const util = require('../../utils/util')

/**
 * Generate 4 heat color shades from a primary color.
 * Returns colors from lightest to darkest.
 */
const generateHeatColors = (hex) => {
  if (!hex || hex.charAt(0) !== '#') {
    return ['#FFE0D0', '#FFB088', '#FF6B35', '#E05520']
  }
  const r = parseInt(hex.slice(1, 3), 16)
  const g = parseInt(hex.slice(3, 5), 16)
  const b = parseInt(hex.slice(5, 7), 16)

  return [
    `rgba(${r},${g},${b},0.15)`,  // lightest
    `rgba(${r},${g},${b},0.35)`,  // light
    `rgba(${r},${g},${b},0.65)`,  // medium
    `rgba(${r},${g},${b},0.95)`   // darkest
  ]
}

const getHeatColor = (duration, colors) => {
  if (!duration || duration <= 0) return 'transparent'
  if (duration < 30) return colors[0]
  if (duration < 60) return colors[1]
  if (duration < 120) return colors[2]
  return colors[3]
}

Component({
  properties: {
    year: { type: Number, value: new Date().getFullYear() },
    month: { type: Number, value: new Date().getMonth() + 1 },
    records: { type: Array, value: [] },
    primaryColor: { type: String, value: '#FF6B35' }
  },

  data: {
    weeks: []
  },

  observers: {
    'year, month, records, primaryColor'(year, month, records, primaryColor) {
      this._compute(year, month, records, primaryColor)
    }
  },

  lifetimes: {
    ready() {
      const { year, month, records, primaryColor } = this.properties
      this._compute(year, month, records, primaryColor)
    }
  },

  methods: {
    _compute(year, month, records, primaryColor) {
      const weeks = util.getMonthCalendar(year, month)
      const recordMap = {}
      if (records && records.length) {
        records.forEach((r) => {
          const d = parseInt(r.date.split('-')[2])
          recordMap[d] = (recordMap[d] || 0) + r.duration
        })
      }

      const heatColors = generateHeatColors(primaryColor || '#FF6B35')

      const data = weeks.map((week) =>
        week.map((day) => {
          if (!day) return null
          const duration = recordMap[day] || 0
          return { day, duration, color: getHeatColor(duration, heatColors) }
        })
      )

      this.setData({ weeks: data })
    },

    onDayTap(e) {
      const day = e.currentTarget.dataset.day
      if (!day) return
      const cell = this.data.weeks.flat().find(c => c && c.day === day)
      if (!cell || cell.duration <= 0) return
      this.triggerEvent('daytap', {
        year: this.properties.year,
        month: this.properties.month,
        day,
        duration: cell.duration
      })
    }
  }
})