/**
 * Unit tests for the finish-reason detection helpers.
 *
 * Guards the single source of truth that truncation-aware callers
 * (Graph.ts sticky finish reason, host continuation retry) rely on.
 */
import {
  TRUNCATION_FINISH_REASONS,
  isTruncationReason,
} from '../finishReasons';

describe('TRUNCATION_FINISH_REASONS', () => {
  it('includes every provider-specific truncation value we support', () => {
    expect(TRUNCATION_FINISH_REASONS.has('max_tokens')).toBe(true);
    expect(TRUNCATION_FINISH_REASONS.has('length')).toBe(true);
    expect(TRUNCATION_FINISH_REASONS.has('MAX_TOKENS')).toBe(true);
  });

  it('is case-sensitive — lowercase vertex value is not accepted', () => {
    // VertexAI uses the uppercase enum name; lowercase would be a wire bug
    // we do not want to silently treat as truncation.
    expect(TRUNCATION_FINISH_REASONS.has('max_Tokens')).toBe(false);
  });
});

describe('isTruncationReason', () => {
  it('returns true for Anthropic/Bedrock max_tokens', () => {
    expect(isTruncationReason('max_tokens')).toBe(true);
  });

  it('returns true for OpenAI length', () => {
    expect(isTruncationReason('length')).toBe(true);
  });

  it('returns true for VertexAI MAX_TOKENS', () => {
    expect(isTruncationReason('MAX_TOKENS')).toBe(true);
  });

  it('returns false for the stop/end_turn happy path', () => {
    expect(isTruncationReason('stop')).toBe(false);
    expect(isTruncationReason('end_turn')).toBe(false);
    expect(isTruncationReason('STOP')).toBe(false);
  });

  it('returns false for tool_use / tool_calls', () => {
    expect(isTruncationReason('tool_use')).toBe(false);
    expect(isTruncationReason('tool_calls')).toBe(false);
  });

  it('returns false for undefined, null, and empty string', () => {
    expect(isTruncationReason(undefined)).toBe(false);
    expect(isTruncationReason(null)).toBe(false);
    expect(isTruncationReason('')).toBe(false);
  });
});