/*
 * Copyright (c) 2009 Sun Microsystems, Inc. All Rights Reserved.
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 * modification, are permitted provided that the following conditions are
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 * - Redistribution of source code must retain the above copyright
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 *   documentation and/or other materials provided with the distribution.
 * 
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 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any kind. ALL
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 * INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
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package com.jogamp.opengl.util.glsl;

import java.io.PrintStream;
import java.nio.*;
import java.util.*;

import javax.media.opengl.*;

public class ShaderUtil {
    static abstract class Impl {
        public abstract String getShaderInfoLog(GL gl, int shaderObj);
        public abstract String getProgramInfoLog(GL gl, int programObj);
        public abstract boolean isShaderStatusValid(GL gl, int shaderObj, int name);
        public abstract boolean isShaderStatusValid(GL gl, int shaderObj, int name, PrintStream verboseOut);
        public abstract boolean isShaderStatusValid(GL gl, IntBuffer shaders, int name);
        public abstract boolean isShaderStatusValid(GL gl, IntBuffer shaders, int name, PrintStream verboseOut);
        public abstract boolean isProgramStatusValid(GL gl, int programObj, int name);
        public abstract boolean isProgramValid(GL gl, int programObj);
        public abstract boolean isProgramValid(GL gl, int programObj, PrintStream verboseOut);
        public abstract void createShader(GL gl, int type, IntBuffer shaders);
        public abstract Set<Integer> getShaderBinaryFormats(GL gl);
        public abstract boolean isShaderCompilerAvailable(GL gl);
        public abstract void shaderSource(GL gl, int shader, java.lang.String[] source);
        public abstract void shaderSource(GL gl, IntBuffer shaders, java.lang.String[][] sources);
        public abstract void shaderBinary(GL gl, IntBuffer shaders, int binFormat, java.nio.Buffer bin);
        public abstract void compileShader(GL gl, IntBuffer shaders);
        public abstract void attachShader(GL gl, int program, IntBuffer shaders);
        public abstract void detachShader(GL gl, int program, IntBuffer shaders);
        public abstract void deleteShader(GL gl, IntBuffer shaders);

        public abstract boolean createAndLoadShader(GL gl, IntBuffer shader, int shaderType,
                                                    int binFormat, java.nio.Buffer bin,
                                                    PrintStream verboseOut);

        public abstract boolean createAndCompileShader(GL gl, IntBuffer shader, int shaderType,
                                                       java.lang.String[][] sources, 
                                                       PrintStream verboseOut);
    }

    static class GL2ES2Impl extends Impl {
        public String getShaderInfoLog(GL _gl, int shaderObj) {
            GL2ES2 gl = _gl.getGL2ES2();
            int[] infoLogLength=new int[1];
            gl.glGetShaderiv(shaderObj, GL2ES2.GL_INFO_LOG_LENGTH, infoLogLength, 0);

            if(infoLogLength[0]==0) {
                return "(no info log)";
            }
            int[] charsWritten=new int[1];
            byte[] infoLogBytes = new byte[infoLogLength[0]];
            gl.glGetShaderInfoLog(shaderObj, infoLogLength[0], charsWritten, 0, infoLogBytes, 0);

            return new String(infoLogBytes, 0, charsWritten[0]);
        }

        public String getProgramInfoLog(GL _gl, int programObj) {
            GL2ES2 gl = _gl.getGL2ES2();
            int[] infoLogLength=new int[1];
            gl.glGetProgramiv(programObj, GL2ES2.GL_INFO_LOG_LENGTH, infoLogLength, 0);

            if(infoLogLength[0]==0) {
                return "(no info log)";
            }
            int[] charsWritten=new int[1];
            byte[] infoLogBytes = new byte[infoLogLength[0]];
            gl.glGetProgramInfoLog(programObj, infoLogLength[0], charsWritten, 0, infoLogBytes, 0);

            return new String(infoLogBytes, 0, charsWritten[0]);
        }

        public boolean isShaderStatusValid(GL _gl, int shaderObj, int name) {
            return isShaderStatusValid(_gl, shaderObj, name, null);
        }

        public boolean isShaderStatusValid(GL _gl, int shaderObj, int name, PrintStream verboseOut) {
            GL2ES2 gl = _gl.getGL2ES2();
            int[] ires = new int[1];
            gl.glGetShaderiv(shaderObj, name, ires, 0);

            boolean res = ires[0]==1;
            if(!res && null!=verboseOut) {
                verboseOut.println("Shader status invalid: "+ getShaderInfoLog(gl, shaderObj));
            }
            return res;
        }

