/**
 * MUI Angular Select Component
 * @module angular/select
 */

import angular from 'angular';

import * as formlib from '../js/lib/forms';
import * as util from '../js/lib/util';
import * as jqLite from '../js/lib/jqLite';


const moduleName = 'mui.select';


angular.module(moduleName, [])
  .directive('muiSelect', ['$timeout', function($timeout) {
    return {
      restrict: 'AE',
      require: ['ngModel'],
      scope: {
        label: '@',
        name: '@',
        placeholder: '@',
        ngDisabled: '=',
        ngModel: '=',
        ngRequired: '='
      },
      replace: true,
      transclude: true,
      template: '<div class="mui-select" ' +
        'ng-blur="onWrapperBlurOrFocus($event)" ' +
        'ng-click="onWrapperClick($event)" ' +
        'ng-focus="onWrapperBlurOrFocus($event)" ' +
        'ng-keydown="onWrapperKeydown($event)" ' +
        'ng-keypress="onWrapperKeypress($event)">' +
        '<select ' +
        'name="{{name}}" ' +
        'ng-class=\'{"mui--text-placeholder": placeholder && ngModel == ""}\' ' +
        'ng-disabled="ngDisabled" ' +
        'ng-model="ngModel" ' +
        'ng-mousedown="onInnerMousedown($event)" ' +
        'ng-required="ngRequired" ' +
        '>' +
        '<option ng-if="placeholder" value="" placeholder>{{placeholder}}</option>' +
        '</select>' +
        '<label tabindex="-1">{{label}}</label>' +
        '<div ' +
        'class="mui-select__menu"' +
        'ng-if="!useDefault && isOpen">' +
        '<div ' +
        'ng-click="chooseOption($event, option)" ' +
        'ng-repeat="option in selectEl.children() track by $index" ' +
        'ng-class=\'{"mui--is-selected": $index === menuIndex, "mui--text-placeholder": option.hasAttribute("placeholder"), "mui--is-disabled": option.disabled}\' ' +
        'ng-disabled="option.disabled" ' +
        'ng-hide="option.hidden" ' +
        '>{{option.innerText}}</div>' +
        '</div>' +
        '</div>',
      link: function(scope, element, attrs, controller, transcludeFn) {
        var wrapperEl = element,
            selectEl = element.find('select'),
            isUndef = angular.isUndefined,
            origValue;

        // disable MUI js
        selectEl[0]._muiSelect = true;

        // init scope
        scope.selectEl = selectEl;
        scope.isOpen = false;
        scope.useDefault = ('ontouchstart' in document.documentElement) 
          ? true : false;
        scope.origTabIndex = selectEl[0].tabIndex;
        scope.menuIndex = 0;
        scope.q = '';
        scope.qTimeout = null;

        // handle `use-default` attribute
        if (!isUndef(attrs.useDefault)) scope.useDefault = true;

        // use tabIndex to make wrapper or inner focusable
        if (scope.useDefault === false) {
          wrapperEl.prop('tabIndex', '0');
          selectEl.prop('tabIndex', '-1');
        } else {
          wrapperEl.prop('tabIndex', '-1');
          selectEl.prop('tabIndex', '0');
        }
        
        // add <option> tags to <select>
        transcludeFn(function(clone) {
          selectEl.append(clone);
        });


        function dispatchChange(option) {
          selectEl[0].selectedIndex = option.index;

          if (option.value !== origValue) {
            scope.ngModel = option.value;

            // trigger change event
            $timeout(function() {
              util.dispatchEvent(selectEl[0], 'change', true, false);
            });
          }
        }
        

        /**
         * Handle blur and focus events on wrapper <div> element.
         * @param {Event} $event - Angular event instance
         */
        scope.onWrapperBlurOrFocus = function($event) {
          // ignore events that bubbled up
          if (document.activeElement !== wrapperEl[0]) return;

          util.dispatchEvent(selectEl[0], $event.type, false, false);
        };


        /**
         * Handle click event on wrapper <div> element.
         * @param {Event} $event - Angular event instance
         */
        scope.onWrapperClick = function($event) {
          // only left click, check default prevented and useDefault
          if ($event.button !== 0 ||
              $event.defaultPrevented ||
              scope.useDefault ||
              selectEl[0].disabled) {
            return;
          }

          // focus wrapper
          wrapperEl[0].focus();

          // open custom menu
          scope.isOpen = true;
        };


        /**
         * Handle keydown event on wrapper element.
         * @param {Event} $event - Angular event instance
         */
        scope.onWrapperKeydown = function($event) {
          // exit if preventDefault() was called or useDefault is true
          if ($event.defaultPrevented || scope.useDefault) return;

          var keyCode = $event.keyCode;

          if (scope.isOpen === false) {
            // spacebar, down, up
            if (keyCode === 32 || keyCode === 38 || keyCode === 40) {
              // prevent win scroll
              $event.preventDefault();

              // open menu
              scope.isOpen = true;
            }

          } else {
            // tab
            if (keyCode === 9) return scope.isOpen = false;

