leetkick/src/commands/fetch.ts

A CLI tool for scaffolding LeetCode exercises with language-specific testing setups

import {Command} from 'commander';
import {fetchProblem} from '../utils/leetcode-api.js';
import {getAvailableLanguages, initializeLanguage} from '../utils/templates.js';
import {createProblemFiles} from '../utils/file-operations.js';
import {findWorkspaceRoot} from '../utils/workspace.js';
import {existsSync} from 'fs';
import {join} from 'path';

export const fetchCommand = new Command('fetch')
  .description('Fetch a LeetCode problem and create exercise files')
  .argument('<problem-slug>', 'LeetCode problem slug (e.g., "two-sum")')
  .option('-l, --language <language>', 'Programming language')
  .option('-f, --force', 'Overwrite existing exercise if it exists')
  .action(
    async (
      problemSlug: string,
      options: {language?: string; force?: boolean},
    ) => {
      try {
        const workspaceRoot = findWorkspaceRoot();

        if (!workspaceRoot) {
          console.log(
            'No leetkick workspace found. Run "leetkick init" first.',
          );
          console.log(
            'Make sure you are in a directory that contains .leetkick.json or run the command from within a leetkick workspace.',
          );
          return;
        }

        console.log(`Fetching problem: ${problemSlug}...`);

        const problem = await fetchProblem(problemSlug);
        console.log(
          `✓ Found: [${problem.questionFrontendId}] ${problem.title}`,
        );

        const availableLanguages = await getAvailableLanguages();

        if (!options.language) {
          console.log('Available languages:', availableLanguages.join(', '));
          throw new Error('Please specify a language with --language <lang>');
        }

        if (!availableLanguages.includes(options.language)) {
          console.log('Available languages:', availableLanguages.join(', '));
          throw new Error(`Language '${options.language}' not supported.`);
        }

        // Check if language workspace exists, initialize if not
        const languageDir = join(workspaceRoot, options.language);
        if (!existsSync(languageDir)) {
          console.log(`Initializing ${options.language} workspace...`);

          // Change to workspace root to create language directory there
          const originalCwd = process.cwd();
          process.chdir(workspaceRoot);

          try {
            await initializeLanguage(options.language);
          } finally {
            process.chdir(originalCwd);
          }
        }

        // Check if exercise already exists
        const paddedId = problem.questionFrontendId.padStart(4, '0');
        let problemDir: string;
        let problemName: string;
        let existingPath: string;

        if (options.language === 'kotlin' || options.language === 'java') {
          problemName = `problem${paddedId}`;
          problemDir = join(
            languageDir,
            'src',
            'main',
            options.language,
            problemName,
          );
          existingPath = problemDir;
        } else if (options.language === 'rust') {
          problemName = `problem_${paddedId}`;
          problemDir = join(languageDir, 'src');
          existingPath = join(problemDir, `${problemName}.rs`);
        } else {
          problemName = `problem_${paddedId}`;
          problemDir = join(languageDir, problemName);
          existingPath = problemDir;
        }

        if (existsSync(existingPath)) {
          if (!options.force) {
            console.log(`❌ Exercise already exists: ${existingPath}`);
            console.log('The exercise file/directory already exists.');
            console.log('Options:');
            console.log('  • Use --force to overwrite existing files');
            console.log('  • Choose a different language');
            console.log('  • Remove the existing file/directory manually');
            return; // Exit gracefully without throwing error
          } else {
            console.log(`⚠️  Overwriting existing exercise: ${problemName}`);
          }
        }

        // Create problem files (change to workspace root since createProblemFiles uses process.cwd())
        const originalCwd = process.cwd();
        process.chdir(workspaceRoot);

        try {
          await createProblemFiles(problem, options.language);
          console.log(
            `✓ Created ${options.language} exercise for: ${problem.title}`,
          );
          console.log(`📁 Problem ID: ${problemName}`);
        } finally {
          process.chdir(originalCwd);
        }
      } catch (error) {
        console.error('Error:', error instanceof Error ? error.message : error);
        throw error;
      }
    },
  );