/*
 * Copyright 2011 Daniel Silverstone <dsilvers@digital-scurf.org>
 *
 * This file is part of NetSurf, http://www.netsurf-browser.org/
 *
 * NetSurf 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; version 2 of the License.
 *
 * NetSurf 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, see <http://www.gnu.org/licenses/>.
 */

#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <sys/select.h>
#include <sys/types.h>
#include <unistd.h>

#include "utils/config.h"
#include "utils/sys_time.h"
#include "utils/log.h"
#include "utils/messages.h"
#include "utils/filepath.h"
#include "utils/nsoption.h"
#include "content/urldb.h"
#include "content/fetchers.h"
#include "content/fetchers/resource.h"
#include "content/hlcache.h"
#include "desktop/gui_misc.h"
#include "desktop/netsurf.h"

#include "monkey/dispatch.h"
#include "monkey/browser.h"
#include "monkey/cert.h"
#include "monkey/401login.h"
#include "monkey/filetype.h"
#include "monkey/fetch.h"
#include "monkey/schedule.h"
#include "monkey/bitmap.h"
#include "monkey/layout.h"

/** maximum number of languages in language vector */
#define LANGV_SIZE 32
/** maximum length of all strings in language vector */
#define LANGS_SIZE 4096

/** resource search path vector */
char **respaths;

static bool monkey_done = false;

/**
 * Cause an abnormal program termination.
 *
 * \note This never returns and is intended to terminate without any cleanup.
 *
 * \param error The message to display to the user.
 */
static void die(const char * const error)
{
  fprintf(stderr, "DIE %s\n", error);
  exit(EXIT_FAILURE);
}

/** obtain language from environment
 *
 * start with GNU extension LANGUAGE environment variable and then try
 * POSIX variables LC_ALL, LC_MESSAGES and LANG
 *
 */
static const char *get_language(void)
{
  const char *lang;

  lang = getenv("LANGUAGE");
  if ((lang != NULL) && (lang[0] != '\0')) {
    return lang;
  }

  lang = getenv("LC_ALL");
  if ((lang != NULL) && (lang[0] != '\0')) {
    return lang;
  }

  lang = getenv("LC_MESSAGES");
  if ((lang != NULL) && (lang[0] != '\0')) {
    return lang;
  }

  lang = getenv("LANG");
  if ((lang != NULL) && (lang[0] != '\0')) {
    return lang;
  }

  return NULL;
}


/** provide a string vector of languages in preference order
 *
 * environment variables are processed to aquire a colon separated
 * list of languages which are converted into a string vector. The
 * vector will always have the C language as its last entry.
 *
 * This implementation creates an internal static representation of
 * the vector when first called and returns that for all subsequent
 * calls. i.e. changing the environment does not change the returned
 * vector on repeated calls.
 *
 * If the environment variables have more than LANGV_SIZE languages or
 * LANGS_SIZE bytes of data the results list will be curtailed.
 */
static const char * const *get_languagev(void)
{
  static const char *langv[LANGV_SIZE];
  int langidx = 0; /* index of next entry in vector */
  static char langs[LANGS_SIZE];
  char *curp; /* next language parameter in langs string */
  const char *lange; /* language from environment variable */
  int lang_len;
  char *cln; /* colon in lange */

  /* return cached vector */
  if (langv[0] != NULL) {
    return &langv[0];
  }

  curp = &langs[0];

  lange = get_language();

  if (lange != NULL) {
    lang_len = strlen(lange) + 1;
    if (lang_len < (LANGS_SIZE - 2)) {
      memcpy(curp, lange, lang_len);
      while ((curp[0] != 0) &&
	     (langidx < (LANGV_SIZE - 2))) {
	/* avoid using strchrnul as it is not portable */
	cln = strchr(curp, ':');
	if (cln == NULL) {
	  langv[langidx++] = curp;
	  curp += lang_len;
	  break;
	} else {
	  if ((cln - curp) > 1) {
	    /* only place non empty entries in vector */
	    langv[langidx++] = curp;
	  }
	  *cln++ = 0; /* null terminate */
	  lang_len -= (cln - curp);
	  curp = cln;
	}
      }
    }
  }

  /* ensure C language is present */
  langv[langidx++] = curp;
  *curp++ = 'C';
  *curp++ = 0;
  langv[langidx] = NULL;

  return &langv[0];
}

/* Stolen from gtk/gui.c */
static char **
nsmonkey_init_resource(const char *resource_path)
{
  const char * const *langv;
  char **pathv; /* resource path string vector */
  char **respath; /* resource paths vector */

  pathv = filepath_path_to_strvec(resource_path);

  langv = get_languagev();

  respath = filepath_generate(pathv, langv);

  filepath_free_strvec(pathv);

  return respath;
}

static void monkey_quit(void)
{
  urldb_save_cookies(nsoption_charp(cookie_jar));
  urldb_save(nsoption_charp(url_file));
  monkey_fetch_filetype_fin();
}

static nserror gui_launch_url(struct nsurl *url)
{
  fprintf(stdout, "GENERIC LAUNCH URL %s\n", nsurl_access(url));
  return NSERROR_OK;
}

static void quit_handler(int argc, char **argv)
{
  monkey_done = true;
}

/**
 * Set option defaults for monkey frontend
 *
 * @param defaults The option table to update.
 * @return error status.
 */
static nserror set_defaults(struct nsoption_s *defaults)
{
  /* Set defaults for absent option strings */
  nsoption_setnull_charp(cookie_file, strdup("~/.netsurf/Cookies"));
  nsoption_setnull_charp(cookie_jar, strdup("~/.netsurf/Cookies"));
  nsoption_setnull_charp(url_file, strdup("~/.netsurf/URLs"));

  return NSERROR_OK;
}

/**
 * Ensures output logging stream is correctly configured
 */
static bool nslog_stream_configure(FILE *fptr)
{
  /* set log stream to be non-buffering */
  setbuf(fptr, NULL);

  return true;
}

static struct gui_misc_table monkey_misc_table = {
  .schedule = monkey_schedule,

