package service

import (
	"context"

	apperrors "with_you/internal/errors"
	"with_you/internal/model"
	"with_you/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)

	// GetRoleDetail 获取角色详情（包含用户数量和权限）
	GetRoleDetail(ctx context.Context, name string) (*RoleDetail, error)

	// GetRolePermissions 获取角色的权限列表
	GetRolePermissions(ctx context.Context, name string) ([]Permission, error)

	// GetAllPermissions 获取系统中所有权限定义
	GetAllPermissions(ctx context.Context) ([]Permission, error)

	// UpdateRolePermissions 更新角色权限
	UpdateRolePermissions(ctx context.Context, roleName string, permissions []Permission) error
}

// Permission 权限定义
type Permission struct {
	Resource string `json:"resource"`
	Action   string `json:"action"`
}

// RoleDetail 角色详情
type RoleDetail struct {
	Name        string       `json:"name"`
	DisplayName string       `json:"display_name"`
	Description string       `json:"description"`
	ParentRole  *string      `json:"parent_role"`
	Priority    int          `json:"priority"`
	UserCount   int64        `json:"user_count"`
	Permissions []Permission `json:"permissions"`
	CreatedAt   string       `json:"created_at"`
	UpdatedAt   string       `json:"updated_at"`
}

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)
}

func (s *roleService) GetRoleDetail(ctx context.Context, name string) (*RoleDetail, error) {
	role, err := s.roleRepo.GetRole(ctx, name)
	if err != nil {
		return nil, apperrors.ErrRoleNotFound
	}

	// 获取用户数量
	userCount, err := s.roleRepo.GetRoleUserCount(ctx, name)
	if err != nil {
		userCount = 0
	}

	// 获取权限
	permissions, err := s.casbinSvc.GetPermissionsForRole(ctx, name)
	if err != nil {
		return nil, err
	}

	perms := make([]Permission, 0)
	for _, p := range permissions {
		if len(p) >= 2 {
			perms = append(perms, Permission{
				Resource: p[0],
				Action:   p[1],
			})
		}
	}

	return &RoleDetail{
		Name:        role.Name,
		DisplayName: role.DisplayName,
		Description: role.Description,
		ParentRole:  role.ParentRole,
		Priority:    role.Priority,
		UserCount:   userCount,
		Permissions: perms,
		CreatedAt:   role.CreatedAt.Format("2006-01-02T15:04:05Z07:00"),
		UpdatedAt:   role.UpdatedAt.Format("2006-01-02T15:04:05Z07:00"),
	}, nil
}

func (s *roleService) GetRolePermissions(ctx context.Context, name string) ([]Permission, error) {
	// 检查角色是否存在
	_, err := s.roleRepo.GetRole(ctx, name)
	if err != nil {
		return nil, apperrors.ErrRoleNotFound
	}

	permissions, err := s.casbinSvc.GetPermissionsForRole(ctx, name)
	if err != nil {
		return nil, err
	}

	// 初始化为空数组，避免 JSON 序列化为 null
	perms := make([]Permission, 0)
	for _, p := range permissions {
		if len(p) >= 2 {
			perms = append(perms, Permission{
				Resource: p[0],
				Action:   p[1],
			})
		}
	}
	return perms, nil
}

func (s *roleService) GetAllPermissions(ctx context.Context) ([]Permission, error) {
	permissions := s.casbinSvc.GetAllPermissions(ctx)

	perms := make([]Permission, 0)
	for _, p := range permissions {
		if len(p) >= 3 {
			// p[0] 是角色名，p[1] 是资源，p[2] 是操作
			perms = append(perms, Permission{
				Resource: p[1],
				Action:   p[2],
			})
		}
	}
	return perms, nil
}

func (s *roleService) UpdateRolePermissions(ctx context.Context, roleName string, permissions []Permission) error {
	// 检查角色是否存在
	_, err := s.roleRepo.GetRole(ctx, roleName)
	if err != nil {
		return apperrors.ErrRoleNotFound
	}

	// 不能修改超级管理员权限
	if roleName == model.RoleSuperAdmin {
		return apperrors.ErrCannotModifySuperAdmin
	}

	// 转换权限格式
	var perms [][]string
	for _, p := range permissions {
		perms = append(perms, []string{p.Resource, p.Action})
	}

	return s.casbinSvc.UpdatePermissionsForRole(ctx, roleName, perms)
}