/**
 * One-time contributor detection and addition script.
 * Discovers missing contributors, determines their contribution types from repo history,
 * and updates .all-contributorsrc via the all-contributors CLI.
 *
 * Usage: node add-missing-contributors.mjs
 */
import { execSync } from 'node:child_process';
import fs from 'node:fs';
import path from 'node:path';
import { fileURLToPath } from 'node:url';
import {
  getContributionTypes,
  getMissingContributors,
  fetchContributorMergedPrs
} from './contributor-report.mjs';
import { setupGracefulShutdown } from './utils/graceful-shutdown.mjs';

const DEFAULT_CMD_TIMEOUT = 30_000; // 30 seconds

setupGracefulShutdown('add-missing-contributors');

/**
 * Get all files touched by a contributor from their merged PRs.
 * @param {string} username
 * @returns {string[]}
 */
const getContributorFiles = (username) => {
  try {
    console.log(`📁 Getting files for contributor: ${username}`);

    const prs = fetchContributorMergedPrs(username, { includeAllFiles: true });

    if (prs.length === 0) {
      console.log(`📭 No merged PRs found for ${username}`);
      return [];
    }

    const files = new Set();
    for (const pr of prs) {
      for (const file of pr.files || []) {
        if (file?.path) {
          files.add(file.path);
        }
      }
    }

    const fileList = Array.from(files);
    console.log(`📄 Found ${fileList.length} unique files for ${username}: ${fileList.slice(0, 3).join(', ')}${fileList.length > 3 ? '...' : ''}`);
    return fileList;

  } catch (error) {
    console.error(`❌ Error getting files for ${username}:`, error.message);
    return [];
  }
};

/**
 * Determine contribution types from a contributor's files.
 * @param {string} username
 * @returns {string}
 */
const analyzeContributor = (username) => {
  try {
    console.log(`🔍 Analyzing contribution types for: ${username}`);
    const files = getContributorFiles(username);

    if (files.length === 0) {
      console.log(`💡 No files found for ${username}, using 'code' fallback`);
      return 'code';
    }

    const contributionTypes = getContributionTypes(files);

    if (!contributionTypes || contributionTypes.trim() === '') {
      console.log(`💡 No matching types found for ${username}, using 'code' fallback`);
      return 'code';
    }

    console.log(`✅ Determined types for ${username}: ${contributionTypes}`);
    return contributionTypes;

  } catch (error) {
    console.error(`❌ Error analyzing files for ${username}:`, error.message);
    return 'code';
  }
};

/**
 * Add a username to the ignore list in .all-contributorsrc.
 * @param {string} username
 * @returns {boolean}
 */
const addToIgnoreList = (username) => {
  try {
    const configPath = path.join(process.cwd(), '.all-contributorsrc');
    const config = JSON.parse(fs.readFileSync(configPath, 'utf-8'));

    const ignoreList = config.ignoreList || config.ignore || [];
    if (!ignoreList.includes(username)) {
      ignoreList.push(username);
      config.ignoreList = ignoreList;
      fs.writeFileSync(configPath, JSON.stringify(config, null, 2));
      console.warn(`⚠️  Added ${username} to ignore list (user not found on GitHub)`);
      return true;
    }
    return false;
  } catch (error) {
    console.error(`❌ Failed to add ${username} to ignore list:`, error.message);
    return false;
  }
};

/**
 * Run the all-contributors CLI to add a contributor to the project.
 * @param {string} username
 * @param {string} types
 * @returns {boolean}
 */
const addContributor = (username, types) => {
  try {
    console.log(`➕ Adding contributor: ${username} with types: ${types}`);

    const command = `npx all-contributors add ${username} ${types}`;

    execSync(command, {
      encoding: 'utf8',
      stdio: ['pipe', 'pipe', 'pipe'],
      timeout: DEFAULT_CMD_TIMEOUT
    });

    return true;

  } catch (error) {
    // System-level errors that should propagate up
    if (error.message.includes('rate limit') || error.message.includes('403')) {
      console.error(`⏱️  Rate limit encountered while adding ${username}.`);
      throw error;
    }
    if (error.message.includes('network') || error.message.includes('timeout')) {
      console.error(`🌐 Network error while adding ${username}.`);
      throw error;
    }

    // User-specific errors that can be skipped
    if (error.message.includes('404') || error.message.includes('not found')) {
      addToIgnoreList(username);
      console.error(`❌ User ${username} not found, added to ignore list`);
      return false;
    }

    // Unknown error - log and skip
    console.error(`❌ Failed to add contributor ${username}:`, error.message);
    return false;
  }
};

