//
// PluginVst2xLinux.c - MrsWatson
// Created by Nik Reiman on 13 May 13.
// Copyright (c) 2013 Teragon Audio. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
//   this list of conditions and the following disclaimer.
// * 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 THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 THE COPYRIGHT HOLDER 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 NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//

#if LINUX
#define VST_FORCE_DEPRECATED 0
#include "aeffectx.h"

extern "C" {
#include <dlfcn.h>
#include <stdlib.h>
#include "base/CharString.h"
#include "base/LinkedList.h"
#include "logging/EventLogger.h"
#include "plugin/PluginVst2xHostCallback.h"

    LinkedList getVst2xPluginLocations(CharString currentDirectory)
    {
        LinkedList locations = newLinkedList();
        CharString locationBuffer;
        char *vstPathEnv;

        linkedListAppend(locations, currentDirectory);

        locationBuffer = newCharString();
        snprintf(locationBuffer->data, (size_t)(locationBuffer->capacity), "%s/.vst", getenv("HOME"));
        linkedListAppend(locations, locationBuffer);

        locationBuffer = newCharString();
        vstPathEnv = getenv("VST_PATH");

        if (vstPathEnv != NULL) {
            snprintf(locationBuffer->data, (size_t)(locationBuffer->capacity), "%s", vstPathEnv);
            linkedListAppend(locations, locationBuffer);
        } else {
            freeCharString(locationBuffer);
        }

        return locations;
    }

    LibraryHandle getLibraryHandleForPlugin(const CharString pluginAbsolutePath)
    {
        void *libraryHandle = dlopen(pluginAbsolutePath->data, RTLD_NOW | RTLD_LOCAL);

        if (libraryHandle == NULL) {
            logError("Could not open library, %s", dlerror());
            return NULL;
        }

        return libraryHandle;
    }

    AEffect *loadVst2xPlugin(LibraryHandle libraryHandle)
    {
        // Somewhat cheap hack to avoid a tricky compiler warning. Casting from void* to a proper function
        // pointer will cause GCC to warn that "ISO C++ forbids casting between pointer-to-function and
        // pointer-to-object". Here, we represent both types in a union and use the correct one in the given
        // context, thus avoiding the need to cast anything.
        // See also: http://stackoverflow.com/a/2742234/14302
        union {
            Vst2xPluginEntryFunc entryPointFuncPtr;
            void *entryPointVoidPtr;
        } entryPoint;

        entryPoint.entryPointVoidPtr = dlsym(libraryHandle, "VSTPluginMain");

        if (entryPoint.entryPointVoidPtr == NULL) {
            entryPoint.entryPointVoidPtr = dlsym(libraryHandle, "main");

            if (entryPoint.entryPointVoidPtr == NULL) {
                logError("Couldn't get a pointer to plugin's main()");
                return NULL;
            }
        }

        Vst2xPluginEntryFunc mainEntryPoint = entryPoint.entryPointFuncPtr;
        AEffect *plugin = mainEntryPoint(pluginVst2xHostCallback);
        return plugin;
    }

    void closeLibraryHandle(LibraryHandle libraryHandle)
    {
        if (dlclose(libraryHandle) != 0) {
            logWarn("Could not safely close plugin, possible resource leak");
        }
    }

} // extern "C"
#endif