<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>
