import { describe, it, expect, vi, beforeEach } from "vitest";

// Mock crypto utilities
vi.mock("$lib/crypto/utils", () => ({
  KyberCrypto: {
    generateKeyPair: vi.fn(),
    encapsulate: vi.fn(),
    decapsulate: vi.fn(),
  },
  AESCrypto: {
    generateSessionKey: vi.fn(),
    encrypt: vi.fn(),
    decrypt: vi.fn(),
  },
  BufferUtils: {
    from: vi.fn(() => new Uint8Array()),
    toString: vi.fn(() => "mock-string"),
    concat: vi.fn(() => new Uint8Array()),
    randomBytes: vi.fn((length: number) => new Uint8Array(length)),
    equals: vi.fn(),
    xor: vi.fn(),
  },
  ShamirSecretSharing: {
    splitSecret: vi.fn(),
    reconstructSecret: vi.fn(),
  },
}));

vi.mock("$lib/logger", () => ({
  default: {
    setContext: vi.fn(() => ({
      debug: vi.fn(),
      error: vi.fn(),
      warn: vi.fn(),
    })),
  },
}));

// Import after mocking
import { KyberCrypto, AESCrypto, BufferUtils, ShamirSecretSharing } from "$lib/crypto/utils";

describe("Crypto Utilities for Appointment System", () => {
  beforeEach(() => {
    vi.clearAllMocks();
  });

  describe("KyberCrypto Operations", () => {
    it("should generate ML-KEM-768 key pair", () => {
      const mockKeyPair = {
        publicKey: new Uint8Array(32),
        privateKey: new Uint8Array(64),
      };

      vi.mocked(KyberCrypto.generateKeyPair).mockReturnValue(mockKeyPair);

      const keyPair = KyberCrypto.generateKeyPair();

      expect(keyPair).toEqual(mockKeyPair);
      expect(KyberCrypto.generateKeyPair).toHaveBeenCalledOnce();
    });

    it("should perform key encapsulation", () => {
      const mockPublicKey = new Uint8Array(32);
      const mockEncapsulationResult = {
        sharedSecret: new Uint8Array(32),
        encapsulatedSecret: new Uint8Array(48),
      };

      vi.mocked(KyberCrypto.encapsulate).mockReturnValue(mockEncapsulationResult);

      const result = KyberCrypto.encapsulate(mockPublicKey);

      expect(result).toEqual(mockEncapsulationResult);
      expect(KyberCrypto.encapsulate).toHaveBeenCalledWith(mockPublicKey);
    });

    it("should perform key decapsulation", () => {
      const mockPrivateKey = new Uint8Array(64);
      const mockCiphertext = new Uint8Array(48);
      const mockSharedSecret = new Uint8Array(32);

      vi.mocked(KyberCrypto.decapsulate).mockReturnValue(mockSharedSecret);

      const result = KyberCrypto.decapsulate(mockPrivateKey, mockCiphertext);

      expect(result).toEqual(mockSharedSecret);
      expect(KyberCrypto.decapsulate).toHaveBeenCalledWith(mockPrivateKey, mockCiphertext);
    });
  });

  describe("AES-256-GCM Operations", () => {
    it("should generate 256-bit AES session key", () => {
      const mockKey = new Uint8Array(32);

      vi.mocked(AESCrypto.generateSessionKey).mockReturnValue(mockKey);

      const key = AESCrypto.generateSessionKey();

      expect(key).toEqual(mockKey);
      expect(key.length).toBe(32); // 256 bits = 32 bytes
      expect(AESCrypto.generateSessionKey).toHaveBeenCalledOnce();
    });

    it("should encrypt data with AES-256-GCM", async () => {
      const mockData = "sensitive appointment data";
      const mockKey = new Uint8Array(32);
      const mockEncryptedResult = {
        encrypted: new Uint8Array(24),
        iv: new Uint8Array(16),
        tag: new Uint8Array(16),
      };

      vi.mocked(AESCrypto.encrypt).mockResolvedValue(mockEncryptedResult);

      const result = await AESCrypto.encrypt(mockData, mockKey);

      expect(result).toEqual(mockEncryptedResult);
      expect(AESCrypto.encrypt).toHaveBeenCalledWith(mockData, mockKey);
    });

    it("should decrypt data with AES-256-GCM", async () => {
      const mockCiphertext = new Uint8Array(24);
      const mockKey = new Uint8Array(32);
      const mockIv = new Uint8Array(16);
      const mockTag = new Uint8Array(16);
      const mockDecryptedData = "original appointment data";

      vi.mocked(AESCrypto.decrypt).mockResolvedValue(mockDecryptedData);

      const result = await AESCrypto.decrypt(mockCiphertext, mockKey, mockIv, mockTag);

