/*
  Copyright (C) 2005, 2006, 2007, 2008, 2011, 2012, 2013, 2014 Tadashi Watanabe <wac@umiushi.org>

  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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include "skk_dictionary.hpp"
#include "skk_server.hpp"
#include "skk_utility.hpp"
#include "skk_command_line.hpp"
#include "skk_simple_string.hpp"

namespace YaSkkServ
{
namespace
{
#define SERVER_IDENTIFIER "normal"
char version_string[] = YASKKSERV_VERSION ":yaskkserv_" SERVER_IDENTIFIER " ";

class LocalSkkServer :
        private SkkServer
{
        LocalSkkServer(LocalSkkServer &source);
        LocalSkkServer& operator=(LocalSkkServer &source);

public:
        virtual ~LocalSkkServer()
        {
        }

        LocalSkkServer(int port = 1178, int log_level = 0) :
                SkkServer("yaskkserv_" SERVER_IDENTIFIER, port, log_level),

                skk_dictionary_(0),
                dictionary_filename_table_(0),

                skk_dictionary_length_(0),
                max_connection_(0),
                listen_queue_(0),

                dictionary_check_update_flag_(false),
                no_daemonize_flag_(false)
        {
        }

        void initialize(SkkDictionary *skk_dictionary,
                        const char * const *dictionary_filename_table,
                        int skk_dictionary_length,
                        int max_connection,
                        int listen_queue,
                        bool dictionary_check_update_flag,
                        bool no_daemonize_flag)
        {
                skk_dictionary_ = skk_dictionary;
                dictionary_filename_table_ = dictionary_filename_table;

                skk_dictionary_length_ = skk_dictionary_length;
                max_connection_ = max_connection;
                listen_queue_ = listen_queue;

                dictionary_check_update_flag_ = dictionary_check_update_flag;
                no_daemonize_flag_ = no_daemonize_flag;
        }

        bool mainLoop()
        {
                bool result = main_loop_initialize(max_connection_, listen_queue_);
                if (result)
                {
#ifndef YASKKSERV_DEBUG
                        if (!no_daemonize_flag_)
                        {
                                if (fork() != 0)
                                {
                                        exit(0);
                                }
                                if (chdir("/") != 0)
                                {
                                        // why?
                                }
                                close(2);
                                close(1);
                                close(0);

                                printFirstSyslog();
                        }
#endif  // YASKKSERV_DEBUG
                        result = local_main_loop();
                        if (result)
                        {
                                result = main_loop_finalize();
                        }
                }
                return result;
        }

private:
        bool local_main_loop();
        bool local_main_loop_1_search_single_dictionary(int work_index);
        void main_loop_get_plural_dictionary_information(int work_index,
                                                         SkkDictionary *skk_dictionary,
                                                         int skk_dictionary_length,
                                                         int &found_times,
                                                         int &candidate_length,
                                                         int &total_henkanmojiretsu_size);
        bool local_main_loop_1_search_plural_dictionary(int work_index, int candidate_length, int total_henkanmojiretsu_size);
        bool local_main_loop_1_search(int work_index);
/// バッファをリセットすべきならば真を返します。
        bool local_main_loop_1(int work_index, int recv_result);

private:
        SkkDictionary *skk_dictionary_;
        const char * const *dictionary_filename_table_;

        int skk_dictionary_length_;
        int max_connection_;
        int listen_queue_;

        bool dictionary_check_update_flag_;
        bool no_daemonize_flag_;
};

bool LocalSkkServer::local_main_loop_1_search_single_dictionary(int work_index)
{
        if (skk_dictionary_->search((work_ + work_index)->read_buffer + 1))
        {
                main_loop_send_found(work_index, skk_dictionary_);
                return true;
        }
        else
        {
                return false;
        }
}

void LocalSkkServer::main_loop_get_plural_dictionary_information(int work_index,
                                                                 SkkDictionary *skk_dictionary,
                                                                 int skk_dictionary_length,
                                                                 int &found_times,
                                                                 int &candidate_length,
                                                                 int &total_henkanmojiretsu_size)
{
        found_times = 0;
        candidate_length = 0;
        total_henkanmojiretsu_size = 0;
        for (int h = 0; h != skk_dictionary_length; ++h)
        {
                if ((skk_dictionary + h)->search((work_ + work_index)->read_buffer + 1))
                {
                        const int cr_size = 1;
                        total_henkanmojiretsu_size += (skk_dictionary + h)->getHenkanmojiretsuSize() + cr_size;
                        candidate_length += SkkUtility::getCandidateLength((skk_dictionary + h)->getHenkanmojiretsuPointer());
                        ++found_times;
                }
        }
}

bool LocalSkkServer::local_main_loop_1_search_plural_dictionary(int work_index, int candidate_length, int total_henkanmojiretsu_size)
{
// candidate_length を最適な hash_table_length に変換します。
        int hash_table_length = SkkUtility::Hash<SkkUtility::HASH_TYPE_CANDIDATE>::getPrimeHashTableLength(candidate_length);
        if (hash_table_length == 0)
        {
                return false;
        }

