'use strict';

/**

* Binds a CodeMirror widget to a <textarea> element.
*/

angular.module('ui.codemirror', [])

.constant('uiCodemirrorConfig', {})
.directive('uiCodemirror', ['uiCodemirrorConfig', function (uiCodemirrorConfig) {

  return {
    restrict: 'EA',
    require: '?ngModel',
    priority: 1,
    compile: function compile() {

      // Require CodeMirror
      if (angular.isUndefined(window.CodeMirror)) {
        throw new Error('ui-codemirror need CodeMirror to work... (o rly?)');
      }

      return function postLink(scope, iElement, iAttrs, ngModel) {

        var options, opts, codeMirror, initialTextValue;

        initialTextValue = iElement.text();

        options = uiCodemirrorConfig.codemirror || {};
        opts = angular.extend({ value: initialTextValue }, options, scope.$eval(iAttrs.uiCodemirror), scope.$eval(iAttrs.uiCodemirrorOpts));

        if (iElement[0].tagName === 'TEXTAREA') {
          // Might bug but still ...
          codeMirror = window.CodeMirror.fromTextArea(iElement[0], opts);
        } else {
          iElement.html('');
          codeMirror = new window.CodeMirror(function(cm_el) {
            iElement.append(cm_el);
          }, opts);
        }

        if (iAttrs.uiCodemirror || iAttrs.uiCodemirrorOpts) {
          var codemirrorDefaultsKeys = Object.keys(window.CodeMirror.defaults);
          scope.$watch(iAttrs.uiCodemirror || iAttrs.uiCodemirrorOpts, function updateOptions(newValues, oldValue) {
            if (! angular.isObject(newValues)){
              return;
            }
            codemirrorDefaultsKeys.forEach(function (key) {
              if (newValues.hasOwnProperty(key)) {

                if (oldValue && newValues[key] === oldValue[key]){
                  return;
                }

                codeMirror.setOption(key, newValues[key]);
              }
            });
          }, true);
        }

        if (ngModel) {
          // CodeMirror expects a string, so make sure it gets one.
          // This does not change the model.
          ngModel.$formatters.push(function (value) {
            if (angular.isUndefined(value) || value === null) {
              return '';
            } else if (angular.isObject(value) || angular.isArray(value)) {
              throw new Error('ui-codemirror cannot use an object or an array as a model');
            }
            return value;
          });

          // Override the ngModelController $render method, which is what gets called when the model is updated.
          // This takes care of the synchronizing the codeMirror element with the underlying model, in the case that it is changed by something else.
          ngModel.$render = function () {
            //Code mirror expects a string so make sure it gets one
            //Although the formatter have already done this, it can be possible that another formatter returns undefined (for example the required directive)
            var safeViewValue = ngModel.$viewValue || '';
            codeMirror.setValue(safeViewValue);
          };

          // Keep the ngModel in sync with changes from CodeMirror
          codeMirror.on('change', function (instance) {
            var newValue = instance.getValue();
            if (newValue !== ngModel.$viewValue) {
              // Changes to the model from a callback need to be wrapped in $apply or angular will not notice them
              scope.$apply(function() {
                ngModel.$setViewValue(newValue);
              });
            }
          });
        }

        // Watch ui-refresh and refresh the directive
        if (iAttrs.uiRefresh) {
          scope.$watch(iAttrs.uiRefresh, function (newVal, oldVal) {
            // Skip the initial watch firing
            if (newVal !== oldVal) {
              codeMirror.refresh();
            }
          });
        }

        // Allow access to the CodeMirror instance through a broadcasted event
        // eg: $broadcast('CodeMirror', function(cm){...});
        scope.$on('CodeMirror', function(event, callback) {
          if (angular.isFunction(callback)) {
            callback(codeMirror);
          } else {
            throw new Error('the CodeMirror event requires a callback function');
          }
        });

        // onLoad callback
        if (angular.isFunction(opts.onLoad)) {
          opts.onLoad(codeMirror);
        }

      };
    }
  };
}]);