define([
    'jquery',
    'underscore',
    'utils',
    'constants',
    'settings',
    'eventMgr',
    'crel',
    'mousetrap',
    'hammerjs',
], function($, _, utils, constants, settings, eventMgr, crel, mousetrap, hammer) {
    var layout = {};

    var resizerSize = 32;
    var togglerSize = 60;
    var navbarHeight = 50;
    var editorMinSize = {
        width: 250,
        height: 140
    };
    var previewMinSize = {
        width: 330,
        height: 160
    };
    var menuPanelWidth = 280;
    var documentPanelWidth = 320;
    var titleMinWidth = 200;
    var previewButtonsDropdownMargin = 130;
    var previewButtonsOffset = {
        x: -45,
        y: -6
    };
    var windowSize;

    var wrapperL1, wrapperL2, wrapperL3;
    var navbar, menuPanel, documentPanel, editor, previewPanel, previewContainer, navbarToggler, previewToggler, previewResizer, previewButtons;

    var animate = false;
    function startAnimation() {
        animate = true;
        wrapperL1.$elt.addClass('layout-animate');
    }
    function endAnimation() {
        animate = false;
        wrapperL1.$elt.removeClass('layout-animate');
    }

    function DomObject(selector) {
        this.selector = selector;
        this.elt = document.querySelector(selector);
        this.$elt = $(this.elt);
    }

    var transitionEndTimeoutId;
    var transitionEndCallbacks = [];
    function onTransitionEnd(evt) {
        if(!evt ||
            evt.target === wrapperL1.elt ||
            evt.target === wrapperL2.elt ||
            evt.target === previewPanel.elt
        ) {
            transitionEndCallbacks.forEach(function(callback) {
                callback();
            });
            endAnimation();
            transitionEndCallbacks.length !== 0 && onResize();
            transitionEndCallbacks = [];
        }
    }
    DomObject.prototype.applyCss = function() {

        // Top/left/Bottom/Right
        this.top !== undefined && (this.elt.style.top = this.top + 'px');
        this.left !== undefined && (this.elt.style.left = this.left + 'px');
        this.bottom !== undefined && (this.elt.style.bottom = this.bottom + 'px');
        this.right !== undefined && (this.elt.style.right = this.right + 'px');

        // Translate
        if(this.x !== undefined || this.y !== undefined) {
            this.x = this.x || 0;
            this.y = this.y || 0;
            this.elt.style['-webkit-transform'] = 'translate(' + this.x + 'px, ' + this.y + 'px)';
            this.elt.style['-ms-transform'] = 'translate(' + this.x + 'px, ' + this.y + 'px)';
            this.elt.style.transform = 'translate(' + this.x + 'px, ' + this.y + 'px)';
        }

        // Width (deferred when animate if new width is smaller)
        if(animate && this.width < this.oldWidth) {
            transitionEndCallbacks.push(_.bind(function() {
                this.elt.style.width = this.width + 'px';
            }, this));
        }
        else {
            this.width !== undefined && (this.elt.style.width = this.width + 'px');
        }
        this.oldWidth = this.width;

        // Height (deferred when animate if new height is smaller)
        if(animate && this.height < this.oldHeight) {
            transitionEndCallbacks.push(_.bind(function() {
                this.elt.style.height = this.height + 'px';
            }, this));
        }
        else {
            this.height !== undefined && (this.elt.style.height = this.height + 'px');
        }
        this.oldHeight = this.height;

        // Just in case transitionEnd event doesn't happen
        clearTimeout(transitionEndTimeoutId);
        animate && (transitionEndTimeoutId = setTimeout(onTransitionEnd, 800));
    };

