text: import * as utils from '@interactjs/utils';
  import InteractableMethods from './InteractableMethods';
  
  function init (scope) {
    const {
      interact,
      interactions,
      defaults,
      Signals,
    } = scope;
  
    interact.use(InteractableMethods);
  
    // set cursor style on mousedown
    interactions.signals.on('down', function ({ interaction, pointer, event, eventTarget }) {
      if (interaction.interacting()) { return; }
  
      const actionInfo = getActionInfo(interaction, pointer, event, eventTarget, scope);
      prepare(interaction, actionInfo, scope);
    });
  
    // set cursor style on mousemove
    interactions.signals.on('move', function ({ interaction, pointer, event, eventTarget }) {
      if (interaction.pointerType !== 'mouse'
          || interaction.pointerIsDown
          || interaction.interacting()) { return; }
  
      const actionInfo = getActionInfo(interaction, pointer, event, eventTarget, scope);
      prepare(interaction, actionInfo, scope);
    });
  
    interactions.signals.on('move', function (arg) {
      const { interaction, event } = arg;
  
      if (!interaction.pointerIsDown
          || interaction.interacting()
          || !interaction.pointerWasMoved
          || !interaction.prepared.name) {
        return;
      }
  
      scope.autoStart.signals.fire('before-start', arg);
  
      const target = interaction.target;
  
      if (interaction.prepared.name && target) {
        // check manualStart and interaction limit
        if (target.options[interaction.prepared.name].manualStart
            || !withinInteractionLimit(target, interaction.element, interaction.prepared, scope)) {
          interaction.stop(event);
        }
        else {
          interaction.start(interaction.prepared, target, interaction.element);
        }
      }
    });
  
    interactions.signals.on('stop', function ({ interaction }) {
      const target = interaction.target;
  
      if (target && target.options.styleCursor) {
        setCursor(interaction.element, '', scope);
      }
    });
  
    interact.maxInteractions = maxInteractions;
  
    defaults.base.actionChecker = null;
    defaults.base.styleCursor = true;
  
    utils.extend(defaults.perAction, {
      manualStart: false,
      max: Infinity,
      maxPerElement: 1,
      allowFrom:  null,
      ignoreFrom: null,
  
      // only allow left button by default
      // see https://developer.mozilla.org/en-US/docs/Web/API/MouseEvent/buttons#Return_value
      mouseButtons: 1,
    });
  
    /**
     * Returns or sets the maximum number of concurrent interactions allowed.  By
     * default only 1 interaction is allowed at a time (for backwards
     * compatibility). To allow multiple interactions on the same Interactables and
     * elements, you need to enable it in the draggable, resizable and gesturable
     * `'max'` and `'maxPerElement'` options.
     *
     * @alias module:interact.maxInteractions
     *
     * @param {number} [newValue] Any number. newValue <= 0 means no interactions.
     */
    interact.maxInteractions = newValue => maxInteractions(newValue, scope);
  
    scope.autoStart = {
      // Allow this many interactions to happen simultaneously
      maxInteractions: Infinity,
      withinInteractionLimit,
      cursorElement: null,
      signals: new Signals(),
    };
  }
  
  // Check if the current target supports the action.
  // If so, return the validated action. Otherwise, return null
  function validateAction (action, interactable, element, eventTarget, scope) {
    if (utils.is.object(action)
        && interactable.testIgnoreAllow(interactable.options[action.name], element, eventTarget)
        && interactable.options[action.name].enabled
        && withinInteractionLimit(interactable, element, action, scope)) {
      return action;
    }
  
    return null;
  }
  
  function validateSelector (interaction, pointer, event, matches, matchElements, eventTarget, scope) {
    for (let i = 0, len = matches.length; i < len; i++) {
      const match = matches[i];
      const matchElement = matchElements[i];
      const action = validateAction(
        match.getAction(pointer, event, interaction, matchElement),
        match,
        matchElement,
        eventTarget,
        scope);
  
      if (action) {
        return {
          action,
          target: match,
          element: matchElement,
        };
      }
    }
  
    return {};
  }
  
  function getActionInfo (interaction, pointer, event, eventTarget, scope) {
    let matches = [];
    let matchElements = [];
  
    let element = eventTarget;
  
    function pushMatches (interactable) {
      matches.push(interactable);
      matchElements.push(element);
    }
  
    while (utils.is.element(element)) {
      matches = [];
      matchElements = [];
  
      scope.interactables.forEachMatch(element, pushMatches);
  
      const actionInfo = validateSelector(interaction, pointer, event, matches, matchElements, eventTarget, scope);
  
      if (actionInfo.action
        && !actionInfo.target.options[actionInfo.action.name].manualStart) {
        return actionInfo;
      }
  
      element = utils.dom.parentNode(element);
    }
  
    return {};
  }
  
  function prepare (interaction, { action, target, element }, scope) {
    action = action || {};
  
    if (interaction.target && interaction.target.options.styleCursor) {
      setCursor(interaction.element, '', scope);
    }
  
    interaction.target = target;
    interaction.element = element;
    utils.copyAction(interaction.prepared, action);
  
    if (target && target.options.styleCursor) {
      const cursor = action? scope.actions[action.name].getCursor(action) : '';
      setCursor(interaction.element, cursor, scope);
    }
  
    scope.autoStart.signals.fire('prepared', { interaction: interaction });
  }
  
  function withinInteractionLimit (interactable, element, action, scope) {
    const options = interactable.options;
    const maxActions = options[action.name].max;
    const maxPerElement = options[action.name].maxPerElement;
    const autoStartMax = scope.autoStart.maxInteractions;
    let activeInteractions = 0;
    let targetCount = 0;
    let targetElementCount = 0;
  
    // no actions if any of these values == 0
    if (!(maxActions && maxPerElement && autoStartMax)) { return; }
  
    for (const interaction of scope.interactions.list) {
      const otherAction = interaction.prepared.name;
  
      if (!interaction.interacting()) { continue; }
  
      activeInteractions++;
  
      if (activeInteractions >= autoStartMax) {
        return false;
      }
  
      if (interaction.target !== interactable) { continue; }
  
      targetCount += (otherAction === action.name)|0;
  
      if (targetCount >= maxActions) {
        return false;
      }
  
      if (interaction.element === element) {
        targetElementCount++;
  
        if (otherAction === action.name && targetElementCount >= maxPerElement) {
          return false;
        }
      }
    }
  
    return autoStartMax > 0;
  }
  
  function maxInteractions (newValue, scope) {
    if (utils.is.number(newValue)) {
      scope.autoStart.maxInteractions = newValue;
  
      return this;
    }
  
    return scope.autoStart.maxInteractions;
  }
  
  function setCursor (element, cursor, scope) {
    if (scope.autoStart.cursorElement) {
      scope.autoStart.cursorElement.style.cursor = '';
    }
  
    element.ownerDocument.documentElement.style.cursor = cursor;
    element.style.cursor = cursor;
    scope.autoStart.cursorElement = cursor ? element : null;
  }
  
  export default {
    init,
    maxInteractions,
    withinInteractionLimit,
    validateAction,
  };
  