#include "replay.h"

// Return the unixtime timestamp at the start of a line,
// or -1 if a timestamp couldn't be extracted
int gettimestamp(char *str) {
  int timestamp;
  char timestr[TIMELEN];
  int count = 0;

  // Make sure we're starting with a digit
  if (!isdigit(str[0])) {
    return -1;
  }

  // Extract each digit until we encounter a non-digit
  for (int i = 0; i < TIMELEN; i++) {
    if (isdigit(str[i])) {
      timestr[count] = str[i];
      count++;
    }
  }

  timestr[count] = '\0'; // Null terminate

  timestamp = strtol(timestr, NULL, 10); // Convert resulting string to an integer, base 10

  return timestamp;
}

// Set 'str' to a string with the leading unixtime timestamp removed.
// Returns 1 on success, 0 on failure
int striptimestamp(char *str) {
  char line[MAXCHAR];
  int count = 0;

  // Make sure we're starting with a digit
  if (!isdigit(str[0])) {
    return 0;
  }

  // Skip over each digit until we encounter a non-digit, record the position
  for (int i = 0; i < TIMELEN; i++) {
    if (isdigit(str[i])) {
      count++;
    }
  }

  // Skip over the space
  count++;

  int count2 = 0;

  // Copy from the end of the digits (and the space) until the end of the string
  for (size_t i = count; i < strlen(str); i++) {
    line[count2] = str[i];
    count2++;
  }

  strncpy(str, line, count2);
  str[count2] = '\0';

  return 1;
}

// Take a string like:
// 1557592901 :foo!bar@baz PRIVMSG foo :hello world
// And convert it to:
// :foo!bar@baz PRIVMSG foo :[17:41:41] hello world
// Only inserts the formatted time for PRIVMSGs at the moment (and maybe only needs to!).
void formattime(char *str) {
  // Extract the timestamp for conversion into [HH:MM:SS]
  char timestr[TIMELEN];
  sprintf(timestr, "%d", gettimestamp(str)); // Convert int time to string time
  struct tm tm;
  strptime(timestr, "%s", &tm);
  char timestampf[TIMELEN]; // Formatted timestamp
  // Convert into [HH:MM:SS]
  strftime(timestampf, TIMELEN, "[%H:%M:%S]", &tm);

  // Strip the original unixtimestamp
  striptimestamp(str);

  // Take note of the length
  int len = strlen(str);

  // Find the start of the message if it's a PRIVMSG
  char *ret;
  int pos1;
  if ((ret = strstr(str, "PRIVMSG")) != NULL) {
    // Position within str of "PRIVMSG"
    pos1 = ret - str;
  } else {
    // If it's not a PRIVMSG, stop here
    return;
  }

  char *ret2;
  int pos2;
  // Find the start of the actual message within the PRIVMSG
  // TODO - What if it's some other message with a colon in it?  Find PRIVMSG or not properly.
  if ((ret2 = strstr(ret, ":")) != NULL) {
    // Position within ret of ":"
    pos2 = ret2 - ret;
  } else {
    // Didn't find the real message, weird.
    return;
  }

  // Position of start of PRIVMSG colon in original string
  int realpos = pos1 + pos2 + 1;

  // Build the new formatted string
  char newline[MAXCHAR];

  // First bit (:foo!bar@baz PRIVMSG foo :)
  for (int i = 0; i < realpos; i++) {
    newline[i] = str[i];
  }

  // Second bit (:foo!bar@baz PRIVMSG foo :[HH:MM:SS])
  int j = 0;
  for (int i = realpos; i < TIMELEN + realpos - 1; i++) { // -1 to avoid the null char from timestampf
    newline[i] = timestampf[j];
    j++;
  }

  // Insert a space after the formatted timestamp
  newline[TIMELEN + realpos - 1] = ' ';

  // Final bit (the original PRIVMSG contents)
  for (int i = TIMELEN + realpos; i < len + TIMELEN; i++) {
    newline[i] = str[i - TIMELEN];
  }

  // Copy the whole thing back to str and null terminate
  strncpy(str, newline, len + TIMELEN);
  str[len + TIMELEN] = '\0';
}

// Return the number of lines in the replay log since 'seconds' seconds ago, or -1 if there a problem.
// 'basedir' is the directory in which to find 'replay.log'.
int replaylines(int seconds, char *basedir) {
  FILE *fp;
  char str[MAXCHAR];
  char filename[PATH_MAX];

