From f6fc50de03debdc9b26078b828dc6d0c66507bff Mon Sep 17 00:00:00 2001
From: kolaente <k@knt.li>
Date: Wed, 6 Mar 2024 17:59:00 +0100
Subject: [PATCH] feat(filter): add autocompletion poc for labels

---
 .../components/input/AutocompleteDropdown.vue | 237 ++++++++++++++++++
 .../project/partials/FilterInput.vue          |  95 +++++--
 2 files changed, 307 insertions(+), 25 deletions(-)
 create mode 100644 frontend/src/components/input/AutocompleteDropdown.vue

diff --git a/frontend/src/components/input/AutocompleteDropdown.vue b/frontend/src/components/input/AutocompleteDropdown.vue
new file mode 100644
index 000000000..096ee09c7
--- /dev/null
+++ b/frontend/src/components/input/AutocompleteDropdown.vue
@@ -0,0 +1,237 @@
+<script setup lang="ts">
+import {type ComponentPublicInstance, 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(-1)
+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 emit = defineEmits(['blur'])
+
+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: any[],
+	suggestion?: string,
+	maxHeight?: number,
+}>(), {
+	maxHeight: 200,
+})
+
+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') {
+		emit('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()
+			select(-1)
+			break
+		case ARROW_DOWN:
+			e.preventDefault()
+			select(1)
+			break
+	}
+}
+
+const resultRefs = ref<(HTMLElement | null)[]>([])
+
+function setResultRefs(el: Element | ComponentPublicInstance | null, index: number) {
+	resultRefs.value[index] = el as (HTMLElement | null)
+}
+
+function select(offset: number) {
+
+	let index = selectedIndex.value + offset
+
+	if (!isFinite(index)) {
+		index = 0
+	}
+
+	if (index >= props.options.length) {
+		// At the last index, now moving back to the top
+		index = 0
+	}
+
+	if (index < 0) {
+		// Arrow up but we're already at the top
+		index = props.options.length - 1
+	}
+	let elems = resultRefs.value[index]
+	if (
+		typeof elems === 'undefined'
+	) {
+		return
+	}
+
+	selectedIndex.value = index
+	updateSuggestionScroll()
+
+	if (Array.isArray(elems)) {
+		elems[0].focus()
+		return
+	}
+	elems?.focus()
+}
+
+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">
+			<slot
+				name="input"
+				:spacerText
+				:placeholderText
+				:onUpdateField
+				:onFocusField
+				:onKeydown
+			>
+				<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>
+			</slot>
+		</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"
+						:ref="(el: Element | ComponentPublicInstance | null) => setResultRefs(el, index)"
+					>
+						<slot
+							name="result"
+							:item
+							:selected="index === selectedIndex"
+						>
+							{{ item }}
+						</slot>
+					</button>
+				</div>
+			</div>
+		</div>
+	</div>
+</template>
diff --git a/frontend/src/components/project/partials/FilterInput.vue b/frontend/src/components/project/partials/FilterInput.vue
index 667564db4..06b32a684 100644
--- a/frontend/src/components/project/partials/FilterInput.vue
+++ b/frontend/src/components/project/partials/FilterInput.vue
@@ -5,6 +5,7 @@ import DatepickerWithValues from '@/components/date/datepickerWithValues.vue'
 import UserService from '@/services/user'
 import {getAvatarUrl, getDisplayName} from '@/models/user'
 import {createRandomID} from '@/helpers/randomId'
+import AutocompleteDropdown from '@/components/input/AutocompleteDropdown.vue'
 
 const {
 	modelValue,
@@ -40,14 +41,18 @@ const assigneeFields = [
 	'assignees',
 ]
 
+const labelFields = [
+	'labels',
+]
+
 const availableFilterFields = [
 	'done',
 	'priority',
 	'usePriority',
 	'percentDone',
-	'labels',
 	...dateFields,
 	...assigneeFields,
+	...labelFields,
 ]
 
 const filterOperators = [
@@ -69,6 +74,9 @@ const filterJoinOperators = [
 	')',
 ]
 
