#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <dirent.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <ctype.h>
#include <stdbool.h>
#include <pwd.h>

#define BUF_SZ 130000

struct Task {
	char pid[1000];
	char task_name[1000];
	char state[500];
	char user[500];
	char task[500];
};

char proc_name[100];
char pid[1000];
char task_name[1000];
char state[500];
char user[500];
char task[500];

int tot_tasks;
char interrups[100];
char switches[100];
char forks[100];
int task_list;
int task_tot = 0;


int is_reg_file(const char *path) {
	struct stat path_stat;
	stat(path, &path_stat);

	return S_ISREG(path_stat.st_mode);
}

void combining_digits(char *temp, int start, int end, char* var) {
	bool seen = false;
	for (int j = start; j < end; j++) {
		if (isdigit(temp[j]) && seen == false) {
			int len = strlen(var);
			var[len] = temp[j];
			var[len + 1] = '\0';
			int holder = j + 1;
			if (holder != end) {
				for (int k = holder; k < end; k++) {
					if (isdigit(temp[k])) {
						int len = strlen(var);
						var[len] = temp[k];
						var[len + 1] = '\0';
					} else {
						seen = true;
						break;
					}
				}
			}
			break;
		}
	}
}

void task_info_helper(char *filename) {
	int file_d = open(filename, O_RDONLY);
	char buff[BUF_SZ];

	memset(buff, 0, BUF_SZ);
	if (file_d == -1) {
		printf("There was a problem opening file %s.\n", filename);
	} else {
		if (strstr(filename, "comm")) {
			read(file_d, buff, 10000);
			char *char_set = "\n";
			int len = strcspn(buff, char_set);
			int tracker = 0;

			for (int i = 0; i < len; i++) {
				tracker++;
				if (tracker <= 25) {
					int tn_len = strlen(task_name);
					task_name[tn_len] = buff[i];
					task_name[tn_len + 1] = '\0';
				} else {
					break;
				}
			}
		} else if (strstr(filename, "status")) {
			read(file_d, buff, BUF_SZ);
			char temp[25000];
			memset(temp, 0, 25000);
			int tracker = 0;

			for (int i = 0; i < strlen(buff); i++) {
				if (buff[i] != '\n') {
					int len = strlen(temp);
					temp[len] = buff[i];
					temp[len + 1] = '\0';
				} else {
					if (strlen(state) == 0 || strlen(pid) == 0 || strlen(user) == 0 || strlen(task) == 0) {
						if (strstr(temp, "State")) {
							char *char_set = "State:";
							int start = strspn(temp, char_set);
							int end = strcspn(temp, "\n");

							for (int j = start; j < end; j++) {
								if( (temp[j] >= 'a' && temp[j] <= 'z')) {
									int s_len = strlen(state);
									state[s_len] = temp[j];
									state[s_len + 1] = '\0';
								}
							}
						} else if (strstr(temp, "Pid")) {
							if (temp[0] == 'P' && temp[1] == 'i' && temp[2] == 'd') {
								char *char_set = "Pid:";
								int start = strspn(temp, char_set);
								int end = strcspn(temp, "\n");

								for (int j = start; j < end; j++) {
									if (isdigit(temp[j])) {
										int p_len = strlen(pid);
										pid[p_len] = temp[j];
										pid[p_len + 1] = '\0';
									}
								}
							}
						} else if (strstr(temp, "Uid")) {
							tracker++;
							if (tracker <= 15) {
								char *char_set = "Uid:";
								int start = strspn(temp, char_set);
								int end = strcspn(temp, "\n");
								combining_digits(temp, start, end, user);
							}
						} else if (strstr(temp, "Threads")) {
							char *char_set = "Threads:";
							int start = strspn(temp, char_set);
							int end = strcspn(temp, "\n");

							for (int j = start; j < end; j++) {
								if (isdigit(temp[j])) {
									int t_len = strlen(task);
									task[t_len] = temp[j];
									task[t_len + 1] = '\0';
								}
							}
						}
					}
					strcpy(temp, "");
				}
			}
		}
	}
	close(file_d);
}

void task_info(char *filename) {
	DIR *dir = opendir(filename);
	struct dirent *sub_dir;

	if (dir != NULL) {
		while ((sub_dir = readdir(dir)) != NULL) {
			char *new_name = sub_dir->d_name;
			char *temp = "/";
			char *new_dir = (char *) malloc(1 + strlen(filename) + strlen(new_name));
			char *a = (char *) malloc(1 + strlen(filename) + strlen(temp));
			strcpy(a, filename);
			strcat(a, temp);
			strcpy(new_dir, a);
			strcat(new_dir, new_name);

			if (strcmp(sub_dir->d_name, "comm") == 0) {
				task_info_helper(new_dir);
			} else if (strcmp(sub_dir->d_name, "status") == 0) {
				task_info_helper(new_dir);
			} else if (strcmp(sub_dir->d_name, ".") == 0 || strcmp(sub_dir->d_name, "..") == 0) {