      expect(result).toEqual(mockDecryptedData);
      expect(AESCrypto.decrypt).toHaveBeenCalledWith(mockCiphertext, mockKey, mockIv, mockTag);
    });

    it("should fail decryption with invalid authentication tag", async () => {
      const mockCiphertext = new Uint8Array(24);
      const mockKey = new Uint8Array(32);
      const mockIv = new Uint8Array(16);
      const mockInvalidTag = new Uint8Array(16);

      vi.mocked(AESCrypto.decrypt).mockRejectedValue(
        new Error("Authentication verification failed"),
      );

      await expect(
        AESCrypto.decrypt(mockCiphertext, mockKey, mockIv, mockInvalidTag),
      ).rejects.toThrow("Authentication verification failed");
    });
  });

  describe("Buffer Utilities", () => {
    it("should convert string to CryptoBuffer", () => {
      const testString = "test data";
      const expectedBuffer = new Uint8Array(8);

      vi.mocked(BufferUtils.from).mockReturnValue(expectedBuffer);

      const result = BufferUtils.from(testString);

      expect(result).toEqual(expectedBuffer);
      expect(BufferUtils.from).toHaveBeenCalledWith(testString);
    });

    it("should convert CryptoBuffer to string", () => {
      const testBuffer = new Uint8Array(8);
      const expectedString = "test data";

      vi.mocked(BufferUtils.toString).mockReturnValue(expectedString);

      const result = BufferUtils.toString(testBuffer);

      expect(result).toBe(expectedString);
      expect(BufferUtils.toString).toHaveBeenCalledWith(testBuffer);
    });

    it("should concatenate multiple CryptoBuffers", () => {
      const buffer1 = new Uint8Array(5);
      const buffer2 = new Uint8Array(5);
      const expectedBuffer = new Uint8Array(10);

      vi.mocked(BufferUtils.concat).mockReturnValue(expectedBuffer);

      const result = BufferUtils.concat([buffer1, buffer2]);

      expect(result).toEqual(expectedBuffer);
      expect(BufferUtils.concat).toHaveBeenCalledWith([buffer1, buffer2]);
    });

    it("should generate random bytes", () => {
      const mockRandomBytes = new Uint8Array(32);

      vi.mocked(BufferUtils.randomBytes).mockReturnValue(mockRandomBytes);

      const result = BufferUtils.randomBytes(32);

      expect(result).toEqual(mockRandomBytes);
      expect(result.length).toBe(32);
      expect(BufferUtils.randomBytes).toHaveBeenCalledWith(32);
    });
  });

  describe("Shamir Secret Sharing", () => {
    it("should split secret into shares", () => {
      const mockSecret = new Uint8Array(32);
      const mockShares = [
        { x: 1, y: new Uint8Array(32) },
        { x: 2, y: new Uint8Array(32) },
      ];

      vi.mocked(ShamirSecretSharing.splitSecret).mockReturnValue(mockShares);

      const result = ShamirSecretSharing.splitSecret(mockSecret, 2, 2);

      expect(result).toEqual(mockShares);
      expect(result).toHaveLength(2);
      expect(ShamirSecretSharing.splitSecret).toHaveBeenCalledWith(mockSecret, 2, 2);
    });

    it("should combine shares to reconstruct secret", () => {
      const mockShares = [
        { x: 1, y: new Uint8Array(32) },
        { x: 2, y: new Uint8Array(32) },
      ];
      const mockReconstructedSecret = new Uint8Array(32);

      vi.mocked(ShamirSecretSharing.reconstructSecret).mockReturnValue(mockReconstructedSecret);

      const result = ShamirSecretSharing.reconstructSecret(mockShares);

      expect(result).toEqual(mockReconstructedSecret);
      expect(ShamirSecretSharing.reconstructSecret).toHaveBeenCalledWith(mockShares);
    });
  });

  describe("Basic Error Handling", () => {
    it("should handle crypto operation failures", () => {
      expect(() => {
        // Mock error case for testing error handling patterns
        throw new Error("Crypto operation failed");
      }).toThrow("Crypto operation failed");
    });
  });

  describe("Error Handling in Crypto Operations", () => {
    it("should handle key generation failures", () => {
      vi.mocked(KyberCrypto.generateKeyPair).mockImplementation(() => {
        throw new Error("Random number generation failed");
      });

      expect(() => KyberCrypto.generateKeyPair()).toThrow("Random number generation failed");
    });

    it("should handle AES encryption failures", async () => {
      const mockData = "data to encrypt";
      const invalidKey = new Uint8Array(16); // Invalid key length (should be 32)

      vi.mocked(AESCrypto.encrypt).mockRejectedValue(new Error("Invalid key length for AES-256"));

      await expect(AESCrypto.encrypt(mockData, invalidKey)).rejects.toThrow(
        "Invalid key length for AES-256",
      );
    });
  });
});
