import * as path from 'path';
import * as walkSync from 'walk-sync';

export type ModelMatcher = string | RegExp | Array<string | RegExp>;

function resolveModelFiles(modelMatcher: ModelMatcher, modelDir: string): string[] {
  if (Array.isArray(modelMatcher)) {
    const result: string[] = [];
    for (const matcher of modelMatcher) {
      result.splice(result.length, 0, ...resolveModelFiles(matcher, modelDir));
    }
    return result;
  } else if (modelMatcher instanceof RegExp) {
    const files = walkSync(modelDir, { directories: false });
    return files.filter((f) => modelMatcher.test(f)).map((f) => {
      return path.join(modelDir, f);
    });
  } else if (typeof modelMatcher === 'string') {
    return walkSync(modelDir, { globs: [modelMatcher] }).map((f) => {
      return path.join(modelDir, f);
    });
  } else {
    return [];
  }
};

function getModelFiles(projRoot: string, modelMatcher: ModelMatcher, modelBaseDir: string): string[] {
  const modelDir = path.join(projRoot, modelBaseDir);
  const modelFiles = resolveModelFiles(modelMatcher, modelDir);
  if (modelFiles.length === 0) {
    throw new Error('No model files found.');
  }
  return modelFiles;
};

export default getModelFiles;