2, 3])
            )
        ).toBe(false);
    });

    it("returns false when lengths differ", { timeout: 5000 }, () => {
        expect(
            constantTimeEqual(new Uint8Array([1, 2]), new Uint8Array([1, 2, 3]))
        ).toBe(false);
    });

    it("runs the full loop regardless of mismatch", { timeout: 5000 }, () => {
        // Property check: result only depends on whether any byte differs.
        const a = new Uint8Array(32);
        const b = new Uint8Array(32);
        a[0] = 1;
        b[0] = 2;
        a[31] = 3;
        b[31] = 4;
        expect(constantTimeEqual(a, b)).toBe(false);
        a[0] = 0;
        b[0] = 0;
        a[31] = 0;
        b[31] = 0;
        expect(constantTimeEqual(a, b)).toBe(true);
    });
});