// SPDX-FileCopyrightText: 2025 LiveKit, Inc.
//
// SPDX-License-Identifier: Apache-2.0
import {
  type JobContext,
  ServerOptions,
  cli,
  dedent,
  defineAgent,
  inference,
  llm,
  voice,
} from '@livekit/agents';
import { fileURLToPath } from 'node:url';
import { z } from 'zod';

// Shared data that's used by the storyteller agent.
// This structure is passed as a parameter to function calls.
type StoryData = {
  name?: string;
  location?: string;
};

// Use inheritance to create agent with custom hooks
class IntroAgent extends voice.Agent<StoryData> {
  async onEnter() {
    this.session.generateReply({
      instructions: '"greet the user and gather information"',
    });
  }

  static createIntroAgent() {
    return new IntroAgent({
      instructions: `You are a story teller. Your goal is to gather a few pieces of information from the user to make the story personalized and engaging. Ask the user for their name and where they are from.`,
      tools: [
        llm.tool({
          name: 'informationGathered',
          description:
            'Called when the user has provided the information needed to make the story personalized and engaging.',
          parameters: z.object({
            name: z.string().describe('The name of the user'),
            location: z.string().describe('The location of the user'),
          }),
          execute: async ({ name, location }, { ctx }: llm.ToolOptions<StoryData>) => {
            ctx.userData.name = name;
            ctx.userData.location = location;

            const storyAgent = StoryAgent.createStoryAgent(name, location);
            return llm.handoff({ agent: storyAgent, returns: "Let's start the story!" });
          },
        }),
      ],
    });
  }
}

class StoryAgent extends voice.Agent<StoryData> {
  async onEnter() {
    this.session.generateReply();
  }

  static createStoryAgent(name: string, location: string) {
    return new StoryAgent({
      instructions: dedent`
        You are a storyteller. Use the user's information in order to make the story personalized.
        The user's name is ${name}, from ${location}
      `,
    });
  }
}

export default defineAgent({
  entry: async (ctx: JobContext) => {
    const userdata: StoryData = {};

    const session = new voice.AgentSession({
      stt: new inference.STT({ model: 'deepgram/nova-3', language: 'en' }),
      tts: new inference.TTS({
        model: 'cartesia/sonic-3',
        voice: '9626c31c-bec5-4cca-baa8-f8ba9e84c8bc',
      }),
      llm: new inference.LLM({ model: 'openai/gpt-4.1-mini' }),
      // to use realtime model, replace the stt, llm, tts and vad with the following
      // llm: new openai.realtime.RealtimeModel(),
      userData: userdata,
    });

    await session.start({
      agent: IntroAgent.createIntroAgent(),
      room: ctx.room,
    });

    const participant = await ctx.waitForParticipant();
    console.log('participant joined: ', participant.identity);
  },
});

cli.runApp(new ServerOptions({ agent: fileURLToPath(import.meta.url) }));