package main

import (
	"time"
)

const (
	//dailySupplyCharge = 105.750 / 100    // 1 July 2020 - 30 June 2021
	//dailySupplyCharge = 98.234 / 100 // 1 July 2021 - 30 June 2022
 	//dailySupplyCharge = 98.234 / 100 // 1 July 2021 - 30 June 2022
	dailySupplyCharge = 1.099030 // 1 July 2021 - 30 June 2022
 	
 	//solarFeedInTariff = fixedTariff(8.471 / 100)  // 1 July 2020 - 30 June 2021
 	//solarFeedInTariff = fixedTariff(6.501 / 100) // 1 July 2021 - 30 June 2022
 	solarFeedInTariff = fixedTariff(0.088830) // 1 July 2022 - 30 June 2023
)

var tariff93 = &onOffPeakTariff{
	// 1 July 2020 - 30 June 2021:
	//onPeak:  32.137 / 100,
	//offPeak: 14.963 / 100,
	// 1 July 2021 - 30 June 2022:
	//onPeak:  29.852 / 100,
	//offPeak: 13.9 / 100,
	// 1 July 2022 - 30 June 2023:
	onPeak: 0.333990,
	offPeak: 0.155510,
	isPeak: (&weekdayHours{
		zone: time.FixedZone("UTC+10", +10*60*60),
		on: [24]bool{
			7:  true,
			8:  true,
			9:  true,
			16: true,
			17: true,
			18: true,
			19: true,
			20: true,
		},
	}).isPeak,
}

type tariff interface {
	pricePerKWh(time.Time) float64
}

type fixedTariff float64

func (f fixedTariff) pricePerKWh(time.Time) float64 { return float64(f) }

type onOffPeakTariff struct {
	onPeak, offPeak float64
	isPeak          func(time.Time) bool
}

func (o *onOffPeakTariff) pricePerKWh(t time.Time) float64 {
	if o.isPeak(t) {
		return o.onPeak
	}
	return o.offPeak
}

type weekdayHours struct {
	zone *time.Location
	on   [24]bool
}

func (w *weekdayHours) isPeak(t time.Time) bool {
	t = t.In(w.zone)
	switch t.Weekday() {
	case time.Saturday, time.Sunday:
		return false
	default:
		return w.on[t.Hour()]
	}
}