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


typedef struct process {
    char name[21];
    int execution_time;
} PROCESS;


typedef struct node {
    PROCESS process;
    struct node *next;
} NODE;


void addProcesses(NODE **, NODE **);
void addProcess(NODE **, NODE **, PROCESS *);
void execute(NODE *);
int delete(NODE **, NODE **, PROCESS *);
void deleteRow(NODE **, NODE **);

int main()
{
    NODE *f = 0, *r = 0;
    char choice[6];

    do
    {
        printf("[1] Enter new processes\n");
        printf("[2] Exit\n");
        printf("[START] Start process execution\n");
        printf(">>");

        fscanf(stdin, "%s", choice);

        if (strcmp(choice, "1") == 0)
        {
            addProcesses(&f, &r);
        }
        else if (strcmp(choice, "START") == 0)
        {
            execute(f);
        }
        printf("\n");
    } while(strcmp(choice, "2") != 0);

    deleteRow(&f, &r);
    return 0;
}


void addProcesses(NODE **pf, NODE **pr)
{
    int n;
    char id[3];
    PROCESS temp;

    printf("Enter the number of processes that you wish to add: ");
    do
    {
        fscanf(stdin, "%d", &n);
    } while(n < 0);

    srand(time(NULL));

    for (int i = 0; i < n; i++)
    {
        sprintf(id, "%d", i + 1);
        strcpy(temp.name, "process");
        strcat(temp.name, id);

        temp.execution_time = rand() % 5 + 1;

        addProcess(pf, pr, &temp);
    }
}


void addProcess(NODE **pf, NODE **pr, PROCESS *process)
{
    NODE *new_node = calloc(1, sizeof(NODE));

    new_node->process = *process;
    new_node->next = 0;

    if (*pf == 0)
    {
        *pf = *pr = new_node;
    }
    else
    {
        (*pr)->next = new_node;
        *pr = new_node;
    }
}


void execute(NODE *f)
{
    while(f)
    {
        printf("process_name=%s; execution_time=%d;\n", f->process.name, f->process.execution_time);
        sleep(f->process.execution_time);
        f = f->next;
    }
}


int delete(NODE **pf, NODE **pr, PROCESS *process)
{
    if (*pf == 0)
    {
        return 0;
    }

    NODE *temp = *pf;
    *process = temp->process;

    if (*pf == *pr)
    {
        *pf = *pr = 0;
    }
    else
    {
        *pf = temp->next;
    }

    free(temp);

    return 1;
}


void deleteRow(NODE **pf, NODE **pr)
{
    NODE temp;

    while(delete(pf, pr, &temp));
}