#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "directory.h"

#define MAXLINESIZE 150
/*These below define ishardcoded into scanf strings. 
	Do not change it without changing the %90s strings*/
#define MAXARGSIZE 90

#define TRUE 1
#define FALSE 0

void handle_create (char * args);
void handle_append (char * args);
void handle_mkdir (char * args);
void handle_ln (char * args);
void handle_cd (char * args);
void handle_rm (char * args);
void handle_rmdir (char * args);
void handle_mv (char * args);
void handle_pwd (char * args);
void handle_ls (char * args);
void handle_cat (char * args);
void handle_setread (char * args);
void handle_setwrite (char * args);

int check_args(char * args);
int check_ls_args(char * args);

/*Constant String Declarations*/
const char * create = "create";
const char * append = "append";
const char * mk_dir = "mkdir";
const char * ln = "ln";
const char * cd = "cd";
const char * rm = "rm";
const char * rm_dir = "rmdir";
const char * mv = "mv";
const char * pwd = "pwd";
const char * ls = "ls";
const char * cat = "cat";
const char * setread = "setread";
const char * setwrite = "setwrite";

/*error messages*/
const char * command_not_found = ": command not found";
const char * too_many_args = ": too many arguments";
const char * usage = "usage: ";
const char * invalid_file_name =": invalid filename";
const char * invalid_wild_card =": invalid wild card expression";

int main ( ) {
	char cmd[9];
	char line[MAXLINESIZE];
	int tokenCount;
	int numCharsRead=0;
		
	initialFileSystem ( );
	printf ("> ");
	while (fgets (line, MAXLINESIZE, stdin) != NULL) {
		tokenCount = sscanf (line, "%9s%n", cmd, &numCharsRead);
		while (*(line + numCharsRead) == ' ')
			numCharsRead++;
		if (tokenCount <= 0) {
			/* blank line; do nothing */
		} else if (strcmp (cmd, create) == 0) {
			handle_create (line+numCharsRead);
		} else if (strcmp (cmd, append) == 0) {
			handle_append (line+numCharsRead);
		} else if (strcmp (cmd, mk_dir) == 0) {
			handle_mkdir (line+numCharsRead);
		} else if (strcmp (cmd, ln) == 0) {
			handle_ln (line+numCharsRead);
		} else if (strcmp (cmd, cd) == 0) {
			handle_cd (line+numCharsRead);
		} else if (strcmp (cmd, rm) == 0) {
			handle_rm (line+numCharsRead);
		} else if (strcmp (cmd, rm_dir) == 0) {
			handle_rmdir (line+numCharsRead);
		} else if (strcmp (cmd, mv) == 0) {
			handle_mv (line+numCharsRead);
		} else if (strcmp (cmd, pwd) == 0) {
			handle_pwd (line+numCharsRead);
		} else if (strcmp (cmd, ls) == 0) {
			handle_ls (line+numCharsRead);
		} else if (strcmp (cmd, cat) == 0) {
			handle_cat (line+numCharsRead);
		} else if (strcmp (cmd, setread) == 0) {
			handle_setread (line+numCharsRead);
		} else if (strcmp (cmd, setwrite) == 0) {
			handle_setwrite (line+numCharsRead);
		} else {
			printf ("%s: Command not found.\n", cmd);
		}
		printf ("> ");
	}
	return 0;
}

void handle_create (char * args) {
	int argCount;
	char junk;
	char arg[MAXARGSIZE];
	argCount = sscanf (args, "%90s %1s", arg, &junk);
	if (argCount > 1) {
		printf ("%s%s\n",create,too_many_args);
	} else if (argCount == 0 || argCount == EOF) {
		printf ("%s%s fileName\n",usage,create);
	} else if (!check_args(arg)){
		printf ("%s%s\n",create,invalid_file_name);
	} else {
		createFile (arg);
	}
}

