function createUserMessage(text) {
  return {
    id: `mp_${Date.now()}_${Math.random().toString(16).slice(2)}`,
    role: 'user',
    created: Math.floor(Date.now() / 1000),
    content: [{ type: 'text', text }],
    metadata: {
      source: 'wechat-miniapp',
      userVisible: true,
      agentVisible: true,
      displayText: text
    }
  };
}

function messageText(message) {
  if (!message) return '';
  if (typeof message.text === 'string') return message.text;
  if (Array.isArray(message.content)) {
    return message.content
      .filter((part) => part && part.type === 'text')
      .map((part) => part.text || '')
      .join('');
  }
  return '';
}

function normalizeMessages(messages = []) {
  return messages.map((message) => ({
    id: message.id || `${message.role}_${message.created || Date.now()}`,
    role: message.role || 'assistant',
    text: messageText(message),
    created: message.created || 0
  }));
}

module.exports = {
  createUserMessage,
  messageText,
  normalizeMessages
};