#include "duration.h"
#include "stdlib.h"
#include "string.h"
#include <stdio.h>

enum DurationParserState {
  DURATION_PARSER_STATE_INITIAL,
  DURATION_PARSER_STATE_NUMBER,
  DURATION_PARSER_STATE_SECOND,
  DURATION_PARSER_STATE_MINUTE,
  DURATION_PARSER_STATE_HOUR,
  DURATION_PARSER_STATE_EOS,
};

Duration parseDuration(const char *duration) {
  enum DurationParserState state = DURATION_PARSER_STATE_INITIAL;
  Duration d;
  d.seconds = 0;
  d.hours = 0;
  d.minutes = 0;
  char numBuf[32] = "0";
  for (const char *c = duration; *c; c++) {
    if (state == DURATION_PARSER_STATE_INITIAL) {
      if (*c >= '0' && *c <= '9') {
        state = DURATION_PARSER_STATE_NUMBER;
      } else if (*c == 's' || *c == 'S') {
        state = DURATION_PARSER_STATE_SECOND;
      } else if (*c == 'm' || *c == 'M') {
        state = DURATION_PARSER_STATE_MINUTE;
      } else if (*c == 'h' || *c == 'H') {
        state = DURATION_PARSER_STATE_HOUR;
      }
    }
    if (state == DURATION_PARSER_STATE_NUMBER) {
      const char *start = c;
      while (*c >= '0' && *c <= '9') {
        numBuf[c - start] = *c;
        c++;
      }
      c--;
      state = DURATION_PARSER_STATE_INITIAL;
    } else if (state == DURATION_PARSER_STATE_SECOND) {
      d.seconds = atoi(numBuf);
      strncpy(numBuf, "0", 32);
      state = DURATION_PARSER_STATE_INITIAL;
    } else if (state == DURATION_PARSER_STATE_MINUTE) {
      d.minutes = atoi(numBuf);
      strncpy(numBuf, "0", 32);
      state = DURATION_PARSER_STATE_INITIAL;
    } else if (state == DURATION_PARSER_STATE_HOUR) {
      d.hours = atoi(numBuf);
      strncpy(numBuf, "0", 32);
      state = DURATION_PARSER_STATE_INITIAL;
    }
  }
  return d;
}

unsigned long durationToSeconds(const Duration *d) {
  return d->hours * 3600 + d->minutes * 60 + d->seconds;
}

Duration secondsToDuration(unsigned long seconds) {
  Duration d;
  d.hours = seconds / 3600;
  d.minutes = (seconds % 3600) / 60;
  d.seconds = seconds % 60;
  return d;
}

char* formatDuration(const Duration *d) {
  char buf[32];
  sprintf(buf, "%02lu:%02lu:%02lu", d->hours, d->minutes, d->seconds);
  return strdup(buf);
}