//
// Copyright (c) 2008-2015 the Urho3D project.
// Copyright (c) 2015 Xamarin Inc
// Copyright (c) 2016 THUNDERBEAST GAMES LLC
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//

using System;
using AtomicEngine;

namespace FeatureExamples
{
    public class BillboardsSample : Sample
    {
        Scene scene;
        bool drawDebug;

        public BillboardsSample() : base() { }

        public override void Start()
        {
            base.Start();
            CreateScene();
            SimpleCreateInstructionsWithWasd("\nSpace to toggle debug geometry");
            SetupViewport();
            SubscribeToEvents();
        }

        void SubscribeToEvents()
        {
            SubscribeToEvent<PostRenderUpdateEvent>(e =>
            {
                // If draw debug mode is enabled, draw viewport debug geometry, which will show eg. drawable bounding boxes and skeleton
                // bones. Note that debug geometry has to be separately requested each frame. Disable depth test so that we can see the
                // bones properly
                if (drawDebug)
                    GetSubsystem<Renderer>().DrawDebugGeometry(false);
            });
        }

        protected override void Update(float timeStep)
        {
            SimpleMoveCamera3D(timeStep);
            AnimateScene(timeStep);
            if (GetSubsystem<Input>().GetKeyPress(Constants.KEY_SPACE))
                drawDebug = !drawDebug;
            base.Update(timeStep);
        }

        void AnimateScene(float timeStep)
        {


            var lightNodes = new Vector<Node>();
            var billboardNodes = new Vector<Node>();

            scene.GetChildrenWithComponent<Light>(lightNodes);
            scene.GetChildrenWithComponent<BillboardSet>(billboardNodes);

            const float lightRotationSpeed = 20.0f;
            const float billboardRotationSpeed = 50.0f;

            foreach (var lightNode in lightNodes)
            {
                lightNode.Rotate(new Quaternion(0f, lightRotationSpeed * timeStep, 0f), TransformSpace.TS_WORLD);
            }

            foreach (var billboardNode in billboardNodes)
            {
                var billboardSet = billboardNode.GetComponent<BillboardSet>();
                for (uint i = 0; i < billboardSet.NumBillboards; i++)
                {
                    var bb = billboardSet.GetBillboard(i);
                    bb.Rotation += billboardRotationSpeed * timeStep;
                }
                billboardSet.Commit();
            }
        }

        void SetupViewport()
        {
            var renderer = GetSubsystem<Renderer>();
            renderer.SetViewport(0, new Viewport(scene, CameraNode.GetComponent<Camera>()));
        }

        void CreateScene()
        {
            var cache = GetSubsystem<ResourceCache>();
            scene = new Scene();

            // Create octree, use default volume (-1000, -1000, -1000) to (1000, 1000, 1000)
            // Also create a DebugRenderer component so that we can draw debug geometry
            scene.CreateComponent<Octree>();
            scene.CreateComponent<DebugRenderer>();

            var zoneNode = scene.CreateChild("Zone");
            Zone zone = zoneNode.CreateComponent<Zone>();
            zone.SetBoundingBox(new BoundingBox(-1000.0f, 1000.0f));
            zone.AmbientColor = new Color(0.1f, 0.1f, 0.1f);
            zone.FogStart = 100.0f;
            zone.FogEnd = 300.0f;

            var lightNode = scene.CreateChild("DirectionalLight");
            lightNode.SetDirection(new Vector3(0.5f, -1.0f, 0.5f));
            var light = lightNode.CreateComponent<Light>();
            light.LightType = LightType.LIGHT_DIRECTIONAL;
            light.Color = new Color(0.2f, 0.2f, 0.2f);
            light.SpecularIntensity = 1.0f;

            for (int y = -5; y <= 5; ++y)
            {
                for (int x = -5; x <= 5; ++x)
                {
                    var floorNode = scene.CreateChild("FloorTile");
                    floorNode.Position = new Vector3(x * 20.5f, -0.5f, y * 20.5f);
                    floorNode.Scale = new Vector3(20.0f, 1.0f, 20.0f);
                    var floorObject = floorNode.CreateComponent<StaticModel>();
                    floorObject.Model = cache.Get<Model>("Models/Box.mdl");
                    floorObject.SetMaterial(cache.Get<Material>("Materials/Stone.xml"));
                }
            }

