/**
 * Copyright 2012-2024 JogAmp Community. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are
 * permitted provided that the following conditions are met:
 *
 *    1. Redistributions of source code must retain the above copyright notice, this list of
 *       conditions and the following disclaimer.
 *
 *    2. Redistributions in binary form must reproduce the above copyright notice, this list
 *       of conditions and the following disclaimer in the documentation and/or other materials
 *       provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY JogAmp Community ``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 JogAmp Community OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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 *
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 */
package com.jogamp.opengl.util.texture;

import com.jogamp.opengl.GL;
import com.jogamp.opengl.GLAutoDrawable;
import com.jogamp.opengl.GLRunnable;
import com.jogamp.opengl.GLEventListener;

import com.jogamp.common.av.TimeFrameI;
import com.jogamp.graph.curve.Region;
import com.jogamp.math.Vec4f;
import com.jogamp.math.geom.AABBox;

/**
 * Protocol for texture sequences, like animations, movies, etc.
 * <p>
 * Ensure to respect the texture coordinates provided by
 * {@link TextureFrame}.{@link TextureFrame#getTexture() getTexture()}.{@link Texture#getImageTexCoords() getImageTexCoords()}.
 * </p>
 * The user's shader shall be fitted for this implementation.
 * Assuming we use a base shader code w/o headers using </code>ShaderCode</code>.
 * (Code copied from unit test / demo <code>TexCubeES2</code>)
 * <pre>
 *
    static final String[] es2_prelude = { "#version 100\n", "precision mediump float;\n" };
    static final String gl2_prelude = "#version 110\n";
    static final String shaderBasename = "texsequence_xxx";  // the base shader code w/o headers
    static final String myTextureLookupName = "myTexture2D"; // the desired texture lookup function

    private void initShader(GL2ES2 gl, TextureSequence texSeq) {
        // Create & Compile the shader objects
        ShaderCode rsVp = ShaderCode.create(gl, GL2ES2.GL_VERTEX_SHADER, TexCubeES2.class,
                                            "shader", "shader/bin", shaderBasename, true);
        ShaderCode rsFp = ShaderCode.create(gl, GL2ES2.GL_FRAGMENT_SHADER, TexCubeES2.class,
                                            "shader", "shader/bin", shaderBasename, true);

        // Prelude shader code w/ GLSL profile specifics [ 1. pre-proc, 2. other ]
        int rsFpPos;
        if(gl.isGLES2()) {
            // insert ES2 version string in beginning
            rsVp.insertShaderSource(0, 0, es2_prelude[0]);
            rsFpPos = rsFp.insertShaderSource(0, 0, es2_prelude[0]);
        } else {
            // insert GL2 version string in beginning
            rsVp.insertShaderSource(0, 0, gl2_prelude);
            rsFpPos = rsFp.insertShaderSource(0, 0, gl2_prelude);
        }
        // insert required extensions as determined by TextureSequence implementation.
        rsFpPos = rsFp.insertShaderSource(0, rsFpPos, texSeq.getRequiredExtensionsShaderStub());
        if(gl.isGLES2()) {
            // insert ES2 default precision declaration
            rsFpPos = rsFp.insertShaderSource(0, rsFpPos, es2_prelude[1]);
        }
        // negotiate the texture lookup function name
        final String texLookupFuncName = texSeq.getTextureLookupFunctionName(myTextureLookupName);

        // in case a fixed lookup function is being chosen, replace the name in our code
        rsFp.replaceInShaderSource(myTextureLookupName, texLookupFuncName);

        // Cache the TextureSequence shader details in StringBuilder:
        final StringBuilder sFpIns = new StringBuilder();

        // .. declaration of the texture sampler using the implementation specific type
        sFpIns.append("uniform ").append(texSeq.getTextureSampler2DType()).append(" mgl_ActiveTexture;\n");

        // .. the actual texture lookup function, maybe null in case a built-in function is being used
        sFpIns.append(texSeq.getTextureLookupFragmentShaderImpl());

