import {createGroup} from 'app/client/components/commands';
import {ACIndexImpl, ACItem, ACResults} from 'app/client/lib/ACIndex';
import {IAutocompleteOptions} from 'app/client/lib/autocomplete';
import {IToken, TokenField, tokenFieldStyles} from 'app/client/lib/TokenField';
import {colors, testId} from 'app/client/ui2018/cssVars';
import {menuCssClass} from 'app/client/ui2018/menus';
import {cssInvalidToken} from 'app/client/widgets/ChoiceListCell';
import {createMobileButtons, getButtonMargins} from 'app/client/widgets/EditorButtons';
import {EditorPlacement} from 'app/client/widgets/EditorPlacement';
import {NewBaseEditor, Options} from 'app/client/widgets/NewBaseEditor';
import {cssRefList, renderACItem} from 'app/client/widgets/ReferenceEditor';
import {csvEncodeRow} from 'app/common/csvFormat';
import {CellValue} from "app/common/DocActions";
import {decodeObject, encodeObject} from 'app/plugin/objtypes';
import {dom, styled} from 'grainjs';

class ChoiceItem implements ACItem, IToken {
  public cleanText: string = this.label.toLowerCase().trim();
  constructor(
    public label: string,
    public isInvalid: boolean,  // If set, this token is not one of the valid choices.
    public isNew?: boolean,     // If set, this is a choice to be added to the config.
  ) {}
}

export class ChoiceListEditor extends NewBaseEditor {
  protected cellEditorDiv: HTMLElement;
  protected commandGroup: any;

  private _tokenField: TokenField;
  private _textInput: HTMLInputElement;
  private _dom: HTMLElement;
  private _editorPlacement: EditorPlacement;
  private _contentSizer: HTMLElement;   // Invisible element to size the editor with all the tokens
  private _inputSizer: HTMLElement;     // Part of _contentSizer to size the text input
  private _alignment: string;

  // Whether to include a button to show a new choice. (It would make sense to disable it when
  // user cannot change the column configuration.)
  private _enableAddNew: boolean = true;
  private _showAddNew: boolean = false;

  constructor(options: Options) {
    super(options);

    const choices: string[] = options.field.widgetOptionsJson.peek().choices || [];
    const acItems = choices.map(c => new ChoiceItem(c, false));
    const choiceSet = new Set(choices);

    const acIndex = new ACIndexImpl<ChoiceItem>(acItems);
    const acOptions: IAutocompleteOptions<ChoiceItem> = {
      menuCssClass: menuCssClass + ' ' + cssRefList.className + ' ' + cssChoiceList.className + ' test-autocomplete',
      search: async (term: string) => this._maybeShowAddNew(acIndex.search(term), term),
      renderItem: (item: ChoiceItem, highlightFunc) =>
        renderACItem(item.label, highlightFunc, item.isNew || false, this._showAddNew),
      getItemText: (item) => item.label,
    };

    this.commandGroup = this.autoDispose(createGroup(options.commands, null, true));
    this._alignment = options.field.widgetOptionsJson.peek().alignment || 'left';

    // If starting to edit by typing in a string, ignore previous tokens.
    const cellValue = decodeObject(options.cellValue);
    const startLabels: unknown[] = options.editValue || !Array.isArray(cellValue) ? [] : cellValue;
    const startTokens = startLabels.map(label => new ChoiceItem(String(label), !choiceSet.has(String(label))));

    this._tokenField = TokenField.create(this, {
      initialValue: startTokens,
      renderToken: item => [item.label, cssInvalidToken.cls('-invalid', (item as ChoiceItem).isInvalid)],
      createToken: label => new ChoiceItem(label, !choiceSet.has(label)),
      acOptions,
      openAutocompleteOnFocus: true,
      readonly : options.readonly,
      styles: {cssTokenField, cssToken, cssDeleteButton, cssDeleteIcon},
    });

    this._dom = dom('div.default_editor',
      dom.cls("readonly_editor", options.readonly),
      dom.cls(cssReadonlyStyle.className, options.readonly),
      this.cellEditorDiv = cssCellEditor(testId('widget-text-editor'),
        this._contentSizer = cssContentSizer(),
        elem => this._tokenField.attach(elem),
      ),
      createMobileButtons(options.commands),
    );

    this._textInput = this._tokenField.getTextInput();
    dom.update(this._tokenField.getRootElem(),
      dom.style('justify-content', this._alignment),
    );
    dom.update(this._tokenField.getHiddenInput(),
      this.commandGroup.attach(),
    );
    dom.update(this._textInput,
      // Resize the editor whenever user types into the textbox.
      dom.on('input', () => this.resizeInput(true)),
      dom.prop('value', options.editValue || ''),
      this.commandGroup.attach(),
    );
  }

  public attach(cellElem: Element): void {
    // Attach the editor dom to page DOM.
    this._editorPlacement = EditorPlacement.create(this, this._dom, cellElem, {margins: getButtonMargins()});

    // Reposition the editor if needed for external reasons (in practice, window resize).
    this.autoDispose(this._editorPlacement.onReposition.addListener(() => this.resizeInput()));

    // Update the sizing whenever the tokens change. Delay it till next tick to give a chance for
    // DOM updates that happen around tokenObs changes, to complete.
    this.autoDispose(this._tokenField.tokensObs.addListener(() =>
      Promise.resolve().then(() => this.resizeInput())));

    this.setSizerLimits();

