#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>

#define LEDFILE "/sys/class/leds/ACT/brightness"


//write to the led
int wrLED(int fd, int val){
  char *opts[] = {"0", "1"};
  return write(fd, opts[val], 1);
}

void printVersion(){
  printf("ledctl 1.0\n");
}

void printUsage(char *errormsg){
  if (errormsg != NULL) printf("Error: %s\n", errormsg);
  printVersion();
  printf("Usage:\n");
  printf("  ledctl -v       print version information\n");
  printf("  ledctl -h       print this message\n");
  printf("  ledctl on|off   turn the LED on or off\n");
  printf("  ledctl  1|0\n");
  printf("  ledctl -r REPEAT -s VALUE TIMING [-s VALUE TIMING ...]\n");
}

int main(int argc, char *argv[]){
  if (argc < 2) return 1;
  char path[] = LEDFILE;
  int fd = open(path, O_RDWR);
  
  if (strcmp(argv[1], "on") == 0 || strcmp(argv[1], "1") == 0){
    wrLED(fd, 1);
    close(fd);
    return 0;
  }
  if (strcmp(argv[1], "off") == 0 || strcmp(argv[1], "0") == 0){
    wrLED(fd, 0);
    close(fd);
    return 0;
  }
  if (strcmp(argv[1], "-v") == 0 && argc == 2){
    printVersion(NULL);
    close(fd);
    return 0;
  }
  if (strcmp(argv[1], "-h") == 0 && argc == 2){
    printUsage(NULL);
    close(fd);
    return 0;
  }
  if (strcmp(argv[1], "-r") != 0 || argc < 6 || (argc % 3) != 0){
    printUsage(NULL);
    close(fd);
    return 1;
  }
  if (argc % 3 !=0) {
    printUsage("Invalid number of arguments");
    close(fd);
    return 1;
  }

  // keep track of previous state
  char prev;
  read(fd, &prev, 1);
  
  int pattern_repetitions = atoi(argv[2]);

  char **args_pattern = &argv[3];
  int pattern_steps = (argc-3) / 3;

  int   pattern_values[pattern_steps];
  float pattern_timing[pattern_steps];
  
  //parse arguments into our schema
  for (int i=0; i < pattern_steps; i++){
    int args_pattern_index = i*3;
    if (strcmp(args_pattern[args_pattern_index], "-s") != 0){
      printUsage("Invalid format for -s flag");
      close(fd);
      return 1;
    }
    pattern_values[i] = atoi(args_pattern[args_pattern_index + 1]);
    pattern_timing[i] = atof(args_pattern[args_pattern_index + 2]);

  }
  
  for (int i = 0; i < pattern_repetitions; i++) {
      for (int pstep = 0; pstep < pattern_steps; pstep++) {
          wrLED(fd, pattern_values[pstep]);
          usleep(1000000 * pattern_timing[pstep]);
      }
  } 
  write(fd, &prev, 1);
  close(fd);
}