/**
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 */

import invariant from '@lexical/internal/invariant';
import {
  $createParagraphNode,
  $createPoint,
  $createTextNode,
  $findMatchingParent,
  $getNodeByKey,
  $getSelection,
  $isElementNode,
  $isParagraphNode,
  $normalizeSelection__EXPERIMENTAL,
  type BaseSelection,
  type ElementNode,
  isCurrentlyReadOnlyMode,
  type LexicalNode,
  type NodeKey,
  type PointType,
  TEXT_TYPE_TO_FORMAT,
  type TextFormatType,
  type TextNode,
} from 'lexical';

import {
  $createTableCellNode,
  $isTableCellNode,
  TableCellHeaderStates,
  type TableCellNode,
} from './LexicalTableCellNode';
import {
  $createTableNode,
  $isTableNode,
  type TableNode,
} from './LexicalTableNode';
import {
  $createTableRowNode,
  $isTableRowNode,
  type TableRowNode,
} from './LexicalTableRowNode';
import {$findTableNode} from './LexicalTableSelectionHelpers';
import {
  $computeTableCellRectBoundary,
  $computeTableMap,
  $getTableCellNodeRect,
  $insertTableIntoGrid,
} from './LexicalTableUtils';

const __DEV__ = process.env.NODE_ENV !== 'production';

export type TableSelectionShape = {
  fromX: number;
  fromY: number;
  toX: number;
  toY: number;
};

export type TableMapValueType = {
  cell: TableCellNode;
  startRow: number;
  startColumn: number;
};
export type TableMapType = TableMapValueType[][];

function $getCellNodes(tableSelection: TableSelection): {
  anchorCell: TableCellNode;
  anchorNode: TextNode | ElementNode;
  anchorRow: TableRowNode;
  anchorTable: TableNode;
  focusCell: TableCellNode;
  focusNode: TextNode | ElementNode;
  focusRow: TableRowNode;
  focusTable: TableNode;
} {
  const [
    [anchorNode, anchorCell, anchorRow, anchorTable],
    [focusNode, focusCell, focusRow, focusTable],
  ] = (['anchor', 'focus'] as const).map(
    (k): [ElementNode | TextNode, TableCellNode, TableRowNode, TableNode] => {
      const node = tableSelection[k].getNode();
      const cellNode = $findMatchingParent(node, $isTableCellNode);
      invariant(
        $isTableCellNode(cellNode),
        'Expected TableSelection %s to be (or a child of) TableCellNode, got key %s of type %s',
        k,
        node.getKey(),
        node.getType(),
      );
      const rowNode = cellNode.getParent();
      invariant(
        $isTableRowNode(rowNode),
        'Expected TableSelection %s cell parent to be a TableRowNode',
        k,
      );
      const tableNode = rowNode.getParent();
      invariant(
        $isTableNode(tableNode),
        'Expected TableSelection %s row parent to be a TableNode',
        k,
      );
      return [node, cellNode, rowNode, tableNode];
    },
  );
  // TODO: nested tables may violate this
  invariant(
    anchorTable.is(focusTable),
    'Expected TableSelection anchor and focus to be in the same table',
  );
  return {
    anchorCell,
    anchorNode,
    anchorRow,
    anchorTable,
    focusCell,
    focusNode,
    focusRow,
    focusTable,
  };
}

export class TableSelection implements BaseSelection {
  tableKey: NodeKey;
  anchor: PointType;
  focus: PointType;
  _cachedNodes: LexicalNode[] | null;
  dirty: boolean;

  constructor(tableKey: NodeKey, anchor: PointType, focus: PointType) {
    this.anchor = anchor;
    this.focus = focus;
    anchor._selection = this;
    focus._selection = this;
    this._cachedNodes = null;
    this.dirty = false;
    this.tableKey = tableKey;
  }

  getStartEndPoints(): [PointType, PointType] {
    return [this.anchor, this.focus];
  }