    // Once the editor is attached to DOM, resize it to content, focus, and set cursor.
    this.resizeInput();
    this._textInput.focus();
    const pos = Math.min(this.options.cursorPos, this._textInput.value.length);
    this._textInput.setSelectionRange(pos, pos);
  }

  public getDom(): HTMLElement {
    return this._dom;
  }

  public getCellValue(): CellValue {
    return encodeObject(this._tokenField.tokensObs.get().map(item => item.label));
  }

  public getTextValue() {
    const values = this._tokenField.tokensObs.get().map(t => t.label);
    return csvEncodeRow(values, {prettier: true});
  }

  public getCursorPos(): number {
    return this._textInput.selectionStart || 0;
  }

  public async prepForSave() {
    const tokens = this._tokenField.tokensObs.get() as ChoiceItem[];
    const newChoices = tokens.filter(t => t.isNew).map(t => t.label);
    if (newChoices.length > 0) {
      const choices = this.options.field.widgetOptionsJson.prop('choices');
      await choices.saveOnly([...choices.peek(), ...new Set(newChoices)]);
    }
  }

  public setSizerLimits() {
    // Set the max width of the sizer to the max we could possibly grow to, so that it knows to wrap
    // once we reach it.
    const rootElem = this._tokenField.getRootElem();
    const maxSize = this._editorPlacement.calcSizeWithPadding(rootElem,
      {width: Infinity, height: Infinity}, {calcOnly: true});
    this._contentSizer.style.maxWidth = Math.ceil(maxSize.width) + 'px';
  }

  /**
   * Helper which resizes the token-field to match its content.
   */
  protected resizeInput(onlyTextInput: boolean = false) {
    if (this.isDisposed()) { return; }

    const rootElem = this._tokenField.getRootElem();

    // To size the content, we need both the tokens and the text typed into _textInput. We
    // re-create the tokens using cloneNode(true) copies all styles and properties, but not event
    // handlers. We can skip this step when we know that only _textInput changed.
    if (!onlyTextInput || !this._inputSizer) {
      this._contentSizer.innerHTML = '';

      dom.update(this._contentSizer,
        dom.update(rootElem.cloneNode(true) as HTMLElement,
          dom.style('width', ''),
          dom.style('height', ''),
          this._inputSizer = cssInputSizer(),

          // Remove the testId('tokenfield') from the cloned element, to simplify tests (so that
          // selecting .test-tokenfield only returns the actual visible tokenfield container).
          dom.cls('test-tokenfield', false),
        )
      );
    }

    // Use a separate sizer to size _textInput to the text inside it.
    // \u200B is a zero-width space; so the sizer will have height even when empty.
    this._inputSizer.textContent = this._textInput.value + '\u200B';
    const rect = this._contentSizer.getBoundingClientRect();

    const size = this._editorPlacement.calcSizeWithPadding(rootElem, rect);
    rootElem.style.width = size.width + 'px';
    rootElem.style.height = size.height + 'px';
    this._textInput.style.width = this._inputSizer.getBoundingClientRect().width + 'px';
  }

  private _maybeShowAddNew(result: ACResults<ChoiceItem>, text: string): ACResults<ChoiceItem> {
    // If the search text does not match anything exactly, add 'new' item for it. See also prepForSave.
    this._showAddNew = false;
    if (this._enableAddNew && text) {
      const addNewItem = new ChoiceItem(text, false, true);
      if (!result.items.find((item) => item.cleanText === addNewItem.cleanText)) {
        result.items.push(addNewItem);
        this._showAddNew = true;
      }
    }
    return result;
  }
}

const cssCellEditor = styled('div', `
  background-color: white;
  font-family: var(--grist-font-family-data);
  font-size: var(--grist-medium-font-size);
`);

const cssTokenField = styled(tokenFieldStyles.cssTokenField, `
  border: none;
  align-items: start;
  align-content: start;
  padding: 0 3px;
  height: min-content;
  min-height: 22px;
  color: black;
  flex-wrap: wrap;
`);

const cssToken = styled(tokenFieldStyles.cssToken, `
  padding: 1px 4px;
  margin: 2px;
  line-height: 16px;
`);

const cssDeleteButton = styled(tokenFieldStyles.cssDeleteButton, `
  position: absolute;
  top: -8px;
  right: -6px;
  border-radius: 16px;
  background-color: ${colors.dark};
  width: 14px;
  height: 14px;
  cursor: pointer;
  z-index: 1;
  display: none;
  align-items: center;
  justify-content: center;

  .${cssToken.className}:hover & {
    display: flex;
  }
  .${cssTokenField.className}.token-dragactive & {
    cursor: unset;
  }
`);

const cssDeleteIcon = styled(tokenFieldStyles.cssDeleteIcon, `
  --icon-color: ${colors.light};
  &:hover {
    --icon-color: ${colors.darkGrey};
  }
`);

const cssContentSizer = styled('div', `
  position: absolute;
  left: 0;
  top: -100px;
  border: none;
  visibility: hidden;
  overflow: visible;
  width: max-content;

  & .${tokenFieldStyles.cssInputWrapper.className} {
    display: none;
  }
`);

const cssInputSizer = styled('div', `
  flex: auto;
  min-width: 24px;
  margin: 3px 2px;
`);

// Set z-index to be higher than the 1000 set for .cell_editor.
const cssChoiceList = styled('div', `
  z-index: 1001;
  box-shadow: 0 0px 8px 0 rgba(38,38,51,0.6)
`);

const cssReadonlyStyle = styled('div', `
  padding-left: 16px;
  background: white;
`);