gemini-cli-chat/lib/chat.js

Gemini AI CLI with markdown and colorful UX

import inquirer from "inquirer";
import chalk from "chalk";
import ora from "ora";
import { GoogleGenerativeAI } from "@google/generative-ai";
import { getApiKey, setConfig } from "./config.js";
import { marked } from "marked";
import TerminalRenderer from "marked-terminal";
import wrap from "word-wrap";

// MARKDOWN RENDERING SETUP
marked.setOptions({
  renderer: new TerminalRenderer({
    reflowText: true,
    strong: chalk.yellow.bold,
    listItem: chalk.green,
    heading: chalk.cyan.bold,
    codespan: chalk.magenta,
    code: chalk.magenta,
    link: chalk.blue.underline,
  }),
});

function colorizeDiagrams(text) {
  return text
    .split("\n")
    .map((line) => (line.match(/[+|>-]/) ? chalk.cyan(line) : line))
    .join("\n");
}
function enhanceBold(text) {
  return text.replace(/\*\*(.*?)\*\*/g, chalk.yellow.bold("$1"));
}

function renderMarkdownResponse(response) {
  // Wrap text to fit terminal width before applying markdown
  const wrappedText = wrap(response, {
    width: process.stdout.columns ? process.stdout.columns - 2 : 80,
    indent: "",
    trim: true,
  });
  const markdownOutput = marked(wrappedText);
  const diagramColored = colorizeDiagrams(markdownOutput);
  return enhanceBold(diagramColored);
}

// PAGINATED DISPLAY
async function displayPaginatedResponse(text) {
  const lines = text.split("\n");
  const pageSize = process.stdout.rows - 3; // Leave space for prompt and margin
  let currentPage = 0;

  while (currentPage * pageSize < lines.length) {
    const pageLines = lines.slice(
      currentPage * pageSize,
      (currentPage + 1) * pageSize
    );
    console.log(pageLines.join("\n"));

    const remainingLines = lines.length - (currentPage + 1) * pageSize;
    if (remainingLines > 0) {
      await inquirer.prompt([
        {
          type: "input",
          name: "continuePrompt",
          message: chalk.dim(`-- More (${remainingLines} lines remaining) --`),
        },
      ]);
      // Clear the "More" prompt line before showing the next page
      process.stdout.write("\x1B[1A\x1B[K");
    } else {
      console.log(); // Add a newline at the end of the response
      break;
    }
    currentPage++;
  }
}

// API KEY SETUP
async function ensureApiKey() {
  let apiKey = getApiKey();
  if (!apiKey) {
    console.log(chalk.yellow.bold("\nNo API key found!"));
    console.log(chalk.cyan("Follow these steps to get your Gemini API key:\n"));

    console.log(
      chalk.green("1.") +
        " Go to " +
        chalk.blue.underline("https://aistudio.google.com/app/apikey")
    );
    console.log(chalk.green("2.") + " Sign in with your Google account.");
    console.log(
      chalk.green("3.") +
        " Click " +
        chalk.bold('"Create API key"') +
        " and copy the generated key."
    );
    console.log(
      chalk.green("4.") +
        " The key will look like " +
        chalk.magenta("AIzaSy...")
    );
    console.log(chalk.green("5.") + " Paste it below when prompted.\n");

    try {
      const { key } = await inquirer.prompt([
        {
          type: "input",
          name: "key",
          message: "Enter your Gemini API Key:",
          validate: (input) => {
            if (!input || input.trim() === "")
              return "API key cannot be empty!";
            return true;
          },
        },
      ]);
      setConfig("API_KEY", key);
      apiKey = key;
    } catch (err) {
      if (err.name === "ExitPromptError") {
        console.log(chalk.yellow("\nGoodbye! (Ctrl+C)"));
        process.exit(0);
      }
      throw err;
    }
  }
  return apiKey;
}


// VALIDATE API KEY
async function validateApiKey(key) {
  try {
    const genAI = new GoogleGenerativeAI({ apiKey: key });
    const model = genAI.getGenerativeModel({ model: "gemini-1.5-flash" });
    await model.generateContent("ping");
    return true;
  } catch (err) {
    return false;
  }
}

// MAIN CHAT LOOP
export async function startChat() {
  console.clear();
  console.log(
    chalk.cyanBright.bold("Welcome to Gemini CLI!") +
      " " +
      chalk.green("Ask me anything...\n")
  );

  const apiKey = await ensureApiKey();

  if (!(await validateApiKey(apiKey))) {
    console.log(chalk.red("Invalid API Key! Please check and try again."));
    process.exit(1);
  }

  // Initialize Gemini model (FIX for correct constructor args)
  const genAI = new GoogleGenerativeAI({ apiKey });
  const model = genAI.getGenerativeModel({ model: "gemini-1.5-flash" });

  console.log(chalk.green('Type "exit" or ctrl+c to quit\n'));

  while (true) {
    try {
      const { userInput } = await inquirer.prompt([
        { type: "input", name: "userInput", message: chalk.blue("You:") },
      ]);
      if (userInput.trim() === "") {
        continue;
      }
      if (userInput.toLowerCase() === "exit") {
        console.log(chalk.yellow("Goodbye!"));
        break;
      }

      const spinner = ora("Thinking...").start();
      const result = await model.generateContent(userInput);
      spinner.stop();

      const responseText = renderMarkdownResponse(result.response.text());
      await displayPaginatedResponse(responseText);
    } catch (err) {
      if (err.name === "ExitPromptError") {
        console.log(chalk.yellow("\nGoodbye! (Ctrl+C)"));
        process.exit(0);
      }
      console.log(chalk.red("Error:"), err.message);
    }
  }
}