// 見付かった複数の辞書の candidate を分解、合成します。

// 文字列は string に追加されます。重複チェックは hash でおこないます。
// 変換文字列サイズにマージンを加えたものを temporary_buffer_size とし
// ます。
        int temporary_buffer_size = total_henkanmojiretsu_size;
        {
                const int protocol_header_margin_size = 8;
                const int terminator_size = 1;
                const int margin_size = 8;
                temporary_buffer_size += protocol_header_margin_size;
                temporary_buffer_size += terminator_size;
                temporary_buffer_size += margin_size;
        }

        SkkSimpleString string(temporary_buffer_size);
        SkkUtility::Hash<SkkUtility::HASH_TYPE_CANDIDATE> hash(hash_table_length);

// protocol header + first slash
        string.appendFast("1/");

        for (int h = 0; h != skk_dictionary_length_; ++h)
        {
                if ((skk_dictionary_ + h)->isSuccess())
                {
                        char *p = const_cast<char*>((skk_dictionary_ + h)->getHenkanmojiretsuPointer());
                        int length = SkkUtility::getCandidateLength(p);
                        for (int g = 0; g != length; ++g)
                        {
                                const char *start;
                                int size;
                                if (SkkUtility::getCandidateInformation(p, g, start, size))
                                {
                                        if (!hash.contain(start, size))
                                        {
                                                hash.add(start, size);
                                                const int tail_slash_size = 1;
                                                if (!string.append(start, size + tail_slash_size))
                                                {
                                                        return false;
                                                }
                                        }
                                }
                                else
                                {
                                        return false;
                                }
                        }
                }
        }

        string.append('\n');

        if (!send((work_ + work_index)->file_descriptor, string.getBuffer(), string.getSize()))
        {
                (work_ + work_index)->closeAndReset();
        }
        return true;
}

bool LocalSkkServer::local_main_loop_1_search(int work_index)
{
//
// 探索処理は、おおまかに以下のように分けられます。
//
//    - 指定された辞書が 1 つの場合
//
//    - 指定された辞書が複数の場合
//
//        = エントリが 1 つの辞書でしか見付からなかった場合
//
//        = エントリが複数の辞書で見付かった場合
//
        if (skk_dictionary_length_ == 1)
        {
// 指定された辞書が 1 つ。
                return local_main_loop_1_search_single_dictionary(work_index);
        }

// 指定された辞書が複数。
        int found_times;
        int candidate_length;
        int total_henkanmojiretsu_size;
        main_loop_get_plural_dictionary_information(work_index,
                                                    skk_dictionary_,
                                                    skk_dictionary_length_,
                                                    found_times,
                                                    candidate_length,
                                                    total_henkanmojiretsu_size);
        if (found_times == 0)
        {
// 見付からなかった。
                return false;
        }

        if (found_times == 1)
        {
// エントリが 1 つの辞書でしか見付からなかった。
                for (int h = 0; h != skk_dictionary_length_; ++h)
                {
                        if ((skk_dictionary_ + h)->isSuccess())
                        {
                                main_loop_send_found(work_index,
                                                     skk_dictionary_ + h);
                        }
                }

                return true;
        }
 
// エントリが複数の辞書で見付かった。
        return local_main_loop_1_search_plural_dictionary(work_index, candidate_length, total_henkanmojiretsu_size);
}

bool LocalSkkServer::local_main_loop_1(int work_index, int recv_result)
{
        bool illegal_protocol_flag;
        bool result = main_loop_check_buffer(work_index, recv_result, illegal_protocol_flag);
        if (result)
        {
                bool found_flag = false;
                if (!illegal_protocol_flag)
                {
                        found_flag = local_main_loop_1_search(work_index);
                }

                if (!found_flag)
                {
                        main_loop_send_not_found(work_index, recv_result);
                }
        }
        return result;
}

