/* $OpenBSD$ */

/*

 * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>

 *

 * Permission to use, copy, modify, and distribute this software for any

 * purpose with or without fee is hereby granted, provided that the above

 * copyright notice and this permission notice appear in all copies.

 *

 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES

 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR

 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

 * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER

 * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING

 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

 */

#include <sys/types.h>

#include <sys/time.h>

#include <string.h>

#include <stdlib.h>

#include <unistd.h>

#include <time.h>

#include "tmux.h"

struct sessions   sessions;

u_int     next_session_id;

struct session_groups session_groups = RB_INITIALIZER(&session_groups);

static void session_free(int, short, void *);

static void session_lock_timer(int, short, void *);

static struct winlink *session_next_alert(struct winlink *);

static struct winlink *session_previous_alert(struct winlink *);

static void session_group_remove(struct session *);

static void session_group_synchronize1(struct session *, struct session *);

int

session_cmp(struct session *s1, struct session *s2)

{

  return (strcmp(s1->name, s2->name));

}

RB_GENERATE(sessions, session, entry, session_cmp);

int

session_group_cmp(struct session_group *s1, struct session_group *s2)

{

  return (strcmp(s1->name, s2->name));

}

RB_GENERATE(session_groups, session_group, entry, session_group_cmp);

/*

 * Find if session is still alive. This is true if it is still on the global

 * sessions list.

 */

int

session_alive(struct session *s)

{

  struct session *s_loop;

  RB_FOREACH(s_loop, sessions, &sessions) {

    if (s_loop == s)

      return (1);

  }

  return (0);

}

/* Find session by name. */

struct session *

session_find(const char *name)

{

  struct session  s;

  s.name = (char *) name;

  return (RB_FIND(sessions, &sessions, &s));

}

/* Find session by id parsed from a string. */

struct session *

session_find_by_id_str(const char *s)

{

  const char  *errstr;

  u_int    id;

  if (*s != '$')

    return (NULL);

  id = strtonum(s + 1, 0, UINT_MAX, &errstr);

  if (errstr != NULL)

    return (NULL);

  return (session_find_by_id(id));

}

/* Find session by id. */

struct session *

session_find_by_id(u_int id)

{

  struct session  *s;

  RB_FOREACH(s, sessions, &sessions) {

    if (s->id == id)

      return (s);

  }

  return (NULL);

}

/* Create a new session. */

struct session *

session_create(const char *prefix, const char *name, const char *cwd,

    struct environ *env, struct options *oo, struct termios *tio)

{

  struct session  *s;

  s = xcalloc(1, sizeof *s);

  s->references = 1;

  s->flags = 0;

  s->cwd = xstrdup(cwd);

  TAILQ_INIT(&s->lastw);

  RB_INIT(&s->windows);

  s->environ = env;

  s->options = oo;

  status_update_cache(s);

  s->tio = NULL;

  if (tio != NULL) {

    s->tio = xmalloc(sizeof *s->tio);

    memcpy(s->tio, tio, sizeof *s->tio);

  }

  if (name != NULL) {

    s->name = xstrdup(name);

    s->id = next_session_id++;

  } else {

    do {

      s->id = next_session_id++;

      free(s->name);

      if (prefix != NULL)

        xasprintf(&s->name, "%s-%u", prefix, s->id);

      else

        xasprintf(&s->name, "%u", s->id);

    } while (RB_FIND(sessions, &sessions, s) != NULL);

  }

  RB_INSERT(sessions, &sessions, s);

  log_debug("new session %s $%u", s->name, s->id);

  if (gettimeofday(&s->creation_time, NULL) != 0)

    fatal("gettimeofday failed");

  session_update_activity(s, &s->creation_time);

  return (s);

}

/* Add a reference to a session. */

void

session_add_ref(struct session *s, const char *from)

{

  s->references++;

  log_debug("%s: %s %s, now %d", __func__, s->name, from, s->references);

}

/* Remove a reference from a session. */

void

session_remove_ref(struct session *s, const char *from)

