'use strict';

import {some, isObject, isFunction} from '../../../../min-dash';

var WILDCARD = '*';

export default function CamundaModdleExtension(eventBus) {
    var self = this;

    eventBus.on('moddleCopy.canCopyProperty', function (context) {
        var property = context.property;
        var parent = context.parent;

        return self.canCopyProperty(property, parent);
    });
}

CamundaModdleExtension.$inject = ['eventBus'];

/**
 * Check wether to disallow copying property.
 */
CamundaModdleExtension.prototype.canCopyProperty = function (property, parent) {
    // (1) check wether property is allowed in parent
    if (isObject(property) && !isAllowedInParent(property, parent)) {
        return false;
    }

    // (2) check more complex scenarios

    if (is(property, 'camunda:InputOutput') && !this.canHostInputOutput(parent)) {
        return false;
    }

    if (isAny(property, ['camunda:Connector', 'camunda:Field']) && !this.canHostConnector(parent)) {
        return false;
    }

    if (is(property, 'camunda:In') && !this.canHostIn(parent)) {
        return false;
    }
};

CamundaModdleExtension.prototype.canHostInputOutput = function (parent) {
    // allowed in camunda:Connector
    var connector = getParent(parent, 'camunda:Connector');

    if (connector) {
        return true;
    }

    // special rules inside bpmn:FlowNode
    var flowNode = getParent(parent, 'bpmn:FlowNode');

    if (!flowNode) {
        return false;
    }

    if (isAny(flowNode, ['bpmn:StartEvent', 'bpmn:Gateway', 'bpmn:BoundaryEvent'])) {
        return false;
    }

    if (is(flowNode, 'bpmn:SubProcess') && flowNode.get('triggeredByEvent')) {
        return false;
    }

    return true;
};

CamundaModdleExtension.prototype.canHostConnector = function (parent) {
    var serviceTaskLike = getParent(parent, 'camunda:ServiceTaskLike');

    if (is(serviceTaskLike, 'bpmn:MessageEventDefinition')) {
        // only allow on throw and end events
        return getParent(parent, 'bpmn:IntermediateThrowEvent') || getParent(parent, 'bpmn:EndEvent');
    }

    return true;
};

CamundaModdleExtension.prototype.canHostIn = function (parent) {
    var callActivity = getParent(parent, 'bpmn:CallActivity');

    if (callActivity) {
        return true;
    }

    var signalEventDefinition = getParent(parent, 'bpmn:SignalEventDefinition');

    if (signalEventDefinition) {
        // only allow on throw and end events
        return getParent(parent, 'bpmn:IntermediateThrowEvent') || getParent(parent, 'bpmn:EndEvent');
    }

    return true;
};

// helpers //////////

function is(element, type) {
    return element && isFunction(element.$instanceOf) && element.$instanceOf(type);
}

function isAny(element, types) {
    return some(types, function (t) {
        return is(element, t);
    });
}

function getParent(element, type) {
    if (!type) {
        return element.$parent;
    }

    if (is(element, type)) {
        return element;
    }

    if (!element.$parent) {
        return;
    }

    return getParent(element.$parent, type);
}

function isAllowedInParent(property, parent) {
    // (1) find property descriptor
    var descriptor = property.$type && property.$model.getTypeDescriptor(property.$type);

    var allowedIn = descriptor && descriptor.meta && descriptor.meta.allowedIn;

    if (!allowedIn || isWildcard(allowedIn)) {
        return true;
    }

    // (2) check wether property has parent of allowed type
    return some(allowedIn, function (type) {
        return getParent(parent, type);
    });
}

function isWildcard(allowedIn) {
    return allowedIn.indexOf(WILDCARD) !== -1;
}