  // Build path
  snprintf(filename, PATH_MAX, "%s/replay.log", basedir);

  int numlines = 0;

  fp = fopen(filename, "r");

  if (fp == NULL) {
    printf("error: could not open replay log '%s'.\n", filename);
    // Assume the file just doesn't exist yet - TODO - Interpret error codes to see what happened.
    fclose(fp);
    return 0;
  }

  // Get the current time for comparison later
  int timenow = (int)time(NULL);

  while (fgets(str, MAXCHAR, fp) != NULL) {
    // Read the timestamp from each line
    int timestamp = gettimestamp(str);
    if (timestamp < 1) {
      printf("Error reading timestamp from replay log file.\n");
      fclose(fp);
      return -1;
    }
    
    // If the line is within range of the requested time, count it
    if (timestamp > timenow - seconds) {
      numlines++;
    }
  }

  fclose(fp);
  return numlines;
}

// Set 'str' to the line in the log with a timestamp of greater than 'seconds'
// seconds ago, plus however many lines 'linenum' is set to.  'basedir' is the
// directory in which to find 'replay.log'.
// Also modify the line to include a timestamp in the form "[HH:MM:SS]".
// Returns 1 on success, or 0 on failure.
// TODO - This is horribly inefficient since it re-reads the entire file each call, rewrite this!
int readreplayline(int seconds, int linenum, char *str, char *basedir) {
  FILE *fp;
  char line[MAXCHAR];
  char filename[PATH_MAX];

  // Build path
  snprintf(filename, PATH_MAX, "%s/replay.log", basedir);

  int count = 0;

  fp = fopen(filename, "r");

  if (fp == NULL) {
    debugprint(DEBUG_CRIT, "error: could not open replay log '%s'.\n", filename);
    fclose(fp);
    return 0;
  }

  // Get the current time for comparison later
  int timenow = (int)time(NULL);

  while (fgets(line, MAXCHAR, fp) != NULL) {
    // Read the timestamp from each line
    int timestamp = gettimestamp(line);
    if (timestamp < 1) {
      debugprint(DEBUG_CRIT, "Error reading timestamp from replay log file.\n");
      fclose(fp);
      return 0;
    }

    // If the line is within range of the requested time...
    if (timestamp > timenow - seconds) {
      // ...and it is the current requested line then return it
      if (count == linenum) {
        // Insert our formatted [HH:MM:SS] timestamp into the message
        formattime(line);

        strncpy(str, line, strlen(line));
        str[strlen(line)] = '\0';
        fclose(fp);
        return 1;
      }
      count++;
    }
  }

  // If we got here something went wrong
  fclose(fp);
  return 0;
}

// Write the line 'str' to the replay log file after prepending it with
// the current unixtime timestamp.  'basedir' is the directory in which
// to write to 'replay.log'.
// Expects a string in the format:
// :from!bar@baz PRIVMSG to :hello world
// With the ":foo!bar@baz "prefix being important.
// Returns 1 on success or 0 on failure.
int writereplayline(char *str, char *basedir) {
  FILE *fp;
  char line[MAXCHAR];
  char filename[PATH_MAX];

  // Build path
  snprintf(filename, PATH_MAX, "%s/replay.log", basedir);

  int bytes = 0;

  fp = fopen(filename, "a");

  if (fp == NULL) {
    debugprint(DEBUG_CRIT, "error: could not open replay log '%s' for writing.\n", filename);
    fclose(fp);
    return 0;
  }

  // Get the current time and manipulate it into a C string
  time_t timenow = time(NULL);
  int timenowlen = snprintf(NULL, 0, "%ld", timenow);
  char timenowstr[timenowlen + 1]; // TODO - Make this Year 2038 proof.
  snprintf(timenowstr, timenowlen + 1, "%ld", timenow);

  // Prepend the unixtime timestamp
  snprintf(line, MAXCHAR, "%s %s", timenowstr, str);

  // Ensure the line finishes with CRLF
  appendcrlf(line);

  debugprint(DEBUG_FULL, "Complete replay log string to write: '%s', length '%ld'.\n", line, strlen(line));

  // Write complete line to file
  if ((bytes = fprintf(fp, "%s", line)) < 0) {
    debugprint(DEBUG_CRIT, "error: could not write to replay log file.\n");
    fclose(fp);
    return 0;
  }

  fclose(fp);
  return bytes;
}