        public boolean isShaderStatusValid(GL _gl, IntBuffer shaders, int name) {
            return isShaderStatusValid(_gl, shaders, name, null);
        }

        public boolean isShaderStatusValid(GL _gl, IntBuffer shaders, int name, PrintStream verboseOut) {
            boolean res = true;
            for (int i = shaders.position(); i < shaders.limit(); i++) {
                res = isShaderStatusValid(_gl, shaders.get(i), name, verboseOut) && res;
            }
            return res;
        }

        public boolean isProgramStatusValid(GL _gl, int programObj, int name) {
            GL2ES2 gl = _gl.getGL2ES2();
            int[] ires = new int[1];
            gl.glGetProgramiv(programObj, name, ires, 0);

            return ires[0]==1;
        }

        public boolean isProgramValid(GL _gl, int programObj) {
            return isProgramValid(_gl, programObj, null);
        }

        public boolean isProgramValid(GL _gl, int programObj, PrintStream verboseOut) {
            GL2ES2 gl = _gl.getGL2ES2();
            if(!gl.glIsProgram(programObj)) {
                if(null!=verboseOut) {
                    verboseOut.println("Program name invalid: "+programObj);
                }
                return false;
            }
            if(!isProgramStatusValid(gl, programObj, GL2ES2.GL_LINK_STATUS)) {
                if(null!=verboseOut) {
                    verboseOut.println("Program link failed: "+programObj+"\n\t"+ getProgramInfoLog(gl, programObj));
                }
                return false;
            }
            if ( !gl.isGLES2() || isShaderCompilerAvailable(gl) ) {
                // failed on APX2500 (ES2.0, no compiler) for valid programs
                gl.glValidateProgram(programObj);
                if(!isProgramStatusValid(gl, programObj, GL2ES2.GL_VALIDATE_STATUS)) {
                    if(null!=verboseOut) {
                        verboseOut.println("Program validation failed: "+programObj+"\n\t"+ getProgramInfoLog(gl, programObj));
                    }
                    return false;
                }
            }
            return true;
        }

        public void createShader(GL _gl, int type, IntBuffer shaders) {
            GL2ES2 gl = _gl.getGL2ES2();
            for (int i = shaders.position(); i < shaders.limit(); i++) {
                shaders.put(i, gl.glCreateShader(type));
            }
        }

        private Boolean shaderCompilerAvailable = null;
        private Set<Integer> shaderBinaryFormats = null;

        public Set<Integer> getShaderBinaryFormats(GL _gl) {
            GL2ES2 gl = _gl.getGL2ES2();
            if(null==shaderBinaryFormats) {
                gl.getContext().validateCurrent();

                int[] param = new int[1];
                shaderBinaryFormats = new HashSet<Integer>();

                if (gl.isGLES2()) {
                    gl.glGetIntegerv(GL2ES2.GL_NUM_SHADER_BINARY_FORMATS, param, 0);
                    int numFormats = param[0];
                    if(numFormats>0) {
                        int[] formats = new int[numFormats];
                        gl.glGetIntegerv(GL2ES2.GL_SHADER_BINARY_FORMATS, formats, 0);
                        for(int i=0; i<numFormats; i++) {
                            shaderBinaryFormats.add(new Integer(formats[i]));
                        }
                    }
                }
            }
            return shaderBinaryFormats;
        }


        public boolean isShaderCompilerAvailable(GL _gl) {
            GL2ES2 gl = _gl.getGL2ES2();
            if(null==shaderCompilerAvailable) {
                gl.getContext().validateCurrent();
                Set<Integer> bfs = getShaderBinaryFormats(gl);
                if(gl.isGLES2()) {
                    byte[] param = new byte[1];
                    gl.glGetBooleanv(GL2ES2.GL_SHADER_COMPILER, param, 0);
                    boolean v = param[0]!=(byte)0x00;
                    if(!v && bfs.size()==0) {
                        // no supported binary formats, hence a compiler must be available!
                        v = true;
                    }
                    shaderCompilerAvailable = new Boolean(v);
                } else if( gl.isGL2ES2() ) {
                    shaderCompilerAvailable = new Boolean(true);
                } else {
                    throw new GLException("Invalid OpenGL profile");
                }
            }
            return shaderCompilerAvailable.booleanValue();
        }

        public void shaderSource(GL _gl, int shader, java.lang.String[] source)
        {
            GL2ES2 gl = _gl.getGL2ES2();
            if(!isShaderCompilerAvailable(_gl)) {
                throw new GLException("No compiler is available");
            }

            int count = (null!=source)?source.length:0;
            if(count==0) {
                throw new GLException("No sources specified");
            }

