<template>
    <div :class="containerClass">
        <div class="p-orderlist-controls">
            <slot name="controlsstart"></slot>
            <OLButton type="button" icon="pi pi-angle-up" @click="moveUp" :aria-label="moveUpAriaLabel" :disabled="moveDisabled()" v-bind="moveUpButtonProps"></OLButton>
            <OLButton type="button" icon="pi pi-angle-double-up" @click="moveTop" :aria-label="moveTopAriaLabel" :disabled="moveDisabled()" v-bind="moveTopButtonProps"></OLButton>
            <OLButton type="button" icon="pi pi-angle-down" @click="moveDown" :aria-label="moveDownAriaLabel" :disabled="moveDisabled()" v-bind="moveDownButtonProps"></OLButton>
            <OLButton type="button" icon="pi pi-angle-double-down" @click="moveBottom" :aria-label="moveBottomAriaLabel" :disabled="moveDisabled()" v-bind="moveBottomButtonProps"></OLButton>
            <slot name="controlsend"></slot>
        </div>
        <div class="p-orderlist-list-container">
            <div v-if="$slots.header" class="p-orderlist-header">
                <slot name="header"></slot>
            </div>
            <transition-group
                :ref="listRef"
                :id="id + '_list'"
                name="p-orderlist-flip"
                tag="ul"
                class="p-orderlist-list"
                :style="listStyle"
                role="listbox"
                aria-multiselectable="true"
                :tabindex="tabindex"
                :aria-activedescendant="focused ? focusedOptionId : undefined"
                :aria-label="ariaLabel"
                :aria-labelledby="ariaLabelledby"
                @focus="onListFocus"
                @blur="onListBlur"
                @keydown="onListKeyDown"
                v-bind="listProps"
            >
                <template v-for="(item, i) of modelValue" :key="getItemKey(item, i)">
                    <li :id="id + '_' + i" v-ripple role="option" :class="itemClass(item, `${id}_${i}`)" @click="onItemClick($event, item, i)" @touchend="onItemTouchEnd" :aria-selected="isSelected(item)" @mousedown="onOptionMouseDown(i)">
                        <slot name="item" :item="item" :index="i"> </slot>
                    </li>
                </template>
            </transition-group>
        </div>
    </div>
</template>

<script>
import Button from 'primevue/button';
import Ripple from 'primevue/ripple';
import { DomHandler, ObjectUtils, UniqueComponentId } from 'primevue/utils';

export default {
    name: 'OrderList',
    emits: ['update:modelValue', 'reorder', 'update:selection', 'selection-change', 'focus', 'blur'],
    props: {
        modelValue: {
            type: Array,
            default: null
        },
        selection: {
            type: Array,
            default: null
        },
        dataKey: {
            type: String,
            default: null
        },
        listStyle: {
            type: null,
            default: null
        },
        metaKeySelection: {
            type: Boolean,
            default: true
        },
        responsive: {
            type: Boolean,
            default: true
        },
        breakpoint: {
            type: String,
            default: '960px'
        },
        stripedRows: {
            type: Boolean,
            default: false
        },
        tabindex: {
            type: Number,
            default: 0
        },
        listProps: {
            type: null,
            default: null
        },
        moveUpButtonProps: {
            type: null,
            default: null
        },
        moveTopButtonProps: {
            type: null,
            default: null
        },
        moveDownButtonProps: {
            type: null,
            default: null
        },
        moveBottomButtonProps: {
            type: null,
            default: null
        },
        'aria-labelledby': {
            type: String,
            default: null
        },
        'aria-label': {
            type: String,
            default: null
        }
    },
    itemTouched: false,
    reorderDirection: null,
    styleElement: null,
    list: null,
    data() {
        return {
            id: this.$attrs.id,
            d_selection: this.selection,
            focused: false,
            focusedOptionIndex: -1
        };
    },
    watch: {
        '$attrs.id': function (newValue) {
            this.id = newValue || UniqueComponentId();
        }
    },
    beforeUnmount() {
        this.destroyStyle();
    },
    updated() {
        if (this.reorderDirection) {
            this.updateListScroll();
            this.reorderDirection = null;
        }
    },
    mounted() {
        this.id = this.id || UniqueComponentId();

        if (this.responsive) {
            this.createStyle();
        }
    },
    methods: {
        getItemKey(item, index) {
            return this.dataKey ? ObjectUtils.resolveFieldData(item, this.dataKey) : index;
        },
        isSelected(item) {
            return ObjectUtils.findIndexInList(item, this.d_selection) != -1;
        },
        onListFocus(event) {
            const selectedFirstItem = DomHandler.findSingle(this.list, 'li.p-orderlist-item.p-highlight');
            const findIndex = ObjectUtils.findIndexInList(selectedFirstItem, this.list.children);

            this.focused = true;

