var MAX_SWAP_IMG_SIZE = 400;

angular.module('diff_viewer', []).
config(['$routeProvider', function($routeProvider) {
    // Show the list of differences by default
    $routeProvider.
    otherwise({ templateUrl: '/diff_list.html', controller: DiffListController});
}]).
directive('swapImg', function() {
    // Custom directive for showing an image that gets swapped my mouseover.
    return {
        restrict: 'E', // The directive can be used as an element name
        replace: true, // The directive replaces itself with the template
        template: '<canvas ng-mouseenter="swap()" ng-mouseleave="swap()"></canvas>',
        scope: { // The attributes below are bound to the scope
            leftSrc: '@',
            rightSrc: '@',
            side: '@'
        },
        link: function(scope, elm, attrs, ctrl) {
            var leftImage = new Image();
            var rightImage = new Image();
            var ctx = elm[0].getContext('2d');

            scope.render = function() {
                var image;
                if (scope.side == "left") {
                    image = leftImage;
                } else {
                    image = rightImage;
                }

                // Make it so the maximum size of an image is MAX_SWAP_IMG_SIZE, and the images are
                // scaled down in halves.
                var divisor = 1;
                while ((image.width / divisor) > MAX_SWAP_IMG_SIZE) {
                    divisor *= 2;
                }

                // Set canvas to correct size and draw the image into it
                elm[0].width = image.width / divisor;
                elm[0].height = image.height / divisor;
                ctx.drawImage(image, 0, 0, elm[0].width, elm[0].height);
            };

            // When the leftSrc attribute changes, load the image and then rerender
            attrs.$observe('leftSrc', function(value) {
                leftImage.src = value;
                leftImage.onload = function() {
                    if (scope.side == "left") {
                        scope.render();
                    }
                };
            });

            // When the rightSrc attribute changes, load the image and then rerender
            attrs.$observe('rightSrc', function(value) {
                rightImage.src = value;
                rightImage.onload = function() {
                    if (scope.side == "right") {
                        scope.render();
                    }
                };
            });

            // Swap which side to draw onto the canvas and then rerender
            scope.swap = function() {
                if (scope.side == "left") {
                    scope.side = "right";
                } else {
                    scope.side = "left";
                }
                scope.render();
            };
        }
    };
});

function DiffListController($scope, $http, $timeout) {
    // Label each kind of differ for the sort buttons.
    $scope.differs = [
        {
            "title": "Different Pixels"
        },
        {
            "title": "Perceptual Difference"
        }
    ];

    // Puts the records within AngularJS scope
    $scope.records = SkPDiffRecords.records;

    // Indicates which diff metric is used for sorting
    $scope.sortIndex = 1;

    // Called by the sort buttons to adjust the metric used for sorting
    $scope.setSortIndex = function(idx) {
        $scope.sortIndex = idx;
    };

    // A predicate for pulling out the number used for sorting
    $scope.sortingDiffer = function(record) {
        return record.diffs[$scope.sortIndex].result;
    };

    // Flash status indicators on the rows, and then remove them so the style can potentially be
    // reapplied later.
    $scope.flashRowStatus = function(success, record) {
        var flashStyle = success ? "success-flash" : "failure-flash";
        var flashDurationMillis = success ? 500 : 800;

        // Store the style in the record. The row will pick up the style this way instead of through
        // index because index can change with sort order.
        record.cssClasses = flashStyle;

        // The animation cannot be repeated unless the class is removed the element.
        $timeout(function() {
            record.cssClasses = "";
        }, flashDurationMillis);
    }

    $scope.setHashOf = function(imagePath, record) {
        $http.post("/set_hash", {
            "path": imagePath
        }).success(function(data) {
            $scope.flashRowStatus(data.success, record);
        }).error(function() {
            $scope.flashRowStatus(false, record);
        });

    };
}