#include <stdlib.h>
#include <stdio.h>
#include <sys/shm.h>
#include <unistd.h>
#include "shared.h"

int CheckArgumentPosition(int argc, char* argv[], char letter);
void CreateChildForks(int forkAmount, int forkType, int sharedID);
int GetSplitAmount(int argc, char* argv[], int forkType);

//  TODO:   Clean up main
//          Add command line arguments for producer and consumer number
int main(int argc, char* argv[])
{
    int producerAmount = GetSplitAmount(argc, argv, 0);
    int consumerAmount = GetSplitAmount(argc, argv, 1);
    int sharedID = shmget(IPC_CREAT | (key_t)1243, sizeof(SharedStruct), IPC_CREAT | 0666);
    if (sharedID < 0)
    {
        fprintf(stderr, "Shmget failed\n");
        exit(1);
    }
    SharedStruct* sharedMem = shmat(sharedID, NULL, 0);
    SharedStructInit(sharedMem);
    // Create child forks
    // TODO: Add creating consumers and producers instead of general forks
    CreateChildForks(producerAmount, 0, sharedID);
    CreateChildForks(consumerAmount, 1, sharedID);
    return 0;    
}

int CheckArgumentPosition(int argc, char* argv[], char letter)
{
    char argumentHyphen = '-';
    char argumentLetter = letter;
    for (int i = 1; i < argc; i++)
    {
        if ((*(argv[i]) == argumentHyphen) && (*(argv[i]+1) == argumentLetter))
        {
            return i;
        }
    }
    return -1;
}

//  Function creates an amount of children based on given type
//  forkAmount: Amount of children to create
//  forkType: 0 for creating producers, non-zero for consumers
//  sharedID: ID number of shared memory
void CreateChildForks(int forkAmount, int forkType, int sharedID)
{
    int forkID;
    for (int i = 0; i < forkAmount; i++)
    {
        forkID = fork();
        if (forkID < 0)
        {
            fprintf(stderr, "fork failed\n");
            exit(1);
        }
        if (forkID == 0)
        {            
            break;
        }
    }
    if (forkID != 0)
        return;
    //  TODO: Pass through sharedID
    char sharedIDStr[16];
    sprintf(sharedIDStr, "%d", sharedID);
    if (forkType == 0)
        execlp("./producer.out", "./producer.out", sharedIDStr, NULL);
    if (forkType != 0)
        execlp("./consumer.out", "./consumer.out", sharedIDStr, NULL);
    exit(0);
}

//  Takes in argc, argv, and type of fork to check for
//  forkType: 0 for creating producers, non-zero for consumers
int GetSplitAmount(int argc, char* argv[], int forkType)
{
    char letter;
    int position;
    if (forkType == 0)
        letter = 'p';
    if (forkType != 0)
        letter = 'c';
    position = CheckArgumentPosition(argc, argv, letter);
    if (position == -1)
        return 1;
    return StringToNumber(argv[position+1]);

}