    DomObject.prototype.createToggler = function(backdrop) {
        var backdropElt;
        var pushedEvents = 0;
        this.toggle = function(show) {
            if(show === this.isOpen) {
                return;
            }
            this.isOpen = _.isBoolean(show) ? show : !this.isOpen;
            if(this.isOpen) {
                this.$elt.addClass('panel-open').trigger('show.layout.toggle');
                if(backdrop) {
                    $(backdropElt = utils.createBackdrop(wrapperL1.elt)).click(_.bind(function() {
                        this.toggle(false);
                    }, this));
                    this.$elt.addClass('bring-to-front');
                }
                transitionEndCallbacks.push(_.bind(function() {
                    if(--pushedEvents === 0) {
                        this.isOpen && this.$elt.trigger('shown.layout.toggle');
                    }
                }, this));
            }
            else {
                this.$elt.trigger('hide.layout.toggle');
                backdropElt && backdropElt.removeBackdrop();
                backdropElt = undefined;
                transitionEndCallbacks.push(_.bind(function() {
                    if(--pushedEvents === 0) {
                        !this.isOpen && this.$elt.removeClass('panel-open bring-to-front').trigger('hidden.layout.toggle');
                    }
                }, this));
            }
            pushedEvents++;
            startAnimation();
            resizeAll();
        };
    };
    DomObject.prototype.initHammer = function(drag) {
        this.hammer = hammer(this.elt, {
            drag: drag ? true : false,
            drag_max_touches: 0,
            gesture: false,
            hold: false,
            release: false,
            swipe: drag ? false : true,
            tap: false,
            touch: false,
            transform: false
        });
    };

    var maxWidthMap = [
        { screenWidth: 0, maxWidth: 600 * settings.maxWidthRatio },
        { screenWidth: 1000, maxWidth: 700 * settings.maxWidthRatio },
        { screenWidth: 1200, maxWidth: 800 * settings.maxWidthRatio },
        { screenWidth: 1400, maxWidth: 900 * settings.maxWidthRatio },
    ];
    var maxWidthMapReversed = maxWidthMap.slice(0).reverse();
    function getMaxWidth() {
        return _.find(maxWidthMapReversed, function(value) {
            return windowSize.width > value.screenWidth;
        }).maxWidth;
    }

    var editorContentElt;
    var previewContentElt;
    var editorMarginElt;
    var navbarInnerElt;
    var navbarDropdownElt;
    var $navbarDropdownBtnElt;
    var navbarTitleContainerElt;
    var $navbarTitleElt;
    var navbarBtnGroups = [];
    var navbarBtnGroupsWidth = [80, 80, 160, 160, 80, 40].map(function(width) {
        return width + 18; // Add margin
    });
    var navbarMarginWidth = 18 * 2 + 25 + 25;
    var buttonsDropdownWidth = 40;
    var workingIndicatorWidth = 18 + 70;
    function onResize() {
        var paddingBottom = wrapperL3.height - 60;

        var editorPadding = (editor.elt.offsetWidth - getMaxWidth()) / 2;
        if(editorPadding < constants.EDITOR_DEFAULT_PADDING) {
            editorPadding = constants.EDITOR_DEFAULT_PADDING;
        }
        editorContentElt.style.paddingLeft = editorPadding + 'px';
        editorContentElt.style.paddingRight = editorPadding + 'px';
        editorContentElt.style.paddingBottom = paddingBottom + 'px';
        editorMarginElt.style.width = editorPadding + 'px';

        var previewPadding = (previewContainer.elt.offsetWidth - getMaxWidth()) / 2;
        if(previewPadding < constants.EDITOR_DEFAULT_PADDING) {
            previewPadding = constants.EDITOR_DEFAULT_PADDING;
        }
        previewContentElt.style.paddingLeft = previewPadding + 'px';
        previewContentElt.style.paddingRight = previewPadding + 'px';
        previewContentElt.style.paddingBottom = paddingBottom + 'px';

        var maxWidth = navbarMarginWidth + workingIndicatorWidth + titleMinWidth + buttonsDropdownWidth;
        var titleWidth = windowSize.width - maxWidth + titleMinWidth;
        navbarBtnGroups.forEach(function(group, index) {
            maxWidth += group.width;
            index === navbarBtnGroups.length - 1 && (maxWidth -= buttonsDropdownWidth);
            if(windowSize.width < maxWidth) {
                navbarDropdownElt.appendChild(group.elt);
            }
            else {
                navbarInnerElt.insertBefore(group.elt, navbarTitleContainerElt);
                titleWidth = windowSize.width - maxWidth + titleMinWidth;
            }
        });
        $navbarTitleElt.css({
            maxWidth: titleWidth
        });
        $navbarDropdownBtnElt.toggleClass('hide', navbarDropdownElt.children.length === 0);

        eventMgr.onLayoutResize();
    }

    var isVertical = settings.layoutOrientation == "vertical";
    function resizeAll() {
        windowSize = {
            width: window.innerWidth,
            height: window.innerHeight
        };