{

  s->references--;

  log_debug("%s: %s %s, now %d", __func__, s->name, from, s->references);

  if (s->references == 0)

    event_once(-1, EV_TIMEOUT, session_free, s, NULL);

}

/* Free session. */

static void

session_free(__unused int fd, __unused short events, void *arg)

{

  struct session  *s = arg;

  log_debug("session %s freed (%d references)", s->name, s->references);

  if (s->references == 0) {

    environ_free(s->environ);

    options_free(s->options);

    free(s->name);

    free(s);

  }

}

/* Destroy a session. */

void

session_destroy(struct session *s, int notify, const char *from)

{

  struct winlink  *wl;

  log_debug("session %s destroyed (%s)", s->name, from);

  if (s->curw == NULL)

    return;

  s->curw = NULL;

  RB_REMOVE(sessions, &sessions, s);

  if (notify)

    notify_session("session-closed", s);

  free(s->tio);

  if (event_initialized(&s->lock_timer))

    event_del(&s->lock_timer);

  session_group_remove(s);

  while (!TAILQ_EMPTY(&s->lastw))

    winlink_stack_remove(&s->lastw, TAILQ_FIRST(&s->lastw));

  while (!RB_EMPTY(&s->windows)) {

    wl = RB_ROOT(&s->windows);

    notify_session_window("window-unlinked", s, wl->window);

    winlink_remove(&s->windows, wl);

  }

  free((void *)s->cwd);

  session_remove_ref(s, __func__);

}

/* Sanitize session name. */

char *

session_check_name(const char *name)

{

  char  *copy, *cp, *new_name;

  if (*name == '\0')

    return (NULL);

  copy = xstrdup(name);

  for (cp = copy; *cp != '\0'; cp++) {

    if (*cp == ':' || *cp == '.')

      *cp = '_';

  }

  utf8_stravis(&new_name, copy, VIS_OCTAL|VIS_CSTYLE|VIS_TAB|VIS_NL);

  free(copy);

  return (new_name);

}

/* Lock session if it has timed out. */

static void

session_lock_timer(__unused int fd, __unused short events, void *arg)

{

  struct session  *s = arg;

  if (s->attached == 0)

    return;

  log_debug("session %s locked, activity time %lld", s->name,

      (long long)s->activity_time.tv_sec);

  server_lock_session(s);

  recalculate_sizes();

}

/* Update activity time. */

void

session_update_activity(struct session *s, struct timeval *from)

{

  struct timeval   tv;

  if (from == NULL)

    gettimeofday(&s->activity_time, NULL);

  else

    memcpy(&s->activity_time, from, sizeof s->activity_time);

  log_debug("session $%u %s activity %lld.%06d", s->id,

      s->name, (long long)s->activity_time.tv_sec,

      (int)s->activity_time.tv_usec);

  if (evtimer_initialized(&s->lock_timer))

    evtimer_del(&s->lock_timer);

  else

    evtimer_set(&s->lock_timer, session_lock_timer, s);

  if (s->attached != 0) {

    timerclear(&tv);

    tv.tv_sec = options_get_number(s->options, "lock-after-time");

    if (tv.tv_sec != 0)

      evtimer_add(&s->lock_timer, &tv);

  }

}

/* Find the next usable session. */

struct session *

session_next_session(struct session *s)

{

  struct session *s2;

  if (RB_EMPTY(&sessions) || !session_alive(s))

    return (NULL);

  s2 = RB_NEXT(sessions, &sessions, s);

  if (s2 == NULL)

    s2 = RB_MIN(sessions, &sessions);

  if (s2 == s)

    return (NULL);

  return (s2);

}

/* Find the previous usable session. */

struct session *

session_previous_session(struct session *s)

{

  struct session *s2;

  if (RB_EMPTY(&sessions) || !session_alive(s))

    return (NULL);

  s2 = RB_PREV(sessions, &sessions, s);

  if (s2 == NULL)

    s2 = RB_MAX(sessions, &sessions);

  if (s2 == s)

    return (NULL);

  return (s2);

}

/* Attach a window to a session. */

struct winlink *

session_attach(struct session *s, struct window *w, int idx, char **cause)