bool LocalSkkServer::local_main_loop()
{
        bool result = true;
        for (;;)
        {
                fd_set fd_set_read;
                int select_result = main_loop_select(fd_set_read);
                main_loop_check_reload_dictionary(skk_dictionary_, skk_dictionary_length_, dictionary_filename_table_, dictionary_check_update_flag_);
                if (select_result == -1)
                {
                        if (errno == EINTR)
                        {
                                continue;
                        }
                }
                if (!main_loop_accept(fd_set_read, select_result))
                {
                        goto ERROR_BREAK;
                }
                for (int i = 0; i != max_connection_; ++i)
                {
                        if (main_loop_is_recv(i, fd_set_read))
                        {
                                int recv_result;
                                bool error_break_flag;
                                if (main_loop_recv(i, recv_result, error_break_flag))
                                {
                                        if (error_break_flag)
                                        {
                                                goto ERROR_BREAK;
                                        }
                                }
                                else
                                {
                                        bool buffer_reset_flag;
                                        if ((work_ + i)->read_process_index == 0)
                                        {
                                                switch (*(work_ + i)->read_buffer)
                                                {
                                                default:
                                                        buffer_reset_flag = true;
                                                        main_loop_illegal_command(i);
                                                        break;
                                                case '0':
                                                        buffer_reset_flag = true;
                                                        main_loop_0(i);
                                                        break;
                                                case '1':
                                                        buffer_reset_flag = local_main_loop_1(i, recv_result);
                                                        break;
                                                case '2':
                                                        buffer_reset_flag = true;
                                                        main_loop_2(i, version_string, sizeof(version_string));
                                                        break;
                                                case '3':
                                                        buffer_reset_flag = true;
                                                        main_loop_3(i);
                                                        break;
                                                }
                                        }
                                        else
                                        {
                                                buffer_reset_flag = local_main_loop_1(i, recv_result);
                                        }

                                        main_loop_check_buffer_reset(i, recv_result, buffer_reset_flag);
                                }
                        }
                }
        }
ERROR_BREAK:
        result = false;

//SUCCESS_BREAK:
        return result;
}

int print_usage()
{
        SkkUtility::printf("Usage: yaskkserv [OPTION] dictionary [dictionary...]\n"
                           "  -c, --check-update       check update dictionary (default disable)\n"
                           "  -d, --debug              enable debug mode (default disable)\n"
                           "  -h, --help               print this help and exit\n"
                           "  -l, --log-level=LEVEL    loglevel (range [0 - 9]  default 1)\n"
                           "  -m, --max-connection=N   max connection (default 8)\n"
                           "  -p, --port=PORT          set port (default 1178)\n"
                           "  -f, --no-daemonize       not daemonize\n"
                           "  -v, --version            print version\n");
        return EXIT_FAILURE;
}

int print_version()
{
        SkkUtility::printf("yaskkserv_" SERVER_IDENTIFIER " version " YASKKSERV_VERSION "\n");
        SkkUtility::printf("Copyright (C) 2005, 2006, 2007, 2008, 2011, 2012, 2013, 2014 Tadashi Watanabe\n");
        SkkUtility::printf("http://umiushi.org/~wac/yaskkserv/\n");
        return EXIT_FAILURE;
}

enum
{
        OPTION_TABLE_CHECK_UPDATE,
        OPTION_TABLE_DEBUG,
        OPTION_TABLE_HELP,
        OPTION_TABLE_LOG_LEVEL,
        OPTION_TABLE_MAX_CONNECTION,
        OPTION_TABLE_PORT,
        OPTION_TABLE_NO_DAEMONIZE,
        OPTION_TABLE_VERSION,

        OPTION_TABLE_LENGTH
};

const SkkCommandLine::Option option_table[] =
{
        {
                "c", "check-update",
                SkkCommandLine::OPTION_ARGUMENT_NONE,
        },
        {
                "d", "debug",
                SkkCommandLine::OPTION_ARGUMENT_NONE,
        },
        {
                "h", "help",
                SkkCommandLine::OPTION_ARGUMENT_NONE,
        },
        {
                "l", "log-level",
                SkkCommandLine::OPTION_ARGUMENT_INTEGER,
        },
        {
                "m", "max-connection",
                SkkCommandLine::OPTION_ARGUMENT_INTEGER,
        },
        {
                "p", "port",
                SkkCommandLine::OPTION_ARGUMENT_INTEGER,
        },
        {
                "f", "no-daemonize",
                SkkCommandLine::OPTION_ARGUMENT_NONE,
        },
        {
                "v", "version",
                SkkCommandLine::OPTION_ARGUMENT_NONE,
        },
        {
                0, 0,
                SkkCommandLine::OPTION_ARGUMENT_TERMINATOR,
        },
};

struct Option
{
        int log_level;
        int max_connection;
        int port;
        bool no_daemonize_flag;
        bool check_update_flag;
        bool debug_flag;
}
option =
{
        1,
        8,
        1178,
        false,
        false,
        false,
};

