/**
 * Codebase maintenance commands
 *
 * Commands for bulk updates across feature packages
 */

import { readFile, writeFile, readdir } from 'fs/promises';
import { resolve, join } from 'path';
import { Logger } from '../../utils/logger';
import { colors } from '../../utils/colors';
import type { CommandContext, CommandResult } from '../types';

const logger = new Logger({ context: 'Codebase' });

// =============================================================================
// Helpers
// =============================================================================

/**
 * Find all backend-api package.json files in the codebase
 */
async function findBackendApiPackages(codebasePath: string): Promise<string[]> {
  const featuresPath = join(codebasePath, 'features');
  const featureDirs = await readdir(featuresPath, { withFileTypes: true });
  const files: string[] = [];

  for (const dir of featureDirs) {
    if (dir.isDirectory()) {
      const pkgPath = join(featuresPath, dir.name, 'backend-api', 'package.json');
      try {
        await readFile(pkgPath);
        files.push(pkgPath);
      } catch {
        // No backend-api/package.json for this feature
      }
    }
  }

  return files.sort();
}

// =============================================================================
// Script Fixes
// =============================================================================

interface ScriptFix {
  name: string;
  description: string;
  pattern: RegExp;
  replacement: string;
}

const SCRIPT_FIXES: ScriptFix[] = [
  {
    name: 'nest-to-npx',
    description: 'Replace bare "nest" commands with "npx --yes @nestjs/cli"',
    pattern: /("(?:start|start:dev|start:debug|start:prod|build)":\s*")nest\s+/g,
    replacement: '$1npx --yes @nestjs/cli ',
  },
  {
    name: 'tsc-to-npx',
    description: 'Replace bare "tsc" commands with "npx tsc"',
    pattern: /("(?:build|type-check|typecheck)":\s*")tsc(\s|")/g,
    replacement: '$1npx tsc$2',
  },
];

/**
 * Fix scripts in all backend-api package.json files
 */
export async function fixScripts(ctx: CommandContext): Promise<CommandResult> {
  const codebasePath = resolve(process.cwd(), 'codebase');
  const dryRun = ctx.args.includes('--dry-run');

  logger.header('Fix Package Scripts');

  if (dryRun) {
    logger.info('Dry run mode - no files will be modified');
    logger.blank();
  }

  const files = await findBackendApiPackages(codebasePath);
  logger.info(`Found ${files.length} backend-api packages`);
  logger.blank();

  let totalFixed = 0;
  let totalSkipped = 0;

  for (const filePath of files) {
    const relativePath = filePath.replace(codebasePath + '/', '');
    const content = await readFile(filePath, 'utf-8');
    let modified = content;
    const appliedFixes: string[] = [];

    for (const fix of SCRIPT_FIXES) {
      if (fix.pattern.test(modified)) {
        // Reset regex state
        fix.pattern.lastIndex = 0;
        modified = modified.replace(fix.pattern, fix.replacement);
        appliedFixes.push(fix.name);
      }
    }

    if (appliedFixes.length > 0) {
      if (!dryRun) {
        await writeFile(filePath, modified, 'utf-8');
      }
      totalFixed++;
      logger.success(`${relativePath}`);
      for (const fixName of appliedFixes) {
        const fix = SCRIPT_FIXES.find(f => f.name === fixName);
        console.log(colors.muted(`    └─ ${fix?.description}`));
      }
    } else {
      totalSkipped++;
    }
  }

  logger.blank();
  logger.hr();
  logger.blank();

  if (totalFixed > 0) {
    logger.info(`${colors.success(`${totalFixed} packages updated`)}, ${totalSkipped} already correct`);
    if (dryRun) {
      logger.blank();
      logger.warn('Dry run - run without --dry-run to apply changes');
    }
  } else {
    logger.success('All packages already have correct scripts');
  }

  return { code: 0 };
}

/**
 * List all available script fixes
 */
export async function listFixes(_ctx: CommandContext): Promise<CommandResult> {
  logger.header('Available Script Fixes');
  logger.blank();

  for (const fix of SCRIPT_FIXES) {
    console.log(`  ${colors.primary(fix.name)}`);
    console.log(colors.muted(`    ${fix.description}`));
    logger.blank();
  }

  return { code: 0 };
}

// =============================================================================
// Dependency Audit
// =============================================================================

interface MissingDep {
  file: string;
  package: string;
  reason: string;
}

/**
 * Audit backend-api packages for common missing dependencies
 */
export async function auditDeps(ctx: CommandContext): Promise<CommandResult> {
  const codebasePath = resolve(process.cwd(), 'codebase');

  logger.header('Audit Backend Dependencies');
  logger.blank();

  const files = await findBackendApiPackages(codebasePath);
  const missing: MissingDep[] = [];

  for (const filePath of files) {
    const relativePath = filePath.replace(codebasePath + '/', '');
    const content = await readFile(filePath, 'utf-8');
    const pkg = JSON.parse(content);

