/*
 * Copyright 2013 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

//#define LOG_NDEBUG 0
#undef LOG_TAG
#define LOG_TAG "RenderEngine"
#define ATRACE_TAG ATRACE_TAG_GRAPHICS

#include <GLES2/gl2.h>
#include <GLES2/gl2ext.h>

#include <ui/ColorSpace.h>
#include <ui/DebugUtils.h>
#include <ui/Rect.h>

#include <utils/String8.h>
#include <utils/Trace.h>

#include <cutils/compiler.h>
#include <gui/ISurfaceComposer.h>
#include <math.h>

#include "GLES20RenderEngine.h"
#include "Program.h"
#include "ProgramCache.h"
#include "Description.h"
#include "Mesh.h"
#include "Texture.h"

#include <sstream>
#include <fstream>

// ---------------------------------------------------------------------------
#ifdef USE_HWC2
bool checkGlError(const char* op, int lineNumber) {
    bool errorFound = false;
    GLint error = glGetError();
    while (error != GL_NO_ERROR) {
        errorFound = true;
        error = glGetError();
        ALOGV("after %s() (line # %d) glError (0x%x)\n", op, lineNumber, error);
    }
    return errorFound;
}

static constexpr bool outputDebugPPMs = false;

void writePPM(const char* basename, GLuint width, GLuint height) {
    ALOGV("writePPM #%s: %d x %d", basename, width, height);

    std::vector<GLubyte> pixels(width * height * 4);
    std::vector<GLubyte> outBuffer(width * height * 3);

    // TODO(courtneygo): We can now have float formats, need
    // to remove this code or update to support.
    // Make returned pixels fit in uint32_t, one byte per component
    glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, pixels.data());
    if (checkGlError(__FUNCTION__, __LINE__)) {
        return;
    }

    std::string filename(basename);
    filename.append(".ppm");
    std::ofstream file(filename.c_str(), std::ios::binary);
    if (!file.is_open()) {
        ALOGE("Unable to open file: %s", filename.c_str());
        ALOGE("You may need to do: \"adb shell setenforce 0\" to enable "
              "surfaceflinger to write debug images");
        return;
    }

    file << "P6\n";
    file << width << "\n";
    file << height << "\n";
    file << 255 << "\n";

    auto ptr = reinterpret_cast<char*>(pixels.data());
    auto outPtr = reinterpret_cast<char*>(outBuffer.data());
    for (int y = height - 1; y >= 0; y--) {
        char* data = ptr + y * width * sizeof(uint32_t);

        for (GLuint x = 0; x < width; x++) {
            // Only copy R, G and B components
            outPtr[0] = data[0];
            outPtr[1] = data[1];
            outPtr[2] = data[2];
            data += sizeof(uint32_t);
            outPtr += 3;
        }
    }
    file.write(reinterpret_cast<char*>(outBuffer.data()), outBuffer.size());
}
#endif

// ---------------------------------------------------------------------------
namespace android {
// ---------------------------------------------------------------------------

GLES20RenderEngine::GLES20RenderEngine(uint32_t featureFlags) :
         mVpWidth(0),
         mVpHeight(0),
         mPlatformHasWideColor((featureFlags & WIDE_COLOR_SUPPORT) != 0) {

    glGetIntegerv(GL_MAX_TEXTURE_SIZE, &mMaxTextureSize);
    glGetIntegerv(GL_MAX_VIEWPORT_DIMS, mMaxViewportDims);

    glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
    glPixelStorei(GL_PACK_ALIGNMENT, 4);

    const uint16_t protTexData[] = { 0 };
    glGenTextures(1, &mProtectedTexName);
    glBindTexture(GL_TEXTURE_2D, mProtectedTexName);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 1, 1, 0,
            GL_RGB, GL_UNSIGNED_SHORT_5_6_5, protTexData);

    //mColorBlindnessCorrection = M;

#ifdef USE_HWC2
    if (mPlatformHasWideColor) {
        // Compute sRGB to DisplayP3 color transform
        // NOTE: For now, we are limiting wide-color support to
        // Display-P3 only.
        mat3 srgbToP3 = ColorSpaceConnector(ColorSpace::sRGB(), ColorSpace::DisplayP3()).getTransform();

        // color transform needs to be expanded to 4x4 to be what the shader wants
        // mat has an initializer that expands mat3 to mat4, but
        // not an assignment operator
        mat4 gamutTransform(srgbToP3);
        mSrgbToDisplayP3 = gamutTransform;
    }
#endif
}