            int[] lengths = new int[count];
            for(int i=0; i<count; i++) {
                lengths[i] = source[i].length();
            }
            gl.glShaderSource(shader, count, source, lengths, 0);
        }

        public void shaderSource(GL _gl, IntBuffer shaders, java.lang.String[][] sources)
        {
            int sourceNum = (null!=sources)?sources.length:0;
            int shaderNum = (null!=shaders)?shaders.remaining():0;
            if(shaderNum<=0 || sourceNum<=0 || shaderNum!=sourceNum) {
                throw new GLException("Invalid number of shaders and/or sources: shaders="+
                                      shaderNum+", sources="+sourceNum);
            }
            for(int i=0; i<sourceNum; i++) {
                shaderSource(_gl, shaders.get(shaders.position() + i), sources[i]);
            }
        }

        public void shaderBinary(GL _gl, IntBuffer shaders, int binFormat, java.nio.Buffer bin)
        {
            GL2ES2 gl = _gl.getGL2ES2();
            if(getShaderBinaryFormats(gl).size()<=0) {
                throw new GLException("No binary formats are supported");
            }

            int shaderNum = shaders.remaining();
            if(shaderNum<=0) {
                throw new GLException("No shaders specified");
            }
            if(null==bin) {
                throw new GLException("Null shader binary");
            }
            int binLength = bin.remaining();
            if(0>=binLength) {
                throw new GLException("Empty shader binary (remaining == 0)");
            }
            gl.glShaderBinary(shaderNum, shaders, binFormat, bin, binLength);
        }

        public void compileShader(GL _gl, IntBuffer shaders)
        {
            GL2ES2 gl = _gl.getGL2ES2();
            for (int i = shaders.position(); i < shaders.limit(); i++) {
                gl.glCompileShader(shaders.get(i));
            }
        }

        public void attachShader(GL _gl, int program, IntBuffer shaders)
        {
            GL2ES2 gl = _gl.getGL2ES2();
            for (int i = shaders.position(); i < shaders.limit(); i++) {
                gl.glAttachShader(program, shaders.get(i));
            }
        }

        public void detachShader(GL _gl, int program, IntBuffer shaders)
        {
            GL2ES2 gl = _gl.getGL2ES2();
            for (int i = shaders.position(); i < shaders.limit(); i++) {
                gl.glDetachShader(program, shaders.get(i));
            }
        }

        public void deleteShader(GL _gl, IntBuffer shaders)
        {
            GL2ES2 gl = _gl.getGL2ES2();
            for (int i = shaders.position(); i < shaders.limit(); i++) {
                gl.glDeleteShader(shaders.get(i));

            }
        }

        public boolean createAndLoadShader(GL _gl, IntBuffer shader, int shaderType,
                                           int binFormat, java.nio.Buffer bin,
                                           PrintStream verboseOut)
        {
            GL2ES2 gl = _gl.getGL2ES2();
            int err = gl.glGetError(); // flush previous errors ..
            if(err!=GL.GL_NO_ERROR && null!=verboseOut) {
                verboseOut.println("createAndLoadShader: Pre GL Error: 0x"+Integer.toHexString(err));
            }

            createShader(gl, shaderType, shader);
            err = gl.glGetError(); 
            if(err!=GL.GL_NO_ERROR) {
                throw new GLException("createAndLoadShader: CreateShader failed, GL Error: 0x"+Integer.toHexString(err));
            }


            shaderBinary(gl, shader, binFormat, bin);

            err = gl.glGetError();
            if(err!=GL.GL_NO_ERROR && null!=verboseOut) {
                verboseOut.println("createAndLoadShader: ShaderBinary failed, GL Error: 0x"+Integer.toHexString(err));
            }
            return err == GL.GL_NO_ERROR;
        }

        public boolean createAndCompileShader(GL _gl, IntBuffer shader, int shaderType,
                                              java.lang.String[][] sources, 
                                              PrintStream verboseOut)
        {
            GL2ES2 gl = _gl.getGL2ES2();
            int err = gl.glGetError(); // flush previous errors ..
            if(err!=GL.GL_NO_ERROR && null!=verboseOut) {
                verboseOut.println("createAndCompileShader: Pre GL Error: 0x"+Integer.toHexString(err));
            }

            createShader(gl, shaderType, shader);
            err = gl.glGetError(); 
            if(err!=GL.GL_NO_ERROR) {
                throw new GLException("createAndCompileShader: CreateShader failed, GL Error: 0x"+Integer.toHexString(err));
            }

            shaderSource(gl, shader, sources);
            err = gl.glGetError(); 
            if(err!=GL.GL_NO_ERROR) {
                throw new GLException("createAndCompileShader: ShaderSource failed, GL Error: 0x"+Integer.toHexString(err));
            }

            compileShader(gl, shader);
            err = gl.glGetError(); 
            if(err!=GL.GL_NO_ERROR && null!=verboseOut) {
                verboseOut.println("createAndCompileShader: CompileShader failed, GL Error: 0x"+Integer.toHexString(err));
            }

            return isShaderStatusValid(gl, shader, GL2ES2.GL_COMPILE_STATUS, verboseOut) && err == GL.GL_NO_ERROR;
        }

