package service

import (
	"context"

	apperrors "carrot_bbs/internal/errors"
	"carrot_bbs/internal/model"
	"carrot_bbs/internal/repository"
)

// RoleService 角色管理服务接口
type RoleService interface {
	// GetUserRoles 获取用户的所有角色
	GetUserRoles(ctx context.Context, userID string) ([]model.Role, error)

	// AssignRole 为用户分配角色
	AssignRole(ctx context.Context, operatorID, targetUserID, role string) error

	// RemoveRole 移除用户的角色
	RemoveRole(ctx context.Context, operatorID, targetUserID, role string) error

	// GetAllRoles 获取所有角色定义
	GetAllRoles(ctx context.Context) ([]model.Role, error)

	// GetRole 获取角色详情
	GetRole(ctx context.Context, name string) (*model.Role, error)
}

type roleService struct {
	roleRepo  repository.RoleRepository
	casbinSvc CasbinService
}

// NewRoleService 创建角色管理服务
func NewRoleService(
	roleRepo repository.RoleRepository,
	casbinSvc CasbinService,
) RoleService {
	return &roleService{
		roleRepo:  roleRepo,
		casbinSvc: casbinSvc,
	}
}

func (s *roleService) GetUserRoles(ctx context.Context, userID string) ([]model.Role, error) {
	roleNames, err := s.casbinSvc.GetRolesForUser(ctx, userID)
	if err != nil {
		return nil, err
	}

	var roles []model.Role
	for _, name := range roleNames {
		role, err := s.roleRepo.GetRole(ctx, name)
		if err != nil {
			continue // 忽略找不到的角色
		}
		roles = append(roles, *role)
	}
	return roles, nil
}

func (s *roleService) AssignRole(ctx context.Context, operatorID, targetUserID, role string) error {
	// 不能修改自己的角色
	if operatorID == targetUserID {
		return apperrors.ErrCannotModifyOwnRole
	}

	// 检查目标用户是否已有该角色
	hasRole, err := s.casbinSvc.HasRoleForUser(ctx, targetUserID, role)
	if err != nil {
		return err
	}
	if hasRole {
		return apperrors.ErrRoleAlreadyAssigned
	}

	// 检查角色是否存在
	_, err = s.roleRepo.GetRole(ctx, role)
	if err != nil {
		return apperrors.ErrRoleNotFound
	}

	// 添加角色
	return s.casbinSvc.AddRoleForUser(ctx, targetUserID, role)
}

func (s *roleService) RemoveRole(ctx context.Context, operatorID, targetUserID, role string) error {
	// 不能修改自己的角色
	if operatorID == targetUserID {
		return apperrors.ErrCannotModifyOwnRole
	}

	// 不能修改超级管理员角色
	if role == model.RoleSuperAdmin {
		return apperrors.ErrCannotModifySuperAdmin
	}

	// 检查用户是否有该角色
	hasRole, err := s.casbinSvc.HasRoleForUser(ctx, targetUserID, role)
	if err != nil {
		return err
	}
	if !hasRole {
		return apperrors.ErrRoleNotAssigned
	}

	return s.casbinSvc.DeleteRoleForUser(ctx, targetUserID, role)
}

func (s *roleService) GetAllRoles(ctx context.Context) ([]model.Role, error) {
	return s.roleRepo.GetAllRoles(ctx)
}

func (s *roleService) GetRole(ctx context.Context, name string) (*model.Role, error) {
	return s.roleRepo.GetRole(ctx, name)
}