/***************************************************************************
 *                                                                         *
 *   Copyright (C) 2007 Christian Schoenebeck                              *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   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 General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the Free Software           *
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston,                 *
 *   MA  02111-1307  USA                                                   *
 ***************************************************************************/

#include "InstrumentEditorFactory.h"

#include "../common/global_private.h"

#if defined(WIN32)
#include <windows.h>
#else
#include <dlfcn.h>
#include <errno.h>
#include <dirent.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#endif
#include <string.h>

#ifndef CONFIG_PLUGIN_DIR
# error "Configuration macro CONFIG_PLUGIN_DIR not defined!"
#endif // CONFIG_PLUGIN_DIR

#if defined(WIN32)
typedef void* (*InnerFactoryRegisterFunction)(void);
#endif

namespace LinuxSampler {

    std::map<String, InstrumentEditorFactory::InnerFactory*> InstrumentEditorFactory::InnerFactories;

    bool InstrumentEditorFactory::bPluginsLoaded = false;

    std::list<void*> InstrumentEditorFactory::LoadedDLLs;

    std::vector<String> InstrumentEditorFactory::AvailableEditors() {
        // make sure plugins were loaded already
        LoadPlugins();
        // render result
        std::vector<String> result;
        std::map<String, InnerFactory*>::iterator iter = InnerFactories.begin();
        for (; iter != InnerFactories.end(); iter++)
            result.push_back(iter->first);
        return result;
    }

    std::vector<String> InstrumentEditorFactory::MatchingEditors(String sTypeName, String sTypeVersion) {
        // make sure plugins were loaded already
        LoadPlugins();
        // render result
        std::vector<String> result;
        std::map<String, InnerFactory*>::iterator iter = InnerFactories.begin();
        for (; iter != InnerFactories.end(); iter++) {
            InstrumentEditor* pEditor = iter->second->Create();
            if (pEditor->IsTypeSupported(sTypeName, sTypeVersion))
                result.push_back(iter->first);
            iter->second->Destroy(pEditor);
        }
        return result;
    }

    String InstrumentEditorFactory::AvailableEditorsAsString() {
        std::vector<String> drivers = AvailableEditors();
        String result;
        std::vector<String>::iterator iter = drivers.begin();
        for (; iter != drivers.end(); iter++) {
            if (result != "") result += ",";
            result += "'" + *iter + "'";
        }
        return result;
    }

    InstrumentEditor* InstrumentEditorFactory::Create(String InstrumentEditorName) throw (Exception) {
        if (InnerFactories.count(InstrumentEditorName)) {
            InnerFactory* pInnerFactory = InnerFactories[InstrumentEditorName];
            return pInnerFactory->Create();
        } else throw Exception("unknown instrument editor");
    }

    void InstrumentEditorFactory::Destroy(InstrumentEditor* pInstrumentEditor) throw (Exception) {
        if (InnerFactories.count(pInstrumentEditor->Name())) {
            InnerFactory* pInnerFactory = InnerFactories[pInstrumentEditor->Name()];
            return pInnerFactory->Destroy(pInstrumentEditor);
        } else throw Exception("unknown instrument editor");
    }

    void InstrumentEditorFactory::LoadPlugins() {
        if (!bPluginsLoaded) {
            dmsg(1,("Loading instrument editor plugins..."));
            #if defined(WIN32)
            WIN32_FIND_DATA win32FindData;
            const String plugindir = (String)CONFIG_PLUGIN_DIR + (String)("\\*.DLL");
            HANDLE hDir = FindFirstFile(plugindir.c_str(), &win32FindData);
            if (hDir == INVALID_HANDLE_VALUE) {
                if (GetLastError() != ERROR_FILE_NOT_FOUND) {
                    std::cerr << "Could not open instrument editor plugins "
                              << "directory (" << CONFIG_PLUGIN_DIR << "), "
                              << "Error: " << GetLastError() << std::endl;
                } else {
                    dmsg(1,("None"));
                }
                // either dir doesn't exist or is empty
                return;
            }

            do {
                // skip directory entries
                if (win32FindData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
                    continue;
                // dir entry name as full qualified path
                const String sPath = (String)CONFIG_PLUGIN_DIR + ((String)"\\" + (String)win32FindData.cFileName);
                // load the DLL
                HINSTANCE hinstLib;
                void* pDLL = hinstLib = LoadLibrary(sPath.c_str());
                if (!pDLL) {
                    std::cerr << "Failed to load instrument editor plugin: "
                              << sPath << std::endl;
                    continue;
                }

