/*
 * vchat-client

*/

#include <regex.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <sys/time.h>

#include <readline/readline.h>

#include "vchat-user.h"
#include "vchat.h"

/* version of this module */
char *vchat_us_version =
    "vchat-user.c     $Id$";

typedef struct {
  char *nick;
  enum {
    UL_NONE = 0x00,
    UL_ME = 0x01,
    UL_IN_MY_CHAN = 0x02,
    UL_NOT_IN_LIST = 0x04
  } flags;
  uint64_t last_public;
  uint64_t last_private;
} user;
static user *g_users;        //< all users, incl self
static size_t g_users_count; //< number of users in list
static char *g_nick;         //< own nick
static int g_channel;        //< own channel
unsigned int ul_case_first = 0;

static char **g_dict;
static size_t g_dict_len;

static int ul_nick_lookup(const char *nick, int *exact_match) {
  int i;

  *exact_match = 1;
  for (i = 0; i < g_users_count; ++i)
    if (!strcasecmp(g_users[i].nick, nick))
      return i;
  *exact_match = 0;
  return i;
}

static int64_t ul_now() {
  struct timeval now;
  gettimeofday(&now, (struct timezone *)0);
  return ((uint64_t)now.tv_sec * 1000) + ((uint64_t)now.tv_usec / 1000);
}

/* own nick and channel setters/getters */
void own_nick_set(char *nick) {
  if (nick) {
    int base;
    if (g_nick)
      base = ul_rename(g_nick, nick);
    else
      base = ul_add(nick, 0);
    if (base >= 0) {
      g_users[base].flags |= UL_ME;
      g_nick = g_users[base].nick;
    }
  } else
    ul_del(g_nick);

  setstroption(CF_NICK, nick);
}

void own_channel_set(int channel) {
  if (channel != g_channel) {
    /* Remove all users from my chan, will be re-set on join message */
    int i;
    for (i = 0; i < g_users_count; ++i)
      g_users[i].flags &= ~UL_IN_MY_CHAN;
  }

  g_channel = channel;
}

char const *own_nick_get() { return g_nick; }

int own_nick_check(char *nick) {
  if (!g_nick)
    return -1;
  return !strcasecmp(g_nick, nick);
}

int own_channel_get() { return g_channel; }

/* Add/remove/rename */
int ul_add(char *name, int in_my_chan_flag) {

  /* Test if user is already known */
  int exact_match, base = ul_nick_lookup(name, &exact_match);
  if (!exact_match) {
    /* Make space for new user */
    user *new_users = realloc(g_users, sizeof(user) * (1 + g_users_count));
    if (!new_users)
      return -1;

    /* Copy the tail */
    g_users = new_users;
    memmove(g_users + base + 1, g_users + base,
            (g_users_count - base) * sizeof(user));
    g_users[base].nick = strdup(name);
    g_users[base].flags = UL_NONE;
    g_users[base].last_public = 0;
    g_users[base].last_private = 0;

    g_users_count++;
  }

  g_users[base].flags &= ~UL_NOT_IN_LIST;
  switch (in_my_chan_flag) {
  case 1:
    g_users[base].flags |= UL_IN_MY_CHAN;
    break;
  case 0:
    g_users[base].flags &= ~UL_IN_MY_CHAN;
    break;
  case -1:
  default:
    break;
  }

  return base;
}

int ul_del(char *name) {
  /* Test if user is already known */
  int exact_match, base = ul_nick_lookup(name, &exact_match);
  if (!exact_match)
    return -1;

  /* Release the name buffer */
  free(g_users[base].nick);
  if (g_users[base].flags & UL_ME)
    g_nick = 0;

  /* Copy the tail */
  memmove(g_users + base, g_users + base + 1,
          (g_users_count - base - 1) * sizeof(user));

  /* Shrink user list, realloc to a smaller size never fails */
  g_users = realloc(g_users, sizeof(user) * --g_users_count);
  return 0;
}

int ul_rename(char *oldname, char *newname) {
  /* Ensure user */
  int base = ul_add(oldname, -1);
  if (base >= 0) {
    free(g_users[base].nick);
    g_users[base].nick = strdup(newname);
    if (g_users[base].flags & UL_ME)
      g_nick = g_users[base].nick;
    if (g_users[base].flags & UL_IN_MY_CHAN)
      ul_public_action(newname);
  }
  return base;
}

void ul_clear() {
  int i;
  for (i = 0; i < g_users_count; ++i)
    free(g_users[i].nick);
  free(g_users);
  g_nick = 0;
}

void ul_rebuild_list() {
  int i;
  for (i = 0; i < g_users_count; ++i)
    g_users[i].flags |= UL_NOT_IN_LIST;
}

void ul_clean() {
  int i;
  for (i = 0; i < g_users_count; ++i) {
    if (g_users[i].flags & UL_NOT_IN_LIST) {
      ul_del(g_users[i].nick);
      --i;
    }
  }
}

