/*
Copyright (c) 2019-2020 Timur Gafarov

Boost Software License - Version 1.0 - August 17th, 2003
Permission is hereby granted, free of charge, to any person or organization
obtaining a copy of the software and accompanying documentation covered by
this license (the "Software") to use, reproduce, display, distribute,
execute, and transmit the Software, and to prepare derivative works of the
Software, and to permit third-parties to whom the Software is furnished to
do so, all subject to the following:

The copyright notices in the Software and this entire statement, including
the above license grant, this restriction and the following disclaimer,
must be included in all copies of the Software, in whole or in part, and
all derivative works of the Software, unless such copies or derivative
works are solely in the form of machine-executable object code generated by
a source language processor.

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, TITLE AND NON-INFRINGEMENT. IN NO EVENT
SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.
*/

module dagon.ext.newton.character;

import std.math;
import dlib.core.ownership;
import dlib.core.memory;
import dlib.math.vector;
import dlib.math.matrix;
import dlib.math.transformation;
import dlib.math.quaternion;
import dagon.core.event;
import dagon.core.time;
import dagon.graphics.entity;

import bindbc.newton;
import dagon.ext.newton.world;
import dagon.ext.newton.shape;
import dagon.ext.newton.rigidbody;

class NewtonCharacterComponent: EntityComponent
{
    NewtonSphereShape lowerShape;
    NewtonSphereShape upperShape;
    NewtonCompoundShape shape;
    NewtonRigidBody rbody;
    NewtonRigidBody sensorBody;
    float height;
    float mass;
    bool onGround = false;
    Vector3f targetVelocity = Vector3f(0.0f, 0.0f, 0.0f);
    Matrix4x4f prevTransformation;
    float radius;
    float shapeRadius;
    float eyeHeight;
    
    this(NewtonPhysicsWorld world, Entity e, float height, float mass)
    {
        super(world.eventManager, e);
        this.height = height;
        this.mass = mass;
        radius = height * 0.5f;
        shapeRadius = radius * 0.5f;
        eyeHeight = height * 0.5f;
        lowerShape = New!NewtonSphereShape(shapeRadius, world);
        lowerShape.setTransformation(translationMatrix(Vector3f(0.0f, -shapeRadius, 0.0f)));
        upperShape = New!NewtonSphereShape(shapeRadius, world);
        upperShape.setTransformation(translationMatrix(Vector3f(0.0f, shapeRadius, 0.0f)));
        NewtonCollisionShape[2] shapes = [lowerShape, upperShape];
        shape = New!NewtonCompoundShape(shapes, world);
        
        rbody = world.createDynamicBody(shape, mass);
        rbody.groupId = world.kinematicGroupId;
        rbody.raycastable = false;
        rbody.enableRotation = false;
        
        Quaternionf rot = e.rotation;
        rbody.transformation =
            translationMatrix(e.position) *
            rot.toMatrix4x4;
        NewtonBodySetMatrix(rbody.newtonBody, rbody.transformation.arrayof.ptr);
        prevTransformation = Matrix4x4f.identity;
        
        rbody.createUpVectorConstraint(Vector3f(0.0f, 1.0f, 0.0f));
        rbody.gravity = Vector3f(0.0f, -20.0f, 0.0f);
        
        Vector3f sensorSize = Vector3f(radius, radius * 0.5f, radius);
        auto sensorShape = New!NewtonBoxShape(sensorSize, world);
        sensorBody = world.createDynamicBody(sensorShape, 1.0f);
        sensorBody.groupId = world.sensorGroupId;
        sensorBody.sensor = true;
        sensorBody.collisionCallback = &onSensorCollision;
    }
    
    void onSensorCollision(NewtonRigidBody sensorBody, NewtonRigidBody otherBody)
    {
        onGround = true;
    }
    
    void updateVelocity()
    {
        Vector3f velocityChange = targetVelocity - rbody.velocity;
        velocityChange.y = 0.0f;
        rbody.velocity = rbody.velocity + velocityChange;

        onGround = false;
        auto m = rbody.transformation * translationMatrix(Vector3f(0.0f, -radius, 0.0f));
        NewtonBodySetMatrix(sensorBody.newtonBody, m.arrayof.ptr);

        targetVelocity = Vector3f(0.0f, 0.0f, 0.0f);
    }
    
    override void update(Time t)
    {
        rbody.update(t.delta);

        entity.prevTransformation = prevTransformation;

        entity.position = rbody.position.xyz;
        entity.transformation = rbody.transformation * scaleMatrix(entity.scaling);
        entity.invTransformation = entity.transformation.inverse;
        entity.rotation = rbody.rotation;

        entity.absoluteTransformation = entity.transformation;
        entity.invAbsoluteTransformation = entity.invTransformation;
        entity.prevAbsoluteTransformation = entity.prevTransformation;

        prevTransformation = entity.transformation;
    }
    
    void move(Vector3f direction, float speed)
    {
        targetVelocity += direction * speed;
    }
    
    void jump(float height)
    {
        if (onGround)
        {
            float jumpSpeed = sqrt(2.0f * height * -rbody.gravity.y);
            Vector3f v = rbody.velocity;
            v.y = jumpSpeed;
            rbody.velocity = v;
            onGround = false;
        }
    }
    
    void duck()
    {
        // TODO
        //eyeHeight = 0.0f;
    }
    
    void unduck()
    {
        // TODO
        //eyeHeight = height * 0.5f;
    }
    
    Vector3f position()
    {
        return rbody.position.xyz;
    }
    
    Vector3f eyePoint()
    {
        return rbody.position.xyz + Vector3f(0.0f, eyeHeight, 0.0f);
    }
}

NewtonCharacterComponent makeCharacter(Entity entity, NewtonPhysicsWorld world, float height, float mass)
{
    return New!NewtonCharacterComponent(world, entity, height, mass);
}