package threshold

import (
	"fmt"
	"strings"
)

type Threshold uint8

const (
	Simple Threshold = iota
	OneFifth
	OneQuarter
	OneThird
	OneHalf
	TwoThirds
	TwoFifths
	ThreeQuarters
	ThreeFifths
	FourFifths
	Unanimous
)

func ValidThresholds() []Threshold {
	return []Threshold{
		Simple, Unanimous,
		OneFifth, OneQuarter, OneThird, OneHalf,
		TwoFifths, TwoThirds,
		ThreeFifths, ThreeQuarters, ThreeFifths,
		FourFifths,
	}
}

func FromString(s string) (Threshold, error) {
	for _, t := range ValidThresholds() {
		if strings.ToUpper(t.String()) == strings.ToUpper(s) {
			return t, nil
		}
	}
	return Simple, fmt.Errorf("invalid threshold: %s", s)
}

func (t Threshold) String() string {
	switch t {
	case Simple:
		return "SIMPLE"
	case OneFifth:
		return "1/5"
	case OneQuarter:
		return "1/4"
	case OneThird:
		return "1/3"
	case OneHalf:
		return "1/2"
	case TwoThirds:
		return "2/3"
	case TwoFifths:
		return "2/5"
	case ThreeQuarters:
		return "3/4"
	case ThreeFifths:
		return "3/5"
	case FourFifths:
		return "4/5"
	case Unanimous:
		return "ALL"
	default:
		panic("this code should never be reached")
	}
}

func (t Threshold) IsSatisfied(totalVotes, yesVotes, noVotes int) bool {
	if totalVotes == 0 {
		return false
	}
	switch t {
	case Simple:
		return yesVotes > noVotes
	case OneFifth:
		return yesVotes*5 >= totalVotes
	case OneQuarter:
		return yesVotes*4 >= totalVotes
	case OneThird:
		return yesVotes*3 >= totalVotes
	case OneHalf:
		return yesVotes*2 >= totalVotes
	case TwoThirds:
		return yesVotes*3 >= totalVotes*2
	case TwoFifths:
		return yesVotes*5 >= totalVotes*2
	case ThreeQuarters:
		return yesVotes*4 >= totalVotes*3
	case ThreeFifths:
		return yesVotes*5 >= totalVotes*3
	case FourFifths:
		return yesVotes*5 >= totalVotes*4
	case Unanimous:
		return yesVotes >= totalVotes
	default:
		panic("this code should never be reached")
	}
}