import { describe, it, expect } from 'vitest';
import { renderTemplate } from '../../src/template/engine.js';

describe('renderTemplate', () => {
  it('replaces all placeholders', () => {
    const template = 'You are **{{AGENT_NAME}}**, role: {{ROLE_DESCRIPTION}}';
    const result = renderTemplate(template, {
      AGENT_NAME: 'Jarvis',
      ROLE_DESCRIPTION: 'steward',
    });
    expect(result).toBe('You are **Jarvis**, role: steward');
  });

  it('preserves ${ENV_VAR} references', () => {
    const template = 'Path: ${HOME}/.config, Agent: {{AGENT_NAME}}';
    const result = renderTemplate(template, { AGENT_NAME: 'Test' });
    expect(result).toBe('Path: ${HOME}/.config, Agent: Test');
  });

  it('handles multi-line values', () => {
    const template = '{{PRINCIPLES}}';
    const result = renderTemplate(template, {
      PRINCIPLES: '1. First\n2. Second\n3. Third',
    });
    expect(result).toBe('1. First\n2. Second\n3. Third');
  });

  it('replaces unset vars with empty string by default', () => {
    const template = 'Before {{MISSING}} After';
    const result = renderTemplate(template, {});
    expect(result).toBe('Before  After');
  });

  it('throws in strict mode for missing vars', () => {
    const template = '{{MISSING}}';
    expect(() => renderTemplate(template, {}, { strict: true })).toThrow(
      'Template variable not provided: {{MISSING}}',
    );
  });

  it('handles multiple occurrences of same placeholder', () => {
    const template = '{{NAME}} says hello, {{NAME}}!';
    const result = renderTemplate(template, { NAME: 'Jarvis' });
    expect(result).toBe('Jarvis says hello, Jarvis!');
  });

  it('preserves non-placeholder curly braces', () => {
    const template = 'const x = { foo: {{VALUE}} }';
    const result = renderTemplate(template, { VALUE: '"bar"' });
    expect(result).toBe('const x = { foo: "bar" }');
  });
});