tool.ts

import "jsr:@std/dotenv/load";

const openrouterApiKey = Deno.env.get("OPENROUTER_API_KEY");

async function searchGutenbergBooks(searchTerms: string[]): Promise<any[]> {
  const searchQuery = searchTerms.join(" ");
  const url = "https://gutendex.com/books";
  const response = await fetch(`${url}?search=${searchQuery}`);
  const data = await response.json();

  return data.results.map((book: any) => ({
    id: book.id,
    title: book.title,
    authors: book.authors,
  }));
}

const tools = [
  {
    type: "function",
    function: {
      name: "searchGutenbergBooks",
      description:
        "Search for books in the Project Gutenberg library based on specified search terms",
      parameters: {
        type: "object",
        properties: {
          search_terms: {
            type: "array",
            items: {
              type: "string",
            },
            description:
              "List of search terms to find books in the Gutenberg library (e.g. ['dickens', 'great'] to search for books by Dickens with 'great' in the title)",
          },
        },
        required: ["search_terms"],
      },
    },
  },
];

const TOOL_MAPPING: any = {
  searchGutenbergBooks,
};

const messages: any = [
  { role: "system", content: "You are a helpful assistant." },
];

async function callLLM(messages: any[]): Promise<any> {
  const response = await fetch(
    "https://openrouter.ai/api/v1/chat/completions",
    {
      method: "POST",
      headers: {
        Authorization: `Bearer ${openrouterApiKey}`,
        "Content-Type": "application/json",
      },
      body: JSON.stringify({
        model: "google/gemini-2.0-flash-001",
        tools,
        messages,
      }),
    },
  );

  if (!response.ok) {
    throw new Error(`Response status: ${response.status}`);
  }

  const data = await response.json();

  messages.push(data.choices[0].message);

  return data;
}

async function getToolResponse(responseJson: any): Promise<any> {
  const toolCalls = responseJson.choices[0].message.tool_calls;

  for (const toolCall of toolCalls) {
    const toolName = toolCall.function.name;
    const toolArgs = [];

    const args = JSON.parse(toolCall.function.arguments);

    for (const arg in args) {
      toolArgs.push(args[arg]);
    }

    const toolResponse = await TOOL_MAPPING[toolName](...toolArgs);

    return {
      role: "tool",
      toolCallId: toolCall.id,
      name: toolName,
      content: JSON.stringify(toolResponse),
    };
  }
}

async function main() {
  const readPrompt = prompt("What can I help you with today?");

  messages.push({
    role: "user",
    content: readPrompt,
  });

  console.log("searching...");

  while (true) {
    const json = await callLLM(messages);

    if (json.choices[0].message.tool_calls) {
      messages.push(await getToolResponse(json));
    } else {
      break;
    }
  }

  console.log(messages[messages.length - 1].content);
}

main();