import * as assert from 'assert';
import { FileSystem } from '../../../../lib/json-schema-diff/file-reader/file-system';

interface MockFileSystemHelpers {
  givenReadFileReturnsContent(stringContent: string): void;
  givenReadFileReturnsContents(files: {
    [fileName: string]: Promise<string>;
  }): void;
  givenReadFileReturnsJsonContent(jsonContent: unknown): void;
  givenReadFileReturnsError(error: Error): void;
}

export type MockFileSystem = jasmine.SpyObj<FileSystem> & MockFileSystemHelpers;

export const createMockFileSystem = (): MockFileSystem => {
  const mockFileSystem: MockFileSystem = jasmine.createSpyObj(
    'mockFileSystem',
    ['readFile'],
  );

  mockFileSystem.givenReadFileReturnsContent = stringContent => {
    mockFileSystem.readFile.and.returnValue(Promise.resolve(stringContent));
  };

  mockFileSystem.givenReadFileReturnsContents = files => {
    mockFileSystem.readFile.and.callFake(
      (filePath: string): Promise<string> => {
        const file = files[filePath];
        assert.ok(
          file !== undefined,
          `Unexpected call to fileSystem.readFile with "${filePath}"`,
        );
        return file;
      },
    );
  };

  mockFileSystem.givenReadFileReturnsJsonContent = jsonContent => {
    const contentAsJsonString = JSON.stringify(jsonContent);
    mockFileSystem.givenReadFileReturnsContent(contentAsJsonString);
  };

  mockFileSystem.givenReadFileReturnsError = error => {
    mockFileSystem.readFile.and.returnValue(Promise.reject(error));
  };

  mockFileSystem.givenReadFileReturnsJsonContent({});

  return mockFileSystem;
};