        // Layout wrapper level 1
        wrapperL1.y = navbar.isOpen ? 0 : -navbarHeight;
        wrapperL1.x = menuPanel.isOpen ? 0 : documentPanel.isOpen ? -(menuPanelWidth + documentPanelWidth) : -menuPanelWidth;
        wrapperL1.width = windowSize.width + menuPanelWidth + documentPanelWidth;
        wrapperL1.height = windowSize.height - wrapperL1.y;

        // Layout wrapper level 2
        wrapperL2.left = menuPanelWidth;
        wrapperL2.width = windowSize.width;
        wrapperL2.height = wrapperL1.height;

        // Layout wrapper level 3
        wrapperL3.top = navbarHeight;
        wrapperL3.width = windowSize.width;
        wrapperL3.height = wrapperL1.height - navbarHeight;

        wrapperL1.applyCss();
        wrapperL2.applyCss();
        wrapperL3.applyCss();

        if(window.viewerMode) {
            previewPanel.width = wrapperL3.width;
            previewPanel.height = wrapperL3.height;
            previewContainer.width = wrapperL3.width;
            previewContainer.height = wrapperL3.height;

            previewPanel.applyCss();
            previewContainer.applyCss();
            return onResize();
        }

        while(true) {
            if(navbar.isOpen && wrapperL3.height < editorMinSize.height + resizerSize) {
                navbar.isOpen = false;
                navbar.$elt.trigger('hide.layout.toggle').trigger('hidden.layout.toggle');
                continue;
            }

            if(isVertical) {
                if(!previewPanel.isOpen) {
                    previewPanel.y = wrapperL3.height - resizerSize;
                }
                else {
                    if(previewPanel.halfSize) {
                        previewPanel.height = (wrapperL3.height + resizerSize) / 2;
                    }
                    if(previewPanel.height < previewMinSize.height) {
                        previewPanel.height = previewMinSize.height;
                    }
                    previewPanel.y = wrapperL3.height - previewPanel.height;
                    if(previewPanel.y < editorMinSize.height) {
                        var previewPanelHeight = wrapperL3.height - editorMinSize.height;
                        if(previewPanelHeight < previewMinSize.height) {
                            previewPanel.isOpen = false;
                            previewPanel.$elt.trigger('hide.layout.toggle').trigger('hidden.layout.toggle');
                            continue;
                        }
                        previewPanel.height = previewPanelHeight;
                        previewPanel.y = wrapperL3.height - previewPanel.height;
                    }
                }
                previewPanel.width = wrapperL3.width;
                editor.height = previewPanel.y;
                editor.width = wrapperL3.width;
                previewContainer.top = resizerSize;
                previewContainer.height = previewPanel.height - resizerSize;
                previewContainer.width = previewPanel.width;
                navbarToggler.width = togglerSize;
                previewToggler.width = togglerSize;
                previewToggler.x = (previewPanel.width - togglerSize) / 2;
                previewResizer.width = previewContainer.width;
            }
            else {
                if(!previewPanel.isOpen) {
                    previewPanel.x = wrapperL3.width - resizerSize;
                }
                else {
                    if(previewPanel.halfSize) {
                        previewPanel.width = (wrapperL3.width + resizerSize) / 2;
                    }
                    if(previewPanel.width < previewMinSize.width) {
                        previewPanel.width = previewMinSize.width;
                    }
                    previewPanel.x = wrapperL3.width - previewPanel.width;
                    if(previewPanel.x < editorMinSize.width) {
                        var previewPanelWidth = wrapperL3.width - editorMinSize.width;
                        if(previewPanelWidth < previewMinSize.width) {
                            previewPanel.isOpen = false;
                            previewPanel.$elt.trigger('hide.layout.toggle').trigger('hidden.layout.toggle');
                            continue;
                        }
                        previewPanel.width = previewPanelWidth;
                        previewPanel.x = wrapperL3.width - previewPanel.width;
                    }
                }
                previewPanel.height = wrapperL3.height;
                editor.width = previewPanel.x;
                editor.height = wrapperL3.height;
                previewContainer.left = resizerSize;
                previewContainer.width = previewPanel.width - resizerSize;
                previewContainer.height = previewPanel.height;
                navbarToggler.height = togglerSize;
                previewToggler.height = togglerSize;
                previewToggler.y = (previewPanel.height - togglerSize) / 2;
                previewResizer.height = previewContainer.height;
            }
            break;
        }

