/*
Copyright (C) 2005-2008 Axel Liljencrantz

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License version 2 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 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
*/


/** \file fish.c
	The main loop of <tt>fish</tt>.
*/

#include "config.h"

#include <limits.h>
#include <stddef.h>
#include <stdint.h>
#include <sys/stat.h>
#include <string>
#include <vector>
#include <stdlib.h>
#include <stdio.h>
#include <wchar.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/socket.h> // IWYU pragma: keep - suggests internal header
#include <sys/un.h>
#include <pwd.h>

#ifdef HAVE_GETOPT_H
#include <getopt.h>
#endif

#include <locale.h>

#include "fallback.h" // IWYU pragma: keep

#include "common.h"
#include "reader.h"
#include "builtin.h"
#include "function.h"
#include "wutil.h"
#include "env.h"
#include "proc.h"
#include "parser.h"
#include "expand.h"
#include "intern.h"
#include "event.h"
#include "history.h"
#include "path.h"
#include "input.h"
#include "io.h"
#include "fish_version.h"

/* PATH_MAX may not exist */
#ifndef PATH_MAX
#define PATH_MAX 1024
#endif

/**
   The string describing the single-character options accepted by the main fish binary
*/
#define GETOPT_STRING "+hilnvc:p:d:"

/* If we are doing profiling, the filename to output to */
static const char *s_profiling_output_filename = NULL;

static bool has_suffix(const std::string &path, const char *suffix, bool ignore_case)
{
    size_t pathlen = path.size(), suffixlen = strlen(suffix);
    return pathlen >= suffixlen && !(ignore_case ? strcasecmp : strcmp)(path.c_str() + pathlen - suffixlen, suffix);
}

/* Modifies the given path by calling realpath. Returns true if realpath succeeded, false otherwise */
static bool get_realpath(std::string &path)
{
    char buff[PATH_MAX], *ptr;
    if ((ptr = realpath(path.c_str(), buff)))
    {
        path = ptr;
    }
    return ptr != NULL;
}

/* OS X function for getting the executable path */
extern "C" {
    int _NSGetExecutablePath(char* buf, uint32_t* bufsize);
}

/* Return the path to the current executable. This needs to be realpath'd. */
static std::string get_executable_path(const char *argv0)
{
    char buff[PATH_MAX];
#if __APPLE__
    {
        /* Returns 0 on success, -1 if the buffer is too small */
        uint32_t buffSize = sizeof buff;
        if (0 == _NSGetExecutablePath(buff, &buffSize))
            return std::string(buff);

        /* Loop until we're big enough */
        char *mbuff = (char *)malloc(buffSize);
        while (0 > _NSGetExecutablePath(mbuff, &buffSize))
            mbuff = (char *)realloc(mbuff, buffSize);

        /* Return the string */
        std::string result = mbuff;
        free(mbuff);
        return result;
    }
#endif
    {
        /* On other Unixes, try /proc directory. This might be worth breaking out into macros. */
        if (0 < readlink("/proc/self/exe", buff, sizeof buff) || // Linux
                0 < readlink("/proc/curproc/file", buff, sizeof buff) || // BSD
                0 < readlink("/proc/self/path/a.out", buff, sizeof buff)) // Solaris
        {
            return std::string(buff);
        }
    }

    /* Just return argv0, which probably won't work (i.e. it's not an absolute path or a path relative to the working directory, but instead something the caller found via $PATH). We'll eventually fall back to the compile time paths. */
    return std::string(argv0 ? argv0 : "");
}


static struct config_paths_t determine_config_directory_paths(const char *argv0)
{
    struct config_paths_t paths;
    bool done = false;
    std::string exec_path = get_executable_path(argv0);
    if (get_realpath(exec_path))
    {
#if __APPLE__

        /* On OS X, maybe we're an app bundle, and should use the bundle's files. Since we don't link CF, use this lame approach to test it: see if the resolved path ends with /Contents/MacOS/fish, case insensitive since HFS+ usually is.
         */
        if (! done)
        {
            const char *suffix = "/Contents/MacOS/fish";
            const size_t suffixlen = strlen(suffix);
            if (has_suffix(exec_path, suffix, true))
            {
                /* Looks like we're a bundle. Cut the string at the / prefixing /Contents... and then the rest */
                wcstring wide_resolved_path = str2wcstring(exec_path);
                wide_resolved_path.resize(exec_path.size() - suffixlen);
                wide_resolved_path.append(L"/Contents/Resources/");

