package wheel

import (
	"math"
	"testing"

	"chatapp3-golang/internal/service/prizepool"
)

func TestPickRewardDistribution1000000Draws(t *testing.T) {
	const (
		draws                  = 1000000
		maxAllowedDriftPercent = 1.0
	)

	rewards := []struct {
		id          int64
		name        string
		probability int
	}{
		{id: 1, name: "Coral Crown", probability: 300000},
		{id: 2, name: "Aurora Wing", probability: 220000},
		{id: 3, name: "Moon Card", probability: 150000},
		{id: 4, name: "Snow Pet", probability: 120000},
		{id: 5, name: "Love Banner", probability: 90000},
		{id: 6, name: "Emerald Ring", probability: 60000},
		{id: 7, name: "Royal Chest", probability: 40000},
		{id: 8, name: "Gold", probability: 20000},
	}
	items := make([]prizepool.PickResult, 0, len(rewards))
	for index, reward := range rewards {
		items = append(items, prizepool.PickResult{
			Item: prizepool.Item{
				ID:      reward.id,
				Enabled: true,
				Weight:  reward.probability,
			},
			Index: index,
		})
	}

	counts := make(map[int64]int, len(rewards))
	for index := 0; index < draws; index++ {
		reward, err := prizepool.PickWeighted(items)
		if err != nil {
			t.Fatalf("PickWeighted() error = %v", err)
		}
		counts[reward.Item.ID]++
	}

	for _, reward := range rewards {
		expectedPercent := float64(reward.probability) / probabilityTotal * 100
		actualPercent := float64(counts[reward.id]) / draws * 100
		driftPercent := math.Abs(actualPercent - expectedPercent)
		t.Logf(
			"reward=%s configured=%.2f%% actual=%.2f%% drift=%.2f%% hits=%d/%d",
			reward.name,
			expectedPercent,
			actualPercent,
			driftPercent,
			counts[reward.id],
			draws,
		)
		if driftPercent > maxAllowedDriftPercent {
			t.Fatalf(
				"reward %s probability drift %.2f%% exceeds %.2f%%",
				reward.name,
				driftPercent,
				maxAllowedDriftPercent,
			)
		}
	}
}