  .quit = monkey_quit,
  .launch_url = gui_launch_url,
  .cert_verify = gui_cert_verify,
  .login = gui_401login_open,
};

static void monkey_run(void)
{
  fd_set read_fd_set, write_fd_set, exc_fd_set;
  int max_fd;
  int rdy_fd;
  int schedtm;
  struct timeval tv;
  struct timeval* timeout;

  while (!monkey_done) {

    /* clears fdset */
    fetcher_fdset(&read_fd_set, &write_fd_set, &exc_fd_set, &max_fd);

    /* add stdin to the set */
    if (max_fd < 0) {
      max_fd = 0;
    }
    FD_SET(0, &read_fd_set);
    FD_SET(0, &exc_fd_set);

    /* discover the next scheduled event time */
    schedtm = monkey_schedule_run();

    /* setup timeout */
    switch (schedtm) {
    case -1:
      LOG("Iterate blocking");
      fprintf(stdout, "GENERIC POLL BLOCKING\n");
      timeout = NULL;
      break;

    case 0:
      LOG("Iterate immediate");
      tv.tv_sec = 0;
      tv.tv_usec = 0;
      timeout = &tv;
      break;

    default:
      LOG("Iterate non-blocking");
      fprintf(stdout, "GENERIC POLL TIMED\n");
      tv.tv_sec = schedtm / 1000; /* miliseconds to seconds */
      tv.tv_usec = (schedtm % 1000) * 1000; /* remainder to microseconds */
      timeout = &tv;
      break;
    }

    rdy_fd = select(max_fd + 1,
		    &read_fd_set,
		    &write_fd_set,
		    &exc_fd_set,
		    timeout);
    if (rdy_fd < 0) {
      monkey_done = true;
    } else if (rdy_fd > 0) {
      if (FD_ISSET(0, &read_fd_set)) {
	monkey_process_command();
      }
    }
  }

}

int
main(int argc, char **argv)
{
  char *messages;
  char *options;
  char buf[PATH_MAX];
  nserror ret;
  struct netsurf_table monkey_table = {
    .misc = &monkey_misc_table,
    .window = monkey_window_table,
    .download = monkey_download_table,
    .fetch = monkey_fetch_table,
    .bitmap = monkey_bitmap_table,
    .layout = monkey_layout_table,
  };

  ret = netsurf_register(&monkey_table);
  if (ret != NSERROR_OK) {
    die("NetSurf operation table failed registration");
  }

  /* Unbuffer stdin/out/err */
  setbuf(stdin, NULL);
  setbuf(stdout, NULL);
  setbuf(stderr, NULL);

  /* Prep the search paths */
  respaths = nsmonkey_init_resource("${HOME}/.netsurf/:${NETSURFRES}:"MONKEY_RESPATH":./monkey/res");

  /* initialise logging. Not fatal if it fails but not much we can do
   * about it either.
   */
  nslog_init(nslog_stream_configure, &argc, argv);

  /* user options setup */
  ret = nsoption_init(set_defaults, &nsoptions, &nsoptions_default);
  if (ret != NSERROR_OK) {
    die("Options failed to initialise");
  }
  options = filepath_find(respaths, "Choices");
  nsoption_read(options, nsoptions);
  free(options);
  nsoption_commandline(&argc, argv, nsoptions);

  messages = filepath_find(respaths, "Messages");
  ret = messages_add_from_file(messages);
  if (ret != NSERROR_OK) {
    LOG("Messages failed to load");
  }

  /* common initialisation */
  ret = netsurf_init(NULL);
  free(messages);
  if (ret != NSERROR_OK) {
    die("NetSurf failed to initialise");
  }

  filepath_sfinddef(respaths, buf, "mime.types", "/etc/");
  monkey_fetch_filetype_init(buf);

  urldb_load(nsoption_charp(url_file));
  urldb_load_cookies(nsoption_charp(cookie_file));

  ret = monkey_register_handler("QUIT", quit_handler);
  if (ret != NSERROR_OK) {
    die("quit handler failed to register");
  }

  ret = monkey_register_handler("WINDOW", monkey_window_handle_command);
  if (ret != NSERROR_OK) {
    die("window handler fialed to register");
  }

  fprintf(stdout, "GENERIC STARTED\n");
  monkey_run();

  fprintf(stdout, "GENERIC CLOSING_DOWN\n");
  monkey_kill_browser_windows();

  netsurf_exit();
  fprintf(stdout, "GENERIC FINISHED\n");

  /* finalise options */
  nsoption_finalise(nsoptions, nsoptions_default);

  return 0;
}