        navbarToggler.$elt.toggleClass('open', navbar.isOpen);
        previewToggler.$elt.toggleClass('open', previewPanel.isOpen);
        previewResizer.$elt.toggleClass('open', previewPanel.isOpen);

        editor.applyCss();
        previewPanel.applyCss();
        previewContainer.applyCss();
        previewToggler.applyCss();
        previewResizer.applyCss();
        navbarToggler.applyCss();

        previewButtons.adjustPosition();

        onResize();
    }

    layout.init = function() {

        // Tweak the body element
        (function(bodyStyle) {
            bodyStyle.position = 'absolute';
            bodyStyle.top = 0;
            bodyStyle.left = 0;
            bodyStyle.bottom = 0;
            bodyStyle.right = 0;
            bodyStyle.overflow = 'hidden';
        })(document.body.style);
        document.documentElement.style.overflow = 'hidden';

        wrapperL1 = new DomObject('.layout-wrapper-l1');
        wrapperL2 = new DomObject('.layout-wrapper-l2');
        wrapperL3 = new DomObject('.layout-wrapper-l3');
        navbar = new DomObject('.navbar');
        menuPanel = new DomObject('.menu-panel');
        documentPanel = new DomObject('.document-panel');
        editor = new DomObject('#wmd-input');
        previewPanel = new DomObject('.preview-panel');
        previewContainer = new DomObject('.preview-container');
        navbarToggler = new DomObject('.layout-toggler-navbar');
        previewToggler = new DomObject('.layout-toggler-preview');
        previewResizer = new DomObject('.layout-resizer-preview');
        previewButtons = new DomObject('.extension-preview-buttons');

        editorContentElt = editor.elt.querySelector('.editor-content');
        previewContentElt = document.getElementById('preview-contents');
        editorMarginElt = editor.elt.querySelector('.editor-margin');
        navbarInnerElt = navbar.elt.querySelector('.navbar-inner');
        navbarDropdownElt = navbar.elt.querySelector('.buttons-dropdown .dropdown-menu');
        $navbarDropdownBtnElt = navbar.$elt.find('.buttons-dropdown');
        navbarTitleContainerElt = navbar.elt.querySelector('.title-container');
        $navbarTitleElt = navbar.$elt.find('.file-title-navbar, .input-file-title');

        _.each(navbar.elt.querySelectorAll('.right-buttons'), function(btnGroupElt) {
            navbarBtnGroups.push({
                elt: btnGroupElt,
                width: navbarBtnGroupsWidth.shift()
            });
        });
        _.each(navbar.elt.querySelectorAll('.left-buttons'), function(btnGroupElt) {
            navbarBtnGroups.push({
                elt: btnGroupElt,
                width: navbarBtnGroupsWidth.shift()
            });
        });

        wrapperL1.$elt.toggleClass('layout-vertical', isVertical);
        wrapperL1.$elt.on("webkitTransitionEnd otransitionend oTransitionEnd msTransitionEnd transitionend", onTransitionEnd);

        navbar.isOpen = true;
        navbar.createToggler();
        navbarToggler.$elt.click(_.bind(navbar.toggle, navbar));

        previewPanel.isOpen = true;
        previewPanel.createToggler();
        previewPanel.halfSize = true;
        previewToggler.$elt.click(_.bind(previewPanel.toggle, previewPanel));