/* Seting state */
void ul_leave_chan(char *name) {
  /* Ensure user and kick him off the channel */
  ul_add(name, 0);
}

void ul_enter_chan(char *name) {
  /* Ensure user and put him on the channel */
  int base = ul_add(name, 1);
  if (base >= 0)
    ul_public_action(name);

  /* Reflect in UI */
  if (own_nick_check(name))
    ownjoin(g_channel);
}

void ul_private_action(char *name) {
  /* Ensure user and keep channel state */
  int base = ul_add(name, -1);
  if (base >= 0)
    g_users[base].last_private = ul_now();
}

void ul_public_action(char *name) {
  /* Ensure user and put him on the channel */
  int base = ul_add(name, 1);
  if (base >= 0)
    g_users[base].last_public = ul_now();
}

void ul_add_to_dict(char *dict_items) {
  char *i;
  for (i = strtok(dict_items, " "); i; i = strtok(0, " ")) {
    g_dict = realloc(g_dict, sizeof(char *) * (1 + g_dict_len));
    if (!g_dict)
      exit(1);
    g_dict[g_dict_len++] = strdup(i);
  }
}

/* Finding users ul_finduser? */
char *ul_match_user(char *regex) {
  char *dest = tmpstr;
  int i;
  regex_t preg;

  *dest = 0;
  if (!regcomp(&preg, regex, REG_ICASE | REG_EXTENDED | REG_NEWLINE)) {

    /* does the username match? */
    /* XXX overflow for too many matches */
    for (i = 0; i < g_users_count; ++i)
      if (!regexec(&preg, g_users[i].nick, 0, NULL,
                   0)) /* append username to list */
        dest += snprintf(dest, 256, " %s", g_users[i].nick);
  }
  regfree(&preg);
  return tmpstr;
}

static int ul_compare_private(const void *a, const void *b) {
  const user *_a = (const user *)a, *_b = (const user *)b;
  if (_a->last_private > _b->last_private)
    return -1;
  return 1;
}

static int ul_compare_begin_of_line_ncase(const void *a, const void *b) {
  const user *_a = (const user *)a, *_b = (const user *)b;
  size_t tmpstr_len;
  int a_i, b_i;

  /* First ensure that users in current channel win */
  if (!(_a->flags & UL_IN_MY_CHAN))
    return 1;
  if (!(_b->flags & UL_IN_MY_CHAN))
    return -1;

  tmpstr_len = strlen(tmpstr);
  a_i = strncasecmp(_a->nick, tmpstr, tmpstr_len);
  b_i = strncasecmp(_b->nick, tmpstr, tmpstr_len);

  if (a_i && b_i)
    return 0; // Both nicks dont match
  if (!a_i && b_i)
    return -1; // a matches insensitive, b doesnt
  if (a_i && !b_i)
    return 1; // b matches insensitive, a doesnt

  /* From here both nicks match the prefix, ensure that own_nick
     always appears last */
  if (_a->flags & UL_ME)
    return 1;
  if (_b->flags & UL_ME)
    return -1;

  /* Now the user with the most recent public activity wins */
  if (_a->last_public > _b->last_public)
    return -1;

  return 1;
}

static int ul_compare_begin_of_line_case(const void *a, const void *b) {
  const user *_a = (const user *)a, *_b = (const user *)b;
  size_t tmpstr_len;
  int a_i, b_i, a_s, b_s;

  /* First ensure that users in current channel win */
  if (!(_a->flags & UL_IN_MY_CHAN))
    return 1;
  if (!(_b->flags & UL_IN_MY_CHAN))
    return -1;

  tmpstr_len = strlen(tmpstr);
  a_i = strncasecmp(_a->nick, tmpstr, tmpstr_len);
  a_s = strncmp(_a->nick, tmpstr, tmpstr_len);
  b_i = strncasecmp(_b->nick, tmpstr, tmpstr_len);
  b_s = strncmp(_b->nick, tmpstr, tmpstr_len);

  if (a_i && b_i)
    return 0; // Both nicks dont match at all
  if (!a_i && b_i)
    return -1; // a matches insensitive, b doesnt
  if (a_i && !b_i)
    return 1; // b matches insensitive, a doesnt

  if (!a_s && b_s)
    return -1; // a matches sensitive, b doesnt
  if (a_s && !b_s)
    return 1; // b matches sensitive, a doesnt

  /* From now we know that both match with same quality, ensure
     that own nick always appears last */
  if (_a->flags & UL_ME)
    return 1;
  if (_b->flags & UL_ME)
    return -1;

  /* Now the user with the most recent public activity wins */
  if (_a->last_public > _b->last_public)
    return -1;

  return 1;
}

static int ul_compare_middle_ncase(const void *a, const void *b) {
  const user *_a = (const user *)a, *_b = (const user *)b;

