/**
 * An identity key pair consists of a public and private key.
 * This is the long-term identity for a user/device.
 */
export interface IdentityKeyPair {
  /** The public identity key (33 bytes - Curve25519 compressed) */
  publicKey: Uint8Array;
  /** The private identity key (32 bytes) */
  privateKey: Uint8Array;
}

/**
 * A pre-key record for the X3DH key agreement.
 * Multiple pre-keys are generated and uploaded to the server.
 */
export interface PreKeyRecord {
  /** Unique identifier for this pre-key */
  id: number;
  /** The public pre-key */
  publicKey: Uint8Array;
  /** The private pre-key */
  privateKey: Uint8Array;
}

/**
 * A signed pre-key record for the X3DH key agreement.
 * Signed with the identity key to prove authenticity.
 */
export interface SignedPreKeyRecord {
  /** Unique identifier for this signed pre-key */
  id: number;
  /** The public signed pre-key */
  publicKey: Uint8Array;
  /** The private signed pre-key */
  privateKey: Uint8Array;
  /** Signature of the public key using the identity key */
  signature: Uint8Array;
  /** Timestamp when this key was generated */
  timestamp: number;
}

/**
 * A pre-key bundle is fetched from the server when establishing
 * a new session with a recipient.
 */
export interface PreKeyBundle {
  /** The recipient's registration ID */
  registrationId: number;
  /** The recipient's device ID */
  deviceId: number;
  /** Pre-key ID */
  preKeyId: number;
  /** Pre-key public key */
  preKeyPublic: Uint8Array;
  /** The signed pre-key ID */
  signedPreKeyId: number;
  /** The signed pre-key public key */
  signedPreKeyPublic: Uint8Array;
  /** Signature of the signed pre-key */
  signedPreKeySignature: Uint8Array;
  /** The recipient's identity public key */
  identityKey: Uint8Array;
  /** Optional Kyber (post-quantum) pre-key ID */
  kyberPreKeyId?: number;
  /** Optional Kyber pre-key public key */
  kyberPreKey?: Uint8Array;
  /** Optional Kyber pre-key signature */
  kyberPreKeySignature?: Uint8Array;
}

/**
 * An address identifies a specific user and device.
 */
export interface ProtocolAddress {
  /** User identifier (e.g., phone number, UUID) */
  name: string;
  /** Device identifier within the user's devices */
  deviceId: number;
}

/**
 * Message types in the Signal Protocol.
 */
export type CiphertextMessageType = 'whisper' | 'preKey' | 'senderKey' | 'plaintext';

/**
 * An encrypted message ready to be sent.
 */
export interface CiphertextMessage {
  /** The type of ciphertext message */
  type: CiphertextMessageType;
  /** The encrypted message body */
  body: Uint8Array;
}

/**
 * A decrypted message with sender information.
 */
export interface DecryptedMessage {
  /** The decrypted plaintext */
  plaintext: Uint8Array;
}

/**
 * A Kyber (post-quantum) pre-key record for PQXDH key agreement.
 * Provides quantum-resistant key exchange.
 */
export interface KyberPreKeyRecord {
  /** Unique identifier for this Kyber pre-key */
  id: number;
  /** The public Kyber pre-key */
  publicKey: Uint8Array;
  /** Signature of the public key using the identity key */
  signature: Uint8Array;
  /** Timestamp when this key was generated */
  timestamp: number;
  /** Serialized record for persistence (includes private key) */
  serialized: Uint8Array;
}