// Package account 提供账号管理的业务逻辑服务
// 包含账号创建、查询、更新、删除、密码管理等功能
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")
	}

	// 验证代理账号必须提供 shop_id
	if req.UserType == constants.UserTypeAgent && req.ShopID == nil {
		return nil, errors.New(errors.CodeInvalidParam, "代理账号必须提供店铺ID")
	}

	// 验证企业账号必须提供 enterprise_id
	if req.UserType == constants.UserTypeEnterprise && req.EnterpriseID == nil {
		return nil, errors.New(errors.CodeInvalidParam, "企业账号必须提供企业ID")
	}

	// 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")
	}

	// 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,
		EnterpriseID: req.EnterpriseID,
		Status:       constants.StatusEnabled,
	}

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

	// TODO: 清除店铺的下级 ID 缓存（需要在 Service 层处理）
	// 由于账号层级关系改为通过 Shop 表维护，这里的缓存清理逻辑已废弃

	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
	_, 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)
	}

	// 账号删除后不需要清理缓存
	// 数据权限过滤现在基于店铺层级，店铺相关的缓存清理由 ShopService 负责

	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（支持空数组清空所有角色，超级管理员禁止分配）
func (s *Service) AssignRoles(ctx context.Context, accountID uint, roleIDs []uint) ([]*model.AccountRole, error) {
	currentUserID := middleware.GetUserIDFromContext(ctx)
	if currentUserID == 0 {
		return nil, errors.New(errors.CodeUnauthorized, "未授权访问")
	}

	account, 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)
	}

	// 超级管理员禁止分配角色
	if account.UserType == constants.UserTypeSuperAdmin {
		return nil, errors.New(errors.CodeInvalidParam, "超级管理员不允许分配角色")
	}

	// 空数组：清空所有角色
	if len(roleIDs) == 0 {
		if err := s.accountRoleStore.DeleteByAccountID(ctx, accountID); err != nil {
			return nil, fmt.Errorf("清空账号角色失败: %w", err)
		}
		return []*model.AccountRole{}, nil
	}

	maxRoles := constants.GetMaxRolesForUserType(account.UserType)
	if maxRoles == 0 {
		return nil, errors.New(errors.CodeInvalidParam, "该用户类型不需要分配角色")
	}

	existingCount, err := s.accountRoleStore.CountByAccountID(ctx, accountID)
	if err != nil {
		return nil, fmt.Errorf("统计现有角色数量失败: %w", err)
	}

	newRoleCount := 0
	for _, roleID := range roleIDs {
		exists, _ := s.accountRoleStore.Exists(ctx, accountID, roleID)
		if !exists {
			newRoleCount++
		}
	}

	if maxRoles != -1 && int(existingCount)+newRoleCount > maxRoles {
		return nil, errors.New(errors.CodeInvalidParam, fmt.Sprintf("该用户类型最多只能分配 %d 个角色", maxRoles))
	}

	for _, roleID := range roleIDs {
		role, 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)
		}

		if !constants.IsRoleTypeMatchUserType(role.RoleType, account.UserType) {
			return nil, errors.New(errors.CodeInvalidParam, "角色类型与账号类型不匹配")
		}
	}

	var ars []*model.AccountRole
	for _, roleID := range roleIDs {
		exists, _ := s.accountRoleStore.Exists(ctx, accountID, roleID)
		if exists {
			continue
		}

		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
}

// UpdatePassword 修改账号密码（管理员重置场景，无需旧密码）
func (s *Service) UpdatePassword(ctx context.Context, accountID uint, newPassword string) error {
	currentUserID := middleware.GetUserIDFromContext(ctx)
	if currentUserID == 0 {
		return errors.New(errors.CodeUnauthorized, "未授权访问")
	}

	_, 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)
	}

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

	if err := s.accountStore.UpdatePassword(ctx, accountID, string(hashedPassword), currentUserID); err != nil {
		return fmt.Errorf("更新密码失败: %w", err)
	}

	return nil
}

// UpdateStatus 修改账号状态（启用/禁用）
func (s *Service) UpdateStatus(ctx context.Context, accountID uint, status int) error {
	currentUserID := middleware.GetUserIDFromContext(ctx)
	if currentUserID == 0 {
		return errors.New(errors.CodeUnauthorized, "未授权访问")
	}

	_, 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)
	}

	if err := s.accountStore.UpdateStatus(ctx, accountID, status, currentUserID); err != nil {
		return fmt.Errorf("更新状态失败: %w", err)
	}

	return nil
}

// ListPlatformAccounts 查询平台账号列表（自动筛选 user_type IN (1, 2)）
func (s *Service) ListPlatformAccounts(ctx context.Context, req *model.PlatformAccountListRequest) ([]*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.Status != nil {
		filters["status"] = *req.Status
	}

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

// CreateSystemAccount 系统内部创建账号方法，用于系统初始化场景（绕过当前用户检查）
func (s *Service) CreateSystemAccount(ctx context.Context, account *model.Account) error {
	if account.Username == "" {
		return errors.New(errors.CodeInvalidParam, "用户名不能为空")
	}
	if account.Phone == "" {
		return errors.New(errors.CodeInvalidParam, "手机号不能为空")
	}
	if account.Password == "" {
		return errors.New(errors.CodeInvalidParam, "密码不能为空")
	}

	existing, err := s.accountStore.GetByUsername(ctx, account.Username)
	if err == nil && existing != nil {
		return errors.New(errors.CodeUsernameExists, "用户名已存在")
	}

	existing, err = s.accountStore.GetByPhone(ctx, account.Phone)
	if err == nil && existing != nil {
		return errors.New(errors.CodePhoneExists, "手机号已存在")
	}

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

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

	return nil
}