<template>
    <div class="async-wrapper" :class="{ 'loaded': loaded }">
        <div class="deferred">
            <slot></slot>
        </div>
        <div class="loader-wrapper">
            <div class="loader-ellipsis">
                <div></div>
                <div></div>
                <div></div>
                <div></div>
            </div>
        </div>
    </div>
</template>

<script>

export default {
    name: 'AsyncLoader',
    props: {
        loaded: {
            type: Boolean,
            default: false
        }
    }
};
</script>

<style>
.async-wrapper {
    position: relative;
}

.async-wrapper > .deferred {
    width: 100%;
    height: 100%;
    display: none;
}

.async-wrapper.loaded > .deferred {
    display: block;
}

.async-wrapper > .loader-wrapper {
    display: flex;
    justify-content: center;
    align-items: center;
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

.async-wrapper > .loader-wrapper > .loader-ellipsis {
    color: #17a2b8;
}

.async-wrapper.loaded > .loader-wrapper {
    display: none;
}


.async-wrapper > .loader-wrapper > .loader-ellipsis,
.async-wrapper > .loader-wrapper > .loader-ellipsis div {
    box-sizing: border-box;
}

.async-wrapper > .loader-wrapper > .loader-ellipsis {
    display: inline-block;
    position: relative;
    width: 80px;
    height: 80px;
}

.async-wrapper > .loader-wrapper > .loader-ellipsis div {
    position: absolute;
    top: 33.33333px;
    width: 13.33333px;
    height: 13.33333px;
    border-radius: 50%;
    background: currentColor;
    animation-timing-function: cubic-bezier(0, 1, 1, 0);
}

.async-wrapper > .loader-wrapper > .loader-ellipsis div:nth-child(1) {
    left: 8px;
    animation: loader-ellipsis1 0.6s infinite;
}

.async-wrapper > .loader-wrapper > .loader-ellipsis div:nth-child(2) {
    left: 8px;
    animation: loader-ellipsis2 0.6s infinite;
}

.async-wrapper > .loader-wrapper > .loader-ellipsis div:nth-child(3) {
    left: 32px;
    animation: loader-ellipsis2 0.6s infinite;
}

.async-wrapper > .loader-wrapper > .loader-ellipsis div:nth-child(4) {
    left: 56px;
    animation: loader-ellipsis3 0.6s infinite;
}

@keyframes loader-ellipsis1 {
    0% {
        transform: scale(0);
    }
    100% {
        transform: scale(1);
    }
}

@keyframes loader-ellipsis3 {
    0% {
        transform: scale(1);
    }
    100% {
        transform: scale(0);
    }
}

@keyframes loader-ellipsis2 {
    0% {
        transform: translate(0, 0);
    }
    100% {
        transform: translate(24px, 0);
    }
}
</style>