GLES20RenderEngine::~GLES20RenderEngine() {
}


size_t GLES20RenderEngine::getMaxTextureSize() const {
    return mMaxTextureSize;
}

size_t GLES20RenderEngine::getMaxViewportDims() const {
    return
        mMaxViewportDims[0] < mMaxViewportDims[1] ?
            mMaxViewportDims[0] : mMaxViewportDims[1];
}

void GLES20RenderEngine::setViewportAndProjection(
        size_t vpw, size_t vph, Rect sourceCrop, size_t hwh, bool yswap,
        Transform::orientation_flags rotation) {

    size_t l = sourceCrop.left;
    size_t r = sourceCrop.right;

    // In GL, (0, 0) is the bottom-left corner, so flip y coordinates
    size_t t = hwh - sourceCrop.top;
    size_t b = hwh - sourceCrop.bottom;

    mat4 m;
    if (yswap) {
        m = mat4::ortho(l, r, t, b, 0, 1);
    } else {
        m = mat4::ortho(l, r, b, t, 0, 1);
    }

    // Apply custom rotation to the projection.
    float rot90InRadians = 2.0f * static_cast<float>(M_PI) / 4.0f;
    switch (rotation) {
        case Transform::ROT_0:
            break;
        case Transform::ROT_90:
            m = mat4::rotate(rot90InRadians, vec3(0,0,1)) * m;
            break;
        case Transform::ROT_180:
            m = mat4::rotate(rot90InRadians * 2.0f, vec3(0,0,1)) * m;
            break;
        case Transform::ROT_270:
            m = mat4::rotate(rot90InRadians * 3.0f, vec3(0,0,1)) * m;
            break;
        default:
            break;
    }

    glViewport(0, 0, vpw, vph);
    mState.setProjectionMatrix(m);
    mVpWidth = vpw;
    mVpHeight = vph;
}

#ifdef USE_HWC2
void GLES20RenderEngine::setupLayerBlending(bool premultipliedAlpha,
        bool opaque, float alpha) {
#else
void GLES20RenderEngine::setupLayerBlending(
    bool premultipliedAlpha, bool opaque, int alpha) {
#endif

    mState.setPremultipliedAlpha(premultipliedAlpha);
    mState.setOpaque(opaque);
#ifdef USE_HWC2
    mState.setPlaneAlpha(alpha);

    if (alpha < 1.0f || !opaque) {
#else
    mState.setPlaneAlpha(alpha / 255.0f);

    if (alpha < 0xFF || !opaque) {
#endif
        glEnable(GL_BLEND);
        glBlendFunc(premultipliedAlpha ? GL_ONE : GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    } else {
        glDisable(GL_BLEND);
    }
}

#ifdef USE_HWC2
void GLES20RenderEngine::setupDimLayerBlending(float alpha) {
#else
void GLES20RenderEngine::setupDimLayerBlending(int alpha) {
#endif
    mState.setPlaneAlpha(1.0f);
    mState.setPremultipliedAlpha(true);
    mState.setOpaque(false);
#ifdef USE_HWC2
    mState.setColor(0, 0, 0, alpha);
#else
    mState.setColor(0, 0, 0, alpha/255.0f);
#endif
    mState.disableTexture();

#ifdef USE_HWC2
    if (alpha == 1.0f) {
#else
    if (alpha == 0xFF) {
#endif
        glDisable(GL_BLEND);
    } else {
        glEnable(GL_BLEND);
        glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
    }
}

#ifdef USE_HWC2
void GLES20RenderEngine::setColorMode(android_color_mode mode) {
    ALOGV("setColorMode: %s (0x%x)", decodeColorMode(mode).c_str(), mode);

    if (mColorMode == mode) return;

    if (!mPlatformHasWideColor || !mDisplayHasWideColor || mode == HAL_COLOR_MODE_SRGB ||
        mode == HAL_COLOR_MODE_NATIVE) {
        // We are returning back to our default color_mode
        mUseWideColor = false;
        mWideColorFrameCount = 0;
    } else {
        mUseWideColor = true;
    }

    mColorMode = mode;
}

void GLES20RenderEngine::setSourceDataSpace(android_dataspace source) {
    if (source == HAL_DATASPACE_UNKNOWN) {
        // Treat UNKNOWN as SRGB
        source = HAL_DATASPACE_V0_SRGB;
    }
    mDataSpace = source;
}

void GLES20RenderEngine::setWideColor(bool hasWideColor) {
    ALOGV("setWideColor: %s", hasWideColor ? "true" : "false");
    mDisplayHasWideColor = hasWideColor;
}

