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

typedef struct {
	char *prog;
	char **args;
} COMMAND;

COMMAND parseInput(char* input);
char** splitter(char *token, int *count);

int main(int argc, char *argv[])
{

	while (1) {

		char input[512]; 	//store input line
		char inputcpy[512];
		printf("$sshell "); //shell prompt
		fgets(input, 512, stdin); //read line into string
		input[strlen(input) - 1] = '\0';
		strcpy(inputcpy, input);

		COMMAND comm = parseInput(input);

		printf("INPUT: %s\n", inputcpy);

		//check for exit command
		if (strcmp(comm.prog, "exit") == 0) {
			printf("Bye...\n");
			exit(0);

		}

		if (strcmp(comm.prog, "pwd") == 0) {
			char cwd[512];
			getcwd(cwd, sizeof(cwd));
			printf("%s\n", cwd);
		}

		if (strcmp(comm.prog, "cd") == 0) {
			if (chdir(comm.args[1]) == -1) {
				fprintf(stderr, "Error: no such directory.\n");
			}
		}

		else {

			//create new process
			pid_t PID = fork();

			//if child process
			if (PID == 0) {

				int status;

				//printf("Exec call.\n");
				status = execvp(comm.prog, comm.args);

				//if exec fails
				if (status != 0) {

					fprintf(stderr, "Error: command not found.\n");
					exit(42);

					//else exit the process
				}
				else {

					exit(0);

				}

			}
			else {

				int status;
				wait(&status);
				fprintf(stderr, "+ completed '%s' [%d]\n", input, WEXITSTATUS(status));

			}
		}
	}
	return EXIT_SUCCESS;
}

COMMAND parseInput(char *input) {

	COMMAND comm;
	int i = 1;
	char *token;

	token = strtok(input, " ");
	//printf("Got a token: %s\n", token);

	comm.prog = (char*)malloc(strlen(token) + 1);
	strcpy(comm.prog, token);

	comm.args = (char**)malloc(sizeof(char*) * 512);

	comm.args[0] = (char*)malloc(strlen(token) + 1);
	strcpy(comm.args[0], token);

	while (1) {
		token = strtok(NULL, " \n");

		if (token == NULL) {
			break;
		}

		if (strpbrk(token, "<>|") != NULL) {

			int count = 0;
			char **split = splitter(token, &count);
			int j = 0;

			for (j; j < count; j++) {
				comm.args[i + j] = malloc(sizeof(split[j] + 1);
				strcpy(comm.args[i + j], split[j]);
			}

			i = i + j;

		}
		else {

			comm.args[i] = (char*)malloc(strlen(token) + 1);
			strcpy(comm.args[i], token);
			i++;
		}
	}
	comm.args[i + 1] = (char*)malloc(sizeof((char*)NULL));
	comm.args[i + 1] = (char*)NULL;

	return comm;
}

char** splitter(char *token, int *count) {

	char **tokens = malloc(sizeof(char*) * 512);
	char *temp;
	int i = 0;
	int j = 0;


	while (token[i] != '\0') {

		if (token[i] == '<' || token[i] == '>' || token[i] == '|') {

			tokens[*count] = (char*)malloc(strlen(temp) + 1);
			strcpy(tokens[*count], temp);
			++*count;

			if (token[i] == '<') {
				tokens[*count] = (char*)malloc(strlen("<") + 1);
				strcpy(tokens[*count], "<");
			}
			else if (token[i] == '>') {
				tokens[*count] = (char*)malloc(strlen(">") + 1);
				strcpy(tokens[*count], ">");
			}
			else if (token[i] == '|') {
				tokens[*count] = (char*)malloc(strlen("|") + 1);
				strcpy(tokens[*count], "|");
			}

			++*count;
			temp[0] = 0;			//will hopefully clear the string
			j = 0;
			i++;
		}
		else {
			temp[j] = (char)malloc(sizeof(char));
			temp[j] = token[i];
			i++;
			j++;
		}
	}

	while (*tokens) {
		printf("%s ", *tokens);
		printf("\n");
		++tokens;

	}

	return tokens;
}