/*
 ** Copyright 2007, 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.
 */

#include <EGL/egl.h>
#include <android-base/properties.h>
#include <log/log.h>
#include <stdlib.h>

#include "../egl_impl.h"
#include "CallStack.h"
#include "Loader.h"
#include "egl_display.h"
#include "egl_layers.h"
#include "egl_object.h"
#include "egl_tls.h"
#include "egldefs.h"

namespace android {

egl_connection_t gEGLImpl;
gl_hooks_t gHooks[2];
gl_hooks_t gHooksNoContext;
pthread_key_t gGLWrapperKey = -1;

void setGLHooksThreadSpecific(gl_hooks_t const* value) {
    setGlThreadSpecific(value);
}

static int gl_no_context() {
    if (egl_tls_t::logNoContextCall()) {
        const char* const error = "call to OpenGL ES API with "
                                  "no current context (logged once per thread)";
        if (LOG_NDEBUG) {
            ALOGE(error);
        } else {
            LOG_ALWAYS_FATAL(error);
        }
        if (base::GetBoolProperty("debug.egl.callstack", false)) {
            CallStack::log(LOG_TAG);
        }
    }
    return 0;
}

static void early_egl_init(void) {
    int numHooks = sizeof(gHooksNoContext) / sizeof(EGLFuncPointer);
    EGLFuncPointer* iter = reinterpret_cast<EGLFuncPointer*>(&gHooksNoContext);
    for (int hook = 0; hook < numHooks; ++hook) {
        *(iter++) = reinterpret_cast<EGLFuncPointer>(gl_no_context);
    }

    setGLHooksThreadSpecific(&gHooksNoContext);
}

const GLubyte* egl_get_string_for_current_context(GLenum name) {
    // NOTE: returning NULL here will fall-back to the default
    // implementation.

    EGLContext context = egl_tls_t::getContext();
    if (context == EGL_NO_CONTEXT) return nullptr;

    const egl_context_t* const c = get_context(context);
    if (c == nullptr) // this should never happen, by construction
        return nullptr;

    if (name != GL_EXTENSIONS) return nullptr;

    return (const GLubyte*)c->gl_extensions.c_str();
}

const GLubyte* egl_get_string_for_current_context(GLenum name, GLuint index) {
    // NOTE: returning NULL here will fall-back to the default
    // implementation.

    EGLContext context = egl_tls_t::getContext();
    if (context == EGL_NO_CONTEXT) return nullptr;

    const egl_context_t* const c = get_context(context);
    if (c == nullptr) // this should never happen, by construction
        return nullptr;

    if (name != GL_EXTENSIONS) return nullptr;

    // if index is out of bounds, assume it will be in the default
    // implementation too, so we don't have to generate a GL error here
    if (index >= c->tokenized_gl_extensions.size()) return nullptr;

    return (const GLubyte*)c->tokenized_gl_extensions[index].c_str();
}

GLint egl_get_num_extensions_for_current_context() {
    // NOTE: returning -1 here will fall-back to the default
    // implementation.

    EGLContext context = egl_tls_t::getContext();
    if (context == EGL_NO_CONTEXT) return -1;

    const egl_context_t* const c = get_context(context);
    if (c == nullptr) // this should never happen, by construction
        return -1;

    return (GLint)c->tokenized_gl_extensions.size();
}

egl_connection_t* egl_get_connection() {
    return &gEGLImpl;
}

static pthread_once_t once_control = PTHREAD_ONCE_INIT;
static int sEarlyInitState = pthread_once(&once_control, &early_egl_init);

static EGLBoolean egl_init_drivers_locked() {
    if (sEarlyInitState) {
        // initialized by static ctor. should be set here.
        return EGL_FALSE;
    }

    // get our driver loader
    Loader& loader(Loader::getInstance());

    // dynamically load our EGL implementation
    egl_connection_t* cnx = &gEGLImpl;
    cnx->hooks[egl_connection_t::GLESv1_INDEX] = &gHooks[egl_connection_t::GLESv1_INDEX];
    cnx->hooks[egl_connection_t::GLESv2_INDEX] = &gHooks[egl_connection_t::GLESv2_INDEX];
    cnx->dso = loader.open(cnx);

    // Check to see if any layers are enabled and route functions through them
    if (cnx->dso) {
        // Layers can be enabled long after the drivers have been loaded.
        // They will only be initialized once.
        LayerLoader& layer_loader(LayerLoader::getInstance());
        layer_loader.InitLayers(cnx);
    }

    return cnx->dso ? EGL_TRUE : EGL_FALSE;
}

// this mutex protects driver load logic as a critical section since it accesses to global variable
// like gEGLImpl
static pthread_mutex_t sInitDriverMutex = PTHREAD_MUTEX_INITIALIZER;

EGLBoolean egl_init_drivers() {
    EGLBoolean res;
    pthread_mutex_lock(&sInitDriverMutex);
    res = egl_init_drivers_locked();
    pthread_mutex_unlock(&sInitDriverMutex);
    return res;
}

static pthread_mutex_t sLogPrintMutex = PTHREAD_MUTEX_INITIALIZER;
static std::chrono::steady_clock::time_point sLogPrintTime;
static constexpr std::chrono::seconds DURATION(1);

void gl_unimplemented() {
    bool printLog = false;
    auto now = std::chrono::steady_clock::now();
    pthread_mutex_lock(&sLogPrintMutex);
    if ((now - sLogPrintTime) > DURATION) {
        sLogPrintTime = now;
        printLog = true;
    }
    pthread_mutex_unlock(&sLogPrintMutex);
    if (printLog) {
        ALOGE("called unimplemented OpenGL ES API");
        if (base::GetBoolProperty("debug.egl.callstack", false)) {
            CallStack::log(LOG_TAG);
        }
    }
}

void gl_noop() {}

void setGlThreadSpecific(gl_hooks_t const* value) {
    gl_hooks_t const* volatile* tls_hooks = get_tls_hooks();
    tls_hooks[TLS_SLOT_OPENGL_API] = value;
}

// ----------------------------------------------------------------------------
// GL / EGL hooks
// ----------------------------------------------------------------------------

#undef GL_ENTRY
#undef EGL_ENTRY
#define GL_ENTRY(_r, _api, ...) #_api,
#define EGL_ENTRY(_r, _api, ...) #_api,

char const * const gl_names[] = {
    #include "../entries.in"
    nullptr
};

char const * const gl_names_1[] = {
    #include "../entries_gles1.in"
    nullptr
};

char const * const egl_names[] = {
    #include "egl_entries.in"
    nullptr
};

char const * const platform_names[] = {
    #include "platform_entries.in"
    nullptr
};

#undef GL_ENTRY
#undef EGL_ENTRY

}; // namespace android