package lottery

import (
	"database/sql"
	"encoding/json"
	"time"

	"gorm.io/gorm"
)

// ---- 状态与类型常量 ---------------------------------------------------------

const (
	ActivityStatusDraft   = "draft"
	ActivityStatusRunning = "running"
	ActivityStatusPaused  = "paused"
	ActivityStatusEnded   = "ended"

	UnmetActionBlock      = "block"
	UnmetActionShowReason = "show_reason"

	// PrizeType* 是发奖 handler 注册表的键。Stage 1 只实现前三种。
	PrizeTypeVPNDuration = "vpn_duration"
	PrizeTypeCommission  = "commission"
	PrizeTypeNone        = "none"
	// Stage 2/3 预留。
	PrizeTypeBalance     = "balance"
	PrizeTypeGiftAmount  = "gift_amount"
	PrizeTypeCoupon      = "coupon"
	PrizeTypePoints      = "points"
	PrizeTypeEncrypted   = "encrypted"
	PrizeTypePhysical    = "physical"
	PrizeTypeManualOther = "manual_other"

	// ChanceSource* 是次数入账触发源。
	ChanceSourceDailySignin     = "daily_signin"
	ChanceSourceNewSubscription = "new_subscription"
	ChanceSourceInviteSuccess   = "invite_success"
	ChanceSourceManualGrant     = "manual_grant"

	// DispatchState* 是 lottery_draw.dispatch_state 的取值。
	DispatchStateNone         = "none"
	DispatchStateAutoClaimed  = "auto_claimed"
	DispatchStatePendingClaim = "pending_claim"
	DispatchStatePaid         = "paid"
	DispatchStateExpired      = "expired"
	DispatchStateFailed       = "failed"
)

// ---- 实体 -----------------------------------------------------------------

type Activity struct {
	Id            int64          `gorm:"primaryKey"`
	Title         string         `gorm:"type:varchar(128);not null;default:'';comment:活动标题"`
	Description   string         `gorm:"type:text;comment:活动描述"`
	StartAt       time.Time      `gorm:"not null;comment:开始时间"`
	EndAt         time.Time      `gorm:"not null;comment:结束时间"`
	Status        string         `gorm:"type:varchar(16);not null;default:'draft';comment:状态"`
	GridSize      int            `gorm:"type:tinyint;not null;default:9;comment:九宫格数量"`
	Eligibility   string         `gorm:"type:json;not null;comment:参与门槛（AND/OR 嵌套规则）"`
	ChanceSources string         `gorm:"type:json;not null;comment:次数来源列表"`
	UnmetAction   string         `gorm:"type:varchar(32);not null;default:'block';comment:未达门槛策略"`
	CreatedAt     time.Time      `gorm:"<-:create;comment:Create Time"`
	UpdatedAt     time.Time      `gorm:"comment:Update Time"`
	DeletedAt     gorm.DeletedAt `gorm:"index;comment:Delete Time"`
}

func (Activity) TableName() string { return "lottery_activity" }

type Prize struct {
	Id             int64         `gorm:"primaryKey"`
	ActivityId     int64         `gorm:"type:bigint unsigned;not null;comment:所属活动"`
	Slot           int           `gorm:"type:tinyint;not null;comment:九宫格位置"`
	Type           string        `gorm:"type:varchar(32);not null;comment:奖品类型"`
	Name           string        `gorm:"type:varchar(128);not null;default:'';comment:名称"`
	IconURL        string        `gorm:"type:varchar(512);not null;default:'';comment:图标 URL"`
	Config         string        `gorm:"type:json;not null;comment:类型专属配置"`
	Weight         int           `gorm:"type:int;not null;default:0;comment:加权随机权重"`
	TotalStock     sql.NullInt64 `gorm:"type:bigint;comment:总库存（NULL=无限）"`
	RemainingStock sql.NullInt64 `gorm:"type:bigint;comment:剩余库存（NULL=无限）"`
	IsFallback     bool          `gorm:"type:tinyint(1);not null;default:0;comment:是否为保底奖"`
	Version        int64         `gorm:"type:bigint;not null;default:0;comment:乐观锁"`
	CreatedAt      time.Time     `gorm:"<-:create;comment:Create Time"`
	UpdatedAt      time.Time     `gorm:"comment:Update Time"`
}

func (Prize) TableName() string { return "lottery_prize" }

type ChanceBalance struct {
	Id          int64     `gorm:"primaryKey"`
	UserId      int64     `gorm:"type:bigint unsigned;not null;comment:用户 ID"`
	ActivityId  int64     `gorm:"type:bigint unsigned;not null;comment:活动 ID"`
	Remaining   int64     `gorm:"type:bigint;not null;default:0;comment:剩余次数"`
	TotalEarned int64     `gorm:"type:bigint;not null;default:0;comment:累计入账"`
	TotalSpent  int64     `gorm:"type:bigint;not null;default:0;comment:累计消耗"`
	CreatedAt   time.Time `gorm:"<-:create;comment:Create Time"`
	UpdatedAt   time.Time `gorm:"comment:Update Time"`
}

