import Component from '@ember/component';
import layout from '../templates/components/koenig-plus-menu';
import {CARD_MENU} from '../options/cards';
import {computed} from '@ember/object';
import {htmlSafe} from '@ember/string';
import {run} from '@ember/runloop';

export default Component.extend({
    layout,

    // public attrs
    classNames: ['absolute'],
    attributeBindings: ['style', 'data-kg'],
    editor: null,
    editorRange: null,

    // internal properties
    itemSections: null,
    showButton: false,
    showMenu: false,
    top: 0,
    'data-kg': 'plus-menu',

    // private properties
    _onResizeHandler: null,
    _onWindowMousedownHandler: null,
    _lastEditorRange: null,
    _hasCursorButton: false,
    _onMousemoveHandler: null,
    _onKeydownHandler: null,

    // closure actions
    replaceWithCardSection() {},

    style: computed('top', function () {
        return htmlSafe(`top: ${this.top}px`);
    }),

    init() {
        this._super(...arguments);

        this.itemSections = CARD_MENU;

        this._onResizeHandler = run.bind(this, this._handleResize);
        window.addEventListener('resize', this._onResizeHandler);

        this._onMousemoveHandler = run.bind(this, this._mousemoveRaf);
        window.addEventListener('mousemove', this._onMousemoveHandler);
    },

    didReceiveAttrs() {
        this._super(...arguments);

        let editorRange = this.editorRange;

        // show the (+) button when the cursor is on a blank P tag
        if (!this.showMenu && editorRange !== this._lastEditorRange) {
            this._showOrHideButton(editorRange);
            this._hasCursorButton = this.showButton;
        }

        // re-position again on next runloop, prevents incorrect position after
        // adding a card at the bottom of the doc
        if (this.showButton) {
            run.next(this, this._positionMenu);
        }

        this._lastEditorRange = editorRange;
    },

    willDestroyElement() {
        this._super(...arguments);
        run.cancel(this._throttleResize);
        window.removeEventListener('mousedown', this._onWindowMousedownHandler);
        window.removeEventListener('resize', this._onResizeHandler);
        window.removeEventListener('mousemove', this._onMousemoveHandler);
        window.removeEventListener('keydown', this._onKeydownHandler);
    },

    actions: {
        openMenu() {
            this._showMenu();
        },

        closeMenu() {
            this._hideMenu();
        },

        itemClicked(item) {
            let range = this._editorRange;

            if (item.type === 'card') {
                this.replaceWithCardSection(item.replaceArg, range);
            }

            this._hideButton();
            this._hideMenu();
        }
    },

    _showOrHideButton(editorRange) {
        if (!editorRange) {
            this._hideButton();
            this._hideMenu();
            return;
        }

        let {head: {section}} = editorRange;

        // show the button if the range is a blank paragraph
        if (editorRange && editorRange.isCollapsed && section && !section.isListItem && (section.isBlank || section.text === '')) {
            this._editorRange = editorRange;
            this._showButton();
            this._hideMenu();
        } else {
            this._hideButton();
            this._hideMenu();
        }
    },

    _showButton() {
        this._positionMenu();
        this.set('showButton', true);
    },

    _hideButton() {
        this.set('showButton', false);
    },

    // find the "top" position by grabbing the current sections
    // render node and querying it's bounding rect. Setting "top"
    // positions the button+menu container element [data-kg="plus-menu"]
    _positionMenu() {
        // use the cached range if available because `editorRange` may have been
        // lost due to clicks on the open menu
        let {head: {section}} = this._editorRange || this.editorRange;

        if (section) {
            let containerRect = this.element.parentNode.getBoundingClientRect();
            let selectedElement = section.renderNode.element;
            if (selectedElement) {
                let selectedElementRect = selectedElement.getBoundingClientRect();
                let top = selectedElementRect.top - containerRect.top;

                this.set('top', top);
            }
        }
    },

    _showMenu() {
        this.set('showMenu', true);

        // move the cursor to the blank paragraph, ensures any selected card
        // gets inserted in the correct place because editorRange will be
        // wherever the cursor currently is if the menu was opened via a
        // mouseover button
        this._moveCaretToCachedEditorRange();

        // focus the search immediately so that you can filter immediately
        run.schedule('afterRender', this, function () {
            this._focusSearch();
        });

        // watch the window for mousedown events so that we can close the menu
        // when we detect a click outside
        this._onWindowMousedownHandler = run.bind(this, this._handleWindowMousedown);
        window.addEventListener('mousedown', this._onWindowMousedownHandler);

        // watch for keydown events so that we can close the mnu on Escape
        this._onKeydownHandler = run.bind(this, this._handleKeydown);
        window.addEventListener('keydown', this._onKeydownHandler);
    },

    _hideMenu() {
        if (this.showMenu) {
            // reset our cached editorRange
            this._editorRange = null;

            // stop watching the body for clicks and keydown
            window.removeEventListener('mousedown', this._onWindowMousedownHandler);
            window.removeEventListener('keydown', this._onKeydownHandler);

            // hide the menu
            this.set('showMenu', false);
        }
    },

    _focusSearch() {
        let search = this.element.querySelector('input');
        if (search) {
            search.focus();
        }
    },

    _handleWindowMousedown(event) {
        if (!event.target.closest(`#${this.elementId}`)) {
            this._hideMenu();
        }
    },

    _mousemoveRaf(event) {
        if (!this._mousemoveTicking) {
            requestAnimationFrame(run.bind(this, this._handleMousemove, event));
        }
        this._mousemoveTicking = true;
    },

    // show the (+) button when the mouse is over a blank P tag
    _handleMousemove(event) {
        if (!this.showMenu) {
            let {pageX, pageY} = event;
            let editor = this.editor;

            // add a horizontal buffer to the pointer position so that the
            // (+) button doesn't disappear when the mouse hovers over it due
            // to it being outside of the editor canvas
            let containerRect = this.element.parentNode.getBoundingClientRect();
            if (pageX < containerRect.left) {
                pageX = pageX + 40;
            }

            // grab a range from the editor position under the pointer. We can
            // rely on the same show/hide behaviour of our cursor implementation
            try {
                let position = editor.positionAtPoint(pageX, pageY);
                if (position) {
                    let pointerRange = position.toRange();
                    this._showOrHideButton(pointerRange);
                }
            } catch (e) {
                // mobiledoc-kit can generate the following harmless error
                // from positionAtPoint(x,y) whilst dragging a selection
                // TypeError: Failed to execute 'compareDocumentPosition' on 'Node': parameter 1 is not of type 'Node'.
                if (e instanceof TypeError === false) {
                    throw e;
                }
            }

            // if the button is hidden due to the pointer not being over a blank
            // P but we have a valid cursor position then fall back to the cursor
            // positioning
            if (!this.showButton && this._hasCursorButton) {
                this._showOrHideButton(this.editorRange);
            }
        }

        this._mousemoveTicking = false;
    },

    _handleKeydown(event) {
        if (event.code === 'Escape') {
            // reset the caret position so we have a caret after closing
            this._moveCaretToCachedEditorRange();
            this._hideMenu();
        }
    },

    _handleResize() {
        if (this.showButton) {
            this._throttleResize = run.throttle(this, this._positionMenu, 100);
        }
    },

    _moveCaretToCachedEditorRange() {
        this.set('editorRange', this._editorRange);
        this.editor.selectRange(this._editorRange);
    }

});