export default function () {
  'ngInject'
  /**
   * Creates a new DependenciesEvents object.
   *
   * @param manager DependenciesManager object
   * @constructor
   */
  let DependenciesEvents = function (manager) {
    let self = this

    this.manager = manager

    // Deny the start of a drag when in readonly
    let denyDragWhenReadOnly = function () {
      return !self.manager.pluginScope.readOnly
    }

    this.manager.plumb.bind('beforeDrag', denyDragWhenReadOnly)
    this.manager.plumb.bind('beforeStartDetach', denyDragWhenReadOnly)

    // Deny drop on the same task.
    let denyDropOnSameTask = function (params) {
      return params.sourceId !== params.targetId
    }

    this.manager.plumb.bind('beforeDrop', denyDropOnSameTask)

    // Notify the manager that a connection is being created.
    this.manager.plumb.bind('connectionDrag', function (connection) {
      self.manager.setDraggingConnection(connection)
    })

    this.manager.plumb.bind('connectionDragStop', function () {
      self.manager.setDraggingConnection(undefined)
    })

    this.manager.plumb.bind('beforeDrop', function () {
      self.manager.setDraggingConnection(undefined)
      return true
    })

    let createConnection = function (info, mouseEvent) {
      if (mouseEvent) {
        let oldDependency
        if (info.connection.$dependency) {
          oldDependency = info.connection.$dependency
        }

        let sourceEndpoint = info.sourceEndpoint
        let targetEndpoint = info.targetEndpoint

        let sourceModel = sourceEndpoint.$task.model

        let dependenciesModel = sourceModel.dependencies
        if (dependenciesModel === undefined) {
          dependenciesModel = []
          sourceModel.dependencies = dependenciesModel
        }

        let connectionModel = {to: targetEndpoint.$task.model.id}
        dependenciesModel.push(connectionModel)

        if (oldDependency) {
          oldDependency.removeFromTaskModel()
          self.manager.removeDependency(oldDependency, true) // Connection will be disconnected later by jsPlumb.
        }

        let dependency = self.manager.addDependency(sourceEndpoint.$task, connectionModel)
        info.connection.$dependency = dependency
        dependency.connection = info.connection
        dependency.connection.setParameter('from', sourceEndpoint.$task)
        dependency.connection.setParameter('to', targetEndpoint.$task)
        dependency.connection.canvas.setAttribute('data-fromId', sourceEndpoint.$task.model.id)
        dependency.connection.canvas.setAttribute('data-toId', targetEndpoint.$task.model.id)

        self.manager.api.dependencies.raise.add(dependency)

      }
    }

    let updateConnection = function (info, mouseEvent) {
      if (mouseEvent) {
        let oldDependency
        if (info.connection.$dependency) {
          oldDependency = info.connection.$dependency
        }

        let sourceEndpoint = info.newSourceEndpoint
        let targetEndpoint = info.newTargetEndpoint

        let sourceModel = sourceEndpoint.$task.model

        let dependenciesModel = sourceModel.dependencies
        if (dependenciesModel === undefined) {
          dependenciesModel = []
          sourceModel.dependencies = dependenciesModel
        }

        let connectionModel = {to: targetEndpoint.$task.model.id}
        dependenciesModel.push(connectionModel)

        if (oldDependency) {
          oldDependency.removeFromTaskModel()
          self.manager.removeDependency(oldDependency, true) // Connection will be disconnected later by jsPlumb.
        }

        let dependency = self.manager.addDependency(sourceEndpoint.$task, connectionModel)
        info.connection.$dependency = dependency
        dependency.connection = info.connection
        dependency.connection.setParameter('from', sourceEndpoint.$task)
        dependency.connection.setParameter('to', targetEndpoint.$task)
        dependency.connection.canvas.setAttribute('data-fromId', sourceEndpoint.$task.model.id)
        dependency.connection.canvas.setAttribute('data-toId', targetEndpoint.$task.model.id)

        self.manager.api.dependencies.raise.change(dependency, oldDependency)
      }
    }

    let deleteConnection = function (info, mouseEvent) {
      if (mouseEvent) {
        let dependency = info.connection.$dependency

        dependency.removeFromTaskModel()
        self.manager.removeDependency(dependency, true) // Connection will be disconnected later by jsPlumb.
        self.manager.api.dependencies.raise.remove(dependency)
      }
    }

    this.manager.plumb.bind('connectionMoved', updateConnection)
    this.manager.plumb.bind('connection', createConnection)
    this.manager.plumb.bind('connectionDetached', deleteConnection)

  }
  return DependenciesEvents
}