package service

import (
	"context"

	"go.uber.org/zap"

	"with_you/internal/cache"
	"with_you/internal/dto"
	"with_you/internal/model"
	"with_you/internal/pkg/auth"
	"with_you/internal/repository"
)

// AdminUserService 管理端用户服务接口
type AdminUserService interface {
	// GetUserList 获取用户列表（分页、搜索、状态筛选）
	GetUserList(ctx context.Context, page, pageSize int, keyword, status string) ([]dto.AdminUserListResponse, int64, error)
	// GetUserDetail 获取用户详情（含统计信息）
	GetUserDetail(ctx context.Context, userID string) (*dto.AdminUserDetailResponse, error)
	// UpdateUserStatus 更新用户状态
	UpdateUserStatus(ctx context.Context, userID string, status model.UserStatus) (*dto.AdminUserDetailResponse, error)
}

// adminUserServiceImpl 管理端用户服务实现
//
// sessionSvc 与 cache 用于在封禁/停用用户时撤销其全部登录会话并失效 Principal 缓存，
// 让 RequireAuth 在下一次请求时重新加载用户状态（避免 30s 缓存窗口内仍可访问）。
type adminUserServiceImpl struct {
	userRepo   repository.UserRepository
	sessionSvc SessionService
	cache      cache.Cache
}

// NewAdminUserService 创建管理端用户服务
func NewAdminUserService(userRepo repository.UserRepository, sessionSvc SessionService, cache cache.Cache) AdminUserService {
	return &adminUserServiceImpl{
		userRepo:   userRepo,
		sessionSvc: sessionSvc,
		cache:      cache,
	}
}

// GetUserList 获取用户列表
func (s *adminUserServiceImpl) GetUserList(ctx context.Context, page, pageSize int, keyword, status string) ([]dto.AdminUserListResponse, int64, error) {
	users, total, err := s.userRepo.AdminList(page, pageSize, keyword, status)
	if err != nil {
		return nil, 0, err
	}

	responses := make([]dto.AdminUserListResponse, len(users))
	for i, user := range users {
		responses[i] = convertUserToAdminListResponse(user)
	}

	return responses, total, nil
}

// GetUserDetail 获取用户详情
func (s *adminUserServiceImpl) GetUserDetail(ctx context.Context, userID string) (*dto.AdminUserDetailResponse, error) {
	user, err := s.userRepo.GetByID(userID)
	if err != nil {
		return nil, err
	}

	// 获取帖子数
	postsCount, _ := s.userRepo.GetPostsCount(userID)

	// 获取评论数
	commentsCount, _ := s.userRepo.GetCommentsCount(userID)

	return convertUserToAdminDetailResponse(user, postsCount, commentsCount), nil
}

// UpdateUserStatus 更新用户状态
func (s *adminUserServiceImpl) UpdateUserStatus(ctx context.Context, userID string, status model.UserStatus) (*dto.AdminUserDetailResponse, error) {
	// 先检查用户是否存在
	user, err := s.userRepo.GetByID(userID)
	if err != nil {
		return nil, err
	}

	// 更新状态
	if err := s.userRepo.UpdateStatus(userID, status); err != nil {
		return nil, err
	}

	// 状态变更后的会话/缓存联动：
	//   - banned/inactive：撤销该用户全部会话（refresh token 立即失效）并失效 Principal 缓存，
	//     access token 在剩余 TTL 内仍可用（无状态 JWT 固有限制），但 refresh 已不可续期。
	//   - active：从封禁恢复时同样失效 Principal 缓存，让下次请求重新加载新状态。
	// 失败仅告警不阻塞主流程：状态变更本身已成功，缓存最终会自然过期。
	if status == model.UserStatusBanned || status == model.UserStatusInactive {
		if s.sessionSvc != nil {
			if rerr := s.sessionSvc.RevokeAllByUser(ctx, userID); rerr != nil {
				zap.L().Warn("failed to revoke sessions on user status change",
					zap.String("user_id", userID),
					zap.String("status", string(status)),
					zap.Error(rerr),
				)
			}
		}
	}
	if status != user.Status {
		auth.InvalidatePrincipalCache(s.cache, userID)
	}

	// 重新获取用户信息
	user, err = s.userRepo.GetByID(userID)
	if err != nil {
		return nil, err
	}

	// 获取统计信息
	postsCount, _ := s.userRepo.GetPostsCount(userID)
	commentsCount, _ := s.userRepo.GetCommentsCount(userID)

	return convertUserToAdminDetailResponse(user, postsCount, commentsCount), nil
}

// convertUserToAdminListResponse 转换用户为管理端列表响应
func convertUserToAdminListResponse(user *model.User) dto.AdminUserListResponse {
	var lastLoginAt string
	if user.LastLoginAt != nil {
		lastLoginAt = user.LastLoginAt.Format("2006-01-02 15:04:05")
	}

	return dto.AdminUserListResponse{
		ID:             user.ID,
		Username:       user.Username,
		Nickname:       user.Nickname,
		Email:          user.Email,
		Phone:          user.Phone,
		EmailVerified:  user.EmailVerified,
		Avatar:         user.Avatar,
		Status:         string(user.Status),
		PostsCount:     user.PostsCount,
		FollowersCount: user.FollowersCount,
		FollowingCount: user.FollowingCount,
		LastLoginAt:    lastLoginAt,
		LastLoginIP:    user.LastLoginIP,
		CreatedAt:      user.CreatedAt.Format("2006-01-02 15:04:05"),
	}
}

// convertUserToAdminDetailResponse 转换用户为管理端详情响应
func convertUserToAdminDetailResponse(user *model.User, postsCount, commentsCount int64) *dto.AdminUserDetailResponse {
	var lastLoginAt string
	if user.LastLoginAt != nil {
		lastLoginAt = user.LastLoginAt.Format("2006-01-02 15:04:05")
	}

	return &dto.AdminUserDetailResponse{
		ID:             user.ID,
		Username:       user.Username,
		Nickname:       user.Nickname,
		Email:          user.Email,
		Phone:          user.Phone,
		EmailVerified:  user.EmailVerified,
		Avatar:         user.Avatar,
		CoverURL:       user.CoverURL,
		Bio:            user.Bio,
		Website:        user.Website,
		Location:       user.Location,
		IsVerified:     user.IsVerified,
		Status:         string(user.Status),
		PostsCount:     int(postsCount),
		CommentsCount:  commentsCount,
		FollowersCount: user.FollowersCount,
		FollowingCount: user.FollowingCount,
		LastLoginAt:    lastLoginAt,
		LastLoginIP:    user.LastLoginIP,
		CreatedAt:      user.CreatedAt.Format("2006-01-02 15:04:05"),
		UpdatedAt:      user.UpdatedAt.Format("2006-01-02 15:04:05"),
	}
}