                /* Append share, etc, doc */
                paths.data = wide_resolved_path + L"share/fish";
                paths.sysconf = wide_resolved_path + L"etc/fish";
                paths.doc = wide_resolved_path + L"doc/fish";

                /* But the bin_dir is the resolved_path, minus fish (aka the MacOS directory) */
                paths.bin = str2wcstring(exec_path);
                paths.bin.resize(paths.bin.size() - strlen("/fish"));

                done = true;
            }
        }
#endif

        if (! done)
        {
            /* The next check is that we are in a reloctable directory tree like this:
                 bin/fish
                 etc/fish
                 share/fish

                 Check it!
            */
            const char *suffix = "/bin/fish";
            if (has_suffix(exec_path, suffix, false))
            {
                wcstring base_path = str2wcstring(exec_path);
                base_path.resize(base_path.size() - strlen(suffix));

                paths.data = base_path + L"/share/fish";
                paths.sysconf = base_path + L"/etc/fish";
                paths.doc = base_path + L"/share/doc/fish";
                paths.bin = base_path + L"/bin";

                /* Check only that the data and sysconf directories exist. Handle the doc directories separately */
                struct stat buf;
                if (0 == wstat(paths.data, &buf) && 0 == wstat(paths.sysconf, &buf))
                {
                    /* The docs dir may not exist; in that case fall back to the compiled in path */
                    if (0 != wstat(paths.doc, &buf))
                    {
                        paths.doc = L"" DOCDIR;
                    }
                    done = true;
                }
            }
        }
    }

    if (! done)
    {
        /* Fall back to what got compiled in. */
        paths.data = L"" DATADIR "/fish";
        paths.sysconf = L"" SYSCONFDIR "/fish";
        paths.doc = L"" DOCDIR;
        paths.bin = L"" BINDIR;

        done = true;
    }

    return paths;
}

// Source the file config.fish in the given directory.
static void source_config_in_directory(const wcstring &dir)
{
    // If the config.fish file doesn't exist or isn't readable silently return.
    // Fish versions up thru 2.2.0 would instead try to source the file with
    // stderr redirected to /dev/null to deal with that possibility.
    //
    // This introduces a race condition since the readability of the file can
    // change between this test and the execution of the 'source' command.
    // However, that is not a security problem in this context so we ignore it.
    const wcstring config_pathname = dir + L"/config.fish";
    const wcstring escaped_dir = escape_string(dir, ESCAPE_ALL);
    const wcstring escaped_pathname = escaped_dir + L"/config.fish";
    if (waccess(config_pathname, R_OK) != 0) {
        debug(2, L"not sourcing %ls (not readable or does not exist)",
                escaped_pathname.c_str());
        return;
    }
    debug(2, L"sourcing %ls", escaped_pathname.c_str());

    const wcstring cmd = L"builtin source " + escaped_pathname;
    parser_t &parser = parser_t::principal_parser();
    parser.set_is_within_fish_initialization(true);
    parser.eval(cmd, io_chain_t(), TOP);
    parser.set_is_within_fish_initialization(false);
}

static int try_connect_socket(std::string &name)
{
    int s, r, ret = -1;

    /** Connect to a DGRAM socket rather than the expected STREAM.
      This avoids any notification to a remote socket that we have connected,
      preventing any surprising behaviour.
      If the connection fails with EPROTOTYPE, the connection is probably a
      STREAM; if it succeeds or fails any other way, there is no cause for
      alarm.
      With thanks to Andrew Lutomirski <github.com/amluto>
    */

    if ((s = socket(AF_UNIX, SOCK_DGRAM, 0)) == -1)
    {
        wperror(L"socket");
        return -1;
    }

    debug(3, L"Connect to socket %s at fd %d", name.c_str(), s);

    struct sockaddr_un local = {};
    local.sun_family = AF_UNIX;
    strncpy(local.sun_path, name.c_str(), (sizeof local.sun_path) - 1);

    r = connect(s, (struct sockaddr *)&local, sizeof local);

