#include <regex.h>
#include <stdio.h>
#include <string.h>

regex_t regex;
#define MAX_MATCH 5
// This is the number of capture groups + 1
#define RESET "\x1b[0m"

int regmatch(regex_t *preg, const char *string, size_t nmatch,
             regmatch_t pmatch[], int eflags) {
  // returns number of matches found.  (Max nmatch)
  int matches = 0;
  int offset = 0;
  int ret;

  while (matches < nmatch) {
    ret = regexec(preg, string + offset, nmatch - matches, pmatch + matches,
                  eflags);
    if (!ret) {
      int current = offset;
      offset += pmatch[matches].rm_eo;
      pmatch[matches].rm_so += current;
      pmatch[matches].rm_eo += current;
      matches++;
    } else if (ret == REG_NOMATCH) {
      break;
    } else {
      break;
    }
  }
  return matches;
}

const char *clean_string(const char *badansi) {
  static char buffer[1024];
  char *cp;

  strcpy(buffer, badansi);
  cp = buffer;
  while ((cp = strstr(cp, "\x1b")) != NULL) {
    *cp = '~';
  };
  return buffer;
}

void test(const char *trythis) {
  regmatch_t regmatches[MAX_MATCH];
  int matches, x;
  const char *clean = clean_string(trythis);
  printf("TEST (%s)\n", clean);

  matches = regmatch(&regex, trythis, MAX_MATCH, regmatches, 0);
  if (matches == 0) {
    printf("No matches.\n");
  } else {
    printf("%d matches:\n", matches);
    for (x = 0; x < matches; x++) {
      printf("%d (%d - %d)\n", x, regmatches[x].rm_so, regmatches[x].rm_eo);
      printf("    %*s [%.*s]\n", regmatches[x].rm_so, "",
             regmatches[x].rm_eo - regmatches[x].rm_so,
             clean + regmatches[x].rm_so);
    }
  }
}

void test_(const char *trythis) {
  int ret;
  char msgbuf[100];
  const char *p = trythis;

  // safe printing (maybe)
  strcpy(msgbuf, trythis);
  char *fixup = msgbuf;
  while ((fixup = strstr(fixup, "\x1b")) != NULL) {
    *fixup = '^';
  };

  printf("Test: [%s]%s\n", msgbuf, RESET);

  regmatch_t matches[MAX_MATCH];
  while (1) {
    ret = regexec(&regex, p, MAX_MATCH, matches, 0);

    if (!ret) {
      printf("MATCH!\n");
      for (int i = 0; i < MAX_MATCH; i++) {
        int start, finish;
        if (matches[i].rm_so == -1)
          break;

        start = matches[i].rm_so;
        finish = matches[i].rm_eo;
        // %.*s  = length to print, char * to use
        strncpy(msgbuf, p + start, (finish - start));
        msgbuf[finish - start] = 0;
        fixup = msgbuf;
        while ((fixup = strstr(fixup, "\x1b")) != NULL) {
          *fixup = '^';
        };

        // printf("'%.*s'%s %d : %d - %d\n", (finish - start), p + start, RESET,
        // i, start, finish);
        printf("'%s' %d : %d - %d\n", msgbuf, i, start, finish);
      };
      p += matches[0].rm_eo;
    } else if (ret == REG_NOMATCH) {
      printf("Sorry, no matches.\n");
      break;
    } else {
      regerror(ret, &regex, msgbuf, sizeof(msgbuf));
      fprintf(stderr, "Regex match failed: %s\n", msgbuf);
    }
  }
  return;
}

int main(int argc, char *argv[]) {
  // char RX[] = "(\x1b\[(?:\\d+|;)+[a-zA-Z])";
  // char RX[] = "([a-z][a-z]([0-9]+))";
  char RX[] = "([a-z][a-z]([0-9]+))";
  char msgbuf[100];
  int ret;

  if ((ret = regcomp(&regex, RX, REG_EXTENDED | REG_NEWLINE))) {
    regerror(ret, &regex, msgbuf, sizeof(msgbuf));
    fprintf(stderr, "Regex compile failed: %s\n", msgbuf);
    return 1;
  }

  test("this will fail.");
  test("this has ab5 ab55 zd3 three matches.");

  regfree(&regex);
  // if ( regcomp( &regex, "(\x1b\[(?:[0-9]|;)+[a-zA-Z])",
  // REG_EXTENDED|REG_NEWLINE ) ) { if ( regcomp( &regex,
  // "(\x1b\[([0-9]+|;)+[a-zA-Z])", REG_EXTENDED|REG_NEWLINE ) ) { if ( regcomp(
  // &regex, "\x1b\[[0-9]+(;[0-9]+)+?[a-zA-Z]", REG_EXTENDED|REG_NEWLINE ) ) {
  if (regcomp(&regex, "\x1b\[[0-9]+(;[0-9]+)*?[a-zA-Z]",
              REG_EXTENDED | REG_NEWLINE)) {
    regerror(ret, &regex, msgbuf, sizeof(msgbuf));
    fprintf(stderr, "Regex compile failed: %s\n", msgbuf);
    return 1;
  };

  test("\x1b[1;1H\x1b[2J\x0cMystic BBS\x1b[6n");
  test("\x1b[5;1HMEEP.");
  test("\x1b[0;1;34;47mHello");
  regfree(&regex);

  //   \s matches space, FORM FEED.  Ouch!  NO!

  if (regcomp(&regex, "[a-zA-Z]+( [a-zA-Z]+)+", REG_EXTENDED | REG_NEWLINE)) {
    regerror(ret, &regex, msgbuf, sizeof(msgbuf));
    fprintf(stderr, "Regex compile failed: %s\n", msgbuf);
    return 1;
  };

  test("\x1b[1;1H\x1b[2J\x0cMystic BBS\x1b[6n");
  test("\x1b[5;1HMEEP is cool for cats.");

  regfree(&regex);
  return 0;
}