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

uint16_t compile(const char *prog, uint8_t *tape, uint16_t tape_len, uint8_t **idx, uint8_t eval) {
  uint16_t elapsed = 1;

  while(*prog) {
    uint16_t traveled = 1;

    if(eval && *prog == '>') {
      if(*idx == tape + tape_len) {
        *idx = tape;
      } else {
        *idx += 1;
      }
    } else if(eval && *prog == '<') {
      if(*idx == tape) {
        *idx = tape + tape_len;
      } else {
        *idx -= 1;
      }
    } else if(eval && *prog == '+') {
      if(**idx == (2 << 7) - 1) {
        **idx = 0;
      } else {
        **idx += 1;
      }
    } else if(eval && *prog == '-') {
      if(**idx == 0) {
        **idx = (2 << 7) - 1;
      } else {
        **idx -= 1;
      }
    } else if(eval && *prog == '.') {
      putchar(**idx);
    } else if(eval && *prog == ',') {
      **idx = getchar();
    } else if(*prog == '[') {
      uint8_t should_eval = **idx > 0;

      if(!eval) {
        should_eval = 0;
      }

      traveled = compile(prog + 1, tape, tape_len, idx, should_eval);
    } else if(*prog == ']') {
      if(eval && **idx > 0) {
        return 0;
      } else {
        return elapsed + 1;
      }
    }

    elapsed += traveled;
    prog += traveled;
  }

  return 0;
}

int main(int argc, char **argv) {
  if(argc != 2) {
    return 1;
  }

  const char *prog = argv[1];
  uint8_t tape[30000] = { 0 };
  uint16_t tape_len = sizeof(tape);
  uint8_t *idx = tape;
  uint8_t eval = 1;

  compile(prog, tape, tape_len, &idx, eval);
}