/**
 * Process a single missing contributor: detect types and add via all-contributors CLI.
 * @param {string} username
 * @returns {{added:number, failed:number}}
 */
const processContributor = async (username) => {
  let added = 0;
  let failed = 0;

  try {
    console.log(`📊 Step 2: Analyzing contribution types for ${username}...`);
    const contributionTypes = analyzeContributor(username);

    console.log(`➕ Step 3: Adding ${username} with types: ${contributionTypes}...`);

    const success = addContributor(username, contributionTypes);
    if (success) {
      added++;
      console.log(`✅ Successfully processed ${username}`);
    } else {
      failed++;
      console.log(`❌ Failed to process ${username}`);
    }

  } catch (error) {
    failed++;
    console.error(`💥 Error processing ${username}:`, error.message);
  }

  return { added, failed };
};

/**
 * Main entry point: detect and add missing contributors.
 */
const main = async () => {
  console.log('🚀 Starting add missing contributors script');
  console.log('='.repeat(50));

  try {
    console.log('\n📋 Step 1: Detecting missing contributors...');
    const missingContributors = getMissingContributors();

    if (missingContributors.length === 0) {
      console.log('🎉 No missing contributors found! All contributors are properly recognized.');
      return { processed: 0, added: 0, failed: 0 };
    }

    console.log(`\n🔄 Processing ${missingContributors.length} missing contributors...`);

    let processed = 0;
    let added = 0;
    let failed = 0;

    for (const username of missingContributors) {
      console.log(`\n${'─'.repeat(30)}`);
      console.log(`👤 Processing contributor: ${username}`);

      processed++;

      try {
        const { added: deltaAdded, failed: deltaFailed } = await processContributor(username);
        added += deltaAdded;
        failed += deltaFailed;
      } catch (error) {
        // Re-throw system-level errors (rate limit, network, SIGINT)
        console.error(`💥 System error processing ${username}:`, error.message);
        throw error;
      }
    }

    return { processed, added, failed };
  } catch (error) {
    console.error('\n💥 Fatal error in main execution:', error.message);
    console.error('🛑 Script execution stopped');
    throw error;
  }
};

/**
 * Print a summary report of the run.
 * @param {{processed:number, added:number, failed:number}} results
 */
const printSummaryReport = (results) => {
  const { processed, added, failed } = results;

  console.log('\n' + '='.repeat(50));
  console.log('📊 EXECUTION SUMMARY');
  console.log('='.repeat(50));

  console.log(`📋 Total contributors processed: ${processed}`);
  console.log(`✅ Successfully added: ${added}`);
  console.log(`❌ Failed to add: ${failed}`);

  if (processed === 0) {
    console.log('\n🎉 SUCCESS: No missing contributors found - all contributors are properly recognized!');
  } else if (failed === 0) {
    console.log('\n🎉 SUCCESS: All missing contributors have been successfully added!');
    console.log('💡 Next steps: Review the updated .all-contributorsrc file and commit the changes.');
  } else if (added > 0) {
    console.log('\n⚠️  PARTIAL SUCCESS: Some contributors were added, but some failed.');
    console.log(`💡 ${added} contributors were successfully added.`);
    console.log(`🔄 ${failed} contributors failed - check the error messages above for details.`);
    console.log('💡 You may want to run the script again to retry failed contributors.');
  } else {
    console.log('\n❌ FAILURE: No contributors could be added.');
    console.log('💡 Check the error messages above for troubleshooting guidance.');
    console.log('💡 Common issues: missing GITHUB_TOKEN, network problems, or API rate limits.');
  }

  console.log('\n📝 ACTIONABLE NEXT STEPS:');
  if (added > 0) {
    console.log('• Review the updated .all-contributorsrc file');
    console.log('• Commit and push the changes to update the README');
    console.log('• Consider running "npm run contributors:generate" to update the README');
  }
  if (failed > 0) {
    console.log('• Check error messages above for specific failure reasons');
    console.log('• Verify GITHUB_TOKEN is set and has appropriate permissions');
    console.log('• Consider running the script again after resolving issues');
  }
  if (processed === 0) {
    console.log('• No action needed - all contributors are already recognized!');
  }

  console.log('\n' + '='.repeat(50));
};

if (process.argv[1] && fileURLToPath(import.meta.url) === path.resolve(process.argv[1])) {
  try {
    const results = await main();
    printSummaryReport(results);

    if (results.failed > 0 && results.added === 0) {
      process.exit(1);
    } else if (results.failed > 0) {
      process.exit(2);
    } else {
      process.exit(0);
    }
  } catch (error) {
    console.error('\n💥 Script execution failed:', error.message);
    console.log('\n📝 TROUBLESHOOTING TIPS:');
    console.log('• Ensure you are in a git repository');
    console.log('• Verify all-contributors-cli is installed');
    console.log('• Check that .all-contributorsrc file exists');
    console.log('• Ensure GITHUB_TOKEN environment variable is set');
    process.exit(1);
  }
}