{

  struct winlink  *wl;

  if ((wl = winlink_add(&s->windows, idx)) == NULL) {

    xasprintf(cause, "index in use: %d", idx);

    return (NULL);

  }

  wl->session = s;

  winlink_set_window(wl, w);

  notify_session_window("window-linked", s, w);

  session_group_synchronize_from(s);

  return (wl);

}

/* Detach a window from a session. */

int

session_detach(struct session *s, struct winlink *wl)

{

  if (s->curw == wl &&

      session_last(s) != 0 &&

      session_previous(s, 0) != 0)

    session_next(s, 0);

  wl->flags &= ~WINLINK_ALERTFLAGS;

  notify_session_window("window-unlinked", s, wl->window);

  winlink_stack_remove(&s->lastw, wl);

  winlink_remove(&s->windows, wl);

  session_group_synchronize_from(s);

  if (RB_EMPTY(&s->windows))

    return (1);

  return (0);

}

/* Return if session has window. */

int

session_has(struct session *s, struct window *w)

{

  struct winlink  *wl;

  TAILQ_FOREACH(wl, &w->winlinks, wentry) {

    if (wl->session == s)

      return (1);

  }

  return (0);

}

/*

 * Return 1 if a window is linked outside this session (not including session

 * groups). The window must be in this session!

 */

int

session_is_linked(struct session *s, struct window *w)

{

  struct session_group  *sg;

  if ((sg = session_group_contains(s)) != NULL)

    return (w->references != session_group_count(sg));

  return (w->references != 1);

}

static struct winlink *

session_next_alert(struct winlink *wl)

{

  while (wl != NULL) {

    if (wl->flags & WINLINK_ALERTFLAGS)

      break;

    wl = winlink_next(wl);

  }

  return (wl);

}

/* Move session to next window. */

int

session_next(struct session *s, int alert)

{

  struct winlink  *wl;

  if (s->curw == NULL)

    return (-1);

  wl = winlink_next(s->curw);

  if (alert)

    wl = session_next_alert(wl);

  if (wl == NULL) {

    wl = RB_MIN(winlinks, &s->windows);

    if (alert && ((wl = session_next_alert(wl)) == NULL))

      return (-1);

  }

  return (session_set_current(s, wl));

}

static struct winlink *

session_previous_alert(struct winlink *wl)

{

  while (wl != NULL) {

    if (wl->flags & WINLINK_ALERTFLAGS)

      break;

    wl = winlink_previous(wl);

  }

  return (wl);

}

/* Move session to previous window. */

int

session_previous(struct session *s, int alert)

{

  struct winlink  *wl;

  if (s->curw == NULL)

    return (-1);

  wl = winlink_previous(s->curw);

  if (alert)

    wl = session_previous_alert(wl);

  if (wl == NULL) {

    wl = RB_MAX(winlinks, &s->windows);

    if (alert && (wl = session_previous_alert(wl)) == NULL)

      return (-1);

  }

  return (session_set_current(s, wl));

}

/* Move session to specific window. */

int

session_select(struct session *s, int idx)

{

  struct winlink  *wl;

  wl = winlink_find_by_index(&s->windows, idx);

  return (session_set_current(s, wl));

}

/* Move session to last used window. */

int

session_last(struct session *s)

{

  struct winlink  *wl;

  wl = TAILQ_FIRST(&s->lastw);

  if (wl == NULL)

    return (-1);

  if (wl == s->curw)

    return (1);

  return (session_set_current(s, wl));

}

/* Set current winlink to wl .*/

int

session_set_current(struct session *s, struct winlink *wl)

{

  struct winlink  *old = s->curw;

  if (wl == NULL)

    return (-1);

  if (wl == s->curw)

    return (1);

  winlink_stack_remove(&s->lastw, wl);

  winlink_stack_push(&s->lastw, s->curw);

  s->curw = wl;

  if (options_get_number(global_options, "focus-events")) {

    if (old != NULL)

      window_update_focus(old->window);

    window_update_focus(wl->window);

