package registerreward

import (
	"context"
	"errors"
	"net/http"
	"strconv"
	"strings"
	"time"

	"chatapp3-golang/internal/model"

	"gorm.io/gorm"
)

// GetStatus 返回当前登录用户的注册奖励状态，主要用于后台联调和兜底排查。
func (s *RegisterRewardService) GetStatus(ctx context.Context, user AuthUser) (*RegisterRewardStatusResponse, error) {
	if user.UserID <= 0 {
		return nil, NewAppError(http.StatusUnauthorized, "invalid_user", "authenticated user is required")
	}

	sysOrigin := strings.ToUpper(strings.TrimSpace(user.SysOrigin))
	if sysOrigin == "" {
		return nil, NewAppError(http.StatusUnauthorized, "invalid_sys_origin", "authenticated sysOrigin is required")
	}

	configRow, err := s.loadRegisterRewardConfig(ctx, sysOrigin)
	if err != nil {
		return nil, err
	}

	userInfo, err := s.loadUserBaseInfo(ctx, user.UserID)
	if err != nil {
		return nil, err
	}

	logRecord, err := s.loadRegisterRewardLog(ctx, sysOrigin, user.UserID)
	if err != nil {
		return nil, err
	}

	registerDateMatchesServerDay := false
	registerTime := ""
	if userInfo != nil && !userInfo.CreateTime.IsZero() {
		registerTime = formatRegisterRewardTime(userInfo.CreateTime)
		registerDateMatchesServerDay = isRegisterRewardCurrentServerDate(userInfo.CreateTime)
	}

	goldAmount, rewardGroupID := resolveRegisterRewardPayload(configRow, logRecord)
	rewardStatus := deriveRegisterRewardStatus(logRecord, registerDateMatchesServerDay, configRow != nil && configRow.Enabled)
	hasRewardRecord := logRecord != nil
	errorMessage := ""
	if logRecord != nil {
		errorMessage = strings.TrimSpace(logRecord.ErrorMessage)
	}
	if !registerDateMatchesServerDay {
		errorMessage = ""
		if logRecord == nil {
			goldAmount = 0
			rewardGroupID = nil
		}
	}

	return &RegisterRewardStatusResponse{
		UserID:          user.UserID,
		SysOrigin:       sysOrigin,
		Configured:      configRow != nil,
		CampaignEnabled: configRow != nil && configRow.Enabled,
		IsNewRegister:   registerDateMatchesServerDay,
		HasRewardRecord: hasRewardRecord,
		RewardStatus:    rewardStatus,
		HasClaimed:      rewardStatus == registerRewardStatusSuccess,
		GoldAmount:      goldAmount,
		RewardGroupID:   rewardGroupID,
		RegisterTime:    registerTime,
		ErrorMessage:    errorMessage,
	}, nil
}

// loadRegisterRewardLog 按用户读取注册奖励处理日志，优先按标准 eventId 命中，兼容历史数据则回退最近一条日志。
func (s *RegisterRewardService) loadRegisterRewardLog(ctx context.Context, sysOrigin string, userID int64) (*model.ResidentRegisterRewardLog, error) {
	var record model.ResidentRegisterRewardLog
	eventID := buildRegisterRewardEventID(sysOrigin, userID)
	err := s.repo.DB.WithContext(ctx).
		Where("event_id = ?", eventID).
		First(&record).Error
	if err == nil {
		return &record, nil
	}
	if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
		return nil, err
	}

	err = s.repo.DB.WithContext(ctx).
		Where("sys_origin = ? AND user_id = ?", sysOrigin, userID).
		Order("create_time desc").
		Order("id desc").
		First(&record).Error
	if errors.Is(err, gorm.ErrRecordNotFound) {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}
	return &record, nil
}

// loadUserBaseInfo 读取用户基础资料，用创建时间兜底判断“刚注册但异步日志还没落库”的场景。
func (s *RegisterRewardService) loadUserBaseInfo(ctx context.Context, userID int64) (*model.UserBaseInfo, error) {
	var info model.UserBaseInfo
	err := s.repo.DB.WithContext(ctx).
		Where("id = ?", userID).
		First(&info).Error
	if errors.Is(err, gorm.ErrRecordNotFound) {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}
	return &info, nil
}

// buildRegisterRewardEventID 按 Java 生产者相同规则拼接注册奖励事件 ID。
func buildRegisterRewardEventID(sysOrigin string, userID int64) string {
	return "REGISTER_REWARD:" + strings.ToUpper(strings.TrimSpace(sysOrigin)) + ":" + strconv.FormatInt(userID, 10)
}

// deriveRegisterRewardStatus 统一返回联调接口里的注册奖励状态。
func deriveRegisterRewardStatus(
	logRecord *model.ResidentRegisterRewardLog,
	registerDateMatchesServerDay bool,
	campaignEnabled bool,
) string {
	// 业务要求：只要注册日期与服务器当天日期不一致，就视为该注册奖励已经处理完成，不再继续引导端上查询。
	if !registerDateMatchesServerDay {
		return registerRewardStatusSuccess
	}
	if logRecord != nil {
		switch status := strings.ToUpper(strings.TrimSpace(logRecord.Status)); status {
		case registerRewardStatusPending,
			registerRewardStatusSuccess,
			registerRewardStatusSkipped,
			registerRewardStatusFailed:
			return status
		default:
			return registerRewardStatusPending
		}
	}
	if campaignEnabled {
		return registerRewardStatusProcessing
	}
	return registerRewardStatusNotTriggered
}

// isRegisterRewardCurrentServerDate 判断注册时间是否仍落在“服务器今天”的自然日内。
func isRegisterRewardCurrentServerDate(value time.Time) bool {
	if value.IsZero() {
		return false
	}
	location, err := time.LoadLocation(registerRewardDailyQuotaTimezone)
	if err != nil {
		now := time.Now()
		return value.Format("2006-01-02") == now.Format("2006-01-02")
	}
	return value.In(location).Format("2006-01-02") == time.Now().In(location).Format("2006-01-02")
}

// resolveRegisterRewardPayload 优先返回日志里已命中的奖励内容，没有日志时回退当前后台配置。
func resolveRegisterRewardPayload(
	configRow *model.ResidentRegisterRewardConfig,
	logRecord *model.ResidentRegisterRewardLog,
) (int64, *int64) {
	if logRecord != nil {
		return logRecord.GoldAmount, logRecord.RewardGroupID
	}
	if configRow == nil {
		return 0, nil
	}
	return configRow.GoldAmount, configRow.RewardGroupID
}

// formatRegisterRewardTime 统一格式化注册时间展示值。
func formatRegisterRewardTime(value time.Time) string {
	if value.IsZero() {
		return ""
	}
	return value.Format("2006-01-02 15:04:05")
}