#include "myMonitoringTool.h"
#include <assert.h>
#include <signal.h>
#include <stdio.h>
#include <sys/wait.h>
#include <unistd.h>

#define MAIN 0
#define MEM 1
#define CPU 2
#define CORE 3

bool isint(char *str) {
  ///_|> descry: checks if a string is an integer
  ///_|> str: string to check
  ///_|> returning: true iff is an integer

  int i = 0;
  while (str[i] != '\0') {
    if (!isdigit(str[i])) {
      return false;
    }
    i += 1;
  }
  return true;
}

void sigint_handler(int sig) {
  ///_|> descry: Handles SIGINT, exiting if pressed twice
  ///_|> sig: signal number
  ///_|> returning: void
  static int count = 0;
  if (count == 0) {
    printf("\nPress Ctrl+C again to quit");
    count++;
    char buf[LINE_BUF];
    fgets(buf, sizeof buf, stdin);
    count = 0;
    if (signal(SIGINT, sigint_handler) != 0) {
      perror("signal");
      exit(1);
    }
  } else {
    exit(0);
  }
}

// Parse input, read values, display requested output
int main(int argc, char **argv) {
  ///_|> Parse CLAs, implement children to read data, prints childrens data
  ///_|> argc: number of arguments including function name
  ///_|> argv: list of string arguments
  ///_|> retuning: integer success code
  if (signal(SIGTSTP, SIG_IGN) != 0) {
    perror("signal");
    exit(1);
  }

  bool show_mem = false;
  bool show_cpu = false;
  bool show_cores = false;
  int samples = 20;
  int tdelay = 5e5;
  int nums_given = 0;

  // Parse input
  for (int i = 1; i < argc; i++) {
    char first9[10];
    strncpy(first9, argv[i], 9);
    first9[9] = '\0';
    char first10[11];
    strncpy(first10, argv[i], 10);
    first10[10] = '\0';
    if (strcmp(argv[i], "--memory") == 0) {
      show_mem = true;
    } else if (strcmp(argv[i], "--cpu") == 0) {
      show_cpu = true;
    } else if (strcmp(argv[i], "--cores") == 0) {
      show_cores = true;
    } else if (isint(argv[i])) {
      if (nums_given == 0) {
        samples = atoi(argv[i]);
      } else if (nums_given == 1) {
        tdelay = atoi(argv[i]);
      } else {
        printf("Unknown flag %s\nUsage: myMonitoringTool  [samples [tdelay]] "
               "[--memory] [--cpu] [--cores] [--samples=N] [--tdelay=T]\n",
               argv[i]);
        exit(1);
      }
      nums_given += 1;
    } else if (strcmp(first9, "--tdelay=") == 0) {
      char value[LINE_BUF];
      strncpy(value, argv[i] + 9, 20);
      tdelay = atoi(value);
    } else if (strcmp(first10, "--samples=") == 0) {
      char value[LINE_BUF];
      strncpy(value, argv[i] + 10, 20);
      samples = atoi(value);
    } else {
      printf("Unknown flag %s\nUsage: myMonitoringTool  [samples [tdelay]] "
             "[--memory] [--cpu] [--cores] [--samples=N] [--tdelay=T]\n",
             argv[i]);
      exit(1);
    }
  }
  bool show_all = !(show_mem || show_cpu || show_cores);
  if (show_cores && !(show_mem || show_cpu || show_all)) {
    samples = 1;
  }

  int cpu_cores = get_file_line_value("/proc/cpuinfo", 11);
  int p[2]; // Mem pipe
  int q[2]; // Cpu pipe
  int r[2]; // Core pipe

  if (pipe(p) == -1 || pipe(q) == -1) {
    perror("pipe");
    exit(1);
  }

  int cpu_proc = fork();
  int mem_proc = -2;
  if (cpu_proc != 0) {
    mem_proc = fork();
  }
  if (cpu_proc == -1 || mem_proc == -1) {
    perror("fork");
    exit(1);
  }

  int id = -1;

  if (cpu_proc != 0 && mem_proc > 0) {
    close(p[1]);
    close(q[1]);
    id = MAIN;
    if (signal(SIGINT, sigint_handler) != 0) {
      perror("signal");
      exit(1);
    }
  } else if (cpu_proc == 0 && mem_proc <= 0) {
    close(p[0]);
    close(p[1]);
    close(q[0]);
    id = CPU;
    if (signal(SIGINT, SIG_IGN) != 0) {
      perror("signal");
      exit(1);
    }
  } else {
    assert(cpu_proc != 0 && mem_proc == 0);
    close(p[0]);
    close(q[0]);
    close(q[1]);
    id = MEM;
    if (signal(SIGINT, SIG_IGN) != 0) {
      perror("signal");
      exit(1);
    }
  }

  // Prepare the core info
  char coreinfo[PANE_BUF];
  if (id == MAIN && (show_cores || show_all)) {
    if (pipe(r) == -1) {
      perror("pipe");
      exit(1);
    }
    int pid = fork();
    if (pid == -1) {
      perror("fork");
      exit(1);
    }
    if (pid == 0) {
      close(r[0]);
      int cpu_max_freq = get_file_line_value(
          "/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq", 0);
      draw_cores(cpu_cores, cpu_max_freq, r[1]);
      exit(0);
    } else {
      close(r[1]);
    }
  }

  // Draw the frames

  int mem_total = get_file_line_value("/proc/meminfo", 0);

  // Initialize arrays for values that change, scaled from 0 to 10. For use
  // in children
  int mem_usages[samples];
  int cpu_utils[samples];

  // Values that will be printed, for use in parent
  char meminfo[PANE_BUF];
  char cpuinfo[PANE_BUF];

  // Draw, compute, and display output
  for (int i = 0; i < samples; i++) {

    if (id == MEM && (show_mem || show_all)) {
      assert(mem_proc == 0 && cpu_proc != 0);
      get_mem_usage(mem_total, meminfo, mem_usages, i);
      write(p[1], meminfo, PANE_BUF);

      raise(SIGSTOP);
    }

    if (id == CPU && (show_cpu || show_all)) {
      assert(mem_proc != 0 && cpu_proc == 0);
      get_cpu_usage(cpu_cores, cpuinfo, cpu_utils, i, tdelay / 2);
      write(q[1], cpuinfo, PANE_BUF);

      raise(SIGSTOP);
    }

    // Display cores info
    if (id == MAIN) {
      if (show_mem || show_cpu || show_all) {
        usleep(tdelay);
      }
      draw_reset(samples, tdelay);
      if (show_mem || show_all) {
        // printf("main wait to read mem\n");
        read(p[0], meminfo, PANE_BUF);
        printf("%s", meminfo);
        if (kill(mem_proc, SIGCONT) != 0) {
          perror("kill");
          exit(1);
        };
      }

      if (show_cpu || show_all) {
        read(q[0], cpuinfo, PANE_BUF);
        printf("%s", cpuinfo);
        if (kill(cpu_proc, SIGCONT) != 0) {
          perror("kill");
          exit(1);
        };
      }

      if (show_cores || show_all) {
        // The core info had time to generate, now it should read without
        // generation time
        if (i == 0) {
          read(r[0], coreinfo, PANE_BUF);
        }
        printf("%s", coreinfo);
      }
    }
  }
  return 0;
}