void handle_append (char * args) {
	int argCount;
	char junk;
	char arg[MAXARGSIZE];
	argCount = sscanf (args, "%90s %1s", arg, &junk);
	if (argCount > 1) {
		printf ("%s%s\n",append,too_many_args);
	} else if (argCount == 0 || argCount == EOF) {
		printf ("%s%s fileName\n",usage,append);
	} else if (!check_args(arg)){
		printf ("%s%s\n",append,invalid_file_name);
	} else {
		appendFile (arg);
	}
}

void handle_mkdir (char * args) {
	int argCount;
	char junk;
	char arg[MAXARGSIZE];
	argCount = sscanf (args, "%90s %1s", arg, &junk);
	if (argCount > 1) {
		printf ("%s%s\n",mk_dir,too_many_args);
	} else if (argCount == 0 || argCount == EOF) {
		printf ("%s%s directoryName\n",usage,mk_dir);
	} else if (!check_args(arg)){
		printf ("%s%s\n",mk_dir,invalid_file_name);
	} else {
		createDir (arg);
	}
}

void handle_ln (char * args) {
	int argCount;
	char junk;
	char arg[MAXARGSIZE];
	char arg2[MAXARGSIZE];
	argCount = sscanf (args, "%90s %90s %1s", arg, arg2, &junk);
	if (argCount != 2) {
		printf ("%s%s target linkname\n",usage,ln);
	} else if (!check_args(arg) || !check_args(arg2)){
		printf ("%s%s\n",ln,invalid_file_name);
	} else {
		createSoftLink (arg, arg2);
	}
}

void handle_cd (char * args) {
	int argCount;
	char junk;
	char arg[MAXARGSIZE];
	argCount = sscanf (args, "%90s %1s", arg, &junk);
	if (argCount > 1) {
		printf ("%s%s\n",cd,too_many_args);
	} else if (argCount == 0 || argCount == EOF) {
		printf ("%s%s directoryName\n",usage,cd);
	} else if (!check_args(arg)){
		printf ("%s%s\n",cd,invalid_file_name);
	} else {
		newWorkingDir (arg);
	}
}

void handle_rm (char * args) {
	int argCount;
	char junk;
	char arg[MAXARGSIZE];
	argCount = sscanf (args, "%90s %1s", arg, &junk);
	if (argCount > 1) {
		printf ("%s%s\n",rm,too_many_args);
	} else if (argCount == 0 || argCount == EOF) {
		printf ("%s%s fileName\n",usage,rm);
	} else if (!check_args(arg)){            
		printf ("%s%s\n",rm,invalid_file_name);
	} else {
		removeFile ( arg);
	}
}

void handle_rmdir (char * args) {
	int argCount;
	char junk;
	char arg[MAXARGSIZE];
	argCount = sscanf (args, "%90s %1s", arg, &junk);
	if (argCount > 1) {
		printf ("%s%s\n",rm_dir,too_many_args);
	} else if (argCount == 0 || argCount == EOF) {
		printf ("%s%s directoryName\n",usage,rm_dir);
	} else if (!check_args(arg)){
		printf ("%s%s\n",rm_dir,invalid_file_name);
	} else {
		removeDir (arg);
	}
}

void handle_mv (char * args) {
	int argCount;
	char junk;
	char fromArg[MAXARGSIZE];
	char toArg[MAXARGSIZE];
	argCount = sscanf (args, "%90s %90s %1s", fromArg, toArg, &junk);
	if (argCount > 2) {
		printf ("%s%s\n",mv,too_many_args);
	} else if (argCount < 2) {
		printf ("%s%s file2\n",usage,mv);
	} else if (!check_args(fromArg) || !check_args(toArg)){
		printf ("%s%s\n",mv,invalid_file_name);
	} else {
		moveEntry (fromArg, toArg);
	}
}

void handle_pwd (char * args) {
	int argCount;
	char junk;
	argCount = sscanf (args, "%1s", &junk);
	if (argCount > 0) {
		printf ("%s%s\n",usage,pwd);
	} else {
		printWorkingDir ();
	}
}

