#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <ctype.h>
#include <dirent.h>
#include <pwd.h>
#include <errno.h>
#include "proto.h"

#define BUF_SIZE 256

static int expLiteralChars(char *orig, char *new, int *oldl_ind, int *newl_ind, int *insideQuoteFlag)
{
	if(orig[*oldl_ind] == '"') *insideQuoteFlag = !(*insideQuoteFlag);
	new[*newl_ind] = orig[*oldl_ind];
	(*newl_ind)++;
	(*oldl_ind)++;
	return 0;
}

static int expEnvVars(char *orig, char *new, int *oldl_ind, int *newl_ind)
{
	char *envValue;
	int envNameLen = 0;

	(*oldl_ind)++;
	while(orig[*oldl_ind + envNameLen] != '}')
	{
		if(orig[*oldl_ind + envNameLen] == 0 || orig[*oldl_ind + envNameLen] == '$')
		{
			fprintf(stderr, "msh: no matching }\n");
			return 1;
		}
		envNameLen++;
	}

	orig[*oldl_ind + envNameLen] = 0;
	envValue = getenv(&(orig[*oldl_ind]));


	if(envValue != NULL)
	{
		strcpy(&(new[*newl_ind]), envValue);
		*newl_ind = *newl_ind + strlen(envValue);
	}
	
	*oldl_ind = *oldl_ind + envNameLen + 1;
	// envNameLen = 0;
	return 0;
}

static int expShPid(char *orig, char *new, int *oldl_ind, int *newl_ind)
{
	char pidBuff[8];
	int pid = (int)getpid();
	int i = 0;

	if(sprintf(pidBuff, "%d", pid) > -1)
	{
		while(pidBuff[i])
		{
			new[*newl_ind] = pidBuff[i++];
			(*newl_ind)++;
		}
		(*oldl_ind)++;
		return 0;
	}
	return 1;
}

static int expMainArgs(char *orig, char *new, int *oldl_ind, int *newl_ind) //, int mainargc, char **mainargv, char **shiftedMArgV)
{
	int argInd;
	int argLen;
	char tempChar;
	char *argIndStr = &(orig[*oldl_ind]);

	while(isdigit(orig[*oldl_ind])) (*oldl_ind)++;

	tempChar = orig[(*oldl_ind)];
	orig[*oldl_ind] = 0;
	argInd = atoi(argIndStr);
	orig[*oldl_ind] = tempChar;


	if(m_argc == 1)
	{
		if(argInd >= m_shifted_argc) return 0;
		argLen = strlen(m_argv[0]);
		strcpy(&(new[*newl_ind]), m_argv[0]);
	}
	else
	{
		if((argInd+1) >= m_shifted_argc) return 0;
		if(argInd == 0)
		{
			argLen = strlen(m_argv[1]);
			strcpy(&(new[*newl_ind]), m_argv[1]);
		}
		else
		{
			argLen = strlen(m_shifted_argv[argInd+1]);
			strcpy(&(new[*newl_ind]), m_shifted_argv[argInd+1]);
		}
	}

	*newl_ind = *newl_ind + argLen;
	return 0;
}

static int expMainCount(char *new, int *newl_ind) //, int mainargc)
{
	int argStrLen;
	int offset = 1;

	if(m_argc == 1) offset = 0;

	argStrLen = sprintf(&(new[*newl_ind]), "%d", (m_shifted_argc - offset));

	*newl_ind = *newl_ind + argStrLen;

	return 0;
}

static int expLastExitS(char *new, int *newl_ind)
{
	int exStatStrLen = sprintf(&(new[*newl_ind]), "%d", (last_exit_status));

	*newl_ind = *newl_ind + exStatStrLen;

	return 0;
}

static int expWildCard(char *orig, char *new, int *oldl_ind, int *newl_ind, int filterFlag)
{
	int i;
	int dirLen;
	int matchCount = 0;
	int passedFilterFlag = 0;
	int dirNameStrLen;
	char *dirName;
	char *filterStr;
	char tempChar;
	struct dirent **namelist;

	/* GET ALL THE DIRECTORIES AND PUT THEM IN namelist */
	dirLen = scandir(".", &namelist, 0, alphasort);
	if(dirLen < 0)
	{
		perror("scandir");
		return 1;
	}

	(*oldl_ind)++;
	if(filterFlag)
	{
		filterStr = &(orig[*oldl_ind]);
		while(orig[*oldl_ind] != ' ' && orig[*oldl_ind] != '"' && orig[*oldl_ind] != 0)
		{
			if(orig[*oldl_ind] == '/')
			{
				fprintf(stderr, "./msh: no match\n");
				return 1;
			}
			(*oldl_ind)++;
		}
		tempChar = orig[*oldl_ind];
		orig[*oldl_ind] = 0;
	}

	for(i = 0; i < dirLen; i++)
	{
		dirName = namelist[i]->d_name;
		dirNameStrLen = strlen(dirName);

		if(dirName[0] == '.')
		{
			passedFilterFlag = 0;
		}
		else if(filterFlag)
		{
			if(strlen(filterStr) > dirNameStrLen) passedFilterFlag = 0;
			else
			{
				if(!strcmp(filterStr, &(dirName[dirNameStrLen - strlen(filterStr)]))) passedFilterFlag = 1;
				else passedFilterFlag = 0;
			}
		}
		else passedFilterFlag = 1;

