<template>
  <div>
    <v-sheet
      tile
      height="54"
      class="d-flex"
    >
      <v-btn
        icon
        class="ma-2"
        @click="$refs.calendar.prev()"
      >
        <v-icon>mdi-chevron-left</v-icon>
      </v-btn>
      <v-select
        v-model="type"
        :items="types"
        dense
        outlined
        hide-details
        class="ma-2"
        label="type"
      />
      <v-select
        v-model="mode"
        :items="modes"
        dense
        outlined
        hide-details
        label="event-overlap-mode"
        class="ma-2"
      />
      <v-select
        v-model="weekday"
        :items="weekdays"
        dense
        outlined
        hide-details
        label="weekdays"
        class="ma-2"
      />
      <v-spacer />
      <v-btn
        icon
        class="ma-2"
        @click="$refs.calendar.next()"
      >
        <v-icon>mdi-chevron-right</v-icon>
      </v-btn>
    </v-sheet>
    <v-sheet height="600">
      <v-calendar
        ref="calendar"
        v-model="value"
        :weekdays="weekday"
        :type="type"
        :events="events"
        :event-overlap-mode="mode"
        :event-overlap-threshold="30"
        :event-color="getEventColor"
        @change="getEvents"
      />
    </v-sheet>
  </div>
</template>

<script>
export default {
  name: 'CalendarView',
  data: () => ({
    type: 'month',
    types: ['month', 'week', 'day', '4day'],
    mode: 'stack',
    modes: ['stack', 'column'],
    weekday: [0, 1, 2, 3, 4, 5, 6],
    weekdays: [
      { text: 'Sun - Sat', value: [0, 1, 2, 3, 4, 5, 6] },
      { text: 'Mon - Sun', value: [1, 2, 3, 4, 5, 6, 0] },
      { text: 'Mon - Fri', value: [1, 2, 3, 4, 5] },
      { text: 'Mon, Wed, Fri', value: [1, 3, 5] }
    ],
    value: '',
    events: [],
    colors: ['blue', 'indigo', 'deep-purple', 'cyan', 'green', 'orange', 'grey darken-1'],
    names: ['Meeting', 'Holiday', 'PTO', 'Travel', 'Event', 'Birthday', 'Conference', 'Party']
  }),
  methods: {
    getEvents({ start, end }) {
      const events = []

      const min = new Date(`${start.date}T00:00:00`)
      const max = new Date(`${end.date}T23:59:59`)
      const days = (max.getTime() - min.getTime()) / 86400000
      const eventCount = this.rnd(days, days + 20)

      for (let i = 0; i < eventCount; i++) {
        const allDay = this.rnd(0, 3) === 0
        const firstTimestamp = this.rnd(min.getTime(), max.getTime())
        const first = new Date(firstTimestamp - (firstTimestamp % 900000))
        const secondTimestamp = this.rnd(2, allDay ? 288 : 8) * 900000
        const second = new Date(first.getTime() + secondTimestamp)

        events.push({
          name: this.names[this.rnd(0, this.names.length - 1)],
          start: first,
          end: second,
          color: this.colors[this.rnd(0, this.colors.length - 1)],
          timed: !allDay
        })
      }

      this.events = events
    },
    getEventColor(event) {
      return event.color
    },
    rnd(a, b) {
      return Math.floor((b - a + 1) * Math.random()) + a
    }
  }
}
</script>

<style scoped>

</style>
