import { TpTable } from "./tp-table";

export default class ColumnMover {
  constructor(wrap, handleSelector) {
    this._handleSelector = handleSelector;
    this._mouseDown = this._mouseDown.bind(this);
    this._dragging = this._dragging.bind(this);
    this._draggingEnd = this._draggingEnd.bind(this);
    this._trackingStarted = false;

    // Amount of pixels the handle must be moved before its registered as a tracking gesture.
    this.threshold = 5;

    wrap.addEventListener('mousedown', this._mouseDown, true);
  }

  _mouseDown(e) {
    const handle = e.composedPath().find(node => node.matches && node.matches(this._handleSelector));
    if (!handle) return;

    e.stopPropagation();
    e.preventDefault();
    this._cHandle = handle;
    this._startX = e.pageX;
    this._watchDrag();
  }

  _watchDrag() {
    window.addEventListener('mousemove', this._dragging);
    window.addEventListener('mouseup', this._draggingEnd);
  }

  _stopWatchDrag() {
    window.removeEventListener('mousemove', this._dragging);
    window.removeEventListener('mouseup', this._draggingEnd);
  }

  _dragging(e) {
    if (this._trackingStarted === false && Math.abs(e.pageX - this._startX) >= this.threshold) {
      this._trackingStarted = true;
      this._showClone();
      this._clearSelection();
    }

    if (this._trackingStarted === true) {
      this._positionClone(e.pageX, e.pageY);
      this._cHandle.dispatchEvent(new CustomEvent('track-move', { detail: { target: this._cHandle, state: 'track', x: e.pageX, y: e.pageX }, bubbles: true, composed: true }));
    }
  }

  _draggingEnd(e) {
    this._trackingStarted = false;
    this._cHandle.dispatchEvent(new CustomEvent('track-move', { detail: { target: this._cHandle, state: 'end', x: e.pageX, y: e.pageX }, bubbles: true, composed: true }));
    this._stopWatchDrag();
    this._cHandle = null;
    this._startX = 0;
    this._clearSelection();
    this._clone.remove();
    this._clone = null;
    if (this._indicator) {
      this._indicator.remove();
      this._indicator = null;
    }
  }

  _clearSelection() {
    const sel = window.getSelection ? window.getSelection() : document.selection;
    if (sel) {
      if (sel.removeAllRanges) {
        sel.removeAllRanges();
      } else if (sel.empty) {
        sel.empty();
      }
    }
  }

  /**
   * Show indicator to visualize where a column would be dropped after releasing the mouse.
   * @param {number} x X-coordinate
   * @param {number} y Y-coordinate
   */
  showIndicator(x, y) {
    if (!this._indicator) {
      const icon = document.createElement('tp-icon');
      icon.icon = TpTable.downIcon;
      icon.style.position = 'fixed';
      icon.style.left = '0px';
      icon.style.right = '0px';
      icon.style.zIndex = '100000';
      document.body.appendChild(icon);
      this._indicator = icon;
    }

    const rect = this._indicator.getBoundingClientRect();
    this._indicator.style.transform = `translate(${x - ((rect.right - rect.left) / 2)}px, ${y - rect.height}px)`;
  }

  _showClone() {
    const div = document.createElement('div');
    div.style.background = 'rgba(255, 255, 255, 0.6)';
    div.style.border = 'solid 1px rgba(255, 255, 255, 0.8)';
    div.style.padding = '5px 10px';
    div.style.borderRadius = '2px';
    div.style.position = 'fixed';
    div.style.zIndex = '99999';
    div.style.left = '0px';
    div.style.top = '0px';
    div.style.display = 'flex';
    div.style.alignItems = 'center';
    div.style.justifyContent = 'center';
    div.innerHTML = this._cHandle.column.label;

    this._clone = div;
    document.body.appendChild(div);
  }

  _positionClone(x, y) {
    this._clone.style.transform = `translate(${x + 10}px, ${y}px)`;
  }
}