import { i18n } from 'i18next';

import * as i18nModule from '@grafana/i18n/internal';

import { server } from './loader/pluginLoader.mock';
import { SystemJS } from './loader/systemjs';
import { SystemJSWithLoaderHooks } from './loader/types';
import { addTranslationsToI18n } from './plugin_loader';

describe('plugin_loader', () => {
  describe('addTranslationsToI18n', () => {
    const systemJSPrototype: SystemJSWithLoaderHooks = SystemJS.constructor.prototype;
    const originalFetch = systemJSPrototype.fetch;
    const originalResolve = systemJSPrototype.resolve;
    let addResourceBundleSpy: jest.SpyInstance;

    beforeAll(() => {
      server.listen();
      systemJSPrototype.resolve = (moduleId: string) => moduleId;
      systemJSPrototype.shouldFetch = () => true;
      // because server.listen() patches fetch, we need to reassign this to the systemJSPrototype
      // this is identical to what happens in the original code: https://github.com/systemjs/systemjs/blob/main/src/features/fetch-load.js#L12
      systemJSPrototype.fetch = window.fetch;
    });

    beforeEach(() => {
      addResourceBundleSpy = jest
        .spyOn(i18nModule, 'addResourceBundle')
        .mockImplementation(() => ({}) as unknown as i18n);
    });

    afterEach(() => {
      server.resetHandlers();
      jest.clearAllMocks();
    });

    afterAll(() => {
      SystemJS.constructor.prototype.resolve = originalResolve;
      SystemJS.constructor.prototype.fetch = originalFetch;
      server.close();
    });

    it('should add translations that match the resolved language first', async () => {
      const translations = {
        'en-US': '/public/plugins/test-panel/locales/en-US/test-panel.json',
        'pt-BR': '/public/plugins/test-panel/locales/pt-BR/test-panel.json',
      };

      await addTranslationsToI18n({
        resolvedLanguage: 'pt-BR',
        fallbackLanguage: 'en-US',
        pluginId: 'test-panel',
        translations,
      });

      expect(addResourceBundleSpy).toHaveBeenCalledTimes(1);
      expect(addResourceBundleSpy).toHaveBeenNthCalledWith(1, 'pt-BR', 'test-panel', { testKey: 'valorDeTeste' });
    });

    it('should add translations that match the fallback language if the resolved language is not in the translations', async () => {
      const translations = {
        'en-US': '/public/plugins/test-panel/locales/en-US/test-panel.json',
        'pt-BR': '/public/plugins/test-panel/locales/pt-BR/test-panel.json',
      };

      await addTranslationsToI18n({
        resolvedLanguage: 'sv-SE',
        fallbackLanguage: 'en-US',
        pluginId: 'test-panel',
        translations,
      });

      expect(addResourceBundleSpy).toHaveBeenCalledTimes(1);
      expect(addResourceBundleSpy).toHaveBeenNthCalledWith(1, 'en-US', 'test-panel', { testKey: 'testValue' });
    });

    it('should warn if no translations are found', async () => {
      const translations = {
        'en-US': '/public/plugins/test-panel/locales/en-US/test-panel.json',
        'pt-BR': '/public/plugins/test-panel/locales/pt-BR/test-panel.json',
      };

      const consoleSpy = jest.spyOn(console, 'warn').mockImplementation(() => {});

      await addTranslationsToI18n({
        resolvedLanguage: 'sv-SE',
        fallbackLanguage: 'sv-SE',
        pluginId: 'test-panel',
        translations,
      });

      expect(consoleSpy).toHaveBeenCalledWith('Could not find any translation for plugin test-panel', {
        resolvedLanguage: 'sv-SE',
        fallbackLanguage: 'sv-SE',
      });
    });

    it('should warn if no exported default is found', async () => {
      const translations = {
        'en-US': '/public/plugins/test-panel/locales/en-US/no-default-export.json',
        'pt-BR': '/public/plugins/test-panel/locales/pt-BR/no-default-export.json',
      };

      const consoleSpy = jest.spyOn(console, 'warn').mockImplementation(() => {});

      await addTranslationsToI18n({
        resolvedLanguage: 'en-US',
        fallbackLanguage: 'en-US',
        pluginId: 'test-panel',
        translations,
      });

      expect(consoleSpy).toHaveBeenCalledWith('Could not find default export for plugin test-panel', {
        resolvedLanguage: 'en-US',
        fallbackLanguage: 'en-US',
        path: '/public/plugins/test-panel/locales/en-US/no-default-export.json',
      });
    });

    it('should warn if translations cannot be loaded', async () => {
      const translations = {
        'en-US': '/public/plugins/test-panel/locales/en-US/unknown.json',
        'pt-BR': '/public/plugins/test-panel/locales/pt-BR/unknown.json',
      };

      const consoleSpy = jest.spyOn(console, 'warn').mockImplementation(() => {});

      await addTranslationsToI18n({
        resolvedLanguage: 'en-US',
        fallbackLanguage: 'pt-BR',
        pluginId: 'test-panel',
        translations,
      });

      expect(consoleSpy).toHaveBeenCalledWith('Could not load translation for plugin test-panel', {
        resolvedLanguage: 'en-US',
        fallbackLanguage: 'pt-BR',
        error: new TypeError('Failed to fetch'),
        path: '/public/plugins/test-panel/locales/en-US/unknown.json',
      });
    });
  });
});