  /**
   * {@link $createTableSelection} unfortunately makes it very easy to create
   * nonsense selections, so we have a method to see if the selection probably
   * makes sense.
   *
   * @returns true if the TableSelection is (probably) valid
   */
  isValid(): boolean {
    if (
      this.tableKey === 'root' ||
      this.anchor.key === 'root' ||
      this.anchor.type !== 'element' ||
      this.focus.key === 'root' ||
      this.focus.type !== 'element'
    ) {
      return false;
    }

    // Check if the referenced nodes still exist in the editor
    const tableNode = $getNodeByKey(this.tableKey);
    const anchorNode = $getNodeByKey(this.anchor.key);
    const focusNode = $getNodeByKey(this.focus.key);

    return tableNode !== null && anchorNode !== null && focusNode !== null;
  }

  /**
   * Returns whether the Selection is "backwards", meaning the focus
   * logically precedes the anchor in the EditorState.
   * @returns true if the Selection is backwards, false otherwise.
   */
  isBackward(): boolean {
    return this.focus.isBefore(this.anchor);
  }

  getCachedNodes(): LexicalNode[] | null {
    return this._cachedNodes;
  }

  setCachedNodes(nodes: LexicalNode[] | null): void {
    this._cachedNodes = nodes;
  }

  is(selection: null | BaseSelection): boolean {
    return (
      $isTableSelection(selection) &&
      this.tableKey === selection.tableKey &&
      this.anchor.is(selection.anchor) &&
      this.focus.is(selection.focus)
    );
  }

  set(tableKey: NodeKey, anchorCellKey: NodeKey, focusCellKey: NodeKey): void {
    // note: closure compiler's acorn does not support ||=
    this.dirty =
      this.dirty ||
      tableKey !== this.tableKey ||
      anchorCellKey !== this.anchor.key ||
      focusCellKey !== this.focus.key;
    this.tableKey = tableKey;
    this.anchor.key = anchorCellKey;
    this.focus.key = focusCellKey;
    this._cachedNodes = null;
  }

  clone(): TableSelection {
    return new TableSelection(
      this.tableKey,
      $createPoint(this.anchor.key, this.anchor.offset, this.anchor.type),
      $createPoint(this.focus.key, this.focus.offset, this.focus.type),
    );
  }

  isCollapsed(): boolean {
    return false;
  }

  extract(): LexicalNode[] {
    return this.getNodes();
  }

  insertRawText(text: string): void {
    if (text === '') {
      return;
    }
    const trimmed = text.endsWith('\n') ? text.slice(0, -1) : text;
    const tsvGrid = trimmed.split('\n').map(line => line.split('\t'));
    const tableNode = $createTableNode();
    for (const row of tsvGrid) {
      const rowNode = $createTableRowNode();
      for (const cellText of row) {
        const cellNode = $createTableCellNode(TableCellHeaderStates.NO_STATUS);
        const paragraph = $createParagraphNode();
        if (cellText) {
          paragraph.append($createTextNode(cellText));
        }
        cellNode.append(paragraph);
        rowNode.append(cellNode);
      }
      tableNode.append(rowNode);
    }
    const {anchorCell} = $getCellNodes(this);
    const rangeSelection = anchorCell.select(0, anchorCell.getChildrenSize());
    $insertTableIntoGrid(tableNode, rangeSelection);
  }

  insertText(): void {
    // Do nothing?
  }

  /**
   * Returns whether the provided TextFormatType is present on the Selection.
   * This will be true if any paragraph in table cells has the specified format.
   *
   * @param type the TextFormatType to check for.
   * @returns true if the provided format is currently toggled on the Selection, false otherwise.
   */
  hasFormat(type: TextFormatType): boolean {
    let format = 0;

