<template>
<div v-if="show" ref="el" :class="[$style.root, { [$style.slim]: narrow, [$style.thin]: thin_ }]" :style="{ background: bg }" @click="onClick">
	<div v-if="narrow" :class="$style.buttonsLeft">
		<MkAvatar v-if="props.displayMyAvatar && $i" :class="$style.avatar" :user="$i"/>
	</div>
	<template v-if="metadata">
		<div v-if="!hideTitle" :class="$style.titleContainer" @click="showTabsPopup">
			<MkAvatar v-if="metadata.avatar" :class="$style.titleAvatar" :user="metadata.avatar" indicator/>
			<i v-else-if="metadata.icon" :class="[$style.titleIcon, metadata.icon]"></i>

			<div :class="$style.title">
				<MkUserName v-if="metadata.userName" :user="metadata.userName" :nowrap="true"/>
				<div v-else-if="metadata.title">{{ metadata.title }}</div>
				<div v-if="!narrow && metadata.subtitle" :class="$style.subtitle">
					{{ metadata.subtitle }}
				</div>
				<div v-if="narrow && hasTabs" :class="[$style.subtitle, $style.activeTab]">
					{{ tabs.find(tab => tab.key === props.tab)?.title }}
					<i class="ti ti-chevron-down" :class="$style.chevron"></i>
				</div>
			</div>
		</div>
		<div v-if="!narrow || hideTitle" :class="$style.tabs">
			<button v-for="tab in tabs" :ref="(el) => tabRefs[tab.key] = (el as HTMLElement)" v-tooltip.noDelay="tab.title" class="_button" :class="[$style.tab, { [$style.active]: tab.key != null && tab.key === props.tab }]" @mousedown="(ev) => onTabMousedown(tab, ev)" @click="(ev) => onTabClick(tab, ev)">
				<i v-if="tab.icon" :class="[$style.tabIcon, tab.icon]"></i>
				<span v-if="!tab.iconOnly" :class="$style.tabTitle">{{ tab.title }}</span>
			</button>
			<div ref="tabHighlightEl" :class="$style.tabHighlight"></div>
		</div>
	</template>
	<div :class="$style.buttonsRight">
		<template v-for="action in actions">
			<button v-tooltip.noDelay="action.text" class="_button" :class="[$style.button, { [$style.highlighted]: action.highlighted }]" @click.stop="action.handler" @touchstart="preventDrag"><i :class="action.icon"></i></button>
		</template>
	</div>
</div>
</template>

<script lang="ts" setup>
import { onMounted, onUnmounted, ref, inject, watch, nextTick } from 'vue';
import tinycolor from 'tinycolor2';
import { popupMenu } from '@/os';
import { scrollToTop } from '@/scripts/scroll';
import { globalEvents } from '@/events';
import { injectPageMetadata } from '@/scripts/page-metadata';
import { $i } from '@/account';

type Tab = {
	key: string;
	title: string;
	icon?: string;
	iconOnly?: boolean;
	onClick?: (ev: MouseEvent) => void;
};

const props = withDefaults(defineProps<{
	tabs?: Tab[];
	tab?: string;
	actions?: {
		text: string;
		icon: string;
		highlighted?: boolean;
		handler: (ev: MouseEvent) => void;
	}[];
	thin?: boolean;
	displayMyAvatar?: boolean;
}>(), {
	tabs: () => ([] as Tab[]),
});

const emit = defineEmits<{
	(ev: 'update:tab', key: string);
}>();

const metadata = injectPageMetadata();

const hideTitle = inject('shouldOmitHeaderTitle', false);
const thin_ = props.thin || inject('shouldHeaderThin', false);

const el = $shallowRef<HTMLElement | undefined>(undefined);
const tabRefs: Record<string, HTMLElement | null> = {};
const tabHighlightEl = $shallowRef<HTMLElement | null>(null);
const bg = ref<string | undefined>(undefined);
let narrow = $ref(false);
const hasTabs = $computed(() => props.tabs.length > 0);
const hasActions = $computed(() => props.actions && props.actions.length > 0);
const show = $computed(() => {
	return !hideTitle || hasTabs || hasActions;
});

const showTabsPopup = (ev: MouseEvent) => {
	if (!hasTabs) return;
	if (!narrow) return;
	ev.preventDefault();
	ev.stopPropagation();
	const menu = props.tabs.map(tab => ({
		text: tab.title,
		icon: tab.icon,
		active: tab.key != null && tab.key === props.tab,
		action: (ev) => {
			onTabClick(tab, ev);
		},
	}));
	popupMenu(menu, (ev.currentTarget ?? ev.target) as HTMLElement);
};

const preventDrag = (ev: TouchEvent) => {
	ev.stopPropagation();
};

const onClick = () => {
	if (el) {
		scrollToTop(el as HTMLElement, { behavior: 'smooth' });
	}
};

function onTabMousedown(tab: Tab, ev: MouseEvent): void {
	// ユーザビリティの観点からmousedown時にはonClickは呼ばない
	if (tab.key) {
		emit('update:tab', tab.key);
	}
}

function onTabClick(tab: Tab, ev: MouseEvent): void {
	if (tab.onClick) {
		ev.preventDefault();
		ev.stopPropagation();
		tab.onClick(ev);
	}
	if (tab.key) {
		emit('update:tab', tab.key);
	}
}

