#include <iostream>
#include <cstring>
#include <fstream>
#include <string>
#include <ctime>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <dirent.h>

using namespace std;

/* version */
const char* versinfo = "0.0.5a";

void readmsg(int *x);
void editmsg(char *x);
void get_all_messages(char *x);
void show_version(void);
void show_help(void);
void show_wenda(void);
int msg_filter(const dirent *x);
void countmsgs(void);
char get_msg_filename(int *x);

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

	if (!argv[1]) 
	{
	cout << "Standard program - Just display list of message titles, numbered." << endl;
	exit(0);
	}
	else
	{
	/* check for non-standard arguments */ 
	if (!strcmp(argv[1], "--version"))
	{
	show_version();
	exit(0);
	}
	else if (!strcmp(argv[1], "--help"))
	{
	show_help();
	exit(0);
	}
	/* this is an easter egg - it refers to Wenda from "Where's Wally" */
	else if (!strcmp(argv[1], "--wenda"))
	{
	show_wenda();
	exit(0);
	}
	}

	/* normal argument handler - thanks to Arvind */
	for (int i = 1; i < argc; i++) {    
        if (argv[i][0] == '-') {        
            switch (argv[i][1]) {      
                case 'r':
                    if (argc > i + 1) {
                       	/* thanks to Kamran - this range handler is brilliant :) */ 
			get_all_messages(argv[i + 1]);
                        i++;
                    }
                    else {
                        cout << "Display list of message titles." << endl;
                    }
                    break;

                case 'w':
			// cout << "Write message.";
                    break;

		case 'c':
			countmsgs();
			exit(0);
                    break;

		case 'e':
			if (argc > i + 1) {
			char * emsg;
			emsg = argv[i + 1];
			editmsg(emsg);
			i++;
			}
			else {
			cout << "Please enter a message number to edit." << endl;
			}	
                    break;

                default:
                    cout << "Unknown argument: " << argv[i][1] << endl;
                    break;
            }
        }
        else {
            cout << "Extra arg: " << argv[i] << endl;
        }
    }

    return (0);
}

/* functions */

void readmsg(int *x)
{
	string mbuffer, mbuffertmp;
	int mbuffertest, msglinelength;
	char *themsgfile;
	themsgfile = get_msg_filename(x);
	ifstream msgfile(themsgfile);
	if (! msgfile.is_open())
	{
 	cout << "Error opening file"; exit (1); 
	}
	cout << "\n";
	while (! msgfile.eof())
	{
	getline(msgfile,mbuffer,'\n');
	mbuffertmp = mbuffer;
	mbuffertest = mbuffertmp.empty();
		if (mbuffertest == 0)
		{ 
		mbuffertmp = mbuffertmp.erase(1);
			if (mbuffertmp == "%")
                        {
                        msglinelength = mbuffer.length();
                                if (msglinelength > 1)
                                {
                                mbuffer = mbuffer.substr(2);
                                cout << mbuffer << endl;
                                }
                                else
                                {
                                mbuffer = mbuffer.substr(1);
                                cout << mbuffer << endl;
                                }
                        }
			else if (mbuffertmp == "T")
			{
			mbuffer = mbuffer.substr(7);
			cout << "-----------------------------------------" << endl;
			cout << " " << mbuffer << endl;
			cout << "-----------------------------------------" << endl;
			}
			else if (mbuffertmp == "D")
			{
			mbuffer = mbuffer.substr(6);
			long tmpdate;
			tmpdate = atol(mbuffer.c_str());
			cout << "Last Modified: " << ctime(&tmpdate) << "\n";
			}
		}
	}
	cout << "\n";
}

/* ranges code thanks to Kamran - how cool is it? :D */
void get_all_messages(char *x)
{
	int range1, range2, range[10], i = 0;
	string temp, arg(x);

	/* here's the really messy part. The program first checks whether the argument contains a ','. If yes, it then checks for a '-'. If yes, it handles the argument accordingly. */

	while (arg.length() > 0)
		if (arg.find(",") < arg.length())
			if (arg.find("-") < arg.length())
				{
				int loc = arg.find_first_of(",-");
				switch (arg[loc])
					{
					case '-':
						arg.replace(loc, 1, "%");
						temp = arg.substr(0, loc);
						range1 = atoi(temp.c_str());
						int nextloc;
						nextloc = arg.find_first_of("-,");
						if (nextloc < arg.length())
							{
							temp = arg.substr(loc + 1, nextloc - loc - 1);
							arg.erase(0, nextloc + 1);
							}
						else
							{
							temp = arg.substr(loc + 3);
							arg.erase(0, loc + 1);
							}
						range2 = atoi(temp.c_str());
						while (range1 <= range2)
							range[i++] = range1++;
						break;
					case ',':
						arg.replace(loc, 1, "%");
						temp = arg.substr(0, loc);
						range[i++] = atoi(temp.c_str());
						arg.erase(0, loc + 1);
						break;
					}
				}
			else
				{
				int loc = arg.find(",");
				temp = arg.substr(0, loc);
				range[i++] = atoi(temp.c_str());
				arg.erase(0, loc + 1);
				}
		else if (arg.find("-") < arg.length())
			{
			int loc = arg.find("-");
			temp = arg.substr(0, loc);
			range1 = atoi(temp.c_str());
			temp = arg.substr(loc + 1, arg.length() - loc - 1);
			range2 = atoi(temp.c_str());
			while (range1 <= range2)
				range[i++] = range1++;
			arg.erase(0, loc + 3);
			}
		else
			{
			range[i++] = atoi(arg.c_str());
			break;
			}
	//while ends here
	--i;
	
	for(int j = 0; j <= i; j++)
	{
	readmsg(range[j]);
	}
}

void editmsg(char *x)
{
	pid_t pid = 0;
	x = strcat(x, "_tmp.txt");

	if ((pid = fork ()) == 0)
	{
        // In child.
	execl("/usr/bin/vi", "vi",x,0);

        // Remember, not exit, but use _exit.
        _exit (0);
	}

	waitpid (pid, 0, 0);
	cout << "Message edited." << endl;	

}

int msg_filter(const dirent *x)
{
	char *msgindicator = ".message";
	char *cmsgindicator;
	cmsgindicator = strstr(x->d_name,msgindicator);
		if (cmsgindicator)
		{
 		return (1);
 		}
 		else
 		{
		return (0);
		}
}

void countmsgs(void)
{
	int n,t=0;

	struct dirent **countedlist;
	n = scandir(".", &countedlist, msg_filter, versionsort);
		if (n < 0)
		{
		perror("scandir");
		}
		else
		{
			while(n--) 
			{
			t++;
			free(countedlist[n]);
			}
		free(countedlist);
		}
cout << "There are " << t << " messages." << endl;
} 

char get_msg_filename(int *x)
{
	struct dirent **msgarray;
	x = scandir(".", &msgarray, msg_filter, versionsort);
	char *fn; 
	x = x-1;
	fn = msgarray[x]->d_name;
	return fn;
}

void show_version(void)
{
	cout << "Grim " << versinfo << endl;
}

void show_help(void)
{
	cout << "Help to be implemented" << endl;
}

void show_wenda(void)
{
	cout << "This is an easter egg.  I will make it more interesting later." << endl;
}