From 11bc4764de8114fc7b558c8abf730671f8f0e13a Mon Sep 17 00:00:00 2001
From: kolaente <k@knt.li>
Date: Tue, 5 Mar 2024 10:37:26 +0100
Subject: [PATCH] feat(filters): add basic autocomplete component

---
 .../src/components/input/Autocomplete.vue     | 316 ++++++++++++++++++
 1 file changed, 316 insertions(+)
 create mode 100644 frontend/src/components/input/Autocomplete.vue

diff --git a/frontend/src/components/input/Autocomplete.vue b/frontend/src/components/input/Autocomplete.vue
new file mode 100644
index 000000000..ea8a27b60
--- /dev/null
+++ b/frontend/src/components/input/Autocomplete.vue
@@ -0,0 +1,316 @@
+<script setup lang="ts">
+import {computed, nextTick, ref, watch} from 'vue'
+
+const TAB = 9,
+	ENTER = 13,
+	ESCAPE = 27,
+	ARROW_UP = 38,
+	ARROW_DOWN = 40
+
+type state = 'unfocused' | 'focused'
+
+const selectedIndex = ref(0)
+const state = ref<state>('unfocused')
+const val = ref<string>('')
+const isResizing = ref(false)
+const model = defineModel<string>()
+
+const suggestionScrollerRef = ref<HTMLInputElement | null>(null)
+const containerRef = ref<HTMLInputElement | null>(null)
+const editorRef = ref<HTMLInputElement | null>(null)
+
+watch(
+	() => model.value,
+	newValue => {
+		val.value = newValue
+	},
+)
+
+const placeholderText = computed(() => {
+	const value = (model.value || '').replace(/[\n\r\t]/gi, ' ')
+
+	if (state.value === 'unfocused') {
+		return value ? '' : props.suggestion
+	}
+
+	if (!value || !value.trim()) {
+		return props.suggestion
+	}
+
+	return lookahead()
+})
+
+const spacerText = computed(() => {
+	const value = (model.value || '').replace(/[\n\r\t]/gi, ' ')
+
+	if (!value || !value.trim()) {
+		return props.suggestion
+	}
+
+	return value
+})
+
+const props = withDefaults(defineProps<{
+	options: string[],
+	suggestion?: string,
+	maxHeight?: number,
+}>(), {
+	maxHeight: 200,
+})
+function addSelectedIndex(offset: number) {
+	let nextIndex = Math.max(
+		0,
+		Math.min(selectedIndex.value + offset, props.options.length - 1),
+	)
+	if (!isFinite(nextIndex)) {
+		nextIndex = 0
+	}
+	selectedIndex.value = nextIndex
+	updateSuggestionScroll()
+}
+
+function highlight(words: string, query: string) {
+	return (words || '').replace(new RegExp(query, 'i'), '<mark class="scroll-term">' + query + '</mark>')
+}
+
+function lookahead() {
+	if (!props.options.length) {
+		return model.value
+	}
+	const index = Math.max(0, Math.min(selectedIndex.value, props.options.length - 1))
+	const match = props.options[index]
+	return model.value + (match ? match.substring(model.value?.length) : '')
+}
+
+function updateSuggestionScroll() {
+	nextTick(() => {
+		const scroller = suggestionScrollerRef.value
+		const selectedItem = scroller?.querySelector('.selected')
+		scroller.scrollTop = selectedItem ? selectedItem.offsetTop : 0
+	})
+}
+
+function updateScrollWindowSize() {
+	if (isResizing.value) {
+		return
+	}
+
+	isResizing.value = true
+
+	nextTick(() => {
+		isResizing.value = false
+
+		const scroller = suggestionScrollerRef.value
+		const parent = containerRef.value
+		if (scroller) {
+			const rect = parent.getBoundingClientRect()
+			const pxTop = rect.top
+			const pxBottom = window.innerHeight - rect.bottom
+			const maxHeight = Math.max(pxTop, pxBottom, props.maxHeight)
+			const isReversed = pxBottom < props.maxHeight && pxTop > pxBottom
+			scroller.style.maxHeight = Math.min(isReversed ? pxTop : pxBottom, props.maxHeight) + 'px'
+			scroller.parentNode.style.transform =
+				isReversed ? 'translateY(-100%) translateY(-1.4rem)'
+					: 'translateY(.4rem)'
+		}
+	})
+}
+