    const cellNodes = this.getNodes().filter($isTableCellNode);
    cellNodes.forEach((cellNode: TableCellNode) => {
      const paragraph = cellNode.getFirstChild();
      if ($isParagraphNode(paragraph)) {
        format |= paragraph.getTextFormat();
      }
    });

    const formatFlag = TEXT_TYPE_TO_FORMAT[type];
    return (format & formatFlag) !== 0;
  }

  insertNodes(nodes: LexicalNode[]) {
    const focusNode = this.focus.getNode();
    invariant(
      $isElementNode(focusNode),
      'Expected TableSelection focus to be an ElementNode',
    );
    const selection = $normalizeSelection__EXPERIMENTAL(
      focusNode.select(0, focusNode.getChildrenSize()),
    );
    selection.insertNodes(nodes);
  }

  // TODO Deprecate this method. It's confusing when used with colspan|rowspan
  getShape(): TableSelectionShape {
    const {anchorCell, focusCell} = $getCellNodes(this);
    const anchorCellNodeRect = $getTableCellNodeRect(anchorCell);
    invariant(
      anchorCellNodeRect !== null,
      'getCellRect: expected to find AnchorNode',
    );
    const focusCellNodeRect = $getTableCellNodeRect(focusCell);
    invariant(
      focusCellNodeRect !== null,
      'getCellRect: expected to find focusCellNode',
    );

    const startX = Math.min(
      anchorCellNodeRect.columnIndex,
      focusCellNodeRect.columnIndex,
    );
    const stopX = Math.max(
      anchorCellNodeRect.columnIndex + anchorCellNodeRect.colSpan - 1,
      focusCellNodeRect.columnIndex + focusCellNodeRect.colSpan - 1,
    );

    const startY = Math.min(
      anchorCellNodeRect.rowIndex,
      focusCellNodeRect.rowIndex,
    );
    const stopY = Math.max(
      anchorCellNodeRect.rowIndex + anchorCellNodeRect.rowSpan - 1,
      focusCellNodeRect.rowIndex + focusCellNodeRect.rowSpan - 1,
    );

    return {
      fromX: Math.min(startX, stopX),
      fromY: Math.min(startY, stopY),
      toX: Math.max(startX, stopX),
      toY: Math.max(startY, stopY),
    };
  }

  getNodes(): LexicalNode[] {
    if (!this.isValid()) {
      return [];
    }
    const cachedNodes = this._cachedNodes;
    if (cachedNodes !== null) {
      return cachedNodes;
    }

    const {anchorTable: tableNode, anchorCell, focusCell} = $getCellNodes(this);

    const focusCellGrid = focusCell.getParents()[1];
    if (focusCellGrid !== tableNode) {
      if (!tableNode.isParentOf(focusCell)) {
        // focus is on higher Grid level than anchor
        const gridParent = tableNode.getParent();
        invariant(gridParent != null, 'Expected gridParent to have a parent');
        this.set(this.tableKey, gridParent.getKey(), focusCell.getKey());
      } else {
        // anchor is on higher Grid level than focus
        const focusCellParent = focusCellGrid.getParent();
        invariant(
          focusCellParent != null,
          'Expected focusCellParent to have a parent',
        );
        this.set(this.tableKey, focusCell.getKey(), focusCellParent.getKey());
      }
      return this.getNodes();
    }

    // TODO Mapping the whole Grid every time not efficient. We need to compute the entire state only
    // once (on load) and iterate on it as updates occur. However, to do this we need to have the
    // ability to store a state. Killing TableSelection and moving the logic to the plugin would make
    // this possible.
    const [map, cellAMap, cellBMap] = $computeTableMap(
      tableNode,
      anchorCell,
      focusCell,
    );
    const {minColumn, maxColumn, minRow, maxRow} =
      $computeTableCellRectBoundary(map, cellAMap, cellBMap);

