/**
 * @license
 * Copyright (C) 2017 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import '../../plugins/gr-endpoint-decorator/gr-endpoint-decorator';
import '../../plugins/gr-endpoint-param/gr-endpoint-param';
import '../../shared/gr-button/gr-button';
import '../../shared/gr-editable-label/gr-editable-label';
import '../../shared/gr-rest-api-interface/gr-rest-api-interface';
import '../../shared/gr-storage/gr-storage';
import '../gr-default-editor/gr-default-editor';
import '../../../styles/shared-styles';
import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners';
import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
import {PolymerElement} from '@polymer/polymer/polymer-element';
import {htmlTemplate} from './gr-editor-view_html';
import {KeyboardShortcutMixin} from '../../../mixins/keyboard-shortcut-mixin/keyboard-shortcut-mixin';
import {
  GerritNav,
  GenerateUrlEditViewParameters,
} from '../../core/gr-navigation/gr-navigation';
import {SPECIAL_PATCH_SET_NUM} from '../../../utils/patch-set-util';
import {computeTruncatedPath} from '../../../utils/path-list-util';
import {customElement, property} from '@polymer/decorators';
import {RestApiService} from '../../../services/services/gr-rest-api/gr-rest-api';
import {
  ChangeInfo,
  PatchSetNum,
  EditPreferencesInfo,
  Base64FileContent,
} from '../../../types/common';
import {GrStorage} from '../../shared/gr-storage/gr-storage';

const RESTORED_MESSAGE = 'Content restored from a previous edit.';
const SAVING_MESSAGE = 'Saving changes...';
const SAVED_MESSAGE = 'All changes saved';
const SAVE_FAILED_MSG = 'Failed to save changes';

const STORAGE_DEBOUNCE_INTERVAL_MS = 100;

export interface GrEditorView {
  $: {
    restAPI: RestApiService & Element;
    storage: GrStorage;
  };
}
@customElement('gr-editor-view')
export class GrEditorView extends KeyboardShortcutMixin(
  GestureEventListeners(LegacyElementMixin(PolymerElement))
) {
  static get template() {
    return htmlTemplate;
  }

  /**
   * Fired when the title of the page should change.
   *
   * @event title-change
   */

  /**
   * Fired to notify the user of
   *
   * @event show-alert
   */

  @property({type: Object, observer: '_paramsChanged'})
  params?: GenerateUrlEditViewParameters;

  @property({type: Object})
  _change?: ChangeInfo | null;

  @property({type: Number})
  _changeNum?: number;

  @property({type: String})
  _patchNum?: PatchSetNum;

  @property({type: String})
  _path?: string;

  @property({type: String})
  _type?: string;

  @property({type: String})
  _content?: string;

  @property({type: String})
  _newContent?: string;

  @property({type: Boolean})
  _saving = false;

  @property({type: Boolean})
  _successfulSave = false;

  @property({
    type: Boolean,
    computed: '_computeSaveDisabled(_content, _newContent, _saving)',
  })
  _saveDisabled = true;

  @property({type: Object})
  _prefs?: EditPreferencesInfo;

  @property({type: Number})
  _lineNum?: number;

  get keyBindings() {
    return {
      'ctrl+s meta+s': '_handleSaveShortcut',
    };
  }

  /** @override */
  created() {
    super.created();
    this.addEventListener('content-change', e => {
      this._handleContentChange(e as CustomEvent<{value: string}>);
    });
  }

  /** @override */
  attached() {
    super.attached();
    this._getEditPrefs().then(prefs => {
      this._prefs = prefs;
    });
  }

  get storageKey() {
    return `c${this._changeNum}_ps${this._patchNum}_${this._path}`;
  }

  _getLoggedIn() {
    return this.$.restAPI.getLoggedIn();
  }

  _getEditPrefs() {
    return this.$.restAPI.getEditPreferences();
  }

  _paramsChanged(value: GenerateUrlEditViewParameters) {
    if (value.view !== GerritNav.View.EDIT) {
      return;
    }

    this._changeNum = value.changeNum;
    this._path = value.path;
    this._patchNum =
      value.patchNum || (SPECIAL_PATCH_SET_NUM.EDIT as PatchSetNum);
    this._lineNum =
      typeof value.lineNum === 'string'
        ? parseInt(value.lineNum)
        : value.lineNum;

