(function() {
    'use strict';

    var radioButtonId = 1;

    function getNextRadioButtonId() {
        return 'laz-radio-button-' + (radioButtonId++);
    }

    angular.module('shared')
        .component('lazRadioButton', {
            bindings: {
                name: '@',
                ngChange: '<',
                ngClass: '<',
                ngClick: '<',
                ngModel: '<',
                ngValue: '<',
                ngDisabled: '<',
                overrideClass: '@',
                overrideRadioButtonClass: '@',
                screenReaderLabel: '@'
            },
            controller: 'LazRadioButton',
            require: {
                ngModelCtrl: 'ngModel'
            },
            templateUrl: '/shared/js/angular/ui/laz-radio-button.html',
            transclude: true
        })
        .controller('LazRadioButton', ['$attrs', '$element', function LazRadioButtonCtrl($attrs, $element) {
            var ctrl = this;
            ctrl.radioButtonId = getNextRadioButtonId();

            ctrl.$postLink = function() {
                setupRadioGroup();
                setupRadioButton();
            };

            ctrl.getClass = function() {
                if (ctrl.overrideClass) {
                    return ctrl.overrideClass;
                }
                return 'radioCustom';
            };

            ctrl.getRadioButtonClass = function() {
                if (ctrl.overrideRadioButtonClass) {
                    return ctrl.overrideRadioButtonClass;
                }
                return 'radioCustom_button';
            };

            ctrl.getScreenReaderLabel = function() {
                if (ctrl.screenReaderLabel) {
                    return ctrl.screenReaderLabel;
                }
                return '';
            };

            ctrl.handleChange = function(event) {
                if (ctrl.ngModelCtrl && typeof ctrl.ngModel !== 'function') {
                    ctrl.ngModelCtrl.$setViewValue(ctrl.ngModel);
                }
                if (ctrl.ngChange && typeof ctrl.ngChange === 'function') {
                    ctrl.ngChange(event);
                }
            };

            ctrl.handleClick = function(event) {
                if (ctrl.ngClick) {
                    ctrl.ngClick(event);
                }
                uncheckAllButtonsInGroup();
                checkRadioButton(event.target);
            };

            function setupRadioGroup() {
                var maybeRadioGroup = $element.closest('[role="radiogroup"]');
                if (maybeRadioGroup) {
                    ctrl.radioGroup = maybeRadioGroup[0];
                }
            }

            function setupRadioButton() {
                var radioButton = getRadioButton();
                if (isSelectedRadioButton()) {
                    uncheckAllButtonsInGroup();
                    checkRadioButton(radioButton);
                } else if (!isFirstRadioButtonInGroup(radioButton)) {
                    radioButton.setAttribute('tabindex', -1);
                }
                if (!ctrl.name) {
                    // If no name is given for the radio button,
                    // keyboard accessibility won't be supported by the browser.
                    // We will try to provide this functionality ourselves.
                    $element.on('keydown', handleKeyDown);
                }
            }

            function isFirstRadioButtonInGroup(radioButton) {
                if (!ctrl.radioGroup) {
                    return true;
                }
                var radioButtons = ctrl.radioGroup.querySelectorAll('input[type=radio]');
                return radioButtons && radioButtons[0] === radioButton;
            }

            function getRadioButton() {
                return $element.find('input[type=radio]')[0];
            }

            function isSelectedRadioButton() {
                return (typeof ctrl.ngModel === 'function' && ctrl.ngValue === ctrl.ngModel())
                       || (ctrl.ngModel && ctrl.ngValue === ctrl.ngModel)
            }

            function handleKeyDown(event) {
                switch (event.keyCode) {
                    case 39: // right arrow behaves the same as
                    case 38: // up arrow
                        handleArrowUp(event);
                        break;
                    case 37: // left arrow behaves the same as
                    case 40: // down arrow
                        handleArrowDown(event);
                        break;
                }
            }

            function handleArrowUp(event) {
                if (!ctrl.radioGroup) {
                    return;
                }
                event.preventDefault();
                var radioButton = getRadioButton();
                uncheckRadioButton(radioButton);
                goToNextRadioButton(radioButton);
            }

            function handleArrowDown(event) {
                if (!ctrl.radioGroup) {
                    return;
                }
                event.preventDefault();
                var radioButton = getRadioButton();
                uncheckRadioButton(radioButton);
                goToPreviousRadioButton(radioButton);
            }

            function checkRadioButton(radioButton) {
                radioButton.setAttribute('tabindex', '0');
                radioButton.checked = true;
            }

            function uncheckRadioButton(radioButton) {
                radioButton.setAttribute('tabindex', '-1');
                radioButton.checked = false;
            }

            function uncheckAllButtonsInGroup() {
                if (!ctrl.radioGroup) {
                    return;
                }
                var radioButtons = ctrl.radioGroup.querySelectorAll('input[type=radio]');
                for (var i = 0; i < radioButtons.length; i++) {
                    uncheckRadioButton(radioButtons[i]);
                }
            }

            function goToNextRadioButton(currentRadioButton) {
                if (!ctrl.radioGroup) {
                    return;
                }
                var radioButtons = ctrl.radioGroup.querySelectorAll('input[type=radio]');
                for (var i = 0; i < radioButtons.length; i++) {
                    if (radioButtons[i].id === currentRadioButton.id) {
                        if ((i + 1) !== radioButtons.length) {
                            goToRadioButton(radioButtons[i + 1]);
                        } else {
                            goToRadioButton(radioButtons[0]);
                        }
                        break;
                    }
                }
            }

            function goToPreviousRadioButton(currentRadioButton) {
                if (!ctrl.radioGroup) {
                    return;
                }
                var radioButtons = ctrl.radioGroup.querySelectorAll('input[type=radio]');
                for (var i = 0; i < radioButtons.length; i++) {
                    if (radioButtons[i].id === currentRadioButton.id) {
                        if (i !== 0) {
                            goToRadioButton(radioButtons[i - 1]);
                        } else {
                            goToRadioButton(radioButtons[radioButtons.length - 1]);
                        }
                        break;
                    }
                }
            }

            function goToRadioButton(radioButton) {
                checkRadioButton(radioButton);
                radioButton.click();
                radioButton.focus();
            }
        }]);
})();