        // Open StackEdit Viewer if failing to open the preview
        previewPanel.$elt.on('show.layout.toggle', function() {
            _.defer(function() {
                if(!previewPanel.isOpen) {
                    window.location.href = 'viewer';
                }
            });
        });

        documentPanel.isOpen = false;
        documentPanel.createToggler(true);
        documentPanel.$elt.find('.toggle-button').click(_.bind(documentPanel.toggle, documentPanel));

        // Hide panels when clicking on a non collapse element
        documentPanel.$elt.on('click', 'a[data-toggle!=collapse]', _.bind(documentPanel.toggle, documentPanel, false));

        // Focus on editor when document panel is closed
        documentPanel.$elt.on('hidden.layout.toggle', function() {
            editor.elt.focus();
        });

        menuPanel.isOpen = false;
        if(!window.viewerMode) {
            menuPanel.createToggler(true);
            menuPanel.$elt.find('.toggle-button').click(_.bind(menuPanel.toggle, menuPanel));

            // Hide panels when clicking on a non collapse element
            menuPanel.$elt.on('click', 'a[data-toggle!=collapse]', _.bind(menuPanel.toggle, menuPanel, false));

            // Close all open sub-menus when one submenu opens and when panel is closed
            menuPanel.$elt.on('show.bs.collapse hidden.layout.toggle', function() {
                menuPanel.$elt.find('.in').collapse('hide');
            });

            // Focus on editor when menu panel is closed
            menuPanel.$elt.on('hidden.layout.toggle', function() {
                editor.elt.focus();
            });

            // Gesture

            /*
            navbar.initHammer();
            menuPanel.initHammer();
            documentPanel.initHammer();
            previewButtons.initHammer();

            navbar.hammer.on('swiperight', _.bind(menuPanel.toggle, menuPanel, true));
            navbar.hammer.on('swipeleft', _.bind(documentPanel.toggle, documentPanel, true));
            navbar.hammer.on('swipeup', _.bind(navbar.toggle, navbar, false));

            menuPanel.hammer.on('swiperight', _.bind(menuPanel.toggle, menuPanel, true));
            menuPanel.hammer.on('swipeleft', _.bind(menuPanel.toggle, menuPanel, false));

            documentPanel.hammer.on('swipeleft', _.bind(documentPanel.toggle, documentPanel, true));
            documentPanel.hammer.on('swiperight', _.bind(documentPanel.toggle, documentPanel, false));
            */

            previewResizer.initHammer(true);
            var resizerInitialSize;
            previewResizer.hammer.on('dragstart', function() {
                resizerInitialSize = {
                    width: previewPanel.width,
                    height: previewPanel.height
                };
            }).on('drag', function(evt) {
                if(isVertical) {
                    previewPanel.height = resizerInitialSize.height - evt.gesture.deltaY;
                }
                else {
                    previewPanel.width = resizerInitialSize.width - evt.gesture.deltaX;
                }
                evt.gesture.preventDefault();
                previewPanel.halfSize = false;
                resizeAll();
            });
        }

        previewButtons.initHammer(true);
        previewButtons.adjustPosition = function() {
            if(!previewButtons.isDragged) {
                return;
            }
            var minX = -windowSize.width + previewButtons.elt.offsetWidth;
            var minY = -windowSize.height + previewButtons.elt.offsetHeight;
            this.x < minX && (this.x = minX);
            this.y < minY && (this.y = minY);
            this.x > 0 && (this.x = 0);
            this.y > 0 && (this.y = 0);
            this.applyCss();
        };