    // NOTE: This may be called before attachment (e.g. while parentElement is
    // null). Fire title-change in an async so that, if attachment to the DOM
    // has been queued, the event can bubble up to the handler in gr-app.
    this.async(() => {
      const title = `Editing ${computeTruncatedPath(value.path)}`;
      this.dispatchEvent(
        new CustomEvent('title-change', {
          detail: {title},
          composed: true,
          bubbles: true,
        })
      );
    });

    const promises = [];

    promises.push(this._getChangeDetail(this._changeNum));
    promises.push(
      this._getFileData(this._changeNum, this._path, this._patchNum)
    );
    return Promise.all(promises);
  }

  _getChangeDetail(changeNum: number) {
    return this.$.restAPI.getDiffChangeDetail(changeNum).then(change => {
      this._change = change;
    });
  }

  _handlePathChanged(e: CustomEvent<string>) {
    // TODO(TS) could be cleand up, it was added for type requirements
    if (this._changeNum === undefined || !this._path) {
      return Promise.reject(new Error('changeNum or path undefined'));
    }
    const path = e.detail;
    if (path === this._path) {
      return Promise.resolve();
    }
    return this.$.restAPI
      .renameFileInChangeEdit(this._changeNum, this._path, path)
      .then(res => {
        if (!res || !res.ok) {
          return;
        }

        this._successfulSave = true;
        this._viewEditInChangeView();
      });
  }

  _viewEditInChangeView() {
    const patch = this._successfulSave
      ? (SPECIAL_PATCH_SET_NUM.EDIT as PatchSetNum)
      : this._patchNum;
    if (this._change && patch)
      GerritNav.navigateToChange(
        this._change,
        patch,
        undefined,
        patch !== SPECIAL_PATCH_SET_NUM.EDIT
      );
  }

  _getFileData(changeNum: number, path: string, patchNum?: PatchSetNum) {
    if (patchNum === undefined) {
      return Promise.reject(new Error('patchNum undefined'));
    }
    const storedContent = this.$.storage.getEditableContentItem(
      this.storageKey
    );

    return this.$.restAPI
      .getFileContent(changeNum, path, patchNum)
      .then(res => {
        const content = (res && (res as Base64FileContent).content) || '';
        if (
          storedContent &&
          storedContent.message &&
          storedContent.message !== content
        ) {
          this.dispatchEvent(
            new CustomEvent('show-alert', {
              detail: {message: RESTORED_MESSAGE},
              bubbles: true,
              composed: true,
            })
          );

          this._newContent = storedContent.message;
        } else {
          this._newContent = content;
        }
        this._content = content;

        // A non-ok response may result if the file does not yet exist.
        // The `type` field of the response is only valid when the file
        // already exists.
        if (res && res.ok && res.type) {
          this._type = res.type;
        } else {
          this._type = '';
        }
      });
  }

  _saveEdit() {
    if (this._changeNum === undefined || !this._path) {
      return Promise.reject(new Error('changeNum or path undefined'));
    }
    this._saving = true;
    this._showAlert(SAVING_MESSAGE);
    this.$.storage.eraseEditableContentItem(this.storageKey);
    if (!this._newContent)
      return Promise.reject(new Error('new content undefined'));
    return this.$.restAPI
      .saveChangeEdit(this._changeNum, this._path, this._newContent)
      .then(res => {
        this._saving = false;
        this._showAlert(res.ok ? SAVED_MESSAGE : SAVE_FAILED_MSG);
        if (!res.ok) {
          return;
        }

        this._content = this._newContent;
        this._successfulSave = true;
      });
  }

  _showAlert(message: string) {
    this.dispatchEvent(
      new CustomEvent('show-alert', {
        detail: {message},
        bubbles: true,
        composed: true,
      })
    );
  }

  _computeSaveDisabled(
    content?: string,
    newContent?: string,
    saving?: boolean
  ) {
    // Polymer 2: check for undefined
    if ([content, newContent, saving].includes(undefined)) {
      return true;
    }

    if (saving) {
      return true;
    }
    return content === newContent;
  }

  _handleCloseTap() {
    // TODO(kaspern): Add a confirm dialog if there are unsaved changes.
    this._viewEditInChangeView();
  }

  _handleContentChange(e: CustomEvent<{value: string}>) {
    this.debounce(
      'store',
      () => {
        const content = e.detail.value;
        if (content) {
          this.set('_newContent', e.detail.value);
          this.$.storage.setEditableContentItem(this.storageKey, content);
        } else {
          this.$.storage.eraseEditableContentItem(this.storageKey);
        }
      },
      STORAGE_DEBOUNCE_INTERVAL_MS
    );
  }

  _handleSaveShortcut(e: KeyboardEvent) {
    e.preventDefault();
    if (!this._saveDisabled) {
      this._saveEdit();
    }
  }
}

declare global {
  interface HTMLElementTagNameMap {
    'gr-editor-view': GrEditorView;
  }
}