+function setState(stateName: state) {
+	state.value = stateName
+	if (stateName === 'unfocused') {
+		editorRef.value.blur()
+	} else {
+		updateScrollWindowSize()
+	}
+}
+
+function onFocusField(e) {
+	setState('focused')
+}
+
+function onKeydown(e) {
+	switch (e.keyCode || e.which) {
+		case ESCAPE:
+			e.preventDefault()
+			setState('unfocused')
+			break
+		case ARROW_UP:
+			e.preventDefault()
+			addSelectedIndex(-1)
+			break
+		case ARROW_DOWN:
+			e.preventDefault()
+			addSelectedIndex(1)
+			break
+		case ENTER:
+		case TAB:
+			e.preventDefault()
+			onSelectValue(lookahead() || model.value)
+			break
+	}
+}
+
+function onSelectValue(value) {
+	model.value = value
+	selectedIndex.value = 0
+	setState('unfocused')
+}
+
+function onUpdateField(e) {
+	setState('focused')
+	model.value = e.currentTarget.value
+}
+
+
+</script>
+
+<template>
+	<div class="autocomplete" ref="containerRef">
+		<div class="entry-box">
+			<div class="spacer">{{ spacerText }}</div>
+			<div class="placeholder">{{ placeholderText }}</div>
+			<textarea class="field"
+					  @input="onUpdateField"
+					  @focus="onFocusField"
+					  @keydown="onKeydown"
+					  :class="state"
+					  :value="val"
+					  ref="editorRef"></textarea>
+		</div>
+		<div class="suggestion-list" v-if="state === 'focused' && options.length">
+			<div v-if="options && options.length" class="scroll-list">
+				<div class="items" ref="suggestionScrollerRef" @keydown="onKeydown">
+					<button 
+							v-for="(item, index) in options"
+							class="item"
+							@click="onSelectValue(item)"
+							:class="{ selected: index === selectedIndex }"
+							:key="item"
+							v-html="highlight(item, val)"></button>
+				</div>
+			</div>
+		</div>
+	</div>
+</template>
+
+<style scoped lang="scss">
+
+.autocomplete {
+	position: relative;
+
+	* {
+		font-size: 1rem;
+		font-family: Consolas, Lucida Console, Courier New, monospace;
+	}
+
+	.entry-box {
+		position: relative;
+		width: 180px;
+	}
+
+	.spacer,
+	.placeholder,
+	.field {
+		border: none;
+		height: 100%;
+		padding: .1rem .2rem;
+		width: 100%;
+	}
+
+	.spacer {
+		min-height: 1rem;
+		visibility: hidden;
+	}
+
+	.placeholder {
+		user-select: none;
+		pointer-events: none;
+		opacity: 0.4;
+		z-index: 2;
+	}
+
+	.field {
+		z-index: 1;
+
+		&.focused {
+			color: blue;
+		}
+	}
+
+	.placeholder,
+	.field {
+		left: 0;
+		outline: none;
+		overflow: hidden;
+		position: absolute;
+		resize: none;
+		top: 0;
+	}
+
+	.suggestion-list {
+		position: absolute;
+		width: 100%;
+	}
+
+	.scroll-list {
+		position: absolute;
+		width: 100%;
+		border: solid 1px lightgray;
+		box-shadow: 0 1px 3px rgba(0, 0, 0, 0.12), 0 1px 2px rgba(0, 0, 0, 0.24);
+	}
+
+	.items {
+		margin: 0;
+		max-height: 150px;
+		overflow-y: auto;
+		overflow-x: hidden;
+		padding: 0;
+
+		&::-webkit-scrollbar {
+			width: 10px;
+		}
+
+		&::-webkit-scrollbar-thumb {
+			background: #045068;
+			border-radius: 20px;
+		}
+
+		&::-webkit-scrollbar-track {
+			background: #dfe1e5;
+		}
+	}
+
+	.item {
+		white-space: nowrap;
+		overflow: hidden;
+		text-overflow: ellipsis;
+		border: solid 1px transparent;
+		background-color: white;
+		display: block;
+		width: 100%;
+		text-align: left;
+
+		&:hover {
+			cursor: pointer;
+		}
+
+		&:not(.selected):hover {
+			background-color: #c1dae2;
+			color: black;
+		}
+
+		&.selected {
+			background-color: #00aee6;
+			color: white;
+		}
+	}
+
+	.scroll-term {
+		font-weight: bold;
+		background-color: unset;
+		color: unset;
+	}
+}
+
+</style>
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