    }

    public static String getShaderInfoLog(GL gl, int shaderObj) {
        return getImpl(gl).getShaderInfoLog(gl, shaderObj);
    }

    public static String getProgramInfoLog(GL gl, int programObj) {
        return getImpl(gl).getProgramInfoLog(gl, programObj);
    }

    public static boolean isShaderStatusValid(GL gl, int shaderObj, int name) {
        return getImpl(gl).isShaderStatusValid(gl, shaderObj, name);
    }

    public static boolean isShaderStatusValid(GL gl, int shaderObj, int name, PrintStream verboseOut) {
        return getImpl(gl).isShaderStatusValid(gl, shaderObj, name, verboseOut);
    }

    public static boolean isShaderStatusValid(GL gl, IntBuffer shaders, int name) {
        return getImpl(gl).isShaderStatusValid(gl, shaders, name);
    }

    public static boolean isShaderStatusValid(GL gl, IntBuffer shaders, int name, PrintStream verboseOut) {
        return getImpl(gl).isShaderStatusValid(gl, shaders, name, verboseOut);
    }

    public static boolean isProgramStatusValid(GL gl, int programObj, int name) {
        return getImpl(gl).isProgramStatusValid(gl, programObj, name);
    }

    public static boolean isProgramValid(GL gl, int programObj) {
        return getImpl(gl).isProgramValid(gl, programObj);
    }

    public static boolean isProgramValid(GL gl, int programObj, PrintStream verboseOut) {
        return getImpl(gl).isProgramValid(gl, programObj, verboseOut);
    }

    public static void createShader(GL gl, int type, IntBuffer shaders) {
        getImpl(gl).createShader(gl, type, shaders);
    }

    public static Set<Integer> getShaderBinaryFormats(GL gl) {
        return getImpl(gl).getShaderBinaryFormats(gl);
    }

    public static boolean isShaderCompilerAvailable(GL gl) {
        return getImpl(gl).isShaderCompilerAvailable(gl);
    }

    public static void shaderSource(GL gl, int shader, java.lang.String[] source) {
        getImpl(gl).shaderSource(gl, shader, source);
    }

    public static void shaderSource(GL gl, IntBuffer shaders, java.lang.String[][] sources) {
        getImpl(gl).shaderSource(gl, shaders, sources);
    }

    public static void shaderBinary(GL gl, IntBuffer shaders, int binFormat, java.nio.Buffer bin) {
        getImpl(gl).shaderBinary(gl, shaders, binFormat, bin);
    }

    public static void compileShader(GL gl, IntBuffer shaders) {
        getImpl(gl).compileShader(gl, shaders);
    }

    public static void attachShader(GL gl, int program, IntBuffer shaders) {
        getImpl(gl).attachShader(gl, program, shaders);
    }

    public static void detachShader(GL gl, int program, IntBuffer shaders) {
        getImpl(gl).detachShader(gl, program, shaders);
    }

    public static void deleteShader(GL gl, IntBuffer shaders) {
        getImpl(gl).deleteShader(gl, shaders);
    }

    public static boolean createAndLoadShader(GL gl, IntBuffer shader, int shaderType,
                                              int binFormat, java.nio.Buffer bin,
                                              PrintStream verboseOut) {
        return getImpl(gl).createAndLoadShader(gl, shader, shaderType, binFormat, bin, verboseOut);
    }

    public static boolean createAndCompileShader(GL gl, IntBuffer shader, int shaderType,
                                                 java.lang.String[][] sources, 
                                                 PrintStream verboseOut) {
        return getImpl(gl).createAndCompileShader(gl, shader, shaderType, sources, verboseOut);
    }

    private static Impl getImpl(GL _gl) {
        GL2ES2 gl = _gl.getGL2ES2();
        GLContext context = gl.getContext();
        Impl impl = (Impl) context.getAttachedObject(implObjectKey);
        if (impl == null) {
            impl = new GL2ES2Impl();
            context.attachObject(implObjectKey, impl);
        }
        return impl;
    }
    private static final String implObjectKey = "jogamp.opengl.glsl.ShaderUtilImpl" ;
}