    // We use a Map here because merged cells in the grid would otherwise
    // show up multiple times in the nodes array
    const nodeMap: Map<NodeKey, LexicalNode> = new Map([
      [tableNode.getKey(), tableNode],
    ]);
    let lastRow: null | TableRowNode = null;
    for (let i = minRow; i <= maxRow; i++) {
      for (let j = minColumn; j <= maxColumn; j++) {
        const {cell} = map[i][j];
        const currentRow = cell.getParent();
        invariant(
          $isTableRowNode(currentRow),
          'Expected TableCellNode parent to be a TableRowNode',
        );
        if (currentRow !== lastRow) {
          nodeMap.set(currentRow.getKey(), currentRow);
          lastRow = currentRow;
        }
        if (!nodeMap.has(cell.getKey())) {
          $visitRecursively(cell, childNode => {
            nodeMap.set(childNode.getKey(), childNode);
          });
        }
      }
    }
    const nodes = Array.from(nodeMap.values());

    if (!isCurrentlyReadOnlyMode()) {
      this._cachedNodes = nodes;
    }
    return nodes;
  }

  getTextContent(): string {
    const nodes = this.getNodes().filter(node => $isTableCellNode(node));
    let textContent = '';
    for (let i = 0; i < nodes.length; i++) {
      const node = nodes[i];
      const row = node.__parent;
      const nextRow = (nodes[i + 1] || {}).__parent;
      textContent += node.getTextContent() + (nextRow !== row ? '\n' : '\t');
    }
    return textContent;
  }
}

export function $isTableSelection(x: unknown): x is TableSelection {
  return x instanceof TableSelection;
}

export function $createTableSelection(): TableSelection {
  // TODO this is a suboptimal design, it doesn't make sense to have
  // a table selection that isn't associated with a table. This
  // constructor should have required arguments and in __DEV__ we
  // should check that they point to a table and are element points to
  // cell nodes of that table.
  const anchor = $createPoint('root', 0, 'element');
  const focus = $createPoint('root', 0, 'element');
  return new TableSelection('root', anchor, focus);
}

export function $createTableSelectionFrom(
  tableNode: TableNode,
  anchorCell: TableCellNode,
  focusCell: TableCellNode,
): TableSelection {
  const tableNodeKey = tableNode.getKey();
  const anchorCellKey = anchorCell.getKey();
  const focusCellKey = focusCell.getKey();
  if (__DEV__) {
    invariant(
      tableNode.isAttached(),
      '$createTableSelectionFrom: tableNode %s is not attached',
      tableNodeKey,
    );
    invariant(
      tableNode.is($findTableNode(anchorCell)),
      '$createTableSelectionFrom: anchorCell %s is not in table %s',
      anchorCellKey,
      tableNodeKey,
    );
    invariant(
      tableNode.is($findTableNode(focusCell)),
      '$createTableSelectionFrom: focusCell %s is not in table %s',
      focusCellKey,
      tableNodeKey,
    );
    // TODO: Check for rectangular grid
  }
  const prevSelection = $getSelection();
  const nextSelection = $isTableSelection(prevSelection)
    ? prevSelection.clone()
    : $createTableSelection();
  nextSelection.set(
    tableNode.getKey(),
    anchorCell.getKey(),
    focusCell.getKey(),
  );
  return nextSelection;
}

/**
 * Depth first visitor
 * @param node The starting node
 * @param $visit The function to call for each node. If the function returns false, then children of this node will not be explored
 */
export function $visitRecursively(
  node: LexicalNode,
  $visit: (childNode: LexicalNode) => boolean | undefined | void,
): void {
  const stack = [[node]];
  for (
    let currentArray = stack.at(-1);
    currentArray !== undefined && stack.length > 0;
    currentArray = stack.at(-1)
  ) {
    const currentNode = currentArray.pop();
    if (currentNode === undefined) {
      stack.pop();
    } else if ($visit(currentNode) !== false && $isElementNode(currentNode)) {
      stack.push(currentNode.getChildren());
    }
  }
}