/**
 * Copyright (C) 2013 Citrus Emulator
 *
 * @file    loader.cpp
 * @author  ShizZy <shizzy247@gmail.com>
 * @date    2013-09-18
 * @brief   Loads bootable binaries into the emu
 *
 * @section LICENSE
 * 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 at
 * http://www.gnu.org/copyleft/gpl.html
 *
 * Official project repository can be found at:
 * http://code.google.com/p/gekko-gc-emu/
 */

#include "file_util.h"
#include "loader.h"
#include "system.h"
#include "core.h"
#include "file_sys/directory_file_system.h"
#include "elf/elf_reader.h"

////////////////////////////////////////////////////////////////////////////////////////////////////

/// Loads an extracted CXI from a directory
bool LoadDirectory_CXI(std::string &filename) {
    std::string full_path = filename;
    std::string path, file, extension;
    SplitPath(ReplaceAll(full_path, "\\", "/"), &path, &file, &extension);
#if EMU_PLATFORM == PLATFORM_WINDOWS
    path = ReplaceAll(path, "/", "\\");
#endif
    DirectoryFileSystem *fs = new DirectoryFileSystem(&System::g_ctr_file_system, path);
    System::g_ctr_file_system.Mount("fs:", fs);

    std::string final_name = "fs:/" + file + extension;
    File::IOFile f(filename, "rb");

    if (f.IsOpen()) {
        // TODO(ShizZy): read here to memory....
    }
    ERROR_LOG(TIME, "Unimplemented function!");
    return true;
}

/// Loads a CTR ELF file
bool Load_ELF(std::string &filename) {
    std::string full_path = filename;
    std::string path, file, extension;
    SplitPath(ReplaceAll(full_path, "\\", "/"), &path, &file, &extension);
#if EMU_PLATFORM == PLATFORM_WINDOWS
    path = ReplaceAll(path, "/", "\\");
#endif
    File::IOFile f(filename, "rb");

    if (f.IsOpen()) {
        u64 size = f.GetSize();
        u8* buffer = new u8[size];
        ElfReader* elf_reader = NULL;

        f.ReadBytes(buffer, size);

        elf_reader = new ElfReader(buffer);
        elf_reader->LoadInto(0x00100000);

        Core::g_app_core->SetPC(elf_reader->GetEntryPoint());

        delete[] buffer;
        delete elf_reader;
    } else {
        return false;
    }
    f.Close();

    return true;
}

namespace Loader {

bool IsBootableDirectory() {
    ERROR_LOG(TIME, "Unimplemented function!");
    return true;
}

/**
 * Identifies the type of a bootable file
 * @param filename String filename of bootable file
 * @todo (ShizZy) this function sucks... make it actually check file contents etc.
 * @return FileType of file
 */
FileType IdentifyFile(std::string &filename) {
    if (filename.size() == 0) {
        ERROR_LOG(LOADER, "invalid filename %s", filename.c_str());
        return FILETYPE_ERROR;
    }
    std::string extension = filename.size() >= 5 ? filename.substr(filename.size() - 4) : "";

    if (File::IsDirectory(filename)) {
        if (IsBootableDirectory()) {
            return FILETYPE_DIRECTORY_CXI;
        }
        else {
            return FILETYPE_NORMAL_DIRECTORY;
        }
    }
    else if (!strcasecmp(extension.c_str(), ".elf")) {
        return FILETYPE_CTR_ELF; // TODO(bunnei): Do some filetype checking :p
    }
    else if (!strcasecmp(extension.c_str(), ".zip")) {
        return FILETYPE_ARCHIVE_ZIP;
    }
    else if (!strcasecmp(extension.c_str(), ".rar")) {
        return FILETYPE_ARCHIVE_RAR;
    }
    else if (!strcasecmp(extension.c_str(), ".r00")) {
        return FILETYPE_ARCHIVE_RAR;
    }
    else if (!strcasecmp(extension.c_str(), ".r01")) {
        return FILETYPE_ARCHIVE_RAR;
    }
    return FILETYPE_UNKNOWN;
}

/**
 * Identifies and loads a bootable file
 * @param filename String filename of bootable file
 * @param error_string Point to string to put error message if an error has occurred
 * @return True on success, otherwise false
 */
bool LoadFile(std::string &filename, std::string *error_string) {
    INFO_LOG(LOADER, "Identifying file...");

    // Note that this can modify filename!
    switch (IdentifyFile(filename)) {

    case FILETYPE_CTR_ELF:
        return Load_ELF(filename);

    case FILETYPE_DIRECTORY_CXI:
        return LoadDirectory_CXI(filename);

    case FILETYPE_ERROR:
        ERROR_LOG(LOADER, "Could not read file");
        *error_string = "Error reading file";
        break;

    case FILETYPE_ARCHIVE_RAR:
#ifdef WIN32
        *error_string = "RAR file detected (Require WINRAR)";
#else
        *error_string = "RAR file detected (Require UnRAR)";
#endif
        break;

    case FILETYPE_ARCHIVE_ZIP:
#ifdef WIN32
        *error_string = "ZIP file detected (Require WINRAR)";
#else
        *error_string = "ZIP file detected (Require UnRAR)";
#endif
        break;

    case FILETYPE_NORMAL_DIRECTORY:
        ERROR_LOG(LOADER, "Just a directory.");
        *error_string = "Just a directory.";
        break;

    case FILETYPE_UNKNOWN_BIN:
    case FILETYPE_UNKNOWN_ELF:
    case FILETYPE_UNKNOWN:
    default:
        ERROR_LOG(LOADER, "Failed to identify file");
        *error_string = "Failed to identify file";
        break;
    }
    return false;
}

} // namespace