import { describe, it, expect } from 'bun:test';

describe('ClaudeProvider Resume Parameter Logic', () => {
  function shouldPassResumeParameter(session: {
    memorySessionId: string | null;
    lastPromptNumber: number;
  }): boolean {
    const hasRealMemorySessionId = !!session.memorySessionId;
    return hasRealMemorySessionId && session.lastPromptNumber > 1;
  }

  describe('INIT prompt scenarios (lastPromptNumber === 1)', () => {
    it('should NOT pass resume parameter when lastPromptNumber === 1 even if memorySessionId exists', () => {
      const session = {
        memorySessionId: 'stale-session-id-from-previous-run',
        lastPromptNumber: 1, // INIT prompt
      };

      const hasRealMemorySessionId = !!session.memorySessionId;
      const shouldResume = shouldPassResumeParameter(session);

      expect(hasRealMemorySessionId).toBe(true); 
      expect(shouldResume).toBe(false); 
    });

    it('should NOT pass resume parameter when memorySessionId is null and lastPromptNumber === 1', () => {
      const session = {
        memorySessionId: null,
        lastPromptNumber: 1,
      };

      const hasRealMemorySessionId = !!session.memorySessionId;
      const shouldResume = shouldPassResumeParameter(session);

      expect(hasRealMemorySessionId).toBe(false);
      expect(shouldResume).toBe(false);
    });
  });

  describe('CONTINUATION prompt scenarios (lastPromptNumber > 1)', () => {
    it('should pass resume parameter when lastPromptNumber > 1 AND memorySessionId exists', () => {
      const session = {
        memorySessionId: 'valid-session-id',
        lastPromptNumber: 2, // CONTINUATION prompt
      };

      const hasRealMemorySessionId = !!session.memorySessionId;
      const shouldResume = shouldPassResumeParameter(session);

      expect(hasRealMemorySessionId).toBe(true);
      expect(shouldResume).toBe(true);
    });

    it('should pass resume parameter for higher prompt numbers', () => {
      const session = {
        memorySessionId: 'valid-session-id',
        lastPromptNumber: 5, // 5th prompt in session
      };

      const shouldResume = shouldPassResumeParameter(session);
      expect(shouldResume).toBe(true);
    });

    it('should NOT pass resume parameter when memorySessionId is null even for lastPromptNumber > 1', () => {
      const session = {
        memorySessionId: null,
        lastPromptNumber: 2,
      };

      const hasRealMemorySessionId = !!session.memorySessionId;
      const shouldResume = shouldPassResumeParameter(session);

      expect(hasRealMemorySessionId).toBe(false);
      expect(shouldResume).toBe(false);
    });
  });

  describe('Edge cases', () => {
    it('should handle empty string memorySessionId as falsy', () => {
      const session = {
        memorySessionId: '' as unknown as null,
        lastPromptNumber: 2,
      };

      const hasRealMemorySessionId = !!session.memorySessionId;
      const shouldResume = shouldPassResumeParameter(session);

      expect(hasRealMemorySessionId).toBe(false);
      expect(shouldResume).toBe(false);
    });

    it('should handle undefined memorySessionId as falsy', () => {
      const session = {
        memorySessionId: undefined as unknown as null,
        lastPromptNumber: 2,
      };

      const hasRealMemorySessionId = !!session.memorySessionId;
      const shouldResume = shouldPassResumeParameter(session);

      expect(hasRealMemorySessionId).toBe(false);
      expect(shouldResume).toBe(false);
    });
  });

  describe('Bug reproduction: stale session resume crash', () => {
    it('should NOT resume when worker restarts with stale memorySessionId', () => {

      const session = {
        memorySessionId: '5439891b-7d4b-4ee3-8662-c000f66bc199', // Stale from previous session
        lastPromptNumber: 1, // But this is a NEW session after restart
      };

      const shouldResume = shouldPassResumeParameter(session);

      expect(shouldResume).toBe(false);
    });

    it('should resume correctly for normal continuation (not after restart)', () => {
      const session = {
        memorySessionId: '5439891b-7d4b-4ee3-8662-c000f66bc199',
        lastPromptNumber: 2, // Second prompt in SAME session
      };

      const shouldResume = shouldPassResumeParameter(session);

      expect(shouldResume).toBe(true);
    });
  });
});
