/*
 * Copyright © Canonical Ltd.
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License version 2 or 3,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <mir/graphics/egl_extensions.h>
#include <EGL/egl.h>
#include <boost/throw_exception.hpp>
#include <stdexcept>
#include <cstring>

namespace mg=mir::graphics;

auto mg::has_egl_client_extension(char const* extension) -> bool
{
    return has_egl_extension(EGL_NO_DISPLAY, extension);
}

auto mg::has_egl_extension(EGLDisplay dpy, char const* extension) -> bool
{
    auto const extensions = eglQueryString(dpy, EGL_EXTENSIONS);
    auto found_substring = std::strstr(extensions, extension);
    while (found_substring)
    {
        // Check that we haven't found a prefix of our extension name
        auto end_of_match = found_substring + std::strlen(extension);
        // It's a match if it terminates with the end of the extension string, or with a space
        if (*end_of_match == '\0' || *end_of_match == ' ')
        {
            return true;
        }

        found_substring = std::strstr(end_of_match, extension);
    }
    return false;
}

namespace
{

auto maybe_platform_base_ext() -> std::optional<mg::EGLExtensions::PlatformBaseEXT>
{
    try
    {
        return mg::EGLExtensions::PlatformBaseEXT{};
    }
    catch (std::runtime_error const&)
    {
        return {};
    }
}

}

mg::EGLExtensions::EGLExtensions() :
    platform_base{maybe_platform_base_ext()}
{
}

mg::EGLExtensions::BaseExtensions::BaseExtensions(EGLDisplay dpy) :
    eglCreateImageKHR{
        reinterpret_cast<PFNEGLCREATEIMAGEKHRPROC>(eglGetProcAddress("eglCreateImageKHR"))},
    eglDestroyImageKHR{
        reinterpret_cast<PFNEGLDESTROYIMAGEKHRPROC>(eglGetProcAddress("eglDestroyImageKHR"))},
    /*
     * TODO: Find a non-ES GL equivalent for glEGLImageTargetTexture2DOES
     * It's the LAST remaining ES-specific function. Although Mesa lets you use
     * it in full GL, it theoretically should not work. Mesa just lets you
     * mix ES and GL code. But other drivers won't be so lenient.
     */
    glEGLImageTargetTexture2DOES{
        reinterpret_cast<PFNGLEGLIMAGETARGETTEXTURE2DOESPROC>(eglGetProcAddress("glEGLImageTargetTexture2DOES"))}
{
    auto const egl_extensions = eglQueryString(dpy, EGL_EXTENSIONS);
    if (!egl_extensions || !std::strstr(egl_extensions, "EGL_KHR_image_base") || !eglCreateImageKHR || !eglDestroyImageKHR)
    {
        BOOST_THROW_EXCEPTION(std::runtime_error("EGL display doesn't support EGL_KHR_image_base"));
    }

    if (!glEGLImageTargetTexture2DOES)
    {
        BOOST_THROW_EXCEPTION(std::runtime_error("GLES2 implementation doesn't support updating a texture from an EGLImage"));
    }
}

mg::EGLExtensions::PlatformBaseEXT::PlatformBaseEXT()
    : eglGetPlatformDisplay{
        reinterpret_cast<PFNEGLGETPLATFORMDISPLAYEXTPROC>(eglGetProcAddress("eglGetPlatformDisplayEXT"))
    },
    eglCreatePlatformWindowSurface{
          reinterpret_cast<PFNEGLCREATEPLATFORMWINDOWSURFACEEXTPROC>(
              eglGetProcAddress("eglCreatePlatformWindowSurfaceEXT"))
    }
{
    auto const* client_extensions = eglQueryString(EGL_NO_DISPLAY, EGL_EXTENSIONS);
    if (!client_extensions ||
        !std::strstr(client_extensions, "EGL_EXT_platform_base") ||
        !eglGetPlatformDisplay ||
        !eglCreatePlatformWindowSurface)
    {
        BOOST_THROW_EXCEPTION((std::runtime_error{"EGL implementation doesn't support EGL_EXT_platform_base"}));
    }
}

mg::EGLExtensions::DebugKHR::DebugKHR()
    : eglDebugMessageControlKHR{
        reinterpret_cast<PFNEGLDEBUGMESSAGECONTROLKHRPROC>(eglGetProcAddress("eglDebugMessageControlKHR"))
    },
      eglLabelObjectKHR{
        reinterpret_cast<PFNEGLLABELOBJECTKHRPROC>(eglGetProcAddress("eglLabelObjectKHR"))
    },
      eglQueryDebugKHR{
        reinterpret_cast<PFNEGLQUERYDEBUGKHRPROC>(eglGetProcAddress("eglQueryDebugKHR"))
    }
{
    auto const* client_extensions = eglQueryString(EGL_NO_DISPLAY, EGL_EXTENSIONS);
    if (!client_extensions ||
        !std::strstr(client_extensions, "EGL_KHR_debug") ||
        !eglDebugMessageControlKHR ||
        !eglLabelObjectKHR ||
        !eglQueryDebugKHR)
    {
        BOOST_THROW_EXCEPTION((std::runtime_error{"EGL implementation doesn't support EGL_KHR_debug"}));
    }
}