    if (r == -1 && errno == EPROTOTYPE)
    {
        ret = 0;
    }

    close(s);
    return ret;
}

/**
   Check for a running fishd from old versions and warn about not being able
   to share variables.
   https://github.com/fish-shell/fish-shell/issues/1730
*/
static void check_running_fishd()
{
    /* There are two paths to check:
       $FISHD_SOCKET_DIR/fishd.socket.$USER or /tmp/fishd.socket.$USER
         - referred to as the "old socket"
       $XDG_RUNTIME_DIR/fishd.socket or /tmp/fish.$USER/fishd.socket
         - referred to as the "new socket"
       All existing versions of fish attempt to create the old socket, but
       failure in newer versions is not treated as critical, so both need
       to be checked. */
    const char *uname = getenv("USER");
    if (uname == NULL)
    {
        const struct passwd *pw = getpwuid(getuid());
        uname = pw->pw_name;
    }

    const char *dir_old_socket = getenv("FISHD_SOCKET_DIR");
    std::string path_old_socket;

    if (dir_old_socket == NULL)
    {
        path_old_socket = "/tmp/";
    }
    else
    {
        path_old_socket.append(dir_old_socket);
    }

    path_old_socket.append("fishd.socket.");
    path_old_socket.append(uname);

    const char *dir_new_socket = getenv("XDG_RUNTIME_DIR");
    std::string path_new_socket;
    if (dir_new_socket == NULL)
    {
        path_new_socket = "/tmp/fish.";
        path_new_socket.append(uname);
        path_new_socket.push_back('/');
    }
    else
    {
        path_new_socket.append(dir_new_socket);
    }

    path_new_socket.append("fishd.socket");

    if (try_connect_socket(path_old_socket) == 0 || try_connect_socket(path_new_socket) == 0)
    {
        debug(1, _(L"Old versions of fish appear to be running. You will not be able to share variable values between old and new fish sessions. For best results, restart all running instances of fish."));
    }

}

/**
   Parse init files. exec_path is the path of fish executable as determined by argv[0].
*/
static int read_init(const struct config_paths_t &paths)
{
    source_config_in_directory(paths.data);
    source_config_in_directory(paths.sysconf);

    /* We need to get the configuration directory before we can source the user configuration file. If path_get_config returns false then we have no configuration directory and no custom config to load. */
    wcstring config_dir;
    if (path_get_config(config_dir))
    {
        source_config_in_directory(config_dir);
    }

    return 1;
}

/**
  Parse the argument list, return the index of the first non-switch
  arguments.
 */
static int fish_parse_opt(int argc, char **argv, std::vector<std::string> *cmds)
{
    const struct option long_options[] =
    {
        { "command", required_argument, NULL, 'c' },
        { "debug-level", required_argument, NULL, 'd' },
        { "interactive", no_argument, NULL, 'i' } ,
        { "login", no_argument, NULL, 'l' },
        { "no-execute", no_argument, NULL, 'n' },
        { "profile", required_argument, NULL, 'p' },
        { "help", no_argument, NULL, 'h' },
        { "version", no_argument, NULL, 'v' },
        { NULL, 0, NULL, 0 }
    };

    while (1)
    {
        int opt = getopt_long(argc, argv, GETOPT_STRING, long_options, NULL);
        if (opt == -1)
            break;

        switch (opt)
        {
            case 0:
            {
                break;
            }

            case 'c':
            {
                cmds->push_back(optarg);
                break;
            }

            case 'd':
            {
                char *end;
                long tmp;

                errno = 0;
                tmp = strtol(optarg, &end, 10);

                if (tmp >= 0 && tmp <=10 && !*end && !errno)
                {
                    debug_level = (int)tmp;
                }
                else
                {
                    debug(0, _(L"Invalid value '%s' for debug level switch"), optarg);
                    exit_without_destructors(1);
                }
                break;
            }

            case 'h':
            {
                cmds->push_back("__fish_print_help fish");
                break;
            }

            case 'i':
            {
                is_interactive_session = 1;
                break;
            }

            case 'l':
            {
                is_login = 1;
                break;
            }

            case 'n':
            {
                no_exec = 1;
                break;
            }

            case 'p':
            {
                s_profiling_output_filename = optarg;
                g_profiling_active = true;
                break;
            }

            case 'v':
            {
                fwprintf(stderr, _(L"%s, version %s\n"), PACKAGE_NAME,
                         get_fish_version());
                exit_without_destructors(0);
            }

            default:
            {
                exit_without_destructors(1);
            }

        }
    }

    // If our command name begins with a dash that implies we're a login shell.
    is_login |= argv[0][0] == '-';