        // Now insert the TextureShader details in our shader after the given tag:
        rsFp.insertShaderSource(0, "TEXTURE-SEQUENCE-CODE-BEGIN", 0, sFpIns);

        // Create & Link the shader program
        ShaderProgram sp = new ShaderProgram();
        sp.add(rsVp);
        sp.add(rsFp);
        if(!sp.link(gl, System.err)) {
            throw new GLException("Couldn't link program: "+sp);
        }
        ...
 * </pre>
 * The above procedure might look complicated, however, it allows most flexibility and
 * workarounds to also deal with GLSL bugs.
 *
 */
public interface TextureSequence {
    public static final String samplerExternalOES = "samplerExternalOES";
    public static final String sampler2D = "sampler2D";

    /**
     * Texture holder interface, maybe specialized by implementation
     * to associated related data.
     */
    public static class TextureFrame extends TimeFrameI {
        public TextureFrame(final Texture t, final int pts, final int duration) {
            super(pts, duration);
            texture = t;
        }
        public TextureFrame(final Texture t) {
            texture = t;
        }

        public final Texture getTexture() { return texture; }

        @Override
        public String toString() {
            return "TextureFrame[pts " + pts + " ms, l " + duration + " ms, texID "+ (null != texture ? texture.getTextureObject() : 0) + "]";
        }
        protected final Texture texture;
    }

    /**
     * Event listener to notify users of updates regarding the {@link TextureSequence}.
     * <p>
     * Implementations sending events down to all listeners,
     * while not necessarily making the user's OpenGL context current.
     * </p>
     * <p>
     * Events may be sent from a 3rd-party thread, possibly holding another, maybe shared, OpenGL context current.<br/>
     * Hence a user shall not issue <i>any</i> OpenGL, time consuming
     * or {@link TextureSequence} operations directly.<br>
     * Instead, the user shall:
     * <ul>
     *   <li>off-load complex or {@link TextureSequence} commands on another thread, or</li>
     *   <li>injecting {@link GLRunnable} objects via {@link GLAutoDrawable#invoke(boolean, GLRunnable)}, or</li>
     *   <li>simply changing a volatile state of their {@link GLEventListener} implementation.</li>
     * </ul>
     * </p>
     * */
    public interface TexSeqEventListener<T extends TextureSequence> {
        /**
         * Signaling listeners that a new {@link TextureFrame} is available.
         * <p>
         * User shall utilize {@link TextureSequence#getNextTexture(GL)} to dequeue it to maintain
         * a consistent queue.
         * </p>
         * @param ts the event source
         * @param newFrame the newly enqueued frame
         * @param when system time in msec.
         **/
        public void newFrameAvailable(T ts, TextureFrame newFrame, long when);
    }

    /** Returns the texture target used by implementation. */
    public int getTextureTarget();

    /** Return the texture unit used to render the current frame. */
    public int getTextureUnit();

    public int[] getTextureMinMagFilter();

    public int[] getTextureWrapST();

    /**
     * Returning {@code true} indicates texture correction for aspect-ratio in the shader.
     * Graph's {@link Region} shader will utilize {@link #setTexCoordBBox(Texture, AABBox, boolean, float[], boolean)}
     * for texture-coordinate bounding-box calculation.
     * <p>
     * Returning {@code false} indicates no correction for aspect-ratio in the shader.
     * Graph's {@link Region} shader will utilize {@link #setTexCoordBBoxSimple(Texture, AABBox, float[], boolean)}
     * for texture-coordinate bounding-box calculation.
     * </p>
     * <p>
     * Default value is implementation specific
     * and toggling is optional.
     * </p>
     * @see #setTexCoordBBox(Texture, AABBox, boolean, float[], boolean)
     * @see #setTexCoordBBoxSimple(Texture, AABBox, float[], boolean)
     * @see #useARatioLetterbox()
     */
    public boolean useARatioAdjustment();

    /**
     * Toggles {@link #useARatioLetterbox()}.
     * <p>
     * Default value is implementation specific
     * and toggling is optional.
     * </p>
     * @see #useARatioLetterbox()
     * @see #useARatioAdjustment()
     */
    public void setARatioAdjustment(final boolean v);

