/* $OpenBSD: prompt-history.c,v 1.2 2026/07/13 19:35:22 nicm Exp $ */

/*

 * Copyright (c) 2026 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 <errno.h>

#include <stdlib.h>

#include <string.h>

#include "tmux.h"

static char *prompt_find_history_file(void);

static void  prompt_add_typed_history(char *);

/* Prompt history. */

static char **prompt_hlist[PROMPT_NTYPES];

static u_int    prompt_hsize[PROMPT_NTYPES];

/* Find the history file to load/save from/to. */

static char *

prompt_find_history_file(void)

{

  const char  *home, *history_file;

  char    *path;

  history_file = options_get_string(global_options, "history-file");

  if (*history_file == '\0')

    return (NULL);

  if (*history_file == '/')

    return (xstrdup(history_file));

  if (history_file[0] != '~' || history_file[1] != '/')

    return (NULL);

  if ((home = find_home()) == NULL)

    return (NULL);

  xasprintf(&path, "%s%s", home, history_file + 1);

  return (path);

}

/* Add loaded history item to the appropriate list. */

static void

prompt_add_typed_history(char *line)

{

  char      *typestr;

  enum prompt_type   type = PROMPT_TYPE_INVALID;

  typestr = strsep(&line, ":");

  if (line != NULL)

    type = prompt_type(typestr);

  if (type == PROMPT_TYPE_INVALID) {

    /*

     * Invalid types are not expected, but this provides backward

     * compatibility with old history files.

     */

    if (line != NULL)

      *(--line) = ':';

    prompt_add_history(typestr, PROMPT_TYPE_COMMAND);

  } else

    prompt_add_history(line, type);

}

/* Load prompt history from file. */

void

prompt_load_history(void)

{

  FILE  *f;

  char  *history_file, *line = NULL;

  size_t   length = 0;

  ssize_t  got;

  if ((history_file = prompt_find_history_file()) == NULL)

    return;

  log_debug("loading history from %s", history_file);

  f = fopen(history_file, "r");

  if (f == NULL) {

    log_debug("%s: %s", history_file, strerror(errno));

    free(history_file);

    return;

  }

  free(history_file);

  while ((got = getline(&line, &length, f)) != -1) {

    if (got > 0 && line[got - 1] == '\n')

      line[got - 1] = '\0';

    if (got > 0)

      prompt_add_typed_history(line);

  }

  free(line);

  fclose(f);

}

/* Save prompt history to file. */

void

prompt_save_history(void)

{

  FILE  *f;

  u_int  i, type;

  char  *history_file;

  if ((history_file = prompt_find_history_file()) == NULL)

    return;

  log_debug("saving history to %s", history_file);

  f = fopen(history_file, "w");

  if (f == NULL) {

    log_debug("%s: %s", history_file, strerror(errno));

    free(history_file);

    return;

  }

  free(history_file);

  for (type = 0; type < PROMPT_NTYPES; type++) {

    for (i = 0; i < prompt_hsize[type]; i++) {

      fputs(prompt_type_string(type), f);

      fputc(':', f);

      fputs(prompt_hlist[type][i], f);

      fputc('\n', f);

    }

  }

  fclose(f);

}

/* Get previous line from the history. */

const char *

prompt_up_history(u_int *idx, u_int type)

{

  /*

   * History runs from 0 to size - 1. Index is from 0 to size. Zero is

   * empty.

   */

  if (type >= PROMPT_NTYPES)

    return (NULL);

  if (prompt_hsize[type] == 0 || idx[type] == prompt_hsize[type])

    return (NULL);

  idx[type]++;

  return (prompt_hlist[type][prompt_hsize[type] - idx[type]]);

}

/* Get next line from the history. */

const char *

prompt_down_history(u_int *idx, u_int type)

{

  if (type >= PROMPT_NTYPES)

    return ("");

  if (prompt_hsize[type] == 0 || idx[type] == 0)

    return ("");

  idx[type]--;

  if (idx[type] == 0)

    return ("");

  return (prompt_hlist[type][prompt_hsize[type] - idx[type]]);

}

/* Add line to the history. */

void

prompt_add_history(const char *line, u_int type)

{

  u_int i, oldsize, newsize, freecount, hlimit, new = 1;

  size_t  movesize;

  if (type >= PROMPT_NTYPES)

    return;

  oldsize = prompt_hsize[type];

  if (oldsize > 0 &&

      strcmp(prompt_hlist[type][oldsize - 1], line) == 0)

    new = 0;

  hlimit = options_get_number(global_options, "prompt-history-limit");

  if (hlimit > oldsize) {

    if (new == 0)

      return;

    newsize = oldsize + new;

  } else {

    newsize = hlimit;

    freecount = oldsize + new - newsize;

    if (freecount > oldsize)

      freecount = oldsize;

    if (freecount == 0)

      return;

    for (i = 0; i < freecount; i++)

      free(prompt_hlist[type][i]);

    movesize = (oldsize - freecount) *

        sizeof *prompt_hlist[type];

    if (movesize > 0) {

      memmove(&prompt_hlist[type][0],

          &prompt_hlist[type][freecount], movesize);

    }

  }

  if (newsize == 0) {

    free(prompt_hlist[type]);

    prompt_hlist[type] = NULL;

  } else if (newsize != oldsize) {

    prompt_hlist[type] =

        xreallocarray(prompt_hlist[type], newsize,

      sizeof *prompt_hlist[type]);

  }

  if (new == 1 && newsize > 0)

    prompt_hlist[type][newsize - 1] = xstrdup(line);

  prompt_hsize[type] = newsize;

}

/* Get history size. */

u_int

prompt_history_size(enum prompt_type type)

{

  if (type >= PROMPT_NTYPES)

    return (0);

  return (prompt_hsize[type]);

}

/* Get history entry. */

const char *

prompt_history_get(enum prompt_type type, u_int idx)

{

  if (type >= PROMPT_NTYPES)

    return (NULL);

  if (idx >= prompt_hsize[type])

    return (NULL);

  return (prompt_hlist[type][idx]);

}

/* Clear prompt history. */

void

prompt_history_clear(enum prompt_type type)

{

  u_int idx;

  if (type >= PROMPT_NTYPES)

    return;

  for (idx = 0; idx < prompt_hsize[type]; idx++)

    free(prompt_hlist[type][idx]);

  free(prompt_hlist[type]);

  prompt_hlist[type] = NULL;

  prompt_hsize[type] = 0;

}