            const index = this.focusedOptionIndex !== -1 ? this.focusedOptionIndex : selectedFirstItem ? findIndex : -1;

            this.changeFocusedOptionIndex(index);
            this.$emit('focus', event);
        },
        onListBlur(event) {
            this.focused = false;
            this.focusedOptionIndex = -1;
            this.$emit('blur', event);
        },
        onListKeyDown(event) {
            switch (event.code) {
                case 'ArrowDown':
                    this.onArrowDownKey(event);
                    break;

                case 'ArrowUp':
                    this.onArrowUpKey(event);
                    break;

                case 'Home':
                    this.onHomeKey(event);
                    break;

                case 'End':
                    this.onEndKey(event);
                    break;

                case 'Enter':
                    this.onEnterKey(event);
                    break;

                case 'Space':
                    this.onSpaceKey(event);
                    break;

                case 'KeyA':
                    if (event.ctrlKey) {
                        this.d_selection = [...this.modelValue];
                        this.$emit('update:selection', this.d_selection);
                    }

                default:
                    break;
            }
        },
        onOptionMouseDown(index) {
            this.focused = true;
            this.focusedOptionIndex = index;
        },
        onArrowDownKey(event) {
            const optionIndex = this.findNextOptionIndex(this.focusedOptionIndex);

            this.changeFocusedOptionIndex(optionIndex);

            if (event.shiftKey) {
                this.onEnterKey(event);
            }

            event.preventDefault();
        },
        onArrowUpKey(event) {
            const optionIndex = this.findPrevOptionIndex(this.focusedOptionIndex);

            this.changeFocusedOptionIndex(optionIndex);

            if (event.shiftKey) {
                this.onEnterKey(event);
            }

            event.preventDefault();
        },
        onHomeKey(event) {
            if (event.ctrlKey && event.shiftKey) {
                const items = DomHandler.find(this.list, 'li.p-orderlist-item');
                const focusedItem = DomHandler.findSingle(this.list, `li.p-orderlist-item[id=${this.focusedOptionIndex}]`);
                const matchedOptionIndex = [...items].findIndex((item) => item === focusedItem);

                this.d_selection = [...this.modelValue].slice(0, matchedOptionIndex + 1);
                this.$emit('update:selection', this.d_selection);
            } else {
                this.changeFocusedOptionIndex(0);
            }

            event.preventDefault();
        },
        onEndKey(event) {
            if (event.ctrlKey && event.shiftKey) {
                const items = DomHandler.find(this.list, 'li.p-orderlist-item');
                const focusedItem = DomHandler.findSingle(this.list, `li.p-orderlist-item[id=${this.focusedOptionIndex}]`);
                const matchedOptionIndex = [...items].findIndex((item) => item === focusedItem);

                this.d_selection = [...this.modelValue].slice(matchedOptionIndex, items.length);
                this.$emit('update:selection', this.d_selection);
            } else {
                this.changeFocusedOptionIndex(DomHandler.find(this.list, 'li.p-orderlist-item').length - 1);
            }

            event.preventDefault();
        },
        onEnterKey(event) {
            const items = DomHandler.find(this.list, 'li.p-orderlist-item');
            const focusedItem = DomHandler.findSingle(this.list, `li.p-orderlist-item[id=${this.focusedOptionIndex}]`);
            const matchedOptionIndex = [...items].findIndex((item) => item === focusedItem);

            this.onItemClick(event, this.modelValue[matchedOptionIndex], matchedOptionIndex);

            event.preventDefault();
        },
        onSpaceKey(event) {
            if (event.shiftKey) {
                const items = DomHandler.find(this.list, 'li.p-orderlist-item');
                const selectedItemIndex = ObjectUtils.findIndexInList(this.d_selection[0], [...this.modelValue]);
                const focusedItem = DomHandler.findSingle(this.list, `li.p-orderlist-item[id=${this.focusedOptionIndex}]`);
                const matchedOptionIndex = [...items].findIndex((item) => item === focusedItem);

                this.d_selection = [...this.modelValue].slice(Math.min(selectedItemIndex, matchedOptionIndex), Math.max(selectedItemIndex, matchedOptionIndex) + 1);
                this.$emit('update:selection', this.d_selection);
            } else {
                this.onEnterKey(event);
            }
        },
        findNextOptionIndex(index) {
            const items = DomHandler.find(this.list, 'li.p-orderlist-item');
            const matchedOptionIndex = [...items].findIndex((link) => link.id === index);

            return matchedOptionIndex > -1 ? matchedOptionIndex + 1 : 0;
        },
        findPrevOptionIndex(index) {
            const items = DomHandler.find(this.list, 'li.p-orderlist-item');
            const matchedOptionIndex = [...items].findIndex((link) => link.id === index);

