import { beforeEach, describe, expect, it, vi } from 'vitest';
import { decodeJwtPayload, isJwtExpired } from '../../src/auth/jwt';

function createJwt(payload: Record<string, unknown>) {
    const header = { alg: 'HS256', typ: 'JWT' };
    const encode = (value: object) =>
        btoa(JSON.stringify(value)).replace(/\+/g, '-').replace(/\//g, '_').replace(/=+$/g, '');

    return `${encode(header)}.${encode(payload)}.signature`;
}

describe('decodeJwtPayload', () => {
    it('returns null for malformed tokens or invalid payloads', () => {
        expect(decodeJwtPayload('not-a-jwt')).toBeNull();
        expect(decodeJwtPayload('a.b')).toBeNull();
        expect(decodeJwtPayload('a.b.c.d')).toBeNull();

        const nonJson = 'header.' + btoa('nope') + '.sig';
        expect(decodeJwtPayload(nonJson)).toBeNull();

        const nonObjectPayload = createJwt({ value: 1 }).replace(
            /\.[^.]+\./,
            `.${btoa('1').replace(/=+$/g, '')}.`,
        );
        expect(decodeJwtPayload(nonObjectPayload)).toBeNull();
    });

    it('decodes valid base64url payloads', () => {
        const payload = { sub: 'user-1', role: 'ADMIN', exp: 1735689600 };
        expect(decodeJwtPayload(createJwt(payload))).toEqual(payload);
    });
});

describe('isJwtExpired', () => {
    beforeEach(() => {
        vi.useFakeTimers();
    });

    it('returns false for malformed tokens and invalid exp claim', () => {
        expect(isJwtExpired('not-a-jwt')).toBe(false);
        expect(isJwtExpired(createJwt({}))).toBe(false);
        expect(isJwtExpired(createJwt({ exp: 'nope' }))).toBe(false);
        expect(isJwtExpired(createJwt({ exp: Number.POSITIVE_INFINITY }))).toBe(false);
    });

    it('returns true when token is expired', () => {
        vi.setSystemTime(new Date('2026-01-01T00:00:00Z'));
        const exp = Math.floor(new Date('2025-12-31T23:59:00Z').getTime() / 1000);

        expect(isJwtExpired(createJwt({ exp }))).toBe(true);
    });

    it('applies skew seconds when evaluating expiration', () => {
        vi.setSystemTime(new Date('2026-01-01T00:00:00Z'));
        const exp = Math.floor(new Date('2026-01-01T00:00:10Z').getTime() / 1000);

        expect(isJwtExpired(createJwt({ exp }), 15)).toBe(true);
        expect(isJwtExpired(createJwt({ exp }), 5)).toBe(false);
    });
});