package luckygift

import (
	"fmt"
	"sort"
	"strings"

	"hyapp/pkg/xerr"
	domain "hyapp/services/activity-service/internal/domain/luckygift"
)

const ppmScale int64 = 1_000_000

// DefaultConfig 给后台指定奖池提供规则草稿；真正生效必须由后台显式 enabled。
func DefaultConfig(appCode, poolID string) domain.Config {
	const giftPrice int64 = 10_000
	poolID = normalizePoolID(poolID)
	return domain.Config{
		AppCode:               appCode,
		GiftID:                poolID,
		PoolID:                poolID,
		Enabled:               false,
		GiftPrice:             giftPrice,
		TargetRTPPPM:          950_000,
		PoolRatePPM:           950_000,
		GlobalWindowDraws:     100_000,
		GiftWindowDraws:       100_000,
		NoviceDrawLimit:       2_000,
		IntermediateDrawLimit: 20_000,
		HighMultiplier:        100,
		HighWaterPoolMultiple: 2,
		PlatformPoolWeightPPM: 200_000,
		RoomPoolWeightPPM:     300_000,
		GiftPoolWeightPPM:     500_000,
		InitialPlatformPool:   9_500_000,
		InitialGiftPool:       23_750_000,
		InitialRoomPool:       5_000_000,
		PlatformReserve:       1_000_000,
		GiftReserve:           1_000_000,
		RoomReserve:           100_000,
		MaxSinglePayout:       giftPrice * 500,
		UserHourlyPayoutCap:   3_420_000,
		UserDailyPayoutCap:    61_560_000,
		DeviceDailyPayoutCap:  102_600_000,
		RoomHourlyPayoutCap:   68_400_000,
		AnchorDailyPayoutCap:  1_231_200_000,
		RoomAtmosphereRatePPM: 10_000,
		RoomAtmosphereInitial: 100_000,
		RoomAtmosphereReserve: 10_000,
		ActivityBudget:        0,
		ActivityDailyLimit:    0,
		LargeTierEnabled:      true,
		MultiplierPPMs:        defaultMultiplierPPMs(),
		Tiers:                 defaultTiers(giftPrice),
	}
}

// validateConfig 只校验会破坏线上抽奖不变量的字段；展示类默认值留给后台表单处理。
func validateConfig(config domain.Config) error {
	if normalizePoolID(config.PoolID) == "" {
		return xerr.New(xerr.InvalidArgument, "lucky gift pool id is required")
	}
	// 当前 DB 历史列名仍叫 gift_id，但业务语义已经是 pool_id；这里强制二者一致，避免后台提交真实礼物 ID 后把窗口和奖池切散。
	config.GiftID = normalizePoolID(config.PoolID)
	if config.GiftPrice <= 0 || config.TargetRTPPPM <= 0 || config.TargetRTPPPM > ppmScale {
		return xerr.New(xerr.InvalidArgument, "gift price or target RTP is invalid")
	}
	// 入池比例低于目标 RTP 时，即使长期抽数足够也无法靠奖池支付基础返奖，必须在发布前拒绝。
	if config.PoolRatePPM < config.TargetRTPPPM || config.PoolRatePPM > ppmScale {
		return xerr.New(xerr.InvalidArgument, "pool rate must be between target RTP and 100%")
	}
	if config.GlobalWindowDraws <= 0 || config.GiftWindowDraws <= 0 {
		return xerr.New(xerr.InvalidArgument, "RTP window draws must be positive")
	}
	if config.NoviceDrawLimit < 0 || config.IntermediateDrawLimit < config.NoviceDrawLimit {
		return xerr.New(xerr.InvalidArgument, "experience pool draw limits are invalid")
	}
	if config.HighMultiplier <= 0 || config.HighWaterPoolMultiple <= 0 {
		return xerr.New(xerr.InvalidArgument, "high multiplier config is invalid")
	}
	if config.PlatformPoolWeightPPM < 0 || config.RoomPoolWeightPPM < 0 || config.GiftPoolWeightPPM < 0 ||
		config.PlatformPoolWeightPPM+config.RoomPoolWeightPPM+config.GiftPoolWeightPPM != ppmScale {
		return xerr.New(xerr.InvalidArgument, "pool weights must sum to 1000000")
	}
	if config.MaxSinglePayout <= 0 || config.UserHourlyPayoutCap <= 0 || config.UserDailyPayoutCap <= 0 ||
		config.DeviceDailyPayoutCap <= 0 || config.RoomHourlyPayoutCap <= 0 || config.AnchorDailyPayoutCap <= 0 {
		return xerr.New(xerr.InvalidArgument, "risk payout caps must be positive")
	}
	// tiers 是倍率列表归一化后的运行时候选集合；即使后台只提交 multiplier_ppms，发布前也必须先生成 tiers。
	if len(config.Tiers) == 0 {
		return xerr.New(xerr.InvalidArgument, "reward tiers are required")
	}
	maxMultiplierPPM := int64(0)
	for _, tier := range config.Tiers {
		if tier.Pool == "" || tier.TierID == "" || tier.Weight < 0 || tier.RewardCoins < 0 || tier.MultiplierPPM < 0 {
			return xerr.New(xerr.InvalidArgument, fmt.Sprintf("invalid reward tier: %s", tier.TierID))
		}
		if tier.Enabled && tier.MultiplierPPM > maxMultiplierPPM {
			maxMultiplierPPM = tier.MultiplierPPM
		}
	}
	// 最大倍率低于目标 RTP 时，窗口最后几抽可能没有足够高的基础候选追平目标，只能提前拒绝这类配置。
	if maxMultiplierPPM < config.TargetRTPPPM {
		return xerr.New(xerr.InvalidArgument, "max lucky gift multiplier must not be lower than target RTP")
	}
	return nil
}

