/*
 * Copyright (C) 2023 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 "GraphicsDetectorGl.h"

#include "Egl.h"
#include "Gles.h"

namespace gfxstream {
namespace {

using ::gfxstream::proto::EglAvailability;
using GlesContextAvailability = ::gfxstream::proto::EglAvailability::GlesContextAvailability;

constexpr const char kSurfacelessContextExt[] = "EGL_KHR_surfaceless_context";

class Closer {
  public:
    Closer(std::function<void()> on_close) : on_close_(std::move(on_close)) {}
    ~Closer() { on_close_(); }

  private:
    std::function<void()> on_close_;
};

enum class GlesLoadMethod {
    VIA_EGL,
    VIA_GLESV2,
};

gfxstream::expected<GlesContextAvailability, std::string> GetGlesContextAvailability(
    Egl& egl, EGLDisplay eglDisplay, EGLConfig eglConfig, EGLint contextVersion,
    GlesLoadMethod loadMethod) {
    GlesContextAvailability availability;

    const EGLint contextAttributes[] = {
        // clang-format off
        EGL_CONTEXT_CLIENT_VERSION, contextVersion,
        EGL_NONE,
        // clang-format on
    };

    EGLContext context =
        egl.eglCreateContext(eglDisplay, eglConfig, EGL_NO_CONTEXT, contextAttributes);
    if (context == EGL_NO_CONTEXT) {
        return gfxstream::unexpected("Failed to create context.");
    }
    Closer contextCloser([&]() { egl.eglDestroyContext(eglDisplay, context); });

    if (egl.eglMakeCurrent(eglDisplay, EGL_NO_SURFACE, EGL_NO_SURFACE, context) != EGL_TRUE) {
        return gfxstream::unexpected("Failed to make context current.");
    }

    auto gles = loadMethod == GlesLoadMethod::VIA_EGL ? GFXSTREAM_EXPECT(Gles::LoadFromEgl(&egl))
                                                      : GFXSTREAM_EXPECT(Gles::Load());

    const GLubyte* gles_vendor = gles.glGetString(GL_VENDOR);
    if (gles_vendor == nullptr) {
        return gfxstream::unexpected("Failed to query vendor.");
    }
    const std::string gles_vendor_string((const char*)gles_vendor);
    availability.set_vendor(gles_vendor_string);

    const GLubyte* gles_version = gles.glGetString(GL_VERSION);
    if (gles_version == nullptr) {
        gfxstream::unexpected("Failed to query vendor.");
    }
    const std::string gles_version_string((const char*)gles_version);
    availability.set_version(gles_version_string);

    const GLubyte* gles_renderer = gles.glGetString(GL_RENDERER);
    if (gles_renderer == nullptr) {
        gfxstream::unexpected("Failed to query renderer.");
    }
    const std::string gles_renderer_string((const char*)gles_renderer);
    availability.set_renderer(gles_renderer_string);

    const GLubyte* gles_extensions = gles.glGetString(GL_EXTENSIONS);
    if (gles_extensions == nullptr) {
        return gfxstream::unexpected("Failed to query extensions.");
    }
    const std::string gles_extensions_string((const char*)gles_extensions);
    availability.set_extensions(gles_extensions_string);

    return availability;
}

}  // namespace

gfxstream::expected<Ok, std::string> PopulateEglAndGlesAvailability(
        ::gfxstream::proto::GraphicsAvailability* availability) {
    auto egl = GFXSTREAM_EXPECT(Egl::Load());

    EglAvailability* eglAvailability = availability->mutable_egl();

    EGLDisplay display = egl.eglGetDisplay(EGL_DEFAULT_DISPLAY);
    if (display == EGL_NO_DISPLAY) {
        if (egl.eglGetPlatformDisplayEXT != nullptr) {
            display = egl.eglGetPlatformDisplayEXT(EGL_PLATFORM_SURFACELESS_MESA, EGL_DEFAULT_DISPLAY, NULL);
        }
    }

    if (display == EGL_NO_DISPLAY) {
        return gfxstream::unexpected("Failed to find display.");
    }