            return matchedOptionIndex > -1 ? matchedOptionIndex - 1 : 0;
        },
        changeFocusedOptionIndex(index) {
            const items = DomHandler.find(this.list, 'li.p-orderlist-item');

            let order = index >= items.length ? items.length - 1 : index < 0 ? 0 : index;

            this.focusedOptionIndex = items[order].getAttribute('id');
            this.scrollInView(items[order].getAttribute('id'));
        },
        scrollInView(id) {
            const element = DomHandler.findSingle(this.list, `li[id="${id}"]`);

            if (element) {
                element.scrollIntoView && element.scrollIntoView({ block: 'nearest', inline: 'start' });
            }
        },
        moveUp(event) {
            if (this.d_selection) {
                let value = [...this.modelValue];

                for (let i = 0; i < this.d_selection.length; i++) {
                    let selectedItem = this.d_selection[i];
                    let selectedItemIndex = ObjectUtils.findIndexInList(selectedItem, value);

                    if (selectedItemIndex !== 0) {
                        let movedItem = value[selectedItemIndex];
                        let temp = value[selectedItemIndex - 1];

                        value[selectedItemIndex - 1] = movedItem;
                        value[selectedItemIndex] = temp;
                    } else {
                        break;
                    }
                }

                this.reorderDirection = 'up';
                this.$emit('update:modelValue', value);
                this.$emit('reorder', {
                    originalEvent: event,
                    value: value,
                    direction: this.reorderDirection
                });
            }
        },
        moveTop(event) {
            if (this.d_selection) {
                let value = [...this.modelValue];

                for (let i = 0; i < this.d_selection.length; i++) {
                    let selectedItem = this.d_selection[i];
                    let selectedItemIndex = ObjectUtils.findIndexInList(selectedItem, value);

                    if (selectedItemIndex !== 0) {
                        let movedItem = value.splice(selectedItemIndex, 1)[0];

                        value.unshift(movedItem);
                    } else {
                        break;
                    }
                }

                this.reorderDirection = 'top';
                this.$emit('update:modelValue', value);
                this.$emit('reorder', {
                    originalEvent: event,
                    value: value,
                    direction: this.reorderDirection
                });
            }
        },
        moveDown(event) {
            if (this.d_selection) {
                let value = [...this.modelValue];

                for (let i = this.d_selection.length - 1; i >= 0; i--) {
                    let selectedItem = this.d_selection[i];
                    let selectedItemIndex = ObjectUtils.findIndexInList(selectedItem, value);

                    if (selectedItemIndex !== value.length - 1) {
                        let movedItem = value[selectedItemIndex];
                        let temp = value[selectedItemIndex + 1];

                        value[selectedItemIndex + 1] = movedItem;
                        value[selectedItemIndex] = temp;
                    } else {
                        break;
                    }
                }

                this.reorderDirection = 'down';
                this.$emit('update:modelValue', value);
                this.$emit('reorder', {
                    originalEvent: event,
                    value: value,
                    direction: this.reorderDirection
                });
            }
        },
        moveBottom(event) {
            if (this.d_selection) {
                let value = [...this.modelValue];

                for (let i = this.d_selection.length - 1; i >= 0; i--) {
                    let selectedItem = this.d_selection[i];
                    let selectedItemIndex = ObjectUtils.findIndexInList(selectedItem, value);

                    if (selectedItemIndex !== value.length - 1) {
                        let movedItem = value.splice(selectedItemIndex, 1)[0];

                        value.push(movedItem);
                    } else {
                        break;
                    }
                }

                this.reorderDirection = 'bottom';
                this.$emit('update:modelValue', value);
                this.$emit('reorder', {
                    originalEvent: event,
                    value: value,
                    direction: this.reorderDirection
                });
            }
        },
        onItemClick(event, item, index) {
            this.itemTouched = false;
            const selectedIndex = ObjectUtils.findIndexInList(item, this.d_selection);
            const selected = selectedIndex != -1;
            const metaSelection = this.itemTouched ? false : this.metaKeySelection;
            const selectedId = DomHandler.find(this.list, '.p-orderlist-item')[index].getAttribute('id');

            this.focusedOptionIndex = selectedId;

            if (metaSelection) {
                const metaKey = event.metaKey || event.ctrlKey;

                if (selected && metaKey) {
                    this.d_selection = this.d_selection.filter((val, index) => index !== selectedIndex);
                } else {
                    this.d_selection = metaKey ? (this.d_selection ? [...this.d_selection] : []) : [];
                    ObjectUtils.insertIntoOrderedArray(item, index, this.d_selection, this.modelValue);
                }
            } else {
                if (selected) {
                    this.d_selection = this.d_selection.filter((val, index) => index !== selectedIndex);
                } else {
                    this.d_selection = this.d_selection ? [...this.d_selection] : [];
                    ObjectUtils.insertIntoOrderedArray(item, index, this.d_selection, this.modelValue);
                }
            }

