import Component from '@ember/component';

export default Component.extend({

    // public attrs
    classNames: ['gh-koenig-editor', 'relative', 'w-100', 'vh-100', 'overflow-x-hidden', 'overflow-y-auto', 'z-0'],
    title: '',
    titlePlaceholder: '',
    body: null,
    bodyPlaceholder: '',
    bodyAutofocus: false,

    // internal properties
    _title: null,
    _editor: null,
    _mousedownY: 0,

    // closure actions
    onTitleChange() {},
    onTitleBlur() {},
    onBodyChange() {},
    onEditorCreated() {},
    onWordCountChange() {},

    actions: {
        focusTitle() {
            this._title.focus();
        },

        // triggered when a mousedown is registered on .gh-koenig-editor-pane
        trackMousedown(event) {
            this._mousedownY = event.clientY;
        },

        // triggered when a mouseup is registered on .gh-koenig-editor-pane
        focusEditor(event) {
            if (event.target.classList.contains('gh-koenig-editor-pane')) {
                let editorCanvas = this._editor.element;
                let {bottom} = editorCanvas.getBoundingClientRect();

                // if a mousedown and subsequent mouseup occurs below the editor
                // canvas, focus the editor and put the cursor at the end of the
                // document
                if (this._mousedownY > bottom && event.clientY > bottom) {
                    let {post} = this._editor;
                    let range = post.toRange();
                    let {tailSection} = range;

                    event.preventDefault();
                    this._editor.focus();

                    // we should always have a visible cursor when focusing
                    // at the bottom so create an empty paragraph if last
                    // section is a card
                    if (tailSection.isCardSection) {
                        this._editor.run((postEditor) => {
                            let newSection = postEditor.builder.createMarkupSection('p');
                            postEditor.insertSectionAtEnd(newSection);
                            tailSection = newSection;
                        });
                    }

                    this._editor.selectRange(tailSection.tailPosition());

                    // ensure we're scrolled to the bottom
                    this.element.scrollTop = this.element.scrollHeight;
                }
            }
        },

        /* title related actions -------------------------------------------- */

        onTitleCreated(titleElement) {
            this._title = titleElement;
        },

        onTitleChange(newTitle) {
            this.onTitleChange(newTitle);
        },

        onTitleFocusOut() {
            this.onTitleBlur();
        },

        onTitleKeydown(event) {
            let value = event.target.value;
            let selectionStart = event.target.selectionStart;

            // enter will always focus the editor
            // down arrow will only focus the editor when the cursor is at the
            // end of the input to preserve the default OS behaviour
            if (
                event.key === 'Enter' ||
                event.key === 'Tab' ||
                ((event.key === 'ArrowDown' || event.key === 'ArrowRight') && (!value || selectionStart === value.length))
            ) {
                event.preventDefault();

                // on Enter we also want to create a blank para if necessary
                if (event.key === 'Enter') {
                    this._addParaAtTop();
                }

                this._editor.focus();
            }
        },

        /* body related actions --------------------------------------------- */

        onEditorCreated(koenig) {
            this._setupEditor(koenig);
            this.onEditorCreated(koenig);
        },

        onBodyChange(newMobiledoc) {
            this.onBodyChange(newMobiledoc);
        }
    },

    /* public methods ------------------------------------------------------- */

    /* internal methods ----------------------------------------------------- */

    _setupEditor(koenig) {
        let component = this;

        this._koenig = koenig;
        this._editor = koenig.editor;

        // focus the title when pressing SHIFT+TAB
        this._editor.registerKeyCommand({
            str: 'SHIFT+TAB',
            run() {
                component.send('focusTitle');
                return true;
            }
        });
    },

    _addParaAtTop() {
        if (!this._editor) {
            return;
        }

        let editor = this._editor;
        let section = editor.post.toRange().head.section;

        // create a blank paragraph at the top of the editor unless it's already
        // a blank paragraph
        if (section.isListItem || !section.isBlank || section.text !== '') {
            editor.run((postEditor) => {
                let {builder} = postEditor;
                let newPara = builder.createMarkupSection('p');
                let sections = section.isListItem ? section.parent.parent.sections : section.parent.sections;

                postEditor.insertSectionBefore(sections, newPara, section);
            });
        }
    }
});