import { Rule, Tree } from '@angular-devkit/schematics';
import * as prettier from 'prettier';
import { Observable } from 'rxjs';

export default function(): Rule {
  return (tree: Tree) =>
    new Observable<Tree>(o => {
      prettier.resolveConfig(process.cwd()).then(prettierConfig => {
        if (!prettierConfig) {
          o.error(new Error('Could not resolve prettier configuration'));
          return;
        }

        tree.visit(path => {
          if (path.endsWith('.tsx') || path.endsWith('.ts') || path.endsWith('.jsx') || path.endsWith('.js')) {
            const content = tree.read(path);
            if (content) {
              const formatted = prettier.format(content.toString(), prettierConfig);
              tree.overwrite(path, formatted);
            }
          }

          return false;
        });
        o.next(tree);
        o.complete();
      });
    });
}