bool GLES20RenderEngine::usesWideColor() {
    return mUseWideColor;
}
#endif

void GLES20RenderEngine::setupLayerTexturing(const Texture& texture) {
    GLuint target = texture.getTextureTarget();
    glBindTexture(target, texture.getTextureName());
    GLenum filter = GL_NEAREST;
    if (texture.getFiltering()) {
        filter = GL_LINEAR;
    }
    glTexParameteri(target, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    glTexParameteri(target, GL_TEXTURE_MAG_FILTER, filter);
    glTexParameteri(target, GL_TEXTURE_MIN_FILTER, filter);

    mState.setTexture(texture);
}

void GLES20RenderEngine::setupLayerBlackedOut() {
    glBindTexture(GL_TEXTURE_2D, mProtectedTexName);
    Texture texture(Texture::TEXTURE_2D, mProtectedTexName);
    texture.setDimensions(1, 1); // FIXME: we should get that from somewhere
    mState.setTexture(texture);
}

mat4 GLES20RenderEngine::setupColorTransform(const mat4& colorTransform) {
    mat4 oldTransform = mState.getColorMatrix();
    mState.setColorMatrix(colorTransform);
    return oldTransform;
}

void GLES20RenderEngine::disableTexturing() {
    mState.disableTexture();
}

void GLES20RenderEngine::disableBlending() {
    glDisable(GL_BLEND);
}


void GLES20RenderEngine::bindImageAsFramebuffer(EGLImageKHR image,
        uint32_t* texName, uint32_t* fbName, uint32_t* status) {
    GLuint tname, name;
    // turn our EGLImage into a texture
    glGenTextures(1, &tname);
    glBindTexture(GL_TEXTURE_2D, tname);
    glEGLImageTargetTexture2DOES(GL_TEXTURE_2D, (GLeglImageOES)image);

    // create a Framebuffer Object to render into
    glGenFramebuffers(1, &name);
    glBindFramebuffer(GL_FRAMEBUFFER, name);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, tname, 0);

    *status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
    *texName = tname;
    *fbName = name;
}

void GLES20RenderEngine::unbindFramebuffer(uint32_t texName, uint32_t fbName) {
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
    glDeleteFramebuffers(1, &fbName);
    glDeleteTextures(1, &texName);
}

void GLES20RenderEngine::setupFillWithColor(float r, float g, float b, float a) {
    mState.setPlaneAlpha(1.0f);
    mState.setPremultipliedAlpha(true);
    mState.setOpaque(false);
    mState.setColor(r, g, b, a);
    mState.disableTexture();
    glDisable(GL_BLEND);
}

void GLES20RenderEngine::drawMesh(const Mesh& mesh) {

    if (mesh.getTexCoordsSize()) {
        glEnableVertexAttribArray(Program::texCoords);
        glVertexAttribPointer(Program::texCoords,
                mesh.getTexCoordsSize(),
                GL_FLOAT, GL_FALSE,
                mesh.getByteStride(),
                mesh.getTexCoords());
    }

    glVertexAttribPointer(Program::position,
            mesh.getVertexSize(),
            GL_FLOAT, GL_FALSE,
            mesh.getByteStride(),
            mesh.getPositions());

#ifdef USE_HWC2
    if (usesWideColor()) {
        Description wideColorState = mState;
        if (mDataSpace != HAL_DATASPACE_DISPLAY_P3) {
            wideColorState.setColorMatrix(mState.getColorMatrix() * mSrgbToDisplayP3);
            wideColorState.setWideGamut(true);
            ALOGV("drawMesh: gamut transform applied");
        }
        ProgramCache::getInstance().useProgram(wideColorState);

        glDrawArrays(mesh.getPrimitive(), 0, mesh.getVertexCount());

        if (outputDebugPPMs) {
            std::ostringstream out;
            out << "/data/texture_out" << mWideColorFrameCount++;
            writePPM(out.str().c_str(), mVpWidth, mVpHeight);
        }
    } else {
        ProgramCache::getInstance().useProgram(mState);

        glDrawArrays(mesh.getPrimitive(), 0, mesh.getVertexCount());
    }
#else
    ProgramCache::getInstance().useProgram(mState);

    glDrawArrays(mesh.getPrimitive(), 0, mesh.getVertexCount());
#endif

    if (mesh.getTexCoordsSize()) {
        glDisableVertexAttribArray(Program::texCoords);
    }
}

void GLES20RenderEngine::dump(String8& result) {
    RenderEngine::dump(result);
#ifdef USE_HWC2
    if (usesWideColor()) {
        result.append("Wide-color: On\n");
    } else {
        result.append("Wide-color: Off\n");
    }
#endif
}

// ---------------------------------------------------------------------------
}; // namespace android
// ---------------------------------------------------------------------------

#if defined(__gl_h_)
#error "don't include gl/gl.h in this file"
#endif