<template>
	<span class="zjobosdg">
		<span v-text="hh"></span>
		<span class="colon" :class="{ showColon }">:</span>
		<span v-text="mm"></span>
		<span v-if="showS" class="colon" :class="{ showColon }">:</span>
		<span v-if="showS" v-text="ss"></span>
		<span v-if="showMs" class="colon" :class="{ showColon }">:</span>
		<span v-if="showMs" v-text="ms"></span>
	</span>
</template>

<script lang="ts" setup>
import { onUnmounted, ref, watch } from "vue";

const props = withDefaults(
	defineProps<{
		showS?: boolean;
		showMs?: boolean;
		offset?: number;
	}>(),
	{
		showS: true,
		showMs: false,
		offset: 0 - new Date().getTimezoneOffset(),
	},
);

let intervalId;
const hh = ref("");
const mm = ref("");
const ss = ref("");
const ms = ref("");
const showColon = ref(false);
let prevSec: number | null = null;

watch(showColon, (v) => {
	if (v) {
		window.setTimeout(() => {
			showColon.value = false;
		}, 30);
	}
});

const tick = () => {
	const now = new Date();
	now.setMinutes(
		now.getMinutes() + (new Date().getTimezoneOffset() + props.offset),
	);
	hh.value = now.getHours().toString().padStart(2, "0");
	mm.value = now.getMinutes().toString().padStart(2, "0");
	ss.value = now.getSeconds().toString().padStart(2, "0");
	ms.value = Math.floor(now.getMilliseconds() / 10)
		.toString()
		.padStart(2, "0");
	if (now.getSeconds() !== prevSec) showColon.value = true;
	prevSec = now.getSeconds();
};

tick();

watch(
	() => props.showMs,
	() => {
		if (intervalId) window.clearInterval(intervalId);
		intervalId = window.setInterval(tick, props.showMs ? 10 : 1000);
	},
	{ immediate: true },
);

onUnmounted(() => {
	window.clearInterval(intervalId);
});
</script>

<style lang="scss" scoped>
.zjobosdg {
	> .colon {
		opacity: 0;
		transition: opacity 1s ease;

		&.showColon {
			opacity: 1;
			transition: opacity 0s;
		}
	}
}
</style>
