package main

import (
	"fmt"
	"math"
	"sync"
	"time"

	"github.com/bwmarrin/discordgo"

	"PermissionGacha/db"
)

const notInGeneralNerf = 10

const generalChannelID = "645550570001924098"

var lastMessage = make(map[string]time.Time)
var incrementMutex = sync.Mutex{}
var levelUpRequirementCache [30]int

func init() {
	for i := 1; i <= 30; i++ {
		//Constructed on Desmos:
		//y=2^{\frac{x}{2}}+.1x^{2}+1.2x-1
		fi := float64(i)
		levelUpRequirementCache[i-1] = int(10000 * (math.Pow(2, fi/2) + 0.1*fi*fi + 1.2*fi - 1))
	}
}

func incrementXP(s *discordgo.Session, m *discordgo.MessageCreate) {
	amountToIncrement := calculateIncrement(m.Author.ID)
	if m.ChannelID != generalChannelID {
		amountToIncrement /= notInGeneralNerf
	}
	multiplier, err := db.GetPrestigeMultiplier(m.Author.ID)
	if err != nil {
		logError(s, err)
		return
	}
	amountToIncrement *= multiplier

	err = db.IncrementXP(m.Author.ID, amountToIncrement)
	if err != nil {
		logError(s, err)
		return
	}
	addToLevelQueue(m.Author.ID)
}

func calculateIncrement(discordID string) int {
	incrementMutex.Lock()
	defer incrementMutex.Unlock()

	now := time.Now()
	delta := now.Sub(lastMessage[discordID])
	lastMessage[discordID] = now

	if delta.Seconds() < 0 {
		return 0
	}

	//Constructed on Desmos:
	//y=\frac{100}{\left(1+e^{-\left(\frac{x}{2}-5\right)}\right)}
	return int(100 / (1 + math.Pow(math.E, -((delta.Seconds()/2)-5))))
}

func convertXPIntoLevel(xp int) (int, int) {
	if xp < levelUpRequirementCache[0] {
		return 1, xp
	}
	for i := 0; i < 30; i++ {
		if levelUpRequirementCache[i] > xp {
			return i + 1, xp - levelUpRequirementCache[i-1]
		}
	}
	return 30, xp - levelUpRequirementCache[29]
}

func getLevelAndXP(discordID string) (int, int, error) {
	rawXP, err := db.GetXP(discordID)
	if err != nil {
		return 1, 0, fmt.Errorf("xp: getLevelAndXP: error requesting XP: %w", err)
	}
	level, xp := convertXPIntoLevel(rawXP)
	return level, xp, nil
}