#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>

#define maxCommandLength 80
#define maxCommands 100
#define maxArgs 10
char command[maxCommands][maxCommandLength];
int commandPID[maxCommands];
int commandTimeStamp[maxCommands];
char * args[maxArgs];

void execCommand(char * input){
    char * inputCopy = input;
    char * commandToExec = strtok(inputCopy, " ");

    //Parse Arguments into local list for exec
    for(int argCount = 0; argCount < maxArgs; argCount++){
        char * currentArg = strtok(inputCopy, " ");
        if(currentArg != NULL){
            args[argCount] = currentArg;
        }
        else{
            args[argCount] = "\0";
            break;
        }
    }

    execv(commandToExec, args);
    //printf("Execv: %s \n", commandToExec);
}


int main(int argc, char **argv) {
    if(argc == 1){
        printf("No commands provided");
        return(-1);
    }
    //Initialization
    int commandCurrentCounter = 0;
    int commandTotal = 0;

    //loop to initialize command array
    for(int i = 0; i < maxCommands; i++){
        command[i][0] = '\0';
    }
    //Loop to parse argvs into command array
    for(int i = 0; i < argc; i++){
        char *cur_command = command[commandCurrentCounter];
        if(argv[i][0] != '.'){
            strcat(cur_command, argv[i]);
            strcat(cur_command, " ");
        }
        else{   //is a dot, terminating the command
            if(strlen(cur_command) > 0){
                commandCurrentCounter++;
            }
        }
    }
    if(strlen(command[commandCurrentCounter]) == 0){
        commandTotal = commandCurrentCounter;
    }
    else{
        commandTotal = commandCurrentCounter + 1;
    }

    //Print out Command Array Debug
    for(int i = 0; i < commandTotal; i++){
        printf("command[%d] = \"%s\"\n", i, command[i]);
    }

    //Issue Commands
    for(int i = 0; i < commandTotal; i++){
        pid_t pid;
        printf("About to exec: %s\n", command[i]);
        pid = fork();
        if(pid == 0){
            //Exec function in here
            execCommand(command[i]);
        }
        else{
            commandPID[i] = pid;
            clock_t begin = clock();
            commandTimeStamp[i] = begin;
        }
    }

    //Wait and Restart Loop
    int activeChildren = commandTotal;
    printf("active children: %d\n", activeChildren);
    while(activeChildren > 0){
        siginfo_t childInformation;
        waitid(P_ALL, 1, &childInformation, WEXITED || WSTOPPED);
        if(childInformation.si_code == CLD_EXITED){  //If child successfully completed
            activeChildren--;
            for(int i = 0; i < maxCommands; i++){
                if(commandPID[i] == childInformation.si_pid){
                    commandPID[i] = -1;
                    break;
                }
            }
        }
        else{   //Error code, check for timestamp on whether to restart
            int failedCommand = 0;
            clock_t beginChildTime;
            for(int i = 0; i < maxCommands; i++){
                if(commandPID[i] == childInformation.si_pid){
                    beginChildTime = commandTimeStamp[i];
                    failedCommand = i;
                    break;
                }
            }
            //Check to see if 2 seconds have passed
            clock_t difference = clock() - beginChildTime;
            long seconds = difference / CLOCKS_PER_SEC;
            if(seconds > 2){
                //Fork and exec the command that failed and reset timer
                pid_t pid = fork();
                if(pid == 0){
                    execCommand(command[failedCommand]);
                }
                else{
                    commandPID[failedCommand] = pid;
                    clock_t begin = clock();
                    commandTimeStamp[failedCommand] = begin;
                }
            }
            else{
                printf("Spawning too fast!\n");
                activeChildren--;
                for(int i = 0; i < maxCommands; i++){
                    if(commandPID[i] == childInformation.si_pid){
                        commandPID[i] = -1;
                        break;
                    }
                }
            }
        }
    }


    return 0;
}