void handle_ls (char * args) {
	int argCount;
	char junk;
	char arg[MAXARGSIZE];
	argCount = sscanf (args, "%90s %1s", arg, &junk);
	if (argCount > 1) {
		printf ("%s%s\n",ls,too_many_args);
	} else if (argCount == 1) {
		if (!check_ls_args(arg)){
			printf ("%s%s\n",ls,invalid_wild_card);
		}
		else
			listWithinWorkingDir (arg);
	} else {
		listWorkingDir ();
	}
}

void handle_cat (char * args) {
	int argCount;
	int argSeen = FALSE;
	int numCharsRead;
	char arg[MAXARGSIZE];
	while (TRUE) {
		argCount = sscanf (args, "%90s%n", arg, &numCharsRead);
		if (argCount == 0 || argCount == EOF) {
			if (!argSeen) {
				printf ("%s%s fileName ...\n",usage,cat);
			}
			return;
		}
		argSeen = TRUE;
		if (!check_args(arg)){
			printf ("%s%s\n",cat,invalid_file_name);
			break;
		}
		else{
			listFileContents (arg);
		}
		args = args + numCharsRead;
	}
}

void handle_setread (char * args) {
	int argCount;
	char junk;
	char * junk2;
	int cnt;
	char countstr[MAXARGSIZE];
	char filename[MAXARGSIZE];
	argCount = sscanf (args, "%90s %90s %1s", countstr, filename, &junk);
	if (argCount > 2) {
		printf ("%s%s\n",setread,too_many_args);
	} else if (argCount < 2) {
		printf ("%s%s <0/1> file\n",usage,setread);
	} else if (!check_args(filename)){
		printf ("%s%s\n",setread,invalid_file_name);
	} else {
	  cnt = strtol(countstr,&junk2,0);
	  if (*junk2 != '\0' || ((cnt | 1) != 1))
	    	printf ("%s%s <0/1> file\n",usage,setread);
	  else
	    modifyReadable (cnt, filename);
	}
}

void handle_setwrite (char * args) {
	int argCount;
	char junk;
	char * junk2;
	int cnt;
	char countstr[MAXARGSIZE];
	char filename[MAXARGSIZE];
	argCount = sscanf (args, "%90s %90s %1s", countstr, filename, &junk);
	if (argCount > 2) {
		printf ("%s%s\n",setwrite,too_many_args);
	} else if (argCount < 2) {
		printf ("%s%s <0/1> file\n",usage,setwrite);
	} else if (!check_args(filename)){
		printf ("%s%s\n",setwrite,invalid_file_name);
	} else {
	  cnt = strtol(countstr,&junk2,0);
	  if (*junk2 != '\0' || ((cnt | 1) != 1))
	    	printf ("%s%s <0/1> file\n",usage,setwrite);
	  else
	    modifyWritable (cnt, filename);
	}
}

/*verify that paths only consist of [0-9], [a-z], [A-Z], [.], [/]*/
/*Return 1 if path valid; 0 if invalid*/
int check_args(char * args){
	while (*args != '\0'){
		if ( !(*args >= '0' && *args <= '9') &&
			!(*args >= 'A' && *args <= 'Z') &&
			!(*args >= 'a' && *args <= 'z') &&
      			*args != '.' && *args != '/'){
			return 0;
			}
		args++;
	 }
	 return 1;
}

/*the same as above, but allows '?' to pass and prevents '/' from going through*/
int check_ls_args(char * args){
	while (*args != '\0'){
		if ( !(*args >= '0' && *args <= '9') &&
			!(*args >= 'A' && *args <= 'Z') &&
			!(*args >= 'a' && *args <= 'z') &&
			*args != '.' && *args != '?'){
      			return 0;
      		}
		args++;
	 }
	 return 1;
}