//
// Spine Runtimes License Agreement
// Last updated April 5, 2025. Replaces all prior versions.
//
// Copyright (c) 2013-2025, Esoteric Software LLC
//
// Integration of the Spine Runtimes into software or otherwise creating
// derivative works of the Spine Runtimes is permitted under the terms and
// conditions of Section 2 of the Spine Editor License Agreement:
// http://esotericsoftware.com/spine-editor-license
//
// Otherwise, it is permitted to integrate the Spine Runtimes into software
// or otherwise create derivative works of the Spine Runtimes (collectively,
// "Products"), provided that each user of the Products must obtain their own
// Spine Editor license and redistribution of the Products in any form must
// include this license and copyright notice.
//
// THE SPINE RUNTIMES ARE PROVIDED BY ESOTERIC SOFTWARE LLC "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL ESOTERIC SOFTWARE LLC BE LIABLE FOR ANY
// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES,
// BUSINESS INTERRUPTION, OR LOSS OF USE, DATA, OR PROFITS) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
// THE SPINE RUNTIMES, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//

import 'package:spine_flutter/spine_flutter.dart';
import 'package:flutter/material.dart';

class IkFollowing extends StatefulWidget {
  const IkFollowing({super.key});

  @override
  IkFollowingState createState() => IkFollowingState();
}

class IkFollowingState extends State<IkFollowing> {
  late SpineWidgetController controller;
  Offset? crossHairPosition;

  @override
  void initState() {
    super.initState();

    controller = SpineWidgetController(
      onInitialized: (controller) {
        // Set the walk animation on track 0, let it loop
        controller.animationState.setAnimation(0, "walk", true);
        controller.animationState.setAnimation(1, "aim", true);
      },
      onAfterUpdateWorldTransforms: (controller) {
        final worldPosition = crossHairPosition;
        if (worldPosition == null) return;
        final bone = controller.skeleton.findBone("crosshair")!;
        final parent = bone.parent;
        if (parent != null) {
          final position = parent.appliedPose.worldToLocal(worldPosition.dx, worldPosition.dy);
          bone.appliedPose.x = position.x;
          bone.appliedPose.y = position.y;
        }
      },
    );
  }

  void _updateBonePosition(Offset position) {
    crossHairPosition = controller.toSkeletonCoordinates(position);
  }

  @override
  Widget build(BuildContext context) {
    reportLeaks();

    return Scaffold(
      appBar: AppBar(title: const Text('IK Following')),
      body: GestureDetector(
        onPanDown: (drag) => _updateBonePosition(drag.localPosition),
        onPanUpdate: (drag) => _updateBonePosition(drag.localPosition),
        child: SpineWidget.fromAsset(
          "assets/spineboy.atlas",
          "assets/spineboy-pro.skel",
          controller,
          alignment: Alignment.centerLeft,
        ),
      ),
    );
  }
}