            this.$emit('update:selection', this.d_selection);
            this.$emit('selection-change', {
                originalEvent: event,
                value: this.d_selection
            });
        },
        onItemTouchEnd() {
            this.itemTouched = true;
        },
        findNextItem(item) {
            let nextItem = item.nextElementSibling;

            if (nextItem) return !DomHandler.hasClass(nextItem, 'p-orderlist-item') ? this.findNextItem(nextItem) : nextItem;
            else return null;
        },
        findPrevItem(item) {
            let prevItem = item.previousElementSibling;

            if (prevItem) return !DomHandler.hasClass(prevItem, 'p-orderlist-item') ? this.findPrevItem(prevItem) : prevItem;
            else return null;
        },
        findFirstItem() {
            return DomHandler.findSingle(this.list, '.p-orderlist-item');
        },
        findLastItem() {
            const items = DomHandler.find(this.list, '.p-orderlist-item');

            return items[items.length - 1];
        },
        itemClass(item, id) {
            return ['p-orderlist-item', { 'p-highlight': this.isSelected(item), 'p-focus': id === this.focusedOptionId }];
        },
        updateListScroll() {
            const listItems = DomHandler.find(this.list, '.p-orderlist-item.p-highlight');

            if (listItems && listItems.length) {
                switch (this.reorderDirection) {
                    case 'up':
                        DomHandler.scrollInView(this.list, listItems[0]);
                        break;

                    case 'top':
                        this.list.scrollTop = 0;
                        break;

                    case 'down':
                        DomHandler.scrollInView(this.list, listItems[listItems.length - 1]);
                        break;

                    case 'bottom':
                        this.list.scrollTop = this.list.scrollHeight;
                        break;

                    default:
                        break;
                }
            }
        },
        createStyle() {
            if (!this.styleElement) {
                this.$el.setAttribute(this.attributeSelector, '');
                this.styleElement = document.createElement('style');
                this.styleElement.type = 'text/css';
                document.head.appendChild(this.styleElement);

                let innerHTML = `
@media screen and (max-width: ${this.breakpoint}) {
    .p-orderlist[${this.attributeSelector}] {
        flex-direction: column;
    }

    .p-orderlist[${this.attributeSelector}] .p-orderlist-controls {
        padding: var(--content-padding);
        flex-direction: row;
    }

    .p-orderlist[${this.attributeSelector}] .p-orderlist-controls .p-button {
        margin-right: var(--inline-spacing);
        margin-bottom: 0;
    }

    .p-orderlist[${this.attributeSelector}] .p-orderlist-controls .p-button:last-child {
        margin-right: 0;
    }
}
`;

                this.styleElement.innerHTML = innerHTML;
            }
        },
        destroyStyle() {
            if (this.styleElement) {
                document.head.removeChild(this.styleElement);
                this.styleElement = null;
            }
        },
        moveDisabled() {
            if (!this.d_selection || !this.d_selection.length) {
                return true;
            }
        },
        listRef(el) {
            this.list = el ? el.$el : undefined;
        }
    },
    computed: {
        containerClass() {
            return [
                'p-orderlist p-component',
                {
                    'p-orderlist-striped': this.stripedRows
                }
            ];
        },
        attributeSelector() {
            return UniqueComponentId();
        },
        focusedOptionId() {
            return this.focusedOptionIndex !== -1 ? this.focusedOptionIndex : null;
        },
        moveUpAriaLabel() {
            return this.$primevue.config.locale.aria ? this.$primevue.config.locale.aria.moveUp : undefined;
        },
        moveTopAriaLabel() {
            return this.$primevue.config.locale.aria ? this.$primevue.config.locale.aria.moveTop : undefined;
        },
        moveDownAriaLabel() {
            return this.$primevue.config.locale.aria ? this.$primevue.config.locale.aria.moveDown : undefined;
        },
        moveBottomAriaLabel() {
            return this.$primevue.config.locale.aria ? this.$primevue.config.locale.aria.moveBottom : undefined;
        }
    },
    components: {
        OLButton: Button
    },
    directives: {
        ripple: Ripple
    }
};
</script>

<style>
.p-orderlist {
    display: flex;
}

.p-orderlist-controls {
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.p-orderlist-list-container {
    flex: 1 1 auto;
}

.p-orderlist-list {
    list-style-type: none;
    margin: 0;
    padding: 0;
    overflow: auto;
    min-height: 12rem;
    max-height: 24rem;
}

.p-orderlist-item {
    cursor: pointer;
    overflow: hidden;
    position: relative;
}

.p-orderlist.p-state-disabled .p-orderlist-item,
.p-orderlist.p-state-disabled .p-button {
    cursor: default;
}

.p-orderlist.p-state-disabled .p-orderlist-list {
    overflow: hidden;
}
</style>