            // escape | up | down | enter
            if (keyCode === 27 
                || keyCode === 40
                || keyCode === 38
                || keyCode === 13) {
              $event.preventDefault();
            }

            var options = selectEl.children(),
                nextIndex = null,
                i;
            
            if (keyCode === 27) {
              // escape -> close
              scope.isOpen = false;
            } else if (keyCode === 40) {
              // down -> increment
              i = scope.menuIndex + 1;
              while (i < options.length) {
                // exit if option not disabled
                if (!options[i].disabled && !options[i].hidden) {
                  nextIndex = i;
                  break;
                }
                i += 1;
              }

              if (nextIndex !== null) scope.menuIndex = nextIndex;

            } else if (keyCode === 38) {
              // up -> decrement
              i = scope.menuIndex - 1;
              while (i > -1) {
                // exit if option not disabled
                if (!options[i].disabled && !options[i].hidden) {
                  nextIndex = i;
                  break;
                }
                i -= 1;
              }

              if (nextIndex !== null) scope.menuIndex = nextIndex;
              
            } else if (keyCode === 13) {
              // enter -> choose and close
              dispatchChange(options[scope.menuIndex]);
              scope.isOpen = false;
            }

          }
        };


        /**
         * Handle keypress event on wrapper element.
         * @param {Event} $event - Angular event instance
         */
        scope.onWrapperKeypress = function($event) {
          // exit if preventDefault() was called or useDefault is true or
          // menu is closed
          if ($event.defaultPrevented || scope.useDefault || !scope.isOpen) {
            return;
          }

          // handle query timer
          clearTimeout(scope.qTimeout);
          scope.q += $event.key;
          scope.qTimeout = setTimeout(function() {scope.q = '';}, 600);

          // select first match alphabetically
          var prefixRegex = new RegExp('^' + scope.q, 'i'),
              options = selectEl.children(),
              m = options.length,
              option,
              i;

          for (i=0; i < m; i++) {
            option = options[i];
            if (!option.hidden &&
                !option.disabled &&
                prefixRegex.test(option.innerText)) {
              scope.menuIndex = option.index;
              break;
            }
          }
        }


        /**
         * Handle mousedown event on Inner <select> element
         * @param {Event} $event - Angular event instance
         */
        scope.onInnerMousedown = function($event) {
          // check flag
          if ($event.button !== 0 || scope.useDefault === true) return;

          // prevent built-in menu from opening
          $event.preventDefault();
        };


        /**
         * Choose option the user selected.
         * @param {Object} option - The option selected.
         */
        scope.chooseOption = function($event, option) {
          // prevent bubbling
          $event.stopImmediatePropagation();

          // ignore disabled
          if (option.disabled) return;

          // dispatch change
          dispatchChange(option);

          // close menu
          scope.isOpen = false;
        };
        

        // function to close menu on window resize and document click
        function closeMenuFn() {
          scope.isOpen = false;

          // disable scroll lock
          util.disableScrollLock(true);

          // remove event handlers
          jqLite.off(document, 'click', closeMenuFn);
          jqLite.off(window, 'resize', closeMenuFn);

          scope.$digest();
        }


        /**
         * Open/Close custom select menu
         */
        scope.$watch('isOpen', function(isOpen, oldVal) {
          // ignore first call
          if (isOpen === oldVal) return;

          // exit if use-default is true
          if (scope.useDefault === true) return;

          if (isOpen === true) {
            // enable scroll lock
            util.enableScrollLock();

            // init menuIndex
            var menuEl = element.find('div'),
                value = scope.ngModel,
                options = selectEl.children(),
                m = options.length,
                i;

            origValue = scope.ngModel;
            scope.menuIndex = scope.menuIndex;
            
            $timeout(function() {
              // set position of custom menu
              var props = formlib.getMenuPositionalCSS(
                element[0],
                menuEl[0],
                scope.menuIndex
              );
              
              props.height = 'auto';
              menuEl.css(props);
              jqLite.scrollTop(menuEl[0], props.scrollTop);
              
              // attach event handlers
              jqLite.on(document, 'click', closeMenuFn);
              jqLite.on(window, 'resize', closeMenuFn);
            });

          } else {
            // focus select element
            selectEl[0].focus();

            // disable scroll lock
            util.disableScrollLock(true);

            // remove event handlers
            jqLite.off(document, 'click', closeMenuFn);
            jqLite.off(window, 'resize', closeMenuFn);
          }
        });


        /**
         * Scroll to menu items (if hidden)
         */
        scope.$watch('menuIndex', function(newVal, oldVal) {
          // skip initialization
          if (newVal === oldVal) return;

          // scroll menu after rendering is finished
          $timeout(function() {
            var itemEl = selectEl.children()[scope.menuIndex],
                itemRect = itemEl.getBoundingClientRect(),
                menuEl = itemEl.parentNode;

            if (itemRect.top < 0) {
              // menu item is hidden above visible window
              menuEl.scrollTop = menuEl.scrollTop + itemRect.top - 5;
            } else if (itemRect.top > window.innerHeight) {
              // menu item is hidden below visible window
              menuEl.scrollTop = menuEl.scrollTop +
                (itemRect.top + itemRect.height - window.innerHeight) + 5;
            }
          });
        });


        scope.$watch('ngDisabled', function(newVal) {
          if (newVal === true) wrapperEl.prop('tabIndex', '-1');
          else if (!scope.useDefault) wrapperEl.prop('tabIndex', '0');
        });
      }
    }
  }]);


/** Define module API */
export default moduleName;