            // Create groups of mushrooms, which act as shadow casters
            const uint numMushroomgroups = 25;
            const uint numMushrooms = 25;

            for (uint i = 0; i < numMushroomgroups; ++i)
            {
                var groupNode = scene.CreateChild("MushroomGroup");
                groupNode.Position = new Vector3(NextRandom(190.0f) - 95.0f, 0.0f, NextRandom(190.0f) - 95.0f);

                for (uint j = 0; j < numMushrooms; ++j)
                {
                    var mushroomNode = groupNode.CreateChild("Mushroom");
                    mushroomNode.Position = new Vector3(NextRandom(25.0f) - 12.5f, 0.0f, NextRandom(25.0f) - 12.5f);
                    mushroomNode.Rotation = new Quaternion(0.0f, NextRandom() * 360.0f, 0.0f);
                    mushroomNode.SetScale(1.0f + NextRandom() * 4.0f);
                    var mushroomObject = mushroomNode.CreateComponent<StaticModel>();
                    mushroomObject.Model = cache.Get<Model>("Models/Mushroom.mdl");
                    mushroomObject.SetMaterial(cache.Get<Material>("Materials/Mushroom.xml"));
                    mushroomObject.CastShadows = true;
                }
            }

            // Create billboard sets (floating smoke)
            const uint numBillboardnodes = 25;
            const uint numBillboards = 10;

            for (uint i = 0; i < numBillboardnodes; ++i)
            {
                var smokeNode = scene.CreateChild("Smoke");
                smokeNode.Position = new Vector3(NextRandom(200.0f) - 100.0f, NextRandom(20.0f) + 10.0f, NextRandom(200.0f) - 100.0f);

                var billboardObject = smokeNode.CreateComponent<BillboardSet>();
                billboardObject.NumBillboards = numBillboards;
                billboardObject.Material = cache.Get<Material>("Materials/LitSmoke.xml");
                billboardObject.Sorted = true;

                for (uint j = 0; j < numBillboards; ++j)
                {
                    var bb = billboardObject.GetBillboard(j);
                    bb.Position = new Vector3(NextRandom(12.0f) - 6.0f, NextRandom(8.0f) - 4.0f, NextRandom(12.0f) - 6.0f);
                    bb.Size = new Vector2(NextRandom(2.0f) + 3.0f, NextRandom(2.0f) + 3.0f);
                    bb.Rotation = NextRandom() * 360.0f;
                    bb.Enabled = true;
                }

                // After modifying the billboards, they need to be "commited" so that the BillboardSet updates its internals
                billboardObject.Commit();
            }

            // Create shadow casting spotlights
            const uint numLights = 9;

            for (uint i = 0; i < numLights; ++i)
            {
                lightNode = scene.CreateChild("SpotLight");
                light = lightNode.CreateComponent<Light>();

                float angle = 0.0f;

                Vector3 position = new Vector3((i % 3) * 60.0f - 60.0f, 45.0f, (i / 3) * 60.0f - 60.0f);
                Color color = new Color(((i + 1) & 1) * 0.5f + 0.5f, (((i + 1) >> 1) & 1) * 0.5f + 0.5f, (((i + 1) >> 2) & 1) * 0.5f + 0.5f);

                lightNode.Position = position;
                lightNode.SetDirection(new Vector3((float)Math.Sin(angle), -1.5f, (float)Math.Cos(angle)));

                light.LightType = LightType.LIGHT_SPOT;
                light.Range = 90.0f;
                light.RampTexture = cache.Get<Texture2D>("Textures/RampExtreme.png");
                light.Fov = 45.0f;
                light.Color = color;
                light.SpecularIntensity = 1.0f;
                light.CastShadows = true;
                light.ShadowBias = new BiasParameters(0.00002f, 0.0f);

                // Configure shadow fading for the lights. When they are far away enough, the lights eventually become unshadowed for
                // better GPU performance. Note that we could also set the maximum distance for each object to cast shadows
                light.ShadowFadeDistance = 100.0f; // Fade start distance
                light.ShadowDistance = 125.0f; // Fade end distance, shadows are disabled
                                               // Set half resolution for the shadow maps for increased performance
                light.ShadowResolution = 0.5f;
                // The spot lights will not have anything near them, so move the near plane of the shadow camera farther
                // for better shadow depth resolution
                light.ShadowNearFarRatio = 0.01f;
            }

            // Create the camera. Limit far clip distance to match the fog
            CameraNode = scene.CreateChild("Camera");
            var camera = CameraNode.CreateComponent<Camera>();
            camera.FarClip = 300.0f;
            // Set an initial position for the camera scene node above the plane
            CameraNode.Position = new Vector3(0.0f, 5.0f, 0.0f);
        }
        
    }
}