package services

import (
	"time"

	"github.com/inchstep/server/internal/models"
	"gorm.io/gorm"
)

type PointsService struct {
	db *gorm.DB
}

func NewPointsService(db *gorm.DB) *PointsService {
	return &PointsService{db: db}
}

const (
	PointsCheckIn      = 1
	PointsStreak7      = 5
	PointsStreak30     = 20
	PointsGoalComplete = 10
	PointsPostShare    = 2
	PointsComment      = 1
	PointsInviteUser   = 15
)

// AddPoints 为用户增加积分
func (s *PointsService) AddPoints(userID string, amount int, reason string) error {
	return s.db.Model(&models.User{}).Where("id = ?", userID).
		UpdateColumn("points", gorm.Expr("points + ?", amount)).Error
}

// CheckAndAwardStreak 检查并发放连续打卡奖励
func (s *PointsService) CheckAndAwardStreak(userID string, streak int) error {
	switch streak {
	case 7:
		return s.AddPoints(userID, PointsStreak7, "连续打卡 7 天")
	case 30:
		return s.AddPoints(userID, PointsStreak30, "连续打卡 30 天")
	}
	return nil
}

// AwardCheckIn 打卡奖励
func (s *PointsService) AwardCheckIn(userID string) error {
	return s.AddPoints(userID, PointsCheckIn, "每日打卡")
}

func ptr(s string) *string { return &s }

// predefinedAchievements 预定义成就列表
var predefinedAchievements = []models.Achievement{
	{ID: "first_checkin", Name: "初露锋芒", Rarity: "bronze", Condition: ptr("完成第 1 次打卡")},
	{ID: "streak_7", Name: "七日坚持", Rarity: "bronze", Condition: ptr("连续 7 天打卡")},
	{ID: "streak_15", Name: "半月之约", Rarity: "bronze", Condition: ptr("连续 15 天打卡")},
	{ID: "streak_30", Name: "月满则盈", Rarity: "silver", Condition: ptr("连续 30 天打卡")},
	{ID: "streak_100", Name: "百日筑基", Rarity: "gold", Condition: ptr("连续 100 天打卡")},
	{ID: "all_round", Name: "全面开花", Rarity: "silver", Condition: ptr("同时有 5 个打卡项保持活跃")},
	{ID: "social_star", Name: "社交达人", Rarity: "silver", Condition: ptr("获得 50 个点赞")},
	{ID: "group_star", Name: "小组之星", Rarity: "silver", Condition: ptr("在小组内连续打卡满 30 天")},
	{ID: "makeup_master", Name: "神补刀", Rarity: "bronze", Condition: ptr("使用补卡功能 10 次")},
	{ID: "year_champion", Name: "年度坚持王", Rarity: "gold", Condition: ptr("全年打卡完成率 ≥ 80%")},
}

// InitAchievements 初始化成就数据
func (s *PointsService) InitAchievements() error {
	for _, a := range predefinedAchievements {
		s.db.Where("id = ?", a.ID).FirstOrCreate(&a)
	}
	return nil
}

// UnlockAchievement 解锁成就
func (s *PointsService) UnlockAchievement(userID, achievementID string) (*models.UserAchievement, error) {
	ua := &models.UserAchievement{
		UserID:        userID,
		AchievementID: achievementID,
		UnlockedAt:    time.Now(),
	}
	if err := s.db.Create(ua).Error; err != nil {
		return nil, err
	}
	return ua, nil
}

// GetUserAchievements 获取用户已解锁的成就
func (s *PointsService) GetUserAchievements(userID string) ([]models.UserAchievement, error) {
	var list []models.UserAchievement
	err := s.db.Where("user_id = ?", userID).Preload("Achievement").Find(&list).Error
	return list, err
}

// GetAllAchievements 获取所有成就
func (s *PointsService) GetAllAchievements() ([]models.Achievement, error) {
	var list []models.Achievement
	err := s.db.Find(&list).Error
	return list, err
}

// DeductPoints 扣除积分
func (s *PointsService) DeductPoints(userID string, amount int) error {
	var user models.User
	if err := s.db.First(&user, "id = ?", userID).Error; err != nil {
		return err
	}
	if user.Points < amount {
		return gorm.ErrRecordNotFound // 积分不足
	}
	return s.db.Model(&user).UpdateColumn("points", gorm.Expr("points - ?", amount)).Error
}