package promo

import (
	"context"
	"errors"
	"fmt"

	"github.com/perfect-panel/server/pkg/cache"
	"github.com/redis/go-redis/v9"
	"gorm.io/gorm"
)

const (
	cachePromoRuleIdPrefix      = "cache:promo_rule:id:"
	cacheSubscribePromoIdPrefix = "cache:subscribe_promo:id:"
)

type Model interface {
	InsertRule(ctx context.Context, data *Rule) error
	FindRule(ctx context.Context, id int64) (*Rule, error)
	UpdateRule(ctx context.Context, data *Rule) error
	DeleteRule(ctx context.Context, id int64) error
	QueryRuleList(ctx context.Context, page, size int, ruleType string, enabled *bool, search string) (int64, []*Rule, error)
	UpsertPrices(ctx context.Context, ruleId int64, items []*SubscribePromo) error
	FindPrice(ctx context.Context, id int64) (*SubscribePromo, error)
	DeletePrice(ctx context.Context, id int64) error
	QueryPriceList(ctx context.Context, ruleId int64, page, size int) (int64, []*SubscribePromo, error)
	QueryUsageList(ctx context.Context, params UsageFilter) (int64, []*Usage, error)
	Transaction(ctx context.Context, fn func(db *gorm.DB) error) error
}

type UsageFilter struct {
	Page        int
	Size        int
	RuleId      int64
	UserId      int64
	SubscribeId int64
	OrderNo     string
}

type customPromoModel struct {
	cache.CachedConn
	table string
}

func NewModel(db *gorm.DB, c *redis.Client) Model {
	return &customPromoModel{
		CachedConn: cache.NewConn(db, c),
		table:      "`promo_rule`",
	}
}

func (m *customPromoModel) ruleCacheKey(id int64) string {
	return fmt.Sprintf("%s%d", cachePromoRuleIdPrefix, id)
}

func (m *customPromoModel) priceCacheKey(id int64) string {
	return fmt.Sprintf("%s%d", cacheSubscribePromoIdPrefix, id)
}

func (m *customPromoModel) InsertRule(ctx context.Context, data *Rule) error {
	return m.ExecCtx(ctx, func(conn *gorm.DB) error {
		return conn.Create(data).Error
	}, m.ruleCacheKey(data.Id))
}

func (m *customPromoModel) FindRule(ctx context.Context, id int64) (*Rule, error) {
	var resp Rule
	err := m.QueryCtx(ctx, &resp, m.ruleCacheKey(id), func(conn *gorm.DB, v interface{}) error {
		return conn.Model(&Rule{}).Where("id = ?", id).First(v).Error
	})
	if err != nil {
		return nil, err
	}
	return &resp, nil
}

func (m *customPromoModel) UpdateRule(ctx context.Context, data *Rule) error {
	old, err := m.FindRule(ctx, data.Id)
	if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
		return err
	}
	keys := []string{m.ruleCacheKey(data.Id)}
	if old != nil {
		keys = append(keys, m.ruleCacheKey(old.Id))
	}
	return m.ExecCtx(ctx, func(conn *gorm.DB) error {
		return conn.Save(data).Error
	}, keys...)
}

func (m *customPromoModel) DeleteRule(ctx context.Context, id int64) error {
	data, err := m.FindRule(ctx, id)
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil
		}
		return err
	}
	return m.ExecCtx(ctx, func(conn *gorm.DB) error {
		return conn.Delete(&Rule{}, id).Error
	}, m.ruleCacheKey(data.Id))
}

func (m *customPromoModel) QueryRuleList(ctx context.Context, page, size int, ruleType string, enabled *bool, search string) (int64, []*Rule, error) {
	if page <= 0 {
		page = 1
	}
	if size <= 0 {
		size = 10
	}
	var total int64
	var list []*Rule
	err := m.QueryNoCacheCtx(ctx, &list, func(conn *gorm.DB, v interface{}) error {
		db := conn.Model(&Rule{})
		if ruleType != "" {
			db = db.Where("type = ?", ruleType)
		}
		if enabled != nil {
			db = db.Where("enabled = ?", *enabled)
		}
		if search != "" {
			db = db.Where("name LIKE ?", "%"+search+"%")
		}
		if err := db.Count(&total).Error; err != nil {
			return err
		}
		return db.Order("priority DESC").Order("id DESC").Limit(size).Offset((page - 1) * size).Find(v).Error
	})
	return total, list, err
}