    /**
     * Returns whether {@link #useARatioAdjustment()} shall add letter-box space to match aspect-ratio, otherwise it will be zoomed in.
     * <p>
     * Default value is implementation specific
     * and toggling is optional.
     * </p>
     * @see #useARatioAdjustment()
     * @see #setARatioLetterbox(boolean, Vec4f)
     */
    public boolean useARatioLetterbox();

    /** Returns {@link #useARatioLetterbox()} background color for added letter-box space, defaults to transparent zero. */
    public Vec4f getARatioLetterboxBackColor();

    /**
     * Toggles {@link #useARatioLetterbox()}.
     * <p>
     * Default value is implementation specific
     * and toggling is optional.
     * </p>
     * <p>
     * Impacts only if {@link #useARatioAdjustment()} returns {@code true}.
     * </p>
     * @param v new value for {@link #useARatioLetterbox()}
     * @param backColor optional background color for added letter-box space, defaults to transparent zero
     * @see #useARatioLetterbox()
     * @see #useARatioAdjustment()
     */
    public void setARatioLetterbox(final boolean v, Vec4f backColor);

    /**
     * Returns true if texture source is ready <i>and</i> a texture is available
     * via {@link #getNextTexture(GL)} and {@link #getLastTexture()}.
     */
    public boolean isTextureAvailable();

    /**
     * Returns the last updated texture.
     * <p>
     * In case the instance is just initialized, it shall return a <code>TextureFrame</code>
     * object with valid attributes. The texture content may be undefined
     * until the first call of {@link #getNextTexture(GL)}.<br>
     * </p>
     * Not blocking.
     *
     * @throws IllegalStateException if instance is not initialized
     */
    public TextureFrame getLastTexture() throws IllegalStateException ;

    /**
     * Returns the next texture to be rendered.
     * <p>
     * Implementation shall return the next frame if available, may block if a next frame may arrive <i>soon</i>.
     * Otherwise implementation shall return the last frame.
     * </p>
     * <p>
     * Shall return <code>null</code> in case <i>no</i> next or last frame is available.
     * </p>
     *
     * @throws IllegalStateException if instance is not initialized
     */
    public TextureFrame getNextTexture(GL gl) throws IllegalStateException ;

    /**
     * In case a shader extension is required, based on the implementation
     * and the runtime GL profile, this method returns the preprocessor macros, e.g.:
     * <pre>
     * #extension GL_OES_EGL_image_external : enable
     * </pre>
     *
     * @throws IllegalStateException if instance is not initialized
     */
    public String getRequiredExtensionsShaderStub() throws IllegalStateException ;

    /**
     * Returns either <code>sampler2D</code> or <code>samplerExternalOES</code>
     * depending on {@link #getLastTexture()}.{@link TextureFrame#getTexture() getTexture()}.{@link Texture#getTarget() getTarget()}.
     *
     * @throws IllegalStateException if instance is not initialized
     **/
    public String getTextureSampler2DType() throws IllegalStateException ;

    /**
     * Set the desired shader code's texture lookup function name.
     *
     * @param texLookupFuncName desired lookup function name. If <code>null</code> or ignored by the implementation,
     *                          a build-in name is returned.
     * @return the chosen lookup function name
     *
     * @throws IllegalStateException if instance is not initialized
     * @see #getTextureLookupFunctionName()
     * @see #getTextureFragmentShaderHashCode()
     * @see #getTextureLookupFragmentShaderImpl()
     */
    public String setTextureLookupFunctionName(String texLookupFuncName) throws IllegalStateException ;

    /**
     * Returns the chosen lookup function name, which can be set via {@link #setTextureLookupFunctionName(String)}.
     *
     * @throws IllegalStateException if instance is not initialized
     * @see #setTextureLookupFunctionName(String)
     * @see #getTextureFragmentShaderHashCode()
     * @see #getTextureLookupFragmentShaderImpl()
     */
    public String getTextureLookupFunctionName() throws IllegalStateException ;

