package usecase

import (
	"context"
	"permission/reborn/domain/entity"
	"permission/reborn/domain/errors"
	"permission/reborn/domain/repository"
	"permission/reborn/domain/usecase"
	"time"
)

type userRoleUseCase struct {
	userRoleRepo repository.UserRoleRepository
	roleRepo     repository.RoleRepository
	cache        repository.CacheRepository
}

// NewUserRoleUseCase 建立使用者角色 UseCase
func NewUserRoleUseCase(
	userRoleRepo repository.UserRoleRepository,
	roleRepo repository.RoleRepository,
	cache repository.CacheRepository,
) usecase.UserRoleUseCase {
	return &userRoleUseCase{
		userRoleRepo: userRoleRepo,
		roleRepo:     roleRepo,
		cache:        cache,
	}
}

func (uc *userRoleUseCase) Assign(ctx context.Context, req usecase.AssignRoleRequest) (*usecase.UserRoleResponse, error) {
	// 檢查角色是否存在
	role, err := uc.roleRepo.GetByUID(ctx, req.RoleUID)
	if err != nil {
		return nil, err
	}

	if !role.IsActive() {
		return nil, errors.Wrap(errors.ErrCodeInvalidInput, "role is not active", nil)
	}

	// 檢查使用者是否已有角色
	exists, err := uc.userRoleRepo.Exists(ctx, req.UserUID)
	if err != nil {
		return nil, err
	}

	if exists {
		return nil, errors.ErrUserRoleAlreadyExists
	}

	// 建立使用者角色
	userRole := &entity.UserRole{
		UID:    req.UserUID,
		RoleID: req.RoleUID,
		Brand:  req.Brand,
		Status: entity.StatusActive,
	}

	if err := uc.userRoleRepo.Create(ctx, userRole); err != nil {
		return nil, err
	}

	return uc.toResponse(userRole), nil
}

func (uc *userRoleUseCase) Update(ctx context.Context, userUID, roleUID string) (*usecase.UserRoleResponse, error) {
	// 檢查角色是否存在
	role, err := uc.roleRepo.GetByUID(ctx, roleUID)
	if err != nil {
		return nil, err
	}

	if !role.IsActive() {
		return nil, errors.Wrap(errors.ErrCodeInvalidInput, "role is not active", nil)
	}

	// 更新使用者角色
	userRole, err := uc.userRoleRepo.Update(ctx, userUID, roleUID)
	if err != nil {
		return nil, err
	}

	// 清除使用者權限快取
	if uc.cache != nil {
		_ = uc.cache.Delete(ctx, repository.CacheKeyUserPermission(userUID))
	}

	return uc.toResponse(userRole), nil
}

func (uc *userRoleUseCase) Remove(ctx context.Context, userUID string) error {
	if err := uc.userRoleRepo.Delete(ctx, userUID); err != nil {
		return err
	}

	// 清除使用者權限快取
	if uc.cache != nil {
		_ = uc.cache.Delete(ctx, repository.CacheKeyUserPermission(userUID))
	}

	return nil
}

func (uc *userRoleUseCase) Get(ctx context.Context, userUID string) (*usecase.UserRoleResponse, error) {
	userRole, err := uc.userRoleRepo.Get(ctx, userUID)
	if err != nil {
		return nil, err
	}

	return uc.toResponse(userRole), nil
}

func (uc *userRoleUseCase) GetByRole(ctx context.Context, roleUID string) ([]*usecase.UserRoleResponse, error) {
	// 檢查角色是否存在
	if _, err := uc.roleRepo.GetByUID(ctx, roleUID); err != nil {
		return nil, err
	}

	userRoles, err := uc.userRoleRepo.GetByRoleID(ctx, roleUID)
	if err != nil {
		return nil, err
	}

	result := make([]*usecase.UserRoleResponse, 0, len(userRoles))
	for _, ur := range userRoles {
		result = append(result, uc.toResponse(ur))
	}

	return result, nil
}

func (uc *userRoleUseCase) List(ctx context.Context, filter usecase.UserRoleFilterRequest) ([]*usecase.UserRoleResponse, error) {
	repoFilter := repository.UserRoleFilter{
		Brand:  filter.Brand,
		RoleID: filter.RoleID,
		Status: filter.Status,
	}

	userRoles, err := uc.userRoleRepo.List(ctx, repoFilter)
	if err != nil {
		return nil, err
	}

	result := make([]*usecase.UserRoleResponse, 0, len(userRoles))
	for _, ur := range userRoles {
		result = append(result, uc.toResponse(ur))
	}

	return result, nil
}

func (uc *userRoleUseCase) toResponse(userRole *entity.UserRole) *usecase.UserRoleResponse {
	return &usecase.UserRoleResponse{
		UserUID:    userRole.UID,
		RoleUID:    userRole.RoleID,
		Brand:      userRole.Brand,
		CreateTime: userRole.CreateTime.UTC().Format(time.RFC3339),
		UpdateTime: userRole.UpdateTime.UTC().Format(time.RFC3339),
	}
}