func (m *customPromoModel) UpsertPrices(ctx context.Context, ruleId int64, items []*SubscribePromo) error {
	return m.ExecCtx(ctx, func(conn *gorm.DB) error {
		for _, item := range items {
			if item == nil {
				continue
			}
			item.PromoRuleId = ruleId
			var existing SubscribePromo
			err := conn.Model(&SubscribePromo{}).
				Where("subscribe_id = ? AND quantity = ? AND promo_rule_id = ?", item.SubscribeId, item.Quantity, ruleId).
				First(&existing).Error
			if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
				return err
			}
			if errors.Is(err, gorm.ErrRecordNotFound) {
				if err := conn.Create(item).Error; err != nil {
					return err
				}
				continue
			}
			existing.Quantity = item.Quantity
			existing.PromoPrice = item.PromoPrice
			if err := conn.Save(&existing).Error; err != nil {
				return err
			}
		}
		return nil
	})
}

func (m *customPromoModel) FindPrice(ctx context.Context, id int64) (*SubscribePromo, error) {
	var resp SubscribePromo
	err := m.QueryCtx(ctx, &resp, m.priceCacheKey(id), func(conn *gorm.DB, v interface{}) error {
		return conn.Model(&SubscribePromo{}).Where("id = ?", id).First(v).Error
	})
	if err != nil {
		return nil, err
	}
	return &resp, nil
}

func (m *customPromoModel) DeletePrice(ctx context.Context, id int64) error {
	data, err := m.FindPrice(ctx, id)
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil
		}
		return err
	}
	return m.ExecCtx(ctx, func(conn *gorm.DB) error {
		return conn.Delete(&SubscribePromo{}, id).Error
	}, m.priceCacheKey(data.Id))
}

func (m *customPromoModel) QueryPriceList(ctx context.Context, ruleId int64, page, size int) (int64, []*SubscribePromo, error) {
	if page <= 0 {
		page = 1
	}
	if size <= 0 {
		size = 10
	}
	var total int64
	var list []*SubscribePromo
	err := m.QueryNoCacheCtx(ctx, &list, func(conn *gorm.DB, v interface{}) error {
		db := conn.Model(&SubscribePromo{}).Where("promo_rule_id = ?", ruleId)
		if err := db.Count(&total).Error; err != nil {
			return err
		}
		return db.Order("id DESC").Limit(size).Offset((page - 1) * size).Find(v).Error
	})
	return total, list, err
}

func (m *customPromoModel) QueryUsageList(ctx context.Context, params UsageFilter) (int64, []*Usage, error) {
	if params.Page <= 0 {
		params.Page = 1
	}
	if params.Size <= 0 {
		params.Size = 10
	}
	var total int64
	var list []*Usage
	err := m.QueryNoCacheCtx(ctx, &list, func(conn *gorm.DB, v interface{}) error {
		db := conn.Model(&Usage{})
		if params.RuleId > 0 {
			db = db.Where("promo_rule_id = ?", params.RuleId)
		}
		if params.UserId > 0 {
			db = db.Where("user_id = ?", params.UserId)
		}
		if params.SubscribeId > 0 {
			db = db.Where("subscribe_id = ?", params.SubscribeId)
		}
		if params.OrderNo != "" {
			db = db.Where("order_no = ?", params.OrderNo)
		}
		if err := db.Count(&total).Error; err != nil {
			return err
		}
		return db.Order("id DESC").Limit(params.Size).Offset((params.Page - 1) * params.Size).Find(v).Error
	})
	return total, list, err
}

func (m *customPromoModel) Transaction(ctx context.Context, fn func(db *gorm.DB) error) error {
	return m.TransactCtx(ctx, fn)
}