mg::EGLExtensions::DebugKHR::DebugKHR(
    PFNEGLDEBUGMESSAGECONTROLKHRPROC control,
    PFNEGLLABELOBJECTKHRPROC label,
    PFNEGLQUERYDEBUGKHRPROC query)
    : eglDebugMessageControlKHR{control},
      eglLabelObjectKHR{label},
      eglQueryDebugKHR{query}
{
}

auto mg::EGLExtensions::DebugKHR::extension_or_null_object() -> DebugKHR
{
    return DebugKHR{
        [](EGLDEBUGPROCKHR, EGLAttrib const*) -> EGLint { return EGL_SUCCESS; },
        [](EGLDisplay, EGLenum, EGLObjectKHR, EGLLabelKHR) -> EGLint { return EGL_SUCCESS; },
        [](EGLint, EGLAttrib*) -> EGLBoolean { return EGL_TRUE; }
    };
}

auto mg::EGLExtensions::DebugKHR::maybe_debug_khr() -> std::optional<DebugKHR>
{
    try
    {
        return mg::EGLExtensions::DebugKHR{};
    }
    catch (std::runtime_error const&)
    {
        return {};
    }
}

mg::EGLExtensions::EXTImageDmaBufImportModifiers::EXTImageDmaBufImportModifiers(EGLDisplay dpy)
    : eglQueryDmaBufFormatsExt{
        reinterpret_cast<PFNEGLQUERYDMABUFFORMATSEXTPROC>(
            eglGetProcAddress("eglQueryDmaBufFormatsEXT"))},
      eglQueryDmaBufModifiersExt{
        reinterpret_cast<PFNEGLQUERYDMABUFMODIFIERSEXTPROC>(
            eglGetProcAddress("eglQueryDmaBufModifiersEXT"))}
{
    auto const egl_extensions = eglQueryString(dpy, EGL_EXTENSIONS);
    if (!egl_extensions ||
        !std::strstr(egl_extensions, "EGL_EXT_image_dma_buf_import_modifiers"))
    {
        BOOST_THROW_EXCEPTION((
            std::runtime_error{"EGL_EXT_image_dma_buf_import_modifiers not supported"}));
    }
}

mg::EGLExtensions::MESADmaBufExport::MESADmaBufExport(EGLDisplay dpy)
    : eglExportDMABUFImageMESA{
          reinterpret_cast<PFNEGLEXPORTDMABUFIMAGEMESAPROC>(
              eglGetProcAddress("eglExportDMABUFImageMESA"))},
      eglExportDMABUFImageQueryMESA{
          reinterpret_cast<PFNEGLEXPORTDMABUFIMAGEQUERYMESAPROC>(
              eglGetProcAddress("eglExportDMABUFImageQueryMESA"))}
    {
        if (!std::strstr(eglQueryString(dpy, EGL_EXTENSIONS), "EGL_MESA_image_dma_buf_export"))
        {
            BOOST_THROW_EXCEPTION((std::runtime_error{"Missing required EGL_MESA_image_dma_buf_export extension"}));
        }
    }

auto mg::EGLExtensions::MESADmaBufExport::extension_if_supported(EGLDisplay dpy) -> std::optional<MESADmaBufExport>
{
    try
    {
        return MESADmaBufExport{dpy};
    }
    catch (std::runtime_error const&)
    {
        return std::nullopt;
    }
}

mg::EGLExtensions::DeviceQuery::DeviceQuery()
    : eglQueryDeviceAttribEXT{
          reinterpret_cast<PFNEGLQUERYDEVICEATTRIBEXTPROC>(
              eglGetProcAddress("eglQueryDeviceAttribEXT"))},
      eglQueryDeviceStringEXT{
          reinterpret_cast<PFNEGLQUERYDEVICESTRINGEXTPROC>(
              eglGetProcAddress("eglQueryDeviceStringEXT"))},
     eglQueryDisplayAttribEXT {
          reinterpret_cast<PFNEGLQUERYDISPLAYATTRIBEXTPROC>(
              eglGetProcAddress("eglQueryDisplayAttribEXT"))}
{
    if (!std::strstr(eglQueryString(EGL_NO_DISPLAY, EGL_EXTENSIONS), "EGL_EXT_device_query"))
    {
        BOOST_THROW_EXCEPTION((std::runtime_error{"Missing required EGL_EXT_device_query extension"}));
    }
}