    /**
     * Returns the complete texture2D lookup function code of type
     * <pre>
     *   vec4 <i>funcName</i>(in <i>getTextureSampler2DType()</i> image, in vec2 texCoord) {
     *      vec4 texColor = do_something_with(image, texCoord);
     *      return texColor;
     *   }
     * </pre>
     * <p>
     * <i>funcName</i> is set via {@link #setTextureLookupFunctionName(String)}
     * and queried via {@link #getTextureLookupFunctionName()}.
     * </p>
     * <p>
     * User shall call {@link #setTextureLookupFunctionName(String)} first if intended.
     * </p>
     * <p>
     * Note: This function may return an empty string in case a build-in lookup
     * function is being chosen. If the implementation desires so,
     * {@link #getTextureLookupFunctionName()} will ignore the desired function name
     * and returns the build-in lookup function name.
     * </p>
     * @throws IllegalStateException if instance is not initialized
     * @see #getTextureLookupFunctionName()
     * @see #setTextureLookupFunctionName(String)
     * @see #getTextureFragmentShaderHashID()
     * @see #getTextureFragmentShaderHashCode()
     * @see #getTextureSampler2DType()
     */
    public String getTextureLookupFragmentShaderImpl() throws IllegalStateException;

    /**
     * Returns the concatenated string representing the following values
     * utilized for {@link #getTextureFragmentShaderHashCode()}.
     * <ul>
     *   <li>{@link #getTextureSampler2DType()}</li>
     *   <li>{@link #getTextureLookupFunctionName()}</li>
     *   <li>{@link #getTextureLookupFragmentShaderImpl()}</li>
     * </ul>
     * <p>
     * To reduce string concatenating, implementation may simply return {@link #getTextureLookupFragmentShaderImpl()},
     * if it covers {@link #getTextureSampler2DType()} and {@link #getTextureLookupFunctionName()}.
     * </p>
     * @see #getTextureFragmentShaderHashCode()
     */
    public String getTextureFragmentShaderHashID();

    /**
     * Returns the hash code of the string {@link #getTextureFragmentShaderHashID()}.
     * <p>
     * User shall call {@link #setTextureLookupFunctionName(String)} first if intended.
     * </p>
     * <p>
     * Returns zero if {@link #isTextureAvailable() texture is not available}.
     * </p>
     * The returned hash code allows selection of a matching shader program for this {@link TextureSequence} instance.
     * <p>
     * </p>
     * <p>
     * Implementation caches the resulting hash code, which is reset by {@link #setTextureLookupFunctionName(String)}
     * and this method if {@link #isTextureAvailable() texture is not available}.
     * </p>
     * @see #setTextureLookupFunctionName(String)
     * @see #getTextureLookupFunctionName()
     * @see #getTextureLookupFragmentShaderImpl()
     * @see #getTextureFragmentShaderHashID()
     */
    public int getTextureFragmentShaderHashCode();

    /**
     * Calculates the texture coordinates bounding box w/o correcting aspect-ratio.
     * @param tex the {@link Texture}
     * @param box the {@Link AABBox} of the destination
     * @param colorTexBBox destination float[6] array for the following three texture-coordinate tuples: minX/minY, maxX/maxY, texW/texH
     * @param verbose TODO
     * @see #useARatioAdjustment()
     */
    public static void setTexCoordBBoxSimple(final Texture tex, final AABBox box, final float[] colorTexBBox, final boolean verbose) {
        final TextureCoords tc = tex.getImageTexCoords();
        final float tcW = tc.right() - tc.left();
        final float tcH;
        colorTexBBox[0] = box.getMinX() / tcW;
        colorTexBBox[2] = box.getMaxX() / tcW;
        if( tex.getMustFlipVertically() ) {
            tcH = tc.bottom() - tc.top();
            colorTexBBox[1] = box.getMaxY() / tcH;
            colorTexBBox[3] = box.getMinY() / tcH;
        } else {
            tcH = tc.top() - tc.bottom();
            colorTexBBox[1] = box.getMinY() / tcH;
            colorTexBBox[3] = box.getMaxY() / tcH;
        }
        colorTexBBox[4] = tcW;
        colorTexBBox[5] = tcH;
        if( verbose ) {
            final float colorTexBBoxW = colorTexBBox[2] - colorTexBBox[0];
            final float colorTexBBoxH = colorTexBBox[3] - colorTexBBox[1];
            System.err.println("XXX setTexCoordBBoxSimple:");
            System.err.println("XXX ColorTex "+tex);
            System.err.println("XXX ColorTexBBox min "+colorTexBBox[0]+"/"+colorTexBBox[1]+", max "+colorTexBBox[2]+"/"+colorTexBBox[3]+
                    ", dim "+colorTexBBoxW+" x "+colorTexBBoxH+
                    ", tc-dim "+tcW+" x "+tcH+", tc "+tc);
        }

