import { IStoreState } from '../../index.data';
import * as R from 'rambda';
import { getFrozenWidth } from '../../store/selectors/dimensions';
import { ROW_INDICATOR_WIDTH } from '../../constants';

export class HScrollBarHelper {
  public barOffset: number;
  public barSize: number;
  // public thumbSize: number;
  // public thumbOffset: number;

  private _allVisibleColumnWidth: number = 0;
  private state: IStoreState;

  constructor(state: IStoreState) {
    this.state = state;

    if (
      state.containerBox.w <= 0 ||
      state.containerBox.h <= 0 ||
      R.isEmpty(state.colDimensions) ||
      R.isEmpty(state.rowDimensions)
    ) {
      this.barOffset = 0;
      this.barSize = 0;
      // this.thumbOffset = 0;
      // this.thumbSize = 0;
    } else {
      this.barOffset = this.getBarOffset();
      this.barSize = this.getBarSize();
      this._allVisibleColumnWidth = get_allVisibleColumnWidth_exceptFrozen(this.state);
      // this.thumbSize = this.getThumbSize();
      // this.thumbOffset = this.getThumbOffset();
    }
  }

  getBarOffset() {
    return getFrozenWidth(this.state) + ROW_INDICATOR_WIDTH;
  }

  getBarSize() {
    const state = this.state;
    return Math.max(state.containerBox.w - this.barOffset - 20, 0);
  }

  getThumbOffset() {
    const state = this.state;
    if (state.containerBox.w - this.barOffset <= 0) return 0;
    return (this.barSize / (this._allVisibleColumnWidth + state.padding.right)) * state.scrollX;
  }

  getThumbSize() {
    const state = this.state;
    return (
      (this.barSize / (this._allVisibleColumnWidth + state.padding.right)) *
      (this.barSize + 20) /*即容器真实高度 - 冻结行高度*/
    );
  }
}

function isFrozenColumnByJ(state: IStoreState, j: number): boolean {
  return j <= state.freezeAt.j;
}

export function get_allVisibleColumnWidth_exceptFrozen(state: IStoreState): number {
  const { columns } = state;

  let width = 0;
  for (let j = 0; j < columns.length; j++) {
    const column = columns[j];
    if (!isFrozenColumnByJ(state, j)) {
      width += column.width;
    }
  }

  return width;
}

/**
 * 找到某个区域内的全部可加载列
 */
export function getAllLoadableColumnFlags(state: IStoreState): boolean[] {
  const loadingWidth = state.containerBox.w + state.padding.right;
  return _getAllLoadableColumnFlags(state, loadingWidth, state.scrollX);
}

export function _getAllLoadableColumnFlags(
  state: IStoreState,
  loadingWidth: number,
  scrollX: number,
): boolean[] {
  if (state.freezeAt.j < 0) {
    return R.repeat(true, state.columns.length);
  }

  // console.log('计算时, 一定要注意: scrollX不包含在frozen区域中');
  const { columns, colDimensions } = state;
  const freezeAtJ = state.freezeAt.j;
  const result = R.repeat(false, columns.length);
  for (let j = 0; j < freezeAtJ + 1; j++) {
    result[j] = true;
  }

  const lastFrozenCol = freezeAtJ >= 0 ? columns[freezeAtJ] : null;

  const frozenWidth = lastFrozenCol
    ? colDimensions[lastFrozenCol.id!].width + colDimensions[lastFrozenCol.id!].left
    : 0;
  let usedWidth = frozenWidth;

  for (let j = freezeAtJ + 1; j < columns.length; j++) {
    if (usedWidth >= scrollX + loadingWidth) break;

    const colDim = colDimensions[columns[j].id!];
    if (!colDim) {
      result[j] = true;
      continue;
    }
    const colWidth = colDim.width;

    if (usedWidth + colWidth <= scrollX + frozenWidth) {
      usedWidth += colWidth;
      continue;
    }

    result[j] = true;
    usedWidth += colWidth;
  }

  return result;
}