package account

import (
	"context"
	"fmt"

	"github.com/break/junhong_cmp_fiber/internal/model"
	"github.com/break/junhong_cmp_fiber/internal/store"
	"github.com/break/junhong_cmp_fiber/internal/store/postgres"
	"github.com/break/junhong_cmp_fiber/pkg/constants"
	"github.com/break/junhong_cmp_fiber/pkg/errors"
	"github.com/break/junhong_cmp_fiber/pkg/middleware"
	"golang.org/x/crypto/bcrypt"
	"gorm.io/gorm"
)

// Service 账号业务服务
type Service struct {
	accountStore     *postgres.AccountStore
	roleStore        *postgres.RoleStore
	accountRoleStore *postgres.AccountRoleStore
}

// New 创建账号服务
func New(accountStore *postgres.AccountStore, roleStore *postgres.RoleStore, accountRoleStore *postgres.AccountRoleStore) *Service {
	return &Service{
		accountStore:     accountStore,
		roleStore:        roleStore,
		accountRoleStore: accountRoleStore,
	}
}

// Create 创建账号
func (s *Service) Create(ctx context.Context, req *model.CreateAccountRequest) (*model.Account, error) {
	// 获取当前用户 ID
	currentUserID := middleware.GetUserIDFromContext(ctx)
	if currentUserID == 0 {
		return nil, errors.New(errors.CodeUnauthorized, "未授权访问")
	}

	// 验证非 root 用户必须提供 parent_id
	if req.UserType != constants.UserTypeRoot && req.ParentID == nil {
		return nil, errors.New(errors.CodeParentIDRequired, "非 root 用户必须提供上级账号")
	}

	// 检查用户名唯一性
	existing, err := s.accountStore.GetByUsername(ctx, req.Username)
	if err == nil && existing != nil {
		return nil, errors.New(errors.CodeUsernameExists, "用户名已存在")
	}

	// 检查手机号唯一性
	existing, err = s.accountStore.GetByPhone(ctx, req.Phone)
	if err == nil && existing != nil {
		return nil, errors.New(errors.CodePhoneExists, "手机号已存在")
	}

	// 验证 parent_id 存在（如果提供）
	if req.ParentID != nil {
		parent, err := s.accountStore.GetByID(ctx, *req.ParentID)
		if err != nil || parent == nil {
			return nil, errors.New(errors.CodeInvalidParentID, "上级账号不存在或无效")
		}
	}

	// bcrypt 哈希密码
	hashedPassword, err := bcrypt.GenerateFromPassword([]byte(req.Password), bcrypt.DefaultCost)
	if err != nil {
		return nil, fmt.Errorf("密码哈希失败: %w", err)
	}

	// 创建账号
	account := &model.Account{
		Username: req.Username,
		Phone:    req.Phone,
		Password: string(hashedPassword),
		UserType: req.UserType,
		ShopID:   req.ShopID,
		ParentID: req.ParentID,
		Status:   constants.StatusEnabled,
	}

	if err := s.accountStore.Create(ctx, account); err != nil {
		return nil, fmt.Errorf("创建账号失败: %w", err)
	}

	// 清除父账号的下级 ID 缓存
	if account.ParentID != nil {
		_ = s.accountStore.ClearSubordinatesCacheForParents(ctx, *account.ParentID)
	}

	return account, nil
}

// Get 获取账号
func (s *Service) Get(ctx context.Context, id uint) (*model.Account, error) {
	account, err := s.accountStore.GetByID(ctx, id)
	if err != nil {
		if err == gorm.ErrRecordNotFound {
			return nil, errors.New(errors.CodeAccountNotFound, "账号不存在")
		}
		return nil, fmt.Errorf("获取账号失败: %w", err)
	}
	return account, nil
}

// Update 更新账号
func (s *Service) Update(ctx context.Context, id uint, req *model.UpdateAccountRequest) (*model.Account, error) {
	// 获取当前用户 ID
	currentUserID := middleware.GetUserIDFromContext(ctx)
	if currentUserID == 0 {
		return nil, errors.New(errors.CodeUnauthorized, "未授权访问")
	}

	// 获取现有账号
	account, err := s.accountStore.GetByID(ctx, id)
	if err != nil {
		if err == gorm.ErrRecordNotFound {
			return nil, errors.New(errors.CodeAccountNotFound, "账号不存在")
		}
		return nil, fmt.Errorf("获取账号失败: %w", err)
	}

	// 更新字段
	if req.Username != nil {
		// 检查新用户名唯一性
		existing, err := s.accountStore.GetByUsername(ctx, *req.Username)
		if err == nil && existing != nil && existing.ID != id {
			return nil, errors.New(errors.CodeUsernameExists, "用户名已存在")
		}
		account.Username = *req.Username
	}

	if req.Phone != nil {
		// 检查新手机号唯一性
		existing, err := s.accountStore.GetByPhone(ctx, *req.Phone)
		if err == nil && existing != nil && existing.ID != id {
			return nil, errors.New(errors.CodePhoneExists, "手机号已存在")
		}
		account.Phone = *req.Phone
	}

	if req.Password != nil {
		hashedPassword, err := bcrypt.GenerateFromPassword([]byte(*req.Password), bcrypt.DefaultCost)
		if err != nil {
			return nil, fmt.Errorf("密码哈希失败: %w", err)
		}
		account.Password = string(hashedPassword)
	}

	if req.Status != nil {
		account.Status = *req.Status
	}

	account.Updater = currentUserID

	if err := s.accountStore.Update(ctx, account); err != nil {
		return nil, fmt.Errorf("更新账号失败: %w", err)
	}

	return account, nil
}

// Delete 软删除账号
func (s *Service) Delete(ctx context.Context, id uint) error {
	// 检查账号存在
	account, err := s.accountStore.GetByID(ctx, id)
	if err != nil {
		if err == gorm.ErrRecordNotFound {
			return errors.New(errors.CodeAccountNotFound, "账号不存在")
		}
		return fmt.Errorf("获取账号失败: %w", err)
	}

	if err := s.accountStore.Delete(ctx, id); err != nil {
		return fmt.Errorf("删除账号失败: %w", err)
	}