// normalizeTiers 把后台“可中倍率”转换成三档体验池候选；后台传入的权重不会成为线上概率。
func normalizeTiers(tiers []domain.Tier, multipliers []int64, giftPrice, highMultiplier int64) ([]domain.Tier, []int64) {
	multiplierPPMs := normalizeMultiplierPPMs(multipliers, tiers, giftPrice)
	return buildMultiplierTiers(giftPrice, highMultiplier, multiplierPPMs), multiplierPPMs
}

func normalizeMultiplierPPMs(input []int64, tiers []domain.Tier, giftPrice int64) []int64 {
	// 新后台直接提交 multiplier_ppms；旧调用方如果仍提交 tiers，则从 reward_coins 反推倍率以减少迁移断点。
	values := append([]int64(nil), input...)
	if len(values) == 0 {
		for _, tier := range tiers {
			if tier.MultiplierPPM > 0 || tier.RewardCoins == 0 {
				values = append(values, tier.MultiplierPPM)
				continue
			}
			if giftPrice > 0 && tier.RewardCoins > 0 {
				values = append(values, tier.RewardCoins*ppmScale/giftPrice)
			}
		}
	}
	// 没有任何输入时使用保守默认倍率，保证默认草稿可被后台查看和复制，但仍默认 disabled。
	if len(values) == 0 {
		values = defaultMultiplierPPMs()
	}
	seen := map[int64]bool{}
	out := make([]int64, 0, len(values))
	for _, value := range values {
		// 负倍率没有业务含义；重复倍率会造成同一返奖点被重复计权，因此在入口处去重。
		if value < 0 || seen[value] {
			continue
		}
		seen[value] = true
		out = append(out, value)
	}
	// 全部被过滤时回退默认列表，避免构造出空 tiers 后在更深层事务里失败。
	if len(out) == 0 {
		out = defaultMultiplierPPMs()
	}
	sort.Slice(out, func(i, j int) bool { return out[i] < out[j] })
	return out
}

func buildMultiplierTiers(cost, highMultiplier int64, multipliers []int64) []domain.Tier {
	out := make([]domain.Tier, 0, len(multipliers)*3)
	for _, pool := range []string{domain.PoolNovice, domain.PoolIntermediate, domain.PoolAdvanced} {
		for _, multiplierPPM := range multipliers {
			out = append(out, domain.Tier{
				Pool:          pool,
				TierID:        pool + "_" + multiplierTierID(multiplierPPM),
				RewardCoins:   cost * multiplierPPM / ppmScale,
				MultiplierPPM: multiplierPPM,
				// 权重固定为 0 是有意设计：线上概率由 RTP 缺口、奖池容量和风控容量运行时生成。
				Weight:        0,
				HighWaterOnly: highMultiplier > 0 && multiplierPPM >= highMultiplier*ppmScale,
				Enabled:       true,
			})
		}
	}
	return out
}

func defaultMultiplierPPMs() []int64 {
	return []int64{
		0,
		200_000,
		500_000,
		1_000_000,
		2_000_000,
		5_000_000,
		10_000_000,
		20_000_000,
		50_000_000,
		100_000_000,
		500_000_000,
	}
}

func defaultTiers(cost int64) []domain.Tier {
	return buildMultiplierTiers(cost, 100, defaultMultiplierPPMs())
}

func multiplierTierID(multiplierPPM int64) string {
	if multiplierPPM == 0 {
		return "none"
	}
	whole := multiplierPPM / ppmScale
	fraction := multiplierPPM % ppmScale
	if fraction == 0 {
		return fmt.Sprintf("%dx", whole)
	}
	// 小数倍率用下划线表达，避免 tier_id 出现点号后和后台路径/筛选语法冲突。
	text := strings.TrimRight(strings.TrimRight(fmt.Sprintf("%d_%06dx", whole, fraction), "0"), "_")
	return text
}

func normalizePoolID(poolID string) string {
	poolID = strings.TrimSpace(poolID)
	if poolID == "" {
		return domain.DefaultPoolID
	}
	return poolID
}