                //(InnerFactory*) (*fn)(void);
                InnerFactoryRegisterFunction fn =
                    (InnerFactoryRegisterFunction)
                        GetProcAddress(
                            hinstLib,
                            "createInstrumentEditorInnerFactory"
                        );
                if (fn == NULL) {
                    std::cerr << "ERROR: unable to find "
                                 "createInstrumentEditorInnerFactory() "
                                 "in DLL\n" << std::flush;
                    FreeLibrary(hinstLib);
                    continue;
                }

                // get the plugin instance and register it to the factory

                InnerFactory* pInnerFactory = (InnerFactory*)fn();
                if (!pInnerFactory) {
                    std::cerr << "ERROR: !pInnerFactory\n" << std::flush;
                    FreeLibrary(hinstLib);
                    continue;
                }
                InstrumentEditor* pEditor = pInnerFactory->Create();
                if (InnerFactories.count(pEditor->Name())) {
                    std::cerr << "ERROR: a plugin with name '"
                              << pEditor->Name()
                              << "' already loaded (skipping)\n"
                              << std::flush;
                    pInnerFactory->Destroy(pEditor);
                    FreeLibrary(hinstLib);
                    continue;
                }
                InnerFactories[pEditor->Name()] = pInnerFactory;
                pInnerFactory->Destroy(pEditor);

                LoadedDLLs.push_back(pDLL);
            } while (FindNextFile(hDir, &win32FindData));
            if (hDir != INVALID_HANDLE_VALUE) FindClose(hDir);
            #else // POSIX
            DIR* hDir = opendir(CONFIG_PLUGIN_DIR);
            if (!hDir) {
                std::cerr << "Could not open instrument editor plugins directory "
                          << "(" << CONFIG_PLUGIN_DIR << "): "
                          << strerror(errno) << std::endl;
                return;
            }
            for (dirent* pEntry = readdir(hDir); pEntry; pEntry = readdir(hDir)) {
                // dir entry name as full qualified path
                const String sPath = CONFIG_PLUGIN_DIR + ("/" + String(pEntry->d_name));
                // skip entries that are not regular files
                struct stat entry_stat;
                if (lstat(sPath.c_str(), &entry_stat) != 0 ||
                   (entry_stat.st_mode & S_IFMT) != S_IFREG)
                   continue;
                // skip files that are not .so files
                if (sPath.length() < 3 ||
                    sPath.substr(sPath.length() - 3) != ".so" &&
                    sPath.find(".so.") == String::npos
                ) continue;
                // load the DLL (the plugins should register themselfes automatically)
                void* pDLL = dlopen(sPath.c_str(), RTLD_NOW);
                if (pDLL) LoadedDLLs.push_back(pDLL);
                else {
                    std::cerr << "Failed to load instrument editor plugin: "
                              << sPath << std::endl;
                }
            }
            closedir(hDir);
            #endif
            bPluginsLoaded = true;
            dmsg(1,("OK\n"));
        }
    }

    void InstrumentEditorFactory::ClosePlugins() {
        if (LoadedDLLs.size()) {
            dmsg(1,("Unloading instrument editor plugins..."));
            // free all inner factories
            {
                std::map<String, InnerFactory*>::iterator iter = InnerFactories.begin();
                for (; iter != InnerFactories.end(); iter++) delete iter->second;
                InnerFactories.clear();
            }
            // free the DLLs
            {
                std::list<void*>::iterator iter = LoadedDLLs.begin();
                for (; iter != LoadedDLLs.end(); iter++) {
                    #if defined(WIN32)
                    FreeLibrary((HINSTANCE)*iter);
                    #else
                    dlclose(*iter);
                    #endif
                }
                LoadedDLLs.clear();
                dmsg(1,("OK\n"));
            }
        }
        bPluginsLoaded = false;
    }

} // namespace LinuxSampler