  }

  winlink_clear_flags(wl);

  window_update_activity(wl->window);

  tty_update_window_offset(wl->window);

  notify_session("session-window-changed", s);

  return (0);

}

/* Find the session group containing a session. */

struct session_group *

session_group_contains(struct session *target)

{

  struct session_group  *sg;

  struct session    *s;

  RB_FOREACH(sg, session_groups, &session_groups) {

    TAILQ_FOREACH(s, &sg->sessions, gentry) {

      if (s == target)

        return (sg);

    }

  }

  return (NULL);

}

/* Find session group by name. */

struct session_group *

session_group_find(const char *name)

{

  struct session_group  sg;

  sg.name = name;

  return (RB_FIND(session_groups, &session_groups, &sg));

}

/* Create a new session group. */

struct session_group *

session_group_new(const char *name)

{

  struct session_group  *sg;

  if ((sg = session_group_find(name)) != NULL)

    return (sg);

  sg = xcalloc(1, sizeof *sg);

  sg->name = xstrdup(name);

  TAILQ_INIT(&sg->sessions);

  RB_INSERT(session_groups, &session_groups, sg);

  return (sg);

}

/* Add a session to a session group. */

void

session_group_add(struct session_group *sg, struct session *s)

{

  if (session_group_contains(s) == NULL)

    TAILQ_INSERT_TAIL(&sg->sessions, s, gentry);

}

/* Remove a session from its group and destroy the group if empty. */

static void

session_group_remove(struct session *s)

{

  struct session_group  *sg;

  if ((sg = session_group_contains(s)) == NULL)

    return;

  TAILQ_REMOVE(&sg->sessions, s, gentry);

  if (TAILQ_EMPTY(&sg->sessions)) {

    RB_REMOVE(session_groups, &session_groups, sg);

    free((void *)sg->name);

    free(sg);

  }

}

/* Count number of sessions in session group. */

u_int

session_group_count(struct session_group *sg)

{

  struct session  *s;

  u_int    n;

  n = 0;

  TAILQ_FOREACH(s, &sg->sessions, gentry)

    n++;

  return (n);

}

/* Count number of clients attached to sessions in session group. */

u_int

session_group_attached_count(struct session_group *sg)

{

  struct session  *s;

  u_int    n;

  n = 0;

  TAILQ_FOREACH(s, &sg->sessions, gentry)

    n += s->attached;

  return (n);

}

/* Synchronize a session to its session group. */

void

session_group_synchronize_to(struct session *s)

{

  struct session_group  *sg;

  struct session    *target;

  if ((sg = session_group_contains(s)) == NULL)

    return;

  target = NULL;

  TAILQ_FOREACH(target, &sg->sessions, gentry) {

    if (target != s)

      break;

  }

  if (target != NULL)

    session_group_synchronize1(target, s);

}

/* Synchronize a session group to a session. */

void

session_group_synchronize_from(struct session *target)

{

  struct session_group  *sg;

  struct session    *s;

  if ((sg = session_group_contains(target)) == NULL)

    return;

  TAILQ_FOREACH(s, &sg->sessions, gentry) {

    if (s != target)

      session_group_synchronize1(target, s);

  }

}

/*

 * Synchronize a session with a target session. This means destroying all

 * winlinks then recreating them, then updating the current window, last window

 * stack and alerts.

 */

static void

session_group_synchronize1(struct session *target, struct session *s)

{

  struct winlinks    old_windows, *ww;

  struct winlink_stack   old_lastw;

  struct winlink    *wl, *wl2;

  /* Don't do anything if the session is empty (it'll be destroyed). */

  ww = &target->windows;

  if (RB_EMPTY(ww))

    return;

  /* If the current window has vanished, move to the next now. */

  if (s->curw != NULL &&

      winlink_find_by_index(ww, s->curw->idx) == NULL &&

      session_last(s) != 0 && session_previous(s, 0) != 0)

    session_next(s, 0);

  /* Save the old pointer and reset it. */

  memcpy(&old_windows, &s->windows, sizeof old_windows);

  RB_INIT(&s->windows);

