import type { EditorSelection, SelectionRange, Line } from '@codemirror/state';
import type { ViewUpdate } from '@codemirror/view';

export interface Statistics {
  /** total length of the document */
  length: number;
  /** Get the number of lines in the editor. */
  lineCount: number;
  /** Get the currently line description around the given position. */
  line: Line;
  /** Get the proper [line-break](https://codemirror.net/docs/ref/#state.EditorState^lineSeparator) string for this state. */
  lineBreak: string;
  /** Returns true when the editor is [configured](https://codemirror.net/6/docs/ref/#state.EditorState^readOnly) to be read-only. */
  readOnly: boolean;
  /** The size (in columns) of a tab in the document, determined by the [`tabSize`](https://codemirror.net/6/docs/ref/#state.EditorState^tabSize) facet. */
  tabSize: number;
  /** Cursor Position */
  selection: EditorSelection;
  /** Make sure the selection only has one range. */
  selectionAsSingle: SelectionRange;
  /** Retrieves a list of all current selections. */
  ranges: readonly SelectionRange[];
  /** Get the currently selected code. */
  selectionCode: string;
  /**
   * The length of the given array should be the same as the number of active selections.
   * Replaces the content of the selections with the strings in the array.
   */
  selections: string[];
  /** Return true if any text is selected. */
  selectedText: boolean;
}

export const getStatistics = (view: ViewUpdate): Statistics => {
  return {
    line: view.state.doc.lineAt(view.state.selection.main.from),
    lineCount: view.state.doc.lines,
    lineBreak: view.state.lineBreak,
    length: view.state.doc.length,
    readOnly: view.state.readOnly,
    tabSize: view.state.tabSize,
    selection: view.state.selection,
    selectionAsSingle: view.state.selection.asSingle().main,
    ranges: view.state.selection.ranges,
    selectionCode: view.state.sliceDoc(view.state.selection.main.from, view.state.selection.main.to),
    selections: view.state.selection.ranges.map((r) => view.state.sliceDoc(r.from, r.to)),
    selectedText: view.state.selection.ranges.some((r) => !r.empty),
  };
};