+const FILTER_OPERATORS_REGEX = '(&lt;|&gt;|&lt;=|&gt;=|=|!=)'
+const FILTER_JOIN_OPERATORS_REGEX = '(&amp;&amp;|\|\||\(|\))'
+
 function escapeHtml(unsafe: string): string {
 	return unsafe
 		.replace(/&/g, '&amp;')
@@ -91,7 +99,7 @@ const highlightedFilterQuery = computed(() => {
 	let highlighted = escapeHtml(filterQuery.value)
 	dateFields
 		.forEach(o => {
-			const pattern = new RegExp(o + '(\\s*)(&lt;|&gt;|&lt;=|&gt;=|=|!=)(\\s*)([\'"]?)([^\'"\\s]+\\1?)?', 'ig')
+			const pattern = new RegExp(o + '(\\s*)' + FILTER_OPERATORS_REGEX + '(\\s*)([\'"]?)([^\'"\\s]+\\1?)?', 'ig')
 			highlighted = highlighted.replaceAll(pattern, (match, spacesBefore, token, spacesAfter, start, value, position) => {
 				if (typeof value === 'undefined') {
 					value = ''
@@ -102,7 +110,7 @@ const highlightedFilterQuery = computed(() => {
 		})
 	assigneeFields
 		.forEach(f => {
-			const pattern = new RegExp(f + '\\s*(&lt;|&gt;|&lt;=|&gt;=|=|!=)\\s*([\'"]?)([^\'"\\s]+\\1?)?', 'ig')
+			const pattern = new RegExp(f + '\\s*' + FILTER_OPERATORS_REGEX + '\\s*([\'"]?)([^\'"\\s]+\\1?)?', 'ig')
 			highlighted = highlighted.replaceAll(pattern, (match, token, start, value) => {
 				if (typeof value === 'undefined') {
 					value = ''
@@ -189,33 +197,70 @@ function updateDateInQuery(newDate: string) {
 	currentOldDatepickerValue.value = newDate
 	filterQuery.value = unEscapeHtml(escaped)
 }
+
+function handleFieldInput(e, autocompleteOnInput) {
+	const cursorPosition = filterInput.value.selectionStart
+	const textUpToCursor = filterQuery.value.substring(0, cursorPosition)
+
+	labelFields.forEach(l => {
+		const pattern = new RegExp('(' + l + '\\s*' + FILTER_OPERATORS_REGEX + '\\s*)([\'"]?)([^\'"&\|\(\)]+\\1?)?$', 'ig')
+		const match = pattern.exec(textUpToCursor)
+
+		if (match !== null) {
+			const [matched, prefix, operator, space, keyword] = match
+			if (keyword) {
+				autocompleteResults.value = ['loool', keyword]
+			}
+		}
+	})
+}
+
+const autocompleteResults = ref<any[]>([])
 </script>
 
 <template>
 	<div class="field">
 		<label class="label">{{ $t('filters.query.title') }}</label>
-		<div class="control filter-input">
-			<textarea
-				autocomplete="off"
-				autocorrect="off"
-				autocapitalize="off"
-				spellcheck="false"
-				v-model="filterQuery"
-				class="input"
-				ref="filterInput"
-			></textarea>
-			<div
-				class="filter-input-highlight"
-				:style="{'height': height}"
-				v-html="highlightedFilterQuery"
-			></div>
-			<DatepickerWithValues
-				v-model="currentDatepickerValue"
-				:open="datePickerPopupOpen"
-				@close="() => datePickerPopupOpen = false"
-				@update:model-value="updateDateInQuery"
-			/>
-		</div>
+		<AutocompleteDropdown 
+			:options="autocompleteResults"
+			@blur="filterInput?.blur()"
+		>
+			<template
+				v-slot:input="{ onKeydown, onFocusField, onUpdateField }"
+			>
+				<div class="control filter-input">
+					<textarea
+						@input="e => handleFieldInput(e, onUpdateField)"
+						@focus="onFocusField"
+						@keydown="onKeydown"
+
+						autocomplete="off"
+						autocorrect="off"
+						autocapitalize="off"
+						spellcheck="false"
+						v-model="filterQuery"
+						class="input"
+						ref="filterInput"
+					></textarea>
+					<div
+						class="filter-input-highlight"
+						:style="{'height': height}"
+						v-html="highlightedFilterQuery"
+					></div>
+					<DatepickerWithValues
+						v-model="currentDatepickerValue"
+						:open="datePickerPopupOpen"
+						@close="() => datePickerPopupOpen = false"
+						@update:model-value="updateDateInQuery"
+					/>
+				</div>
+			</template>
+			<template
+				v-slot:result="{ item }"
+			>
+				whoo {{ item }}
+			</template>
+		</AutocompleteDropdown>
 	</div>
 </template>