/*
 * Copyright (c) Contributors to the Open 3D Engine Project.
 * For complete copyright and license terms please see the LICENSE at the root of this distribution.
 *
 * SPDX-License-Identifier: Apache-2.0 OR MIT
 *
 */

#pragma once

#include <AzCore/Component/EntityId.h>
#include <AzCore/EBus/EBus.h>
#include <AzCore/IO/Path/Path.h>
#include <AzCore/Math/Vector3.h>
#include <AzCore/Outcome/Outcome.h>
#include <AzCore/std/containers/vector.h>
#include <AzCore/std/string/string.h>
#include <AzCore/std/string/string_view.h>

namespace AzToolsFramework
{
    using EntityIdList = AZStd::vector<AZ::EntityId>;

    namespace Prefab
    {
        using CreatePrefabResult = AZ::Outcome<AZ::EntityId, AZStd::string>;
        using InstantiatePrefabResult = AZ::Outcome<AZ::EntityId, AZStd::string>;
        using DuplicatePrefabResult = AZ::Outcome<EntityIdList, AZStd::string>;
        using PrefabOperationResult = AZ::Outcome<void, AZStd::string>;

        /**
        * The primary purpose of this bus is to facilitate writing automated tests for prefabs.
        * It calls PrefabPublicInterface internally to talk to the prefab system.
        * If you would like to integrate prefabs into your system, please call PrefabPublicInterface
        * directly for better performance.
        */
        class PrefabPublicRequests
            : public AZ::EBusTraits
        {
        public:
            using Bus = AZ::EBus<PrefabPublicRequests>;

            //////////////////////////////////////////////////////////////////////////
            // EBusTraits overrides
            static const AZ::EBusHandlerPolicy HandlerPolicy = AZ::EBusHandlerPolicy::Single;
            //////////////////////////////////////////////////////////////////////////

            virtual ~PrefabPublicRequests() = default;

            /**
             * Create a prefab out of the entities provided, at the path provided, and keep it in memory.
             * Automatically detects descendants of entities, and discerns between entities and child instances.
             * Return an outcome object with an container entity id of the prefab created if creation succeeded;
             * on failure, it comes with an error message detailing the cause of the error.
             */
            virtual CreatePrefabResult CreatePrefabInMemory(
                const EntityIdList& entityIds, AZStd::string_view filePath) = 0;

            /**
             * Instantiate a prefab from a prefab file.
             * Return an outcome object with an container entity id of the prefab instantiated if instantiation succeeded; 
             * on failure, it comes with an error message detailing the cause of the error.
             */
            virtual InstantiatePrefabResult InstantiatePrefab(
                AZStd::string_view filePath, AZ::EntityId parent, const AZ::Vector3& position) = 0;

            /**
             * Deletes all entities and their descendants from the owning instance. Bails if the entities don't
             * all belong to the same instance.
             * Return an outcome object; on failure, it comes with an error message detailing the cause of the error.
             */
            virtual PrefabOperationResult DeleteEntitiesAndAllDescendantsInInstance(const EntityIdList& entityIds) = 0;

            /**
              * If the entity id is a container entity id, detaches the prefab instance corresponding to it. This includes converting
              * the container entity into a regular entity and putting it under the parent prefab, removing the link between this
              * instance and the parent, removing links between this instance and its nested instances, and adding entities directly
              * owned by this instance under the parent instance.
              * Bails if the entity is not a container entity or belongs to the level prefab instance.
              * Return an outcome object; on failure, it comes with an error message detailing the cause of the error.
              */
            virtual PrefabOperationResult DetachPrefab(const AZ::EntityId& containerEntityId) = 0;

            /**
              * Duplicates all entities in the owning instance. Bails if the entities don't all belong to the same instance.
              * Return an outcome object with a list of ids of given entities' duplicates if duplication succeeded;
              * on failure, it comes with an error message detailing the cause of the error.
              */
            virtual DuplicatePrefabResult DuplicateEntitiesInInstance(const EntityIdList& entityIds) = 0;

            /**
             * Get the file path to the prefab file for the prefab instance owning the entity provided.
             * Returns the path to the prefab, or an empty path if the entity is owned by the level.
             */
            virtual AZStd::string GetOwningInstancePrefabPath(AZ::EntityId entityId) const = 0;
        };

        using PrefabPublicRequestBus = AZ::EBus<PrefabPublicRequests>;

    } // namespace Prefab
} // namespace AzToolsFramework