func (ChanceBalance) TableName() string { return "lottery_chance_balance" }

type ChanceGrant struct {
	Id         int64      `gorm:"primaryKey"`
	UserId     int64      `gorm:"type:bigint unsigned;not null;comment:用户 ID"`
	ActivityId int64      `gorm:"type:bigint unsigned;not null;comment:活动 ID"`
	Source     string     `gorm:"type:varchar(32);not null;comment:触发源"`
	SourceRef  string     `gorm:"type:varchar(128);not null;comment:外部业务幂等键"`
	Amount     int        `gorm:"type:int;not null;default:0;comment:本次发放次数"`
	ExpiresAt  *time.Time `gorm:"default:null;comment:到期时间"`
	GrantedAt  time.Time  `gorm:"<-:create;default:CURRENT_TIMESTAMP;comment:入账时间"`
}

func (ChanceGrant) TableName() string { return "lottery_chance_grant" }

type Draw struct {
	Id            int64         `gorm:"primaryKey"`
	UserId        int64         `gorm:"type:bigint unsigned;not null;comment:用户 ID"`
	ActivityId    int64         `gorm:"type:bigint unsigned;not null;comment:活动 ID"`
	ClientNonce   string        `gorm:"type:varchar(64);not null;comment:前端幂等键"`
	PrizeId       sql.NullInt64 `gorm:"type:bigint unsigned;comment:中奖奖品 ID（谢谢参与=NULL）"`
	IsWin         bool          `gorm:"type:tinyint(1);not null;default:0;comment:是否中奖"`
	DispatchState string        `gorm:"type:varchar(16);not null;default:'none';comment:发放状态"`
	DispatchError string        `gorm:"type:text;comment:发放失败原因"`
	DispatchedAt  *time.Time    `gorm:"default:null;comment:发放完成时间"`
	DrawnAt       time.Time     `gorm:"not null;default:CURRENT_TIMESTAMP;comment:抽奖时间"`
	CreatedAt     time.Time     `gorm:"<-:create;comment:Create Time"`
	UpdatedAt     time.Time     `gorm:"comment:Update Time"`
}

func (Draw) TableName() string { return "lottery_draw" }

type PrizeSnapshot struct {
	Id        int64     `gorm:"primaryKey"`
	DrawId    int64     `gorm:"type:bigint unsigned;not null;uniqueIndex:uk_draw_id;comment:抽奖记录 ID"`
	PrizeId   int64     `gorm:"type:bigint unsigned;not null;comment:奖品 ID"`
	Slot      int       `gorm:"type:tinyint;not null;comment:九宫格位置"`
	Type      string    `gorm:"type:varchar(32);not null;comment:奖品类型"`
	Name      string    `gorm:"type:varchar(128);not null;comment:奖品名称"`
	Config    string    `gorm:"type:json;not null;comment:类型专属配置"`
	CreatedAt time.Time `gorm:"<-:create;comment:Create Time"`
}

func (PrizeSnapshot) TableName() string { return "lottery_prize_snapshot" }

type EligibilitySnapshot struct {
	Id           int64     `gorm:"primaryKey"`
	DrawId       int64     `gorm:"type:bigint unsigned;not null;uniqueIndex:uk_draw_id;comment:抽奖记录 ID"`
	UserId       int64     `gorm:"type:bigint unsigned;not null;comment:用户 ID"`
	ActivityId   int64     `gorm:"type:bigint unsigned;not null;comment:活动 ID"`
	Passed       bool      `gorm:"type:tinyint(1);not null;default:0;comment:是否通过门槛"`
	UnmetReasons string    `gorm:"type:json;comment:未通过项"`
	EvaluatedAt  time.Time `gorm:"not null;default:CURRENT_TIMESTAMP;comment:评估时间"`
}

func (EligibilitySnapshot) TableName() string { return "lottery_eligibility_snapshot" }

// ---- JSON 结构体辅助 -------------------------------------------------------

// EligibilityRule 是持久化在 lottery_activity.eligibility 字段里的门槛规则树。
// 每个节点要么是"叶子"（Type 非空），要么是"聚合"（Op 为 AND/OR + Children）。
type EligibilityRule struct {
	Op       string             `json:"op,omitempty"`
	Children []*EligibilityRule `json:"children,omitempty"`

	Type   string          `json:"type,omitempty"`
	Params json.RawMessage `json:"params,omitempty"`
}

// ChanceSource 描述次数来源的一条配置，持久化在 lottery_activity.chance_sources。
type ChanceSource struct {
	Source     string          `json:"source"`
	Amount     int             `json:"amount"`
	Params     json.RawMessage `json:"params,omitempty"`
	DailyLimit int             `json:"daily_limit,omitempty"`
	Unlimited  bool            `json:"unlimited,omitempty"`
}

// UnmetReason 是门槛评估结果，作为 GET /config 的 unmet_reasons 元素返回。
type UnmetReason struct {
	Rule     string `json:"rule"`
	Hint     string `json:"hint"`
	Current  int64  `json:"current,omitempty"`
	Required int64  `json:"required,omitempty"`
}