    // Check for SWC builder usage without SWC deps
    const nestCliPath = filePath.replace('package.json', 'nest-cli.json');
    try {
      const nestCli = JSON.parse(await readFile(nestCliPath, 'utf-8'));
      if (nestCli.compilerOptions?.builder === 'swc') {
        const devDeps = pkg.devDependencies || {};
        if (!devDeps['@swc/cli']) {
          missing.push({
            file: relativePath,
            package: '@swc/cli',
            reason: 'nest-cli.json uses SWC builder',
          });
        }
        if (!devDeps['@swc/core']) {
          missing.push({
            file: relativePath,
            package: '@swc/core',
            reason: 'nest-cli.json uses SWC builder',
          });
        }
      }
    } catch {
      // No nest-cli.json, skip SWC check
    }
  }

  if (missing.length > 0) {
    logger.warn(`Found ${missing.length} missing dependencies:`);
    logger.blank();

    const byFile = new Map<string, MissingDep[]>();
    for (const dep of missing) {
      const list = byFile.get(dep.file) || [];
      list.push(dep);
      byFile.set(dep.file, list);
    }

    for (const [file, deps] of byFile) {
      console.log(`  ${colors.warning(file)}`);
      for (const dep of deps) {
        console.log(colors.muted(`    └─ Missing ${colors.accent(dep.package)}: ${dep.reason}`));
      }
      logger.blank();
    }

    if (ctx.args.includes('--fix')) {
      logger.info('Fixing missing dependencies...');
      for (const [file, deps] of byFile) {
        const filePath = resolve(codebasePath, file);
        const content = await readFile(filePath, 'utf-8');
        const pkg = JSON.parse(content);

        pkg.devDependencies = pkg.devDependencies || {};
        for (const dep of deps) {
          // Use common versions
          if (dep.package === '@swc/cli') {
            pkg.devDependencies['@swc/cli'] = '^0.7.10';
          } else if (dep.package === '@swc/core') {
            pkg.devDependencies['@swc/core'] = '^1.15.8';
          }
        }

        // Sort devDependencies
        pkg.devDependencies = Object.fromEntries(
          Object.entries(pkg.devDependencies).sort(([a], [b]) => a.localeCompare(b))
        );

        await writeFile(filePath, JSON.stringify(pkg, null, 2) + '\n', 'utf-8');
        logger.success(`Fixed ${file}`);
      }

      logger.blank();
      logger.info('Run ./run install to install the new dependencies');
    } else {
      logger.blank();
      logger.info('Run with --fix to add missing dependencies');
    }

    return { code: missing.length > 0 && !ctx.args.includes('--fix') ? 1 : 0 };
  }

  logger.success('All packages have required dependencies');
  return { code: 0 };
}

// =============================================================================
// Main Entry Point
// =============================================================================

export async function codebase(ctx: CommandContext): Promise<CommandResult> {
  const [subcommand] = ctx.args;

  switch (subcommand) {
    case 'fix-scripts':
      return fixScripts({ ...ctx, args: ctx.args.slice(1) });

    case 'list-fixes':
      return listFixes({ ...ctx, args: ctx.args.slice(1) });

    case 'audit-deps':
      return auditDeps({ ...ctx, args: ctx.args.slice(1) });

    default:
      logger.header('Codebase Maintenance Commands');
      logger.blank();
      console.log(`${colors.accent('Usage:')} ./run codebase <command> [options]`);
      logger.blank();
      console.log(`${colors.accent('Commands:')}`);
      console.log('  fix-scripts      Fix package.json scripts across all backend-api packages');
      console.log('                   --dry-run    Preview changes without modifying files');
      logger.blank();
      console.log('  list-fixes       List all available script fixes');
      logger.blank();
      console.log('  audit-deps       Audit for missing dependencies (SWC, etc.)');
      console.log('                   --fix        Automatically add missing dependencies');
      logger.blank();
      return { code: 0 };
  }
}