			}
		}
	}
	closedir(dir);
}

void task_processor(char *filename) {
	DIR *dir = opendir(filename);
	struct dirent *sub_dir;
	int count = 0;
	char format[4000];

	if (dir != NULL) {
		while ((sub_dir = readdir(dir)) != NULL) {
			char *new_name = sub_dir->d_name;
			char *temp = "/";
			char *new_dir = (char *) malloc(1 + strlen(filename) + strlen(new_name));
			char *a = (char *) malloc(1 + strlen(filename) + strlen(temp));
			strcpy(a, filename);
			strcat(a, temp);
			strcpy(new_dir, a);
			strcat(new_dir, new_name);

			bool is_int = false;
			char *temp_str;
			temp_str = sub_dir->d_name;


			for (int i = 0; i < strlen(temp_str); i++) {
				char c = temp_str[i];
				int x = c - '\0';
				if (isdigit(x)) {
					is_int = true;
				} else {
					is_int = false;
					break;
				}
			}

			if (is_int == true) {
				count++;
				sprintf(format, "task%d", count);
				if (is_reg_file(new_dir) == 0) {
					task_info(new_dir);
					struct Task format;
					struct passwd *pwd;

					pwd = getpwuid(user);
					printf("%s\n", pwd);

					strcpy(format.pid, pid);
					strcpy(format.state, state);
					strcpy(format.task_name, task_name);
					strcpy(format.user, user);
					strcpy(format.task, task);

					task_list++;
					task_tot += atoi(task);
					printf("%5s | %12s | %25s | %15s | %s \n", format.pid, format.state, format.task_name, format.user, format.task);

					memset(pid, 0, 1000);
					memset(task_name, 0, 1000);
					memset(state,0 ,500);
					memset(user, 0, 500);
					memset(task, 0, 500);
				}
			}
		}
	}
	closedir(dir);
}

void get_count(char *filename) {
	DIR *dir = opendir(filename);
	struct dirent *sub_dir;
	int count = 0;
	char format[80];

	if (dir != NULL) {
		while ((sub_dir = readdir(dir)) != NULL) {
			char *new_name = sub_dir->d_name;
			char *temp = "/";
			char *new_dir = (char *) malloc(1 + strlen(filename) + strlen(new_name));
			char *a = (char *) malloc(1 + strlen(filename) + strlen(temp));
			strcpy(a, filename);
			strcat(a, temp);
			strcpy(new_dir, a);
			strcat(new_dir, new_name);

			bool is_int = false;
			char *temp_str;
			temp_str = sub_dir->d_name;


			for (int i = 0; i < strlen(temp_str); i++) {
				char c = temp_str[i];
				int x = c - '\0';
				if (isdigit(x)) {
					is_int = true;
				} else {
					is_int = false;
					break;
				}
			}
			if (is_int == true) {
				if (is_reg_file(new_dir) == 0) {
					count++;
				}
			}
		}
	}
	tot_tasks = count;
	closedir(dir);
}

void gather_info_helper(char *filename) {
	int file_d = open(filename, O_RDONLY);
	char buff[BUF_SZ];

	memset(buff, 0, BUF_SZ);
	if (file_d == -1) {
		printf("There was a problem opening file %s.\n", filename);
	} else {
		read(file_d, buff, BUF_SZ);
		char temp[80000];

		strcpy(temp, "");
		for (int i = 0; i < strlen(buff); i++) {
			if (buff[i] != '\n') {
				int len = strlen(temp);
				temp[len] = buff[i];
				temp[len + 1] = '\0';
			} else {
				if (strstr(temp, "intr")) {
					char *char_set = "intr";
					int start = strspn(temp, char_set);
					int end = strcspn(temp, "\n");
					combining_digits(temp, start, end, interrups);
				} else if (strstr(temp, "ctxt")) {
					char *char_set = "ctxt";
					int start = strspn(temp, char_set);
					int end = strcspn(temp, "\n");
					combining_digits(temp, start, end, switches);
				} else if (strstr(temp, "processes")) {
					char *char_set = "processes";
					int start = strspn(temp, char_set);
					int end = strcspn(temp, "\n");
					combining_digits(temp, start, end, forks);
				}
				strcpy(temp, "");
			}
		}
	}
	close(file_d);
}

void gather_info(char *filename) {
	DIR *dir = opendir(filename);
	struct dirent *sub_dir;

	if (dir != NULL) {
		while ((sub_dir = readdir(dir)) != NULL) {
			char *new_name = sub_dir->d_name;
			char *temp = "/";
			char *new_dir = (char *) malloc(1 + strlen(filename) + strlen(new_name));
			char *a = (char *) malloc(1 + strlen(filename) + strlen(temp));
			strcpy(a, filename);
			strcat(a, temp);
			strcpy(new_dir, a);
			strcat(new_dir, new_name);

			if (is_reg_file(new_dir) != 0) {
				if (strcmp(proc_name, filename) == 0 && strcmp(sub_dir->d_name, "stat") == 0) {
					gather_info_helper(new_dir);
				}
			}
		}
	}
	closedir(dir);
}

// int get_task_list(char *name) {
// 	get_count(name);
// 	int numb = tot_tasks + 2;

// 	return numb;
// }

void print_task(char *name) {

	memset(proc_name, 0, 100);
	strcpy(proc_name, name);
	get_count(name);
	gather_info(name);

	printf("Task Information\n");
	printf("----------------\n");
	printf("Tasks running: %d\n", tot_tasks);
	printf("Since boot:\n");
	printf("	Interrupts: %s\n", interrups);
	printf("	Context Switches: %s\n", switches);
	printf("	Forks: %s\n", forks);
	task_list++;
	printf("%5s | %12s | %25s | %15s | %s \n",
	"PID", "State", "Task Name", "User", "Tasks");
	printf("------+--------------+---------------------------+-----------------+-------\n");
	task_list++;
	task_processor(name);

	// set_task_list(task_list);
	// printf("%d\n", get_task_list());
//
	// printf("Task Count: %d\n", task_tot);
}