        var buttonsInitialCoord;
        previewButtons.hammer.on('dragstart', function() {
            previewButtons.isDragged = true;
            previewButtons.$elt.removeClass('animate');
            wrapperL2.$elt.addClass('dragging');
            buttonsInitialCoord = {
                x: previewButtons.x,
                y: previewButtons.y
            };
        }).on('drag', function(evt) {
            previewButtons.x = buttonsInitialCoord.x + evt.gesture.deltaX;
            previewButtons.y = buttonsInitialCoord.y + evt.gesture.deltaY;
            previewButtons.adjustPosition();
            evt.gesture.preventDefault();
        }).on('dragend', function() {
            wrapperL2.$elt.removeClass('dragging');
            previewButtons.$elt.find('.btn-group').toggleClass('dropup', windowSize.height/2 > -previewButtons.y);
        });

        var isModalShown = false;
        $('.modal').on('show.bs.modal', function() {
            // Close panel if open
            menuPanel.toggle(false);
            documentPanel.toggle(false);
            isModalShown = true;
        }).on('hidden.bs.modal', function() {
            isModalShown = false;
        });

        // Configure Mousetrap
        mousetrap.stopCallback = function() {
            return menuPanel.isOpen || documentPanel.isOpen || isModalShown;
        };

        $(window).resize(resizeAll);

        var styleContent = '';

        // Apply font
        function applyFont(size, screenWidth) {
            screenWidth = screenWidth || 0;
            styleContent += [
                '@media (min-width: ' + screenWidth + 'px) {',
                '#wmd-input {',
                '   font-size: ' + size + 'px;',
                '}',
                '#preview-contents {',
                '   font-size: ' + size + 'px;',
                '}',
                '}',
            ].join('\n');
        }
        applyFont(16 * settings.fontSizeRatio);
        applyFont(17 * settings.fontSizeRatio, 600);
        applyFont(18 * settings.fontSizeRatio, 1200);

        // Apply dynamic stylesheet
        var style = crel('style', {
            type : 'text/css'
        });
        style.innerHTML = styleContent;
        document.head.appendChild(style);

        resizeAll();
    };

    eventMgr.addListener('onReady', function() {
        previewButtons.x = previewButtonsOffset.x;
        previewButtons.y = previewButtonsOffset.y;
        previewButtons.applyCss();

        function openPreviewButtons() {
            clearTimeout(closeTimeoutId);
            if(!previewButtons.isDragged) {
                previewButtons.x = previewButtonsOffset.x;
                previewButtons.applyCss();
            }
        }
        var closeTimeoutId;
        var dropdownOpen = false;
        function closePreviewButtons() {
            clearTimeout(closeTimeoutId);
            closeTimeoutId = setTimeout(function() {
                if(!previewButtons.isDragged && !dropdownOpen) {
                    previewButtons.$elt.addClass('animate');
                    previewButtons.x = previewButtonsOffset.x + previewButtons.elt.offsetWidth;
                    previewButtons.applyCss();
                }
            }, 3000);
        }

        closePreviewButtons();
        previewButtons.$elt.hover(openPreviewButtons, closePreviewButtons).on('show.bs.dropdown', function() {
            dropdownOpen = true;
        }).on('hidden.bs.dropdown', function() {
            dropdownOpen = false;
            closePreviewButtons();
        });

        _.each(previewButtons.elt.querySelectorAll('.btn-group'), function(btnGroupElt) {
            var $btnGroupElt = $(btnGroupElt);
            $btnGroupElt.on('shown.bs.dropdown', function() {
                // Align dropdown to the left of the screen
                $btnGroupElt.find('.dropdown-menu').css({
                    right: -previewButtons.elt.offsetWidth + $btnGroupElt.width() + $btnGroupElt.position().left
                });
                var maxHeight = -previewButtons.y - previewButtonsDropdownMargin;
                // If it's a dropup
                if(windowSize.height/2 > -previewButtons.y) {
                    maxHeight = windowSize.height + previewButtons.y - previewButtons.elt.offsetHeight - previewButtonsDropdownMargin;
                }
                $btnGroupElt.find('.markdown-syntax, .table-of-contents').css({
                    'maxHeight': maxHeight
                });
            }).addClass('dropup');
        });
    });

    eventMgr.onLayoutCreated(layout);
    return layout;
});