<script setup lang="ts" generic="T">
import Dropdown from '@/packages/ui/src/Input/Dropdown.vue';
import { type Component, computed, nextTick, ref, watch } from 'vue';
import MultiselectDropdownItem from '@/packages/ui/src/Input/MultiselectDropdownItem.vue';

const model = defineModel<string[]>({
    default: [],
});

const props = defineProps<{
    items: T[];
    searchPlaceholder: string;
    getKeyFromItem: (item: T) => string;
    getNameForItem: (item: T) => string;
}>();

const searchInput = ref<HTMLInputElement | null>(null);
const open = ref(false);
const dropdownViewport = ref<Component | null>(null);

const searchValue = ref('');

function isItemSelected(id: string) {
    return model.value.includes(id);
}

function addOrRemoveItemFromSelection(id: string) {
    if (model.value.includes(id)) {
        model.value = model.value.filter((itemId) => itemId !== id);
    } else {
        model.value.push(id);
    }
    emit('changed');
}

watch(open, (isOpen) => {
    if (isOpen) {
        nextTick(() => {
            searchInput.value?.focus();
        });

        // sort tags alphabetically
        [...props.items].sort((a, b) => {
            const aIsSelected = model.value.includes(props.getKeyFromItem(a));
            const bIsSelected = model.value.includes(props.getKeyFromItem(b));
            if (aIsSelected === bIsSelected) {
                return props
                    .getNameForItem(a)
                    .localeCompare(props.getNameForItem(b));
            }
            return model.value.includes(props.getKeyFromItem(a)) ? -1 : 1;
        });
        nextTick(() => {
            if (filteredItems.value.length > 0) {
                highlightedItemId.value = props.getKeyFromItem(
                    filteredItems.value[0]
                );
            }
        });
    }
});

const filteredItems = computed<T[]>(() => {
    return props.items.filter((item: T) => {
        return props
            .getNameForItem(item)
            .toLowerCase()
            .includes(searchValue.value?.toLowerCase()?.trim() || '');
    });
});

watch(filteredItems, () => {
    if (filteredItems.value.length > 0) {
        highlightedItemId.value = props.getKeyFromItem(filteredItems.value[0]);
    }
});

function updateSearchValue(event: Event) {
    const newInput = (event.target as HTMLInputElement).value;
    if (newInput === ' ') {
        searchValue.value = '';
        const highlightedTagId = highlightedItemId.value;
        if (highlightedTagId) {
            const highlightedItem = props.items.find(
                (item) => props.getKeyFromItem(item) === highlightedTagId
            );
            if (highlightedItem) {
                addOrRemoveItemFromSelection(
                    props.getKeyFromItem(highlightedItem)
                );
            }
        }
    } else {
        searchValue.value = newInput;
    }
}

const emit = defineEmits(['update:modelValue', 'changed']);

function toggleItem(newValue: string | null) {
    if (newValue !== null) {
        if (model.value.includes(newValue)) {
            model.value = [...model.value].filter((id) => id !== newValue);
        } else {
            model.value = [...model.value, newValue];
        }
        emit('changed');
    }
}

function moveHighlightUp() {
    if (highlightedItem.value) {
        const currentHightlightedIndex = filteredItems.value.indexOf(
            highlightedItem.value
        );
        if (currentHightlightedIndex === 0) {
            highlightedItemId.value = props.getKeyFromItem(
                filteredItems.value[filteredItems.value.length - 1]
            );
        } else {
            highlightedItemId.value = props.getKeyFromItem(
                filteredItems.value[currentHightlightedIndex - 1]
            );
        }
    }
}

function moveHighlightDown() {
    if (highlightedItem.value) {
        const currentHightlightedIndex = filteredItems.value.indexOf(
            highlightedItem.value
        );
        if (currentHightlightedIndex === filteredItems.value.length - 1) {
            highlightedItemId.value = props.getKeyFromItem(
                filteredItems.value[0]
            );
        } else {
            highlightedItemId.value = props.getKeyFromItem(
                filteredItems.value[currentHightlightedIndex + 1]
            );
        }
    }
}

const highlightedItemId = ref<string | null>(null);
const highlightedItem = computed(() => {
    return props.items.find(
        (item) => props.getKeyFromItem(item) === highlightedItemId.value
    );
});
</script>

<template>
    <Dropdown v-model="open" align="start" :close-on-content-click="false">
        <template #trigger>
            <slot name="trigger"></slot>
        </template>
        <template #content>
            <input
                ref="searchInput"
                :value="searchValue"
                class="bg-card-background border-0 placeholder-muted text-sm text-text-primary py-2.5 focus:ring-0 border-b border-card-background-separator focus:border-card-background-separator w-full"
                :placeholder="searchPlaceholder"
                @input="updateSearchValue"
                @keydown.up.prevent="moveHighlightUp"
                @keydown.down.prevent="moveHighlightDown"
                @keydown.enter="toggleItem(highlightedItemId)" />
            <div
                ref="dropdownViewport"
                class="min-w-60 max-w-80 max-h-60 overflow-y-scroll">
                <div
                    v-for="item in filteredItems"
                    :key="props.getKeyFromItem(item)"
                    role="option"
                    :value="props.getKeyFromItem(item)"
                    :class="{
                        'bg-card-background-active':
                            props.getKeyFromItem(item) === highlightedItemId,
                    }"
                    :data-item-id="props.getKeyFromItem(item)">
                    <MultiselectDropdownItem
                        :selected="isItemSelected(props.getKeyFromItem(item))"
                        :name="
                            props.getNameForItem(item)
                        "
                        @click="toggleItem(props.getKeyFromItem(item))"></MultiselectDropdownItem>
                </div>
            </div>
        </template>
    </Dropdown>
</template>

<style scoped></style>