    EGLint client_version_major = 0;
    EGLint client_version_minor = 0;
    if (egl.eglInitialize(display, &client_version_major,
                            &client_version_minor) != EGL_TRUE) {
        return gfxstream::unexpected("Failed to initialize display.");
    }

    const std::string version_string = egl.eglQueryString(display, EGL_VERSION);
    if (version_string.empty()) {
        return gfxstream::unexpected("Failed to query client version.");
    }
    eglAvailability->set_version(version_string);

    const std::string vendor_string = egl.eglQueryString(display, EGL_VENDOR);
    if (vendor_string.empty()) {
        return gfxstream::unexpected("Failed to query vendor.");
    }
    eglAvailability->set_vendor(vendor_string);

    const std::string extensions_string =
        egl.eglQueryString(display, EGL_EXTENSIONS);
    if (extensions_string.empty()) {
        return gfxstream::unexpected("Failed to query extensions.");
    }
    eglAvailability->set_extensions(extensions_string);

    if (extensions_string.find(kSurfacelessContextExt) == std::string::npos) {
        return gfxstream::unexpected("Failed to find extension EGL_KHR_surfaceless_context.");
    }

    const std::string display_apis_string = egl.eglQueryString(display, EGL_CLIENT_APIS);
    if (display_apis_string.empty()) {
        return gfxstream::unexpected("Failed to query display apis.");
    }

    if (egl.eglBindAPI(EGL_OPENGL_ES_API) == EGL_FALSE) {
        return gfxstream::unexpected("Failed to bind GLES API.");
    }

    const EGLint framebufferConfigAttributes[] = {
        // clang-format off
        EGL_SURFACE_TYPE,    EGL_PBUFFER_BIT,
        EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
        EGL_RED_SIZE,        1,
        EGL_GREEN_SIZE,      1,
        EGL_BLUE_SIZE,       1,
        EGL_ALPHA_SIZE,      0,
        EGL_NONE,
        // clang-format on
    };

    EGLConfig framebufferConfig;
    EGLint numFramebufferConfigs = 0;
    if (egl.eglChooseConfig(display, framebufferConfigAttributes, &framebufferConfig, 1,
                            &numFramebufferConfigs) != EGL_TRUE) {
        return gfxstream::unexpected("Failed to find matching framebuffer config.");
    }

    struct GlesContextCheckOptions {
        std::function<GlesContextAvailability*()> availabilityProvider;
        EGLint contextVersion;
        GlesLoadMethod loadMethod;

        std::string to_string() const {
            std::string ret;
            ret += "options {";

            ret += " version: ";
            ret += std::to_string(contextVersion);

            ret += " load-method: ";
            ret += loadMethod == GlesLoadMethod::VIA_EGL ? "via-egl" : "via-glesv2";

            ret += " }";
            return ret;
        }
    };
    const std::vector<GlesContextCheckOptions> contextChecks = {
        GlesContextCheckOptions{
            .availabilityProvider = [&]() { return eglAvailability->mutable_gles2_availability(); },
            .contextVersion = 2,
            .loadMethod = GlesLoadMethod::VIA_EGL,
        },
        GlesContextCheckOptions{
            .availabilityProvider =
                [&]() { return eglAvailability->mutable_gles2_direct_availability(); },
            .contextVersion = 2,
            .loadMethod = GlesLoadMethod::VIA_GLESV2,
        },
        GlesContextCheckOptions{
            .availabilityProvider = [&]() { return eglAvailability->mutable_gles3_availability(); },
            .contextVersion = 3,
            .loadMethod = GlesLoadMethod::VIA_EGL,
        },
        GlesContextCheckOptions{
            .availabilityProvider =
                [&]() { return eglAvailability->mutable_gles3_direct_availability(); },
            .contextVersion = 3,
            .loadMethod = GlesLoadMethod::VIA_GLESV2,
        },
    };

    for (const GlesContextCheckOptions& contextCheck : contextChecks) {
        auto contextCheckResult = GetGlesContextAvailability(
            egl, display, framebufferConfig, contextCheck.contextVersion, contextCheck.loadMethod);
        if (contextCheckResult.ok()) {
            *contextCheck.availabilityProvider() = contextCheckResult.value();
        } else {
            eglAvailability->add_errors("Failed to complete GLES context check using " +
                                        contextCheck.to_string() + ": " +
                                        contextCheckResult.error());
        }
    }

    return Ok{};
}

}  // namespace gfxstream