    // We are an interactive session if we have not been given an explicit
    // command or file to execute and stdin is a tty. Note that the -i or
    // --interactive options also force interactive mode.
    if (cmds->size() == 0 && optind == argc && isatty(STDIN_FILENO))
    {
        is_interactive_session = 1;
    }

    return optind;
}

int main(int argc, char **argv)
{
    int res=1;
    int my_optind=0;

    set_main_thread();
    setup_fork_guards();

    wsetlocale(LC_ALL, L"");
    program_name=L"fish";

    //struct stat tmp;
    //stat("----------FISH_HIT_MAIN----------", &tmp);

    std::vector<std::string> cmds;
    my_optind = fish_parse_opt(argc, argv, &cmds);

    /*
      No-exec is prohibited when in interactive mode
    */
    if (is_interactive_session && no_exec)
    {
        debug(1, _(L"Can not use the no-execute mode when running an interactive session"));
        no_exec = 0;
    }

    /* Only save (and therefore restore) the fg process group if we are interactive. See #197, #1002 */
    if (is_interactive_session)
    {
        save_term_foreground_process_group();
    }

    const struct config_paths_t paths = determine_config_directory_paths(argv[0]);

    proc_init();
    event_init();
    builtin_init();
    function_init();
    env_init(&paths);
    reader_init();
    history_init();
    /* For setcolor to support term256 in config.fish (#1022) */
    update_fish_color_support();

    parser_t &parser = parser_t::principal_parser();

    if (g_log_forks)
        printf("%d: g_fork_count: %d\n", __LINE__, g_fork_count);

    const io_chain_t empty_ios;
    if (read_init(paths))
    {
        /* Stomp the exit status of any initialization commands (#635) */
        proc_set_last_status(STATUS_BUILTIN_OK);

        /* Run the commands specified as arguments, if any */
        if (! cmds.empty())
        {
            /* Do something nasty to support OpenSUSE assuming we're bash. This may modify cmds. */
            if (is_login)
            {
                fish_xdm_login_hack_hack_hack_hack(&cmds, argc - my_optind, argv + my_optind);
            }
            for (size_t i=0; i < cmds.size(); i++)
            {
                const wcstring cmd_wcs = str2wcstring(cmds.at(i));
                res = parser.eval(cmd_wcs, empty_ios, TOP);
            }
            reader_exit(0, 0);
        }
        else
        {
            if (my_optind == argc)
            {
                // Interactive mode
                check_running_fishd();
                res = reader_read(STDIN_FILENO, empty_ios);
            }
            else
            {
                char **ptr;
                char *file = *(argv+(my_optind++));
                int i;
                int fd;


                if ((fd = open(file, O_RDONLY)) == -1)
                {
                    wperror(L"open");
                    return 1;
                }

                // OK to not do this atomically since we cannot have gone multithreaded yet
                set_cloexec(fd);

                if (*(argv+my_optind))
                {
                    wcstring sb;
                    for (i=1,ptr = argv+my_optind; *ptr; i++, ptr++)
                    {
                        if (i != 1)
                            sb.append(ARRAY_SEP_STR);
                        sb.append(str2wcstring(*ptr));
                    }

                    env_set(L"argv", sb.c_str(), 0);
                }

                const wcstring rel_filename = str2wcstring(file);

                reader_push_current_filename(rel_filename.c_str());

                res = reader_read(fd, empty_ios);

                if (res)
                {
                    debug(1,
                          _(L"Error while reading file %ls\n"),
                          reader_current_filename()?reader_current_filename(): _(L"Standard input"));
                }
                reader_pop_current_filename();
            }
        }
    }

    int exit_status = res ? STATUS_UNKNOWN_COMMAND : proc_get_last_status();

    proc_fire_event(L"PROCESS_EXIT", EVENT_EXIT, getpid(), exit_status);

    restore_term_mode();
    restore_term_foreground_process_group();

    if (g_profiling_active)
    {
        parser.emit_profiling(s_profiling_output_filename);
    }

    history_destroy();
    proc_destroy();
    builtin_destroy();
    reader_destroy();
    event_destroy();

    if (g_log_forks)
        printf("%d: g_fork_count: %d\n", __LINE__, g_fork_count);

    exit_without_destructors(exit_status);
    return EXIT_FAILURE; //above line should always exit
}