import { describe, it, expect } from 'vitest';
import { formatMemoriesAsSystemPrompt } from './format.js';
import type { RecallResult, EntityState } from './types.js';

function makeMemory(overrides: Partial<RecallResult> = {}): RecallResult {
  return {
    id: 'mem-1',
    text: 'User prefers dark mode',
    type: 'experience',
    ...overrides,
  };
}

function makeEntities(): Record<string, EntityState> {
  return {
    'ent-1': {
      entity_id: 'ent-1',
      canonical_name: 'Alice',
      observations: [
        { text: 'Works at Acme Corp' },
        { text: 'Prefers TypeScript', mentioned_at: '2025-01-01T00:00:00Z' },
      ],
    },
  };
}

describe('formatMemoriesAsSystemPrompt', () => {
  it('returns empty string when no memories and no entities', () => {
    expect(formatMemoriesAsSystemPrompt([], null)).toBe('');
    expect(formatMemoriesAsSystemPrompt([], {})).toBe('');
    expect(formatMemoriesAsSystemPrompt([], undefined)).toBe('');
  });

  it('formats memories with default preamble', () => {
    const result = formatMemoriesAsSystemPrompt(
      [makeMemory(), makeMemory({ id: 'mem-2', text: 'Likes coffee', type: 'world' })],
      null
    );

    expect(result).toContain(
      'You have access to the following memories about this user'
    );
    expect(result).toContain('<memories>');
    expect(result).toContain('- User prefers dark mode [experience]');
    expect(result).toContain('- Likes coffee [world]');
    expect(result).toContain('</memories>');
    expect(result).not.toContain('<entity_observations>');
  });

  it('formats memories without type suffix when type is null', () => {
    const result = formatMemoriesAsSystemPrompt(
      [makeMemory({ type: null })],
      null
    );
    expect(result).toContain('- User prefers dark mode\n');
    expect(result).not.toContain('[');
  });

  it('includes entity observations', () => {
    const result = formatMemoriesAsSystemPrompt(
      [makeMemory()],
      makeEntities()
    );

    expect(result).toContain('<memories>');
    expect(result).toContain('<entity_observations>');
    expect(result).toContain('## Alice');
    expect(result).toContain('- Works at Acme Corp');
    expect(result).toContain('- Prefers TypeScript');
    expect(result).toContain('</entity_observations>');
  });

  it('shows only entities when no memories', () => {
    const result = formatMemoriesAsSystemPrompt([], makeEntities());

    expect(result).not.toContain('<memories>');
    expect(result).toContain('<entity_observations>');
    expect(result).toContain('## Alice');
  });

  it('uses custom preamble', () => {
    const result = formatMemoriesAsSystemPrompt(
      [makeMemory()],
      null,
      { preamble: 'Here is what I know:' }
    );
    expect(result.startsWith('Here is what I know:')).toBe(true);
  });

  it('limits memories with maxMemories', () => {
    const memories = [
      makeMemory({ id: '1', text: 'First' }),
      makeMemory({ id: '2', text: 'Second' }),
      makeMemory({ id: '3', text: 'Third' }),
    ];
    const result = formatMemoriesAsSystemPrompt(memories, null, {
      maxMemories: 2,
    });
    expect(result).toContain('First');
    expect(result).toContain('Second');
    expect(result).not.toContain('Third');
  });

  it('filters by includeTypes', () => {
    const memories = [
      makeMemory({ id: '1', text: 'World fact', type: 'world' }),
      makeMemory({ id: '2', text: 'Experience', type: 'experience' }),
      makeMemory({ id: '3', text: 'Observation', type: 'observation' }),
    ];
    const result = formatMemoriesAsSystemPrompt(memories, null, {
      includeTypes: ['world', 'observation'],
    });
    expect(result).toContain('World fact');
    expect(result).not.toContain('Experience');
    expect(result).toContain('Observation');
  });

  it('excludes entities when includeEntities is false', () => {
    const result = formatMemoriesAsSystemPrompt(
      [makeMemory()],
      makeEntities(),
      { includeEntities: false }
    );
    expect(result).toContain('<memories>');
    expect(result).not.toContain('<entity_observations>');
  });
});