import { existsSync, readdirSync, statSync } from 'fs';
import { basename, join } from 'path';

export interface BuildingBlockFoldersCollection {
  result: string[];
  skipped: BuildingBlockFolderStats[];
}

export interface BuildingBlockFolderStats {
  folderName: string;
  success: boolean;
  componentExists: boolean;
  moduleExists: boolean;
  markdownExists: boolean;
}

/**
 * Find all suitable folders that contain a Building Block.
 * A Building needs to be an Angular component, with a Markdown Files and Module.
 * All with the same name
 */
export async function collectBuildingBlockFolders(
  source: string
): Promise<BuildingBlockFoldersCollection> {
  const sourceFolder = join(source, 'src', 'lib');

  const files = readdirSync(sourceFolder);
  const result: string[] = [];
  const skipped: BuildingBlockFolderStats[] = [];

  for (const folderName of files) {
    const currentFolderPath = join(sourceFolder, folderName);
    const stats = statSync(currentFolderPath);

    if (stats.isDirectory()) {
      const stats = statsBuildingBlockFolder(currentFolderPath);

      if (false === stats.success) {
        skipped.push(stats);
      } else {
        result.push(currentFolderPath);
      }
    }
  }

  return { result, skipped };
}

/**
 * Create a small stat report about the given folder.
 * Check if all required files for a Building Block do exist
 * and return details of the check for a later analysis/logging
 * to provide some verbose output.
 */
function statsBuildingBlockFolder(folderPath: string): BuildingBlockFolderStats {
  const folderName = basename(folderPath);

  const expectedComponentName = `${folderName}.component.ts`;
  const componentExists = existsSync(join(folderPath, expectedComponentName));

  const expectedModuleName = `${folderName}.module.ts`;
  const moduleExists = existsSync(join(folderPath, expectedModuleName));

  const expectedMarkdownFile = `${folderName}.md`;
  const markdownExists = existsSync(join(folderPath, expectedMarkdownFile));

  const isBuildingBlock = componentExists && moduleExists && markdownExists;

  return {
    folderName,
    success: isBuildingBlock,
    componentExists,
    moduleExists,
    markdownExists
  };
}