package electrosphere.renderer.pipelines;

import org.joml.Matrix4d;
import org.joml.Matrix4f;
import org.joml.Vector3d;
import org.joml.Vector3f;
import org.lwjgl.opengl.GL40;

import electrosphere.engine.Globals;
import electrosphere.entity.Entity;
import electrosphere.entity.EntityDataStrings;
import electrosphere.entity.EntityTags;
import electrosphere.entity.EntityUtils;
import electrosphere.entity.types.camera.CameraEntityUtils;
import electrosphere.renderer.OpenGLState;
import electrosphere.renderer.RenderPipelineState;
import electrosphere.renderer.RenderingEngine;
import electrosphere.renderer.actor.Actor;

/**
 * Shadow map pipeline
 */
public class ShadowMapPipeline implements RenderPipeline {

    @Override
    public void render(OpenGLState openGLState, RenderPipelineState renderPipelineState) {
        Globals.profiler.beginCpuSample("ShadowMapPipeline.render");
        Matrix4d modelTransformMatrix = new Matrix4d();
        
        //set the viewport to shadow map size
        openGLState.glViewport(4096, 4096);
        openGLState.glDepthTest(true);
        openGLState.glDepthFunc(GL40.GL_ALWAYS);
        
        openGLState.setActiveShader(renderPipelineState, RenderingEngine.lightDepthShaderProgram);
        
        RenderingEngine.lightDepthBuffer.bind(openGLState);
        GL40.glClear(GL40.GL_DEPTH_BUFFER_BIT);
        openGLState.glActiveTexture(GL40.GL_TEXTURE0);

        float eyeX = -1.0f;
        float eyeY = 10.0f;
        float eyeZ = -5.5f;
        float nearPlane = 0.01f;
        float eyeDist = (float)Math.sqrt(eyeX * eyeX + eyeY * eyeY + eyeZ * eyeZ);
        float farPlane = eyeDist + 10.0f;
        float sidesMagnitude = (float)Math.sqrt(eyeDist);
        //set matrices for light render
        Matrix4f lightProjection = new Matrix4f().setOrtho(-sidesMagnitude, sidesMagnitude, -sidesMagnitude, sidesMagnitude, nearPlane, farPlane);//glm::ortho(-10.0f, 10.0f, -10.0f, 10.0f, near_plane, far_plane); 
        Matrix4f lightView = new Matrix4f().setLookAt(
                new Vector3f(eyeX, eyeY, eyeZ),
                new Vector3f( 0.0f, 0.0f,  0.0f),
                new Vector3f( 0.0f, 1.0f,  0.0f)
        );
        Globals.lightDepthMatrix = new Matrix4f(lightProjection).mul(lightView);

        GL40.glUniformMatrix4fv(GL40.glGetUniformLocation(openGLState.getActiveShader().getShaderId(), "lightSpaceMatrix"), false, Globals.lightDepthMatrix.get(new float[16]));

    //    glCullFace(GL_FRONT);

        //
        // Set render pipeline state
        //
        renderPipelineState.setUseMeshShader(false);
        renderPipelineState.setBufferStandardUniforms(true);
        renderPipelineState.setBufferNonStandardUniforms(true);
        renderPipelineState.setUseMaterial(false);
        renderPipelineState.setUseShadowMap(false);
        renderPipelineState.setUseBones(true);
        renderPipelineState.setUseLight(false);

        //
        //     D R A W     A L L     E N T I T I E S
        //
        modelTransformMatrix = new Matrix4d();
        for(Entity currentEntity : Globals.clientScene.getEntitiesWithTag(EntityTags.DRAWABLE)){
            Vector3d position = EntityUtils.getPosition(currentEntity);
            if(
                    currentEntity.getData(EntityDataStrings.DATA_STRING_DRAW)!=null && 
                    currentEntity.containsKey(EntityDataStrings.DRAW_CAST_SHADOW)
                    ){
                //fetch actor
                Actor currentActor = EntityUtils.getActor(currentEntity);
                //calculate camera-modified vector3f
                Vector3f cameraCenter = CameraEntityUtils.getCameraCenter(Globals.playerCamera);
                Vector3f cameraModifiedPosition = new Vector3f((float)position.x,(float)position.y,(float)position.z).sub(cameraCenter);
                //calculate and apply model transform
                modelTransformMatrix = modelTransformMatrix.identity();
                modelTransformMatrix.translate(cameraModifiedPosition);
                modelTransformMatrix.rotate(EntityUtils.getRotation(currentEntity));
                modelTransformMatrix.scale(new Vector3d(EntityUtils.getScale(currentEntity)));
                currentActor.applySpatialData(modelTransformMatrix,position);
                //draw
                currentActor.draw(renderPipelineState,openGLState);
            }
        }


        
        //reset texture
        openGLState.glActiveTexture(GL40.GL_TEXTURE0);
        openGLState.glBindTexture(GL40.GL_TEXTURE_2D, 0);
        //bind default framebuffer
        openGLState.glBindFramebuffer(GL40.GL_FRAMEBUFFER,0);
        //reset the viewport to screen size
        openGLState.glViewport(Globals.WINDOW_WIDTH, Globals.WINDOW_HEIGHT);
        //resume culling backface
//        glCullFace(GL_BACK);

        Globals.profiler.endCpuSample();
    }
    
}