		if(passedFilterFlag)
		{
			matchCount++;
			strcpy(&(new[*newl_ind]), dirName);
			if(i != (dirLen -1))
			{
				*newl_ind = *newl_ind + dirNameStrLen + 1;
				new[*newl_ind - 1] = ' ';
			}
			else *newl_ind = *newl_ind + dirNameStrLen;
		}

		free(namelist[i]);
	}

	if(!matchCount)
	{
		new[*newl_ind] = '*';
		(*newl_ind)++;
		if(filterFlag)
		{
			strcpy(&(new[*newl_ind]), filterStr);
			*newl_ind = *newl_ind + strlen(filterStr);
		}
	}

	if(filterFlag) orig[*oldl_ind] = tempChar;
	free(namelist);
	return 0;
}

static int expHomeDir(char *orig, char *new, int *oldl_ind, int *newl_ind)
{
	int i = 1;
	char temp;
	char *name = 0;
	char *hdir;
	struct passwd *pwResult;
	
	/* SEE IF NAME PRESENT AFTER ~ AND PUT NULL TERMINATOR AT END IF THERE IS 
	   IF NOT USE getlogin */
	while(orig[*oldl_ind + i] != ' ' && orig[*oldl_ind + i] != '/' && orig[*oldl_ind + i] != 0) i++;
	temp = orig[*oldl_ind +i];
	if(i == 1) name = getlogin();
	else
	{
		orig[*oldl_ind + i] = 0;
		name = &(orig[*oldl_ind + 1]);
	}
	
	/* GET PASSWD RESULTS, REPLACE NULL(OR NOTHING) WITH TEMP */
	pwResult = getpwnam(name);
	orig[*oldl_ind + i] = temp;
	
	/* UPDATE IND'S. IF THERE ARE NO PASSWD RESULTS, LEAVE LITERAL 
	   TILDA, OTHERWISE COPY HOME FOLDER TO NEW. */
	if(!pwResult)
	{
		new[*newl_ind] = '~';
		*oldl_ind = *oldl_ind + 1;
		*newl_ind = *newl_ind + 1;
	}
	else
	{
		hdir = pwResult->pw_dir;
		strcpy(&(new[*newl_ind]), hdir);
		
		*oldl_ind = *oldl_ind + i;
		*newl_ind = *newl_ind + strlen(hdir);
	}
	
	return 0;
}

static int expCmdOutput(char *orig, char *new, int *oldl_ind, int *newl_ind)
{
	char buf[BUF_SIZE];
	int bytes_read;
	int total_bytes_read = 0;
	int fd[2];
	int parenthCount = 1;
	int i = *oldl_ind + 1;
	
	/* ENSURE MATCHING PARENS - REPLACE LAST PAREN WITH 0 */
	while(parenthCount > 0)
	{
		if(orig[i] == '(') parenthCount++;
		else if(orig[i] == ')') parenthCount--;
		else if(orig[i] == 0)
		{
			fprintf(stderr, "./msh: missing )\n");
			return 1;
		}
		i++;
	}
	orig[i-1] = 0;
	
	/* PIPE, RECURSIVELY CALL PROCESSLINE(should pass 0 for 3rd arg), AND CLOSE WRITE END */
	if(pipe (fd) < 0) perror("pipe");
	processline(&(orig[*oldl_ind + 1]), fd[1], 0);
	close(fd[1]);
	
	/* READ OUTPUT OF COMMAND FROM READ END OF PIPE, THEN CLOSE READ END */
	while((bytes_read = read(fd[0],buf,BUF_SIZE-1)))
	{
		if(bytes_read < 0)
		{
			if(errno == EWOULDBLOCK || errno == EAGAIN) continue;
			else if(errno == EINTR) fprintf(stderr, "WE GOT AN EINTR SIGNAL\n");
			else
			{
				perror("read");
				break; // Or should this be exit?
			}
		}
		else if(bytes_read > 0) total_bytes_read += bytes_read;
	}
	buf[total_bytes_read] = 0;
	close(fd[0]);
	
	/* REPLACE ORIGINAL MATCHING PAREN, UPDATE oldl_ind */
	orig[i-1] = ')';
	*oldl_ind = i;
	
	/* COPY OUTPUT OF COMMAND TO EXPANDED LINE, UPDATE newl_ind */
	i = 0;
	while(buf[i] != 0)// && buf[i] != '\n')
	{
		new[*newl_ind + i] = buf[i];
		i++;
	}
	*newl_ind = *newl_ind + i;
	
	/* REMOVING EXTRA LINES */
	i = 0;
	while(new[i])
	{
		if(new[i] == '\n') new[i] = ' ';// && new[i+1] != 0) new[i] = ' ';
		i++;
	}
	
	return 0;
}

int expand(char *orig, char *new, int newsize) //, int mainargc, char **mainargv, char **shiftedMArgV)
{
	int newl_ind = 0;
	int oldl_ind = 0;
	int insideQuoteFlag = 0;

	while(orig[oldl_