	// 清除该账号和所有上级的下级 ID 缓存
	_ = s.accountStore.ClearSubordinatesCacheForParents(ctx, id)

	// 如果有上级，也需要清除上级的缓存
	if account.ParentID != nil {
		_ = s.accountStore.ClearSubordinatesCacheForParents(ctx, *account.ParentID)
	}

	return nil
}

// List 查询账号列表
func (s *Service) List(ctx context.Context, req *model.AccountListRequest) ([]*model.Account, int64, error) {
	opts := &store.QueryOptions{
		Page:     req.Page,
		PageSize: req.PageSize,
		OrderBy:  "id DESC",
	}
	if opts.Page == 0 {
		opts.Page = 1
	}
	if opts.PageSize == 0 {
		opts.PageSize = constants.DefaultPageSize
	}

	filters := make(map[string]interface{})
	if req.Username != "" {
		filters["username"] = req.Username
	}
	if req.Phone != "" {
		filters["phone"] = req.Phone
	}
	if req.UserType != nil {
		filters["user_type"] = *req.UserType
	}
	if req.Status != nil {
		filters["status"] = *req.Status
	}

	return s.accountStore.List(ctx, opts, filters)
}

// AssignRoles 为账号分配角色
func (s *Service) AssignRoles(ctx context.Context, accountID uint, roleIDs []uint) ([]*model.AccountRole, error) {
	// 获取当前用户 ID
	currentUserID := middleware.GetUserIDFromContext(ctx)
	if currentUserID == 0 {
		return nil, errors.New(errors.CodeUnauthorized, "未授权访问")
	}

	// 检查账号存在
	_, err := s.accountStore.GetByID(ctx, accountID)
	if err != nil {
		if err == gorm.ErrRecordNotFound {
			return nil, errors.New(errors.CodeAccountNotFound, "账号不存在")
		}
		return nil, fmt.Errorf("获取账号失败: %w", err)
	}

	// 验证所有角色存在
	for _, roleID := range roleIDs {
		_, err := s.roleStore.GetByID(ctx, roleID)
		if err != nil {
			if err == gorm.ErrRecordNotFound {
				return nil, errors.New(errors.CodeRoleNotFound, fmt.Sprintf("角色 %d 不存在", roleID))
			}
			return nil, fmt.Errorf("获取角色失败: %w", err)
		}
	}

	// 创建关联
	var ars []*model.AccountRole
	for _, roleID := range roleIDs {
		// 检查是否已分配
		exists, _ := s.accountRoleStore.Exists(ctx, accountID, roleID)
		if exists {
			continue // 跳过已存在的关联
		}

		ar := &model.AccountRole{
			AccountID: accountID,
			RoleID:    roleID,
			Status:    constants.StatusEnabled,
			Creator:   currentUserID,
			Updater:   currentUserID,
		}
		if err := s.accountRoleStore.Create(ctx, ar); err != nil {
			return nil, fmt.Errorf("创建账号-角色关联失败: %w", err)
		}
		ars = append(ars, ar)
	}

	return ars, nil
}

// GetRoles 获取账号的所有角色
func (s *Service) GetRoles(ctx context.Context, accountID uint) ([]*model.Role, error) {
	// 检查账号存在
	_, err := s.accountStore.GetByID(ctx, accountID)
	if err != nil {
		if err == gorm.ErrRecordNotFound {
			return nil, errors.New(errors.CodeAccountNotFound, "账号不存在")
		}
		return nil, fmt.Errorf("获取账号失败: %w", err)
	}

	// 获取角色 ID 列表
	roleIDs, err := s.accountRoleStore.GetRoleIDsByAccountID(ctx, accountID)
	if err != nil {
		return nil, fmt.Errorf("获取账号角色 ID 失败: %w", err)
	}

	if len(roleIDs) == 0 {
		return []*model.Role{}, nil
	}

	// 获取角色详情
	return s.roleStore.GetByIDs(ctx, roleIDs)
}

// RemoveRole 移除账号的角色
func (s *Service) RemoveRole(ctx context.Context, accountID, roleID uint) error {
	// 检查账号存在
	_, err := s.accountStore.GetByID(ctx, accountID)
	if err != nil {
		if err == gorm.ErrRecordNotFound {
			return errors.New(errors.CodeAccountNotFound, "账号不存在")
		}
		return fmt.Errorf("获取账号失败: %w", err)
	}

	// 删除关联
	if err := s.accountRoleStore.Delete(ctx, accountID, roleID); err != nil {
		return fmt.Errorf("删除账号-角色关联失败: %w", err)
	}

	return nil
}

// ValidatePassword 验证密码
func (s *Service) ValidatePassword(plainPassword, hashedPassword string) bool {
	err := bcrypt.CompareHashAndPassword([]byte(hashedPassword), []byte(plainPassword))
	return err == nil
}