openapi-clean-arch-gen/src/generators/dto.generator.ts

import { execSync } from 'child_process';
import fs from 'fs-extra';
import path from 'path';
import { logStep, logSuccess, logError, logDetail } from '../utils/logger';
import { toPascalCase } from '../utils/name-formatter';

/** Invokes `openapi-generator-cli` to generate DTOs into a temporary directory. */
export function generateCode(swaggerFile: string, templatesDir: string): string {
  logStep('Generating code from OpenAPI spec...');

  const tempDir = path.join(process.cwd(), '.temp-generated');

  if (fs.existsSync(tempDir)) {
    fs.removeSync(tempDir);
  }

  try {
    const command = `openapi-generator-cli generate \
      -i "${swaggerFile}" \
      -g typescript-angular \
      --global-property models \
      -t "${templatesDir}" \
      -o "${tempDir}" \
      --additional-properties=ngVersion=17.0.0,modelFileSuffix=.dto,modelNameSuffix=Dto`;

    execSync(command, { stdio: 'pipe' });
    logSuccess('Code generated successfully');

    return tempDir;
  } catch (_error) {
    logError('Error generating code');
    if (fs.existsSync(tempDir)) {
      fs.removeSync(tempDir);
    }
    process.exit(1);
  }
}

/** Copies the generated DTOs from the temporary directory to the output directory, organised by tag subfolder. */
export function organizeFiles(
  tempDir: string,
  outputDir: string,
  schemaTagMap: Record<string, string> = {}
): void {
  logStep('Organising generated DTO files...');

  const sourceDir = path.join(tempDir, 'model');
  const destDir = path.join(outputDir, 'data/dtos');
  let filesMoved = 0;

  if (fs.existsSync(sourceDir)) {
    fs.ensureDirSync(destDir);

    const files = fs.readdirSync(sourceDir).filter((file) => file.endsWith('.dto.ts'));

    files.forEach((file) => {
      // file is like "userResponse.dto.ts" → derive PascalCase schema name to look up tag
      const camelName = file.replace('.dto.ts', '');
      const pascalName = toPascalCase(camelName);
      const tagFolder = schemaTagMap[pascalName] || 'shared';

      const sourcePath = path.join(sourceDir, file);
      const destPath = path.join(destDir, tagFolder, file);
      fs.ensureDirSync(path.dirname(destPath));
      fs.copySync(sourcePath, destPath);
      filesMoved++;
      logDetail('dto', `${file} → ${path.relative(process.cwd(), destPath)}`);
    });
  }

  logSuccess(`${filesMoved} DTOs moved successfully`);
}

/** Post-processes the generated DTOs: adds cross-DTO imports and normalises Array<T> → T[]. */
export function addDtoImports(outputDir: string): void {
  logStep('Post-processing generated DTOs...');

  const dtosDir = path.join(outputDir, 'data/dtos');
  if (!fs.existsSync(dtosDir)) return;

  // Collect all .dto.ts files from all subfolders (1 level deep)
  const allFiles: { subfolder: string; file: string; fullPath: string }[] = [];

  const entries = fs.readdirSync(dtosDir);
  entries.forEach((entry) => {
    const entryPath = path.join(dtosDir, entry);
    if (fs.statSync(entryPath).isDirectory()) {
      fs.readdirSync(entryPath)
        .filter((f) => f.endsWith('.dto.ts'))
        .forEach((file) =>
          allFiles.push({ subfolder: entry, file, fullPath: path.join(entryPath, file) })
        );
    } else if (entry.endsWith('.dto.ts')) {
      allFiles.push({ subfolder: '', file: entry, fullPath: entryPath });
    }
  });

  // Build map: ClassName → { subfolder, fileBase }
  const dtoMap: Record<string, { subfolder: string; fileBase: string }> = {};
  allFiles.forEach(({ subfolder, file, fullPath }) => {
    const content = fs.readFileSync(fullPath, 'utf8');
    const match = content.match(/export interface (\w+)/);
    if (match) dtoMap[match[1]] = { subfolder, fileBase: file.replace('.ts', '') };
  });

  let filesProcessed = 0;

  allFiles.forEach(({ subfolder, file, fullPath }) => {
    const originalContent = fs.readFileSync(fullPath, 'utf8');
    let content = originalContent;

    const selfMatch = content.match(/export interface (\w+)/);
    const selfName = selfMatch ? selfMatch[1] : '';

    content = content.replace(/Array<(\w+)>/g, '$1[]');

    const references = new Set<string>();
    const typeRegex = /\b(\w+Dto)\b/g;
    let match;
    while ((match = typeRegex.exec(content)) !== null) {
      if (match[1] !== selfName) references.add(match[1]);
    }

    const imports: string[] = [];
    references.forEach((ref) => {
      if (dtoMap[ref]) {
        const { subfolder: refSubfolder, fileBase: refFileBase } = dtoMap[ref];
        const fromDir = subfolder ? path.join(dtosDir, subfolder) : dtosDir;
        const toFile = refSubfolder
          ? path.join(dtosDir, refSubfolder, refFileBase)
          : path.join(dtosDir, refFileBase);
        let relPath = path.relative(fromDir, toFile).replace(/\\/g, '/');
        if (!relPath.startsWith('.')) relPath = './' + relPath;
        imports.push(`import { ${ref} } from '${relPath}';`);
      }
    });

    if (imports.length > 0) content = imports.join('\n') + '\n' + content;

    if (content !== originalContent) {
      fs.writeFileSync(fullPath, content);
      filesProcessed++;
      logDetail('dto', `Post-processed ${file} (added ${imports.length} import(s))`);
    }
  });

  logSuccess(`${filesProcessed} DTOs post-processed`);
}