  /* Ensure that own nick appears last in list */
  if (_a->flags & UL_ME)
    return 1;
  if (_b->flags & UL_ME)
    return -1;

  return strcasecmp(_a->nick, _b->nick);
}

static int ul_compare_middle_case(const void *a, const void *b) {
  const user *_a = (const user *)a, *_b = (const user *)b;
  size_t tmpstr_len;
  int a_s, b_s;

  /* Ensure that own nick appears last in list */
  if (_a->flags & UL_ME)
    return 1;
  if (_b->flags & UL_ME)
    return -1;

  tmpstr_len = strlen(tmpstr);
  a_s = strncmp(_a->nick, tmpstr, tmpstr_len);
  b_s = strncmp(_b->nick, tmpstr, tmpstr_len);

  if (!a_s && b_s)
    return -1; // a matches sensitive, b doesnt
  if (a_s && !b_s)
    return 1; // b matches sensitive, a doesnt

  /* From now both strings either both or both dont match
     decide their position by case insensitive match */
  return strcasecmp(_a->nick, _b->nick);
}

/* Nick completion function for readline */
char **ul_complete_user(char *text, int start, int end) {
  char **result = 0;
  int i, result_count = 0, dict_result_count = 0;

  /* Never want readline to complete filenames */
  rl_attempted_completion_over = 1;

  /* Check for amount of custom dict matches */
  if (end && (start != end))
    for (i = 0; i < g_dict_len; ++i)
      if (!strncasecmp(g_dict[i], text + start, end - start))
        ++dict_result_count;

  /* Prepare return array ... of max g_users_count (char*)
     Plus least common prefix in [0] and null terminator
   */
  result = malloc(sizeof(char *) * (2 + g_users_count + dict_result_count));
  if (!result)
    return 0;

  if (start == 0 && end == 0) {
    /* Completion on begin of line yields list of everyone we
       were in private conversation, sorted by time of last .m */
    qsort(g_users, g_users_count, sizeof(user), ul_compare_private);
    for (i = 0; i < g_users_count; ++i)
      if (g_users[i].last_private) {
        snprintf(tmpstr, TMPSTRSIZE, ".m %s", g_users[i].nick);
        result[++result_count] = strdup(tmpstr);
      }
    /* No common prefix */
    if (result_count)
      result[0] = strdup("");

  } else if (start == 0 && end > 0) {
    /* Completion on begin of line with some chars already typed yields
       a list of everyone in channel, matching prefix, sorted by last
       public activity */
    snprintf(tmpstr, end + 1, "%s", text);
    if (ul_case_first)
      qsort(g_users, g_users_count, sizeof(user),
            ul_compare_begin_of_line_case);
    else
      qsort(g_users, g_users_count, sizeof(user),
            ul_compare_begin_of_line_ncase);

    for (i = 0; i < g_users_count; ++i)
      if ((g_users[i].flags & UL_IN_MY_CHAN) &&
          !strncasecmp(g_users[i].nick, tmpstr, end)) {
        snprintf(tmpstr, TMPSTRSIZE, "%s:", g_users[i].nick);
        result[++result_count] = strdup(tmpstr);
      }

    /* Copy matches from personal dict to the end */
    for (i = 0; i < g_dict_len; ++i)
      if (!strncasecmp(g_dict[i], tmpstr, end - start)) {
        snprintf(tmpstr, TMPSTRSIZE, "%s:", g_dict[i]);
        result[++result_count] = strdup(tmpstr);
      }

    /* Copy common prefix */
    if (result_count)
      result[0] = strndup(text, end);
  } else if (start != end) {
    /* Completion in the middle of the line most likely is a .m XY<TAB>
       and thus should complete all users, sorted alphabetically without
       preferences. */
    snprintf(tmpstr, end - start + 1, "%s", text);
    if (ul_case_first)
      qsort(g_users, g_users_count, sizeof(user), ul_compare_middle_case);
    else
      qsort(g_users, g_users_count, sizeof(user), ul_compare_middle_ncase);

    for (i = 0; i < g_users_count; ++i)
      if (!strncasecmp(g_users[i].nick, tmpstr, end - start))
        result[++result_count] = strdup(g_users[i].nick);

    /* Copy matches from personal dict to the end */
    for (i = 0; i < g_dict_len; ++i)
      if (!strncasecmp(g_dict[i], tmpstr, end - start))
        result[++result_count] = strdup(g_dict[i]);

    /* Copy common prefix */
    if (result_count)
      result[0] = strndup(text, end - start);
  } /* else: completion of an empty word in the middle yields nothing */

  if (!result_count) {
    free(result);
    result = 0;
  } else
    result[++result_count] = 0;

  return result;
}