import { describe, it, expect } from 'vitest';
import { diffFields, maskSensitiveFields } from '@/lib/audit';

describe('diffFields', () => {
  it('returns empty array when records are identical', () => {
    const result = diffFields({ name: 'Alice', status: 'active' }, { name: 'Alice', status: 'active' });
    expect(result).toEqual([]);
  });

  it('detects a single field change with correct field/old/new', () => {
    const result = diffFields({ name: 'Alice', status: 'active' }, { name: 'Alice', status: 'inactive' });
    expect(result).toHaveLength(1);
    expect(result[0]).toEqual({ field: 'status', oldValue: 'active', newValue: 'inactive' });
  });

  it('detects multiple field changes', () => {
    const result = diffFields(
      { name: 'Alice', status: 'active', count: 1 },
      { name: 'Bob', status: 'inactive', count: 2 },
    );
    expect(result).toHaveLength(3);
    const fields = result.map((r) => r.field);
    expect(fields).toContain('name');
    expect(fields).toContain('status');
    expect(fields).toContain('count');
  });

  it('detects null-to-value change', () => {
    const result = diffFields({ note: null }, { note: 'hello' });
    expect(result).toHaveLength(1);
    expect(result[0]).toEqual({ field: 'note', oldValue: null, newValue: 'hello' });
  });

  it('detects value-to-null change', () => {
    const result = diffFields({ note: 'hello' }, { note: null });
    expect(result).toHaveLength(1);
    expect(result[0]).toEqual({ field: 'note', oldValue: 'hello', newValue: null });
  });

  it('uses JSON comparison for nested objects', () => {
    const old = { meta: { x: 1, y: 2 } };
    const updated = { meta: { x: 1, y: 3 } };
    const result = diffFields(old, updated);
    expect(result).toHaveLength(1);
    expect(result[0].field).toBe('meta');
  });

  it('no diff when nested objects are deeply equal', () => {
    const result = diffFields({ meta: { x: 1 } }, { meta: { x: 1 } });
    expect(result).toHaveLength(0);
  });

  it('only checks keys present in newRecord', () => {
    // 'extra' key in old is irrelevant
    const result = diffFields({ name: 'Alice', extra: 'ignored' }, { name: 'Alice' });
    expect(result).toHaveLength(0);
  });
});

describe('maskSensitiveFields', () => {
  it('masks email field', () => {
    const result = maskSensitiveFields({ email: 'alice@example.com' });
    expect(result?.email).not.toBe('alice@example.com');
    expect(typeof result?.email).toBe('string');
    expect(result?.email).toContain('***');
  });

  it('masks phone field', () => {
    const result = maskSensitiveFields({ phone: '+61400000000' });
    expect(result?.phone).toContain('***');
  });

  it('masks password field', () => {
    const result = maskSensitiveFields({ password: 'mySecret123' });
    expect(result?.password).toContain('***');
  });

  it('masks credentials_enc field', () => {
    const result = maskSensitiveFields({ credentials_enc: 'eyJpdiI6IjEyMzQ1' });
    expect(result?.credentials_enc).toContain('***');
  });

  it('masks token field', () => {
    const result = maskSensitiveFields({ token: 'abc-def-ghi-jkl' });
    expect(result?.token).toContain('***');
  });

  it('preserves non-sensitive fields unchanged', () => {
    const result = maskSensitiveFields({ name: 'Alice', status: 'active', count: 5 });
    expect(result?.name).toBe('Alice');
    expect(result?.status).toBe('active');
    expect(result?.count).toBe(5);
  });

  it('applies partial masking: first 2 + *** + last 2 chars for strings longer than 4', () => {
    const result = maskSensitiveFields({ email: 'alice@example.com' });
    // 'alice@example.com' length > 4, so al***om
    expect(result?.email).toBe('al***om');
  });

  it('replaces short strings (<=4 chars) with just ***', () => {
    const result = maskSensitiveFields({ email: 'ab@c' }); // length 4
    expect(result?.email).toBe('***');
  });

  it('replaces 1-char sensitive string with ***', () => {
    const result = maskSensitiveFields({ token: 'x' });
    expect(result?.token).toBe('***');
  });

  it('handles undefined input by returning undefined', () => {
    expect(maskSensitiveFields(undefined)).toBeUndefined();
  });

  it('does not mutate the original object', () => {
    const original = { email: 'alice@example.com', name: 'Alice' };
    maskSensitiveFields(original);
    expect(original.email).toBe('alice@example.com');
  });
});