// 戻り値が真ならば呼び出し側で return すべきです。このとき result に戻り値を返します。戻り値が偽の場合 result には触れません。
bool local_main_core_command_line(SkkCommandLine &command_line, int &result, int argc, char *argv[])
{
        if (command_line.parse(argc, argv, option_table))
        {
                if (command_line.isOptionDefined(OPTION_TABLE_HELP))
                {
                        result = print_usage();
                        return true;
                }
                if (command_line.isOptionDefined(OPTION_TABLE_VERSION))
                {
                        result = print_version();
                        return true;
                }
// 辞書指定が無い場合と、念のため非常識な値 (64) より多い指定をはじいておく。
                if ((command_line.getArgumentLength() < 1) || (command_line.getArgumentLength() > 64))
                {
                        result = print_usage();
                        return true;
                }
                if (command_line.isOptionDefined(OPTION_TABLE_CHECK_UPDATE))
                {
                        option.check_update_flag = true;
                }
                if (command_line.isOptionDefined(OPTION_TABLE_DEBUG))
                {
                        option.debug_flag = true;
                }
                if (command_line.isOptionDefined(OPTION_TABLE_LOG_LEVEL))
                {
                        option.log_level = command_line.getOptionArgumentInteger(OPTION_TABLE_LOG_LEVEL);
                        if ((option.log_level < 0) || (option.log_level > 9))
                        {
                                SkkUtility::printf("Illegal log-level %d (0 - 9)\n", option.log_level);
                                result = print_usage();
                                return true;
                        }
                }
                if (command_line.isOptionDefined(OPTION_TABLE_MAX_CONNECTION))
                {
                        option.max_connection = command_line.getOptionArgumentInteger(OPTION_TABLE_MAX_CONNECTION);
                        if ((option.max_connection < 1) || (option.max_connection > 1024))
                        {
                                SkkUtility::printf("Illegal max-connection %d (1 - 1024)\n", option.max_connection);
                                result = print_usage();
                                return true;
                        }
                }
                if (command_line.isOptionDefined(OPTION_TABLE_PORT))
                {
                        option.port = command_line.getOptionArgumentInteger(OPTION_TABLE_PORT);
                        if ((option.port < 1) || (option.port > 65535))
                        {
                                SkkUtility::printf("Illegal port number %d (1 - 65535)\n", option.port);
                                result = print_usage();
                                return true;
                        }
                }
                if (command_line.isOptionDefined(OPTION_TABLE_NO_DAEMONIZE))
                {
                        option.no_daemonize_flag = true;
                }
        }
        else
        {
                SkkUtility::printf("error \"%s\"\n\n", command_line.getErrorString());
                result = print_usage();
                return true;
        }
        return false;
}

// 呼び出し元で返すべき戻り値 EXIT_SUCCESS または EXIT_FAILURE を返します。
int local_main_core_setup_dictionary(const SkkCommandLine &command_line, SkkDictionary *skk_dictionary)
{
        int result = EXIT_SUCCESS;
        int skk_dictionary_length = command_line.getArgumentLength();
        for (int i = 0; i != skk_dictionary_length; ++i)
        {
                SkkUtility::DictionaryPermission dictionary_permission(command_line.getArgumentPointer(i));
                if (!dictionary_permission.isExist())
                {
                        SkkUtility::printf("dictionary file \"%s\" (index = %d) not found\n",
                                           command_line.getArgumentPointer(i),
                                           i);
                        result = EXIT_FAILURE;
                        break;
                }
                if (!dictionary_permission.checkAndPrintPermission())
                {
                        result = EXIT_FAILURE;
                        break;
                }

                if (!(skk_dictionary + i)->open(command_line.getArgumentPointer(i)))
                {
                        SkkUtility::printf("dictionary file \"%s\" (index = %d) open failed\n",
                                           command_line.getArgumentPointer(i),
                                           i);
                        result = EXIT_FAILURE;
                        break;
                }
        }
        return result;
}

int local_main_core(int argc, char *argv[])
{
        int result = EXIT_SUCCESS;
        SkkCommandLine command_line;
        if (local_main_core_command_line(command_line, result, argc, argv))
        {
                return result;
        }

        int skk_dictionary_length = command_line.getArgumentLength();
        SkkDictionary *skk_dictionary = new SkkDictionary[skk_dictionary_length];
        result = local_main_core_setup_dictionary(command_line, skk_dictionary);

        if (result == EXIT_SUCCESS)
        {
                LocalSkkServer *skk_server = new LocalSkkServer(option.port, option.log_level);
                const int listen_queue = 5;
                skk_server->initialize(skk_dictionary,
                                       &argv[command_line.getArgumentArgvIndex()],
                                       skk_dictionary_length,
                                       option.max_connection,
                                       listen_queue,
                                       option.check_update_flag,
                                       option.no_daemonize_flag);
                if (!skk_server->mainLoop())
                {
                        result = EXIT_FAILURE;
                }
                delete skk_server;
        }

        delete[] skk_dictionary;

        return result;
}
}

int local_main(int argc, char *argv[])
{
        return local_main_core(argc, argv);
}
}
