/** @import { OpenAI } from "openai" */
/** @import { SessionDriverInterface, SessionContent, ChatMessage } from "./types.js" */

/**
 * @param {'local'} driver
 */
export function createSessionManager(driver) {
  switch (driver) {
    case "local":
      return createLocalSessionManager();
    default:
      throw new Error("Unknown session manager");
  }
}

/** @returns {SessionDriverInterface} */
function createLocalSessionManager() {
  /** @type {Map<string, SessionContent>} */
  const sessions = new Map();

  return {
    getHistory(from) {
      let chatHistory = sessions.get(from);

      if (!chatHistory) {
        chatHistory = { messages: [] };
        sessions.set(from, chatHistory);
      }

      return chatHistory;
    },

    flush() {
      sessions.clear();
    },

    saveMessage(from, message) {
      const chatHistory = this.getHistory(from);
      chatHistory.messages.push(message);

      if (message.role === "assistant") {
        if (chatHistory.messages.length > Number.parseInt(process.env.MAX_MESSAGES_LIMIT, 10))
          chatHistory.messages.splice(0, 2);
      }
    }
  };
}