  /* Link all the windows from the target. */

  RB_FOREACH(wl, winlinks, ww) {

    wl2 = winlink_add(&s->windows, wl->idx);

    wl2->session = s;

    winlink_set_window(wl2, wl->window);

    notify_session_window("window-linked", s, wl2->window);

    wl2->flags |= wl->flags & WINLINK_ALERTFLAGS;

  }

  /* Fix up the current window. */

  if (s->curw != NULL)

    s->curw = winlink_find_by_index(&s->windows, s->curw->idx);

  else

    s->curw = winlink_find_by_index(&s->windows, target->curw->idx);

  /* Fix up the last window stack. */

  memcpy(&old_lastw, &s->lastw, sizeof old_lastw);

  TAILQ_INIT(&s->lastw);

  TAILQ_FOREACH(wl, &old_lastw, sentry) {

    wl2 = winlink_find_by_index(&s->windows, wl->idx);

    if (wl2 != NULL) {

      TAILQ_INSERT_TAIL(&s->lastw, wl2, sentry);

      wl2->flags |= WINLINK_VISITED;

    }

  }

  /* Then free the old winlinks list. */

  while (!RB_EMPTY(&old_windows)) {

    wl = RB_ROOT(&old_windows);

    wl2 = winlink_find_by_window_id(&s->windows, wl->window->id);

    if (wl2 == NULL)

      notify_session_window("window-unlinked", s, wl->window);

    winlink_remove(&old_windows, wl);

  }

}

/* Renumber the windows across winlinks attached to a specific session. */

void

session_renumber_windows(struct session *s)

{

  struct winlink    *wl, *wl1, *wl_new;

  struct winlinks    old_wins;

  struct winlink_stack   old_lastw;

  int      new_idx, new_curw_idx, marked_idx = -1;

  /* Save and replace old window list. */

  memcpy(&old_wins, &s->windows, sizeof old_wins);

  RB_INIT(&s->windows);

  /* Start renumbering from the base-index if it's set. */

  new_idx = options_get_number(s->options, "base-index");

  new_curw_idx = 0;

  /* Go through the winlinks and assign new indexes. */

  RB_FOREACH(wl, winlinks, &old_wins) {

    wl_new = winlink_add(&s->windows, new_idx);

    wl_new->session = s;

    winlink_set_window(wl_new, wl->window);

    wl_new->flags |= wl->flags & WINLINK_ALERTFLAGS;

    if (wl == marked_pane.wl)

      marked_idx = wl_new->idx;

    if (wl == s->curw)

      new_curw_idx = wl_new->idx;

    new_idx++;

  }

  /* Fix the stack of last windows now. */

  memcpy(&old_lastw, &s->lastw, sizeof old_lastw);

  TAILQ_INIT(&s->lastw);

  TAILQ_FOREACH(wl, &old_lastw, sentry) {

    wl->flags &= ~WINLINK_VISITED;

    wl_new = winlink_find_by_window(&s->windows, wl->window);

    if (wl_new != NULL) {

      TAILQ_INSERT_TAIL(&s->lastw, wl_new, sentry);

      wl_new->flags |= WINLINK_VISITED;

    }

  }

  /* Set the current window. */

  if (marked_idx != -1) {

    marked_pane.wl = winlink_find_by_index(&s->windows, marked_idx);

    if (marked_pane.wl == NULL)

      server_clear_marked();

  }

  s->curw = winlink_find_by_index(&s->windows, new_curw_idx);

  /* Free the old winlinks (reducing window references too). */

  RB_FOREACH_SAFE(wl, winlinks, &old_wins, wl1)

    winlink_remove(&old_wins, wl);

}

/* Set the PANE_THEMECHANGED flag for every pane in this session. */

void

session_theme_changed(struct session *s)

{

  struct window_pane  *wp;

  struct winlink    *wl;

  if (s != NULL) {

    RB_FOREACH(wl, winlinks, &s->windows) {

      TAILQ_FOREACH(wp, &wl->window->panes, entry)

          wp->flags |= PANE_THEMECHANGED;

    }

  }

}