<script setup>
const bpm = ref(40)
const min = 40
const max = 218
const isPlaying = ref(false)

const color = computed(() => {
  if (bpm.value < 100)
    return 'primary'
  if (bpm.value < 125)
    return 'success'
  if (bpm.value < 140)
    return 'info'
  if (bpm.value < 175)
    return 'warning'
  
  return 'error'
})

const animationDuration = computed(() => {
  return `${ 60 / bpm.value }s`
})

const decrement = () => {
  if (bpm.value > min)
    bpm.value -= 1
}

const increment = () => {
  if (bpm.value < max)
    bpm.value += 1
}
</script>

<template>
  <div class="d-flex justify-space-between ma-4">
    <div>
      <span
        class="text-6xl font-weight-light"
        v-text="bpm"
      />
      <span class="subheading font-weight-light me-1">BPM</span>

      <VFadeTransition>
        <VAvatar
          v-if="isPlaying"
          :color="color"
          :style="{
            animationDuration,
          }"
          class="mb-1 v-avatar--metronome"
          size="12"
        />
      </VFadeTransition>
    </div>

    <div>
      <VBtn
        :color="color"
        icon
        elevation="0"
        @click="isPlaying = !isPlaying"
      >
        <VIcon
          size="large"
          :icon="isPlaying ? 'tabler-pause' : 'tabler-play'"
        />
      </VBtn>
    </div>
  </div>

  <VSlider
    v-model="bpm"
    :color="color"
    :step="1"
    :min="min"
    :max="max"
    track-color="secondary"
  >
    <template #prepend>
      <VBtn
        size="small"
        variant="text"
        icon="tabler-minus"
        :color="color"
        @click="decrement"
      />
    </template>

    <template #append>
      <VBtn
        size="small"
        variant="text"
        icon="tabler-plus"
        :color="color"
        @click="increment"
      />
    </template>
  </VSlider>
</template>

<style lang="scss" scoped>
  @keyframes metronome-example {
    from {
      transform: scale(0.5);
    }

    to {
      transform: scale(1);
    }
  }

  .v-avatar--metronome {
    animation-direction: alternate;
    animation-iteration-count: infinite;
    animation-name: metronome-example;
  }
</style>