    }

    /**
     * Calculates the texture coordinates bounding box while correcting for aspect-ratio.
     * @param tex the {@link Texture}
     * @param box the {@Link AABBox} of the destination
     * @param letterBox true to produce letter-box space to match aspect-ratio, otherwise will zoom in
     * @param colorTexBBox destination float[6] array for the following three texture-coordinate tuples: minX/minY, maxX/maxY, texW/texH
     * @param verbose TODO
     * @see #useARatioAdjustment()
     */
    public static void setTexCoordBBox(final Texture tex, final AABBox box, final boolean letterBox, final float[] colorTexBBox, final boolean verbose) {
        final TextureCoords tc = tex.getImageTexCoords();
        final float boxRatio = box.getWidth() / box.getHeight();
        final float imgRatio = tex.getAspectRatio();
        final float box2ImgRatio = boxRatio / imgRatio;
        final float tcW = tc.right() - tc.left();
        final float tcH;
        float boxWidthCut=0, boxHeightCut=0, boxWidthExt=0, boxHeightExt=0;

        if( box2ImgRatio >= 1.0f ) {
            if( letterBox ) {
                boxWidthCut = box.getWidth() * ( 1f - 1f / box2ImgRatio );
                final float tcWH = tcW * 0.5f;
                final float boxWidthCutL = boxWidthCut * tcWH;
                final float boxWidthCutR = boxWidthCut * ( 1f - tcWH );
                colorTexBBox[0] = ( box.getMinX() + boxWidthCutL ) / tcW;
                colorTexBBox[2] = ( box.getMaxX() - boxWidthCutR ) / tcW;
                if( tex.getMustFlipVertically() ) {
                    tcH = tc.bottom() - tc.top();
                    colorTexBBox[1] = box.getMaxY() / tcH;
                    colorTexBBox[3] = box.getMinY() / tcH;
                } else {
                    tcH = tc.top() - tc.bottom();
                    colorTexBBox[1] = box.getMinY() / tcH;
                    colorTexBBox[3] = box.getMaxY() / tcH;
                }
            } else {
                colorTexBBox[0] = box.getMinX() / tcW;
                colorTexBBox[2] = box.getMaxX() / tcW;
                boxHeightExt = box.getHeight() * ( box2ImgRatio - 1f );
                if( tex.getMustFlipVertically() ) {
                    tcH = tc.bottom() - tc.top();
                    final float tcHH = tcH * 0.5f;
                    final float boxHeightExtB = boxHeightExt * tcHH;
                    final float boxHeightExtT = boxHeightExt * ( 1f - tcHH );
                    colorTexBBox[1] = ( box.getMaxY() + boxHeightExtT ) / tcH;
                    colorTexBBox[3] = ( box.getMinY() - boxHeightExtB ) / tcH;
                } else {
                    tcH = tc.top() - tc.bottom();
                    final float tcHH = tcH * 0.5f;
                    final float boxHeightExtB = boxHeightExt * tcHH;
                    final float boxHeightExtT = boxHeightExt * ( 1f - tcHH );
                    colorTexBBox[1] = ( box.getMinY() - boxHeightExtB ) / tcH;
                    colorTexBBox[3] = ( box.getMaxY() + boxHeightExtT ) / tcH;
                }
            }
        } else {
            if( letterBox ) {
                colorTexBBox[0] = box.getMinX() / tcW;
                colorTexBBox[2] = box.getMaxX() / tcW;
