import { DELETED_MESSAGE_CONTENT, type Message } from '../../../shared-kernel';

/** Extracts the effective timestamp from a message (editedAt takes priority). */
export function getMessageTimestamp(msg: Message): number {
  return msg.editedAt || msg.timestamp || 0;
}

/** Computes the most recent timestamp across a batch of messages. */
export function getLatestTimestamp(messages: Message[]): number {
  return messages.reduce(
    (max, msg) => Math.max(max, getMessageTimestamp(msg)),
    0
  );
}

/** Strips sensitive content from a deleted message. */
export function normaliseDeletedMessage(message: Message): Message {
  if (!message.isDeleted)
    return message;

  return {
    ...message,
    content: DELETED_MESSAGE_CONTENT,
    reactions: []
  };
}

/** Whether the given user is allowed to edit this message. */
export function canEditMessage(message: Message, userId: string): boolean {
  return message.senderId === userId;
}