const calcBg = () => {
	const rawBg = metadata?.bg || 'var(--bg)';
	const tinyBg = tinycolor(rawBg.startsWith('var(') ? getComputedStyle(document.documentElement).getPropertyValue(rawBg.slice(4, -1)) : rawBg);
	tinyBg.setAlpha(0.85);
	bg.value = tinyBg.toRgbString();
};

let ro: ResizeObserver | null;

onMounted(() => {
	calcBg();
	globalEvents.on('themeChanged', calcBg);

	watch(() => [props.tab, props.tabs], () => {
		nextTick(() => {
			const tabEl = props.tab ? tabRefs[props.tab] : undefined;
			if (tabEl && tabHighlightEl && tabEl.parentElement) {
				// offsetWidth や offsetLeft は少数を丸めてしまうため getBoundingClientRect を使う必要がある
				// https://developer.mozilla.org/ja/docs/Web/API/HTMLElement/offsetWidth#%E5%80%A4
				const parentRect = tabEl.parentElement.getBoundingClientRect();
				const rect = tabEl.getBoundingClientRect();
				tabHighlightEl.style.width = rect.width + 'px';
				tabHighlightEl.style.left = (rect.left - parentRect.left) + 'px';
			}
		});
	}, {
		immediate: true,
	});

	if (el && el.parentElement) {
		narrow = el.parentElement.offsetWidth < 500;
		ro = new ResizeObserver((entries, observer) => {
			if (el.parentElement && document.body.contains(el as HTMLElement)) {
				narrow = el.parentElement.offsetWidth < 500;
			}
		});
		ro.observe(el.parentElement as HTMLElement);
	}
});

onUnmounted(() => {
	globalEvents.off('themeChanged', calcBg);
	if (ro) ro.disconnect();
});
</script>

<style lang="scss" module>
.root {
	--height: 50px;
	display: flex;
	width: 100%;
	-webkit-backdrop-filter: var(--blur, blur(15px));
	backdrop-filter: var(--blur, blur(15px));
	border-bottom: solid 0.5px var(--divider);
	contain: strict;
	height: var(--height);

	&.thin {
		--height: 42px;

		> .buttons {
			> .button {
				font-size: 0.9em;
			}
		}
	}

	&.slim {
		text-align: center;

		> .titleContainer {
			flex: 1;
			margin: 0 auto;

			> *:first-child {
				margin-left: auto;
			}

			> *:last-child {
				margin-right: auto;
			}
		}
	}
}

.buttons {
	--margin: 8px;
	display: flex;
	align-items: center;
	min-width: var(--height);
	height: var(--height);
	margin: 0 var(--margin);

	&:empty {
		width: var(--height);
	}
}

.buttonsLeft {
	composes: buttons;
	margin-right: auto;
}

.buttonsRight {
	composes: buttons;
	margin-left: auto;
}

.avatar {
	$size: 32px;
	display: inline-block;
	width: $size;
	height: $size;
	vertical-align: bottom;
	margin: 0 8px;
	pointer-events: none;
}

.button {
	display: flex;
	align-items: center;
	justify-content: center;
	height: calc(var(--height) - (var(--margin) * 2));
	width: calc(var(--height) - (var(--margin) * 2));
	box-sizing: border-box;
	position: relative;
	border-radius: 5px;

	&:hover {
		background: rgba(0, 0, 0, 0.05);
	}

	&.highlighted {
		color: var(--accent);
	}
}

.fullButton {
	& + .fullButton {
		margin-left: 12px;
	}
}

.titleContainer {
	display: flex;
	align-items: center;
	max-width: 400px;
	overflow: auto;
	white-space: nowrap;
	text-align: left;
	font-weight: bold;
	flex-shrink: 0;
	margin-left: 24px;
}

.titleAvatar {
	$size: 32px;
	display: inline-block;
	width: $size;
	height: $size;
	vertical-align: bottom;
	margin: 0 8px;
	pointer-events: none;
}

.titleIcon {
	margin-right: 8px;
	width: 16px;
	text-align: center;
}

.title {
	min-width: 0;
	overflow: hidden;
	text-overflow: ellipsis;
	white-space: nowrap;
	line-height: 1.1;
}

.subtitle {
	opacity: 0.6;
	font-size: 0.8em;
	font-weight: normal;
	white-space: nowrap;
	overflow: hidden;
	text-overflow: ellipsis;

	&.activeTab {
		text-align: center;

		> .chevron {
			display: inline-block;
			margin-left: 6px;
		}
	}
}

.tabs {
	position: relative;
	margin-left: 16px;
	font-size: 0.8em;
	overflow: auto;
	white-space: nowrap;
}

.tab {
	display: inline-block;
	position: relative;
	padding: 0 10px;
	height: 100%;
	font-weight: normal;
	opacity: 0.7;

	&:hover {
		opacity: 1;
	}

	&.active {
		opacity: 1;
	}
}

.tabIcon + .tabTitle {
	margin-left: 8px;
}

.tabHighlight {
	position: absolute;
	bottom: 0;
	height: 3px;
	background: var(--accent);
	border-radius: 999px;
	transition: all 0.2s ease;
	pointer-events: none;
}
</style>