                boxHeightCut = box.getHeight() * ( 1f - box2ImgRatio );
                if( tex.getMustFlipVertically() ) {
                    tcH = tc.bottom() - tc.top();
                    final float tcHH = tcH * 0.5f;
                    final float boxHeightCutB = boxHeightCut * tcHH;
                    final float boxHeightCutT = boxHeightCut * ( 1f - tcHH );
                    colorTexBBox[1] = ( box.getMaxY() - boxHeightCutT ) / tcH;
                    colorTexBBox[3] = ( box.getMinY() + boxHeightCutB ) / tcH;
                } else {
                    tcH = tc.top() - tc.bottom();
                    final float tcHH = tcH * 0.5f;
                    final float boxHeightCutB = boxHeightCut * tcHH;
                    final float boxHeightCutT = boxHeightCut * ( 1f - tcHH );
                    colorTexBBox[1] = ( box.getMinY() + boxHeightCutB ) / tcH;
                    colorTexBBox[3] = ( box.getMaxY() - boxHeightCutT ) / tcH;
                }
            } else {
                boxWidthExt = box.getWidth() * ( 1f / box2ImgRatio - 1f );
                final float tcWH = tcW * 0.5f;
                final float boxWidthExtL = boxWidthExt * tcWH;
                final float boxWidthExtR = boxWidthExt * ( 1f - tcWH );
                colorTexBBox[0] = ( box.getMinX() - boxWidthExtL ) / tcW;
                colorTexBBox[2] = ( box.getMaxX() + boxWidthExtR ) / tcW;
                if( tex.getMustFlipVertically() ) {
                    tcH = tc.bottom() - tc.top();
                    colorTexBBox[1] = box.getMaxY() / tcH;
                    colorTexBBox[3] = box.getMinY() / tcH;
                } else {
                    tcH = tc.top() - tc.bottom();
                    colorTexBBox[1] = box.getMinY() / tcH;
                    colorTexBBox[3] = box.getMaxY() / tcH;
                }
            }
        }
        colorTexBBox[4] = tcW;
        colorTexBBox[5] = tcH;
        if( verbose ) {
            final float texWidthRatio = (float)tex.getImageWidth() / (float)tex.getWidth();
            final float texHeightRatio = (float)tex.getImageHeight() / (float)tex.getHeight();
            final float texRatio = ( tc.right() - tc.left() ) / ( tc.bottom() - tc.top() );
            final float box2TexRatio = boxRatio / texRatio;
            final float colorTexBBoxW = colorTexBBox[2] - colorTexBBox[0];
            final float colorTexBBoxH = colorTexBBox[3] - colorTexBBox[1];
            System.err.println("XXX setTexCoordBBox:");
            System.err.println("XXX ColorTex imgRatio "+imgRatio+", texRatio "+texRatio+", texPixelRatio[w "+texWidthRatio+", h "+texHeightRatio+"], "+tex);
            System.err.println("XXX ColorTexBBox lbox "+letterBox+", cut "+boxWidthCut+"/"+boxHeightCut+", ext "+boxWidthExt+"/"+boxHeightExt);
            System.err.println("XXX ColorTexBBox min "+colorTexBBox[0]+"/"+colorTexBBox[1]+", max "+colorTexBBox[2]+"/"+colorTexBBox[3]+
                    ", dim "+colorTexBBoxW+" x "+colorTexBBoxH+
                    ", tc-dim "+tcW+" x "+tcH+", tc "+tc+", box2ImgRatio "+box2ImgRatio+", box2TexRatio "+box2TexRatio);
            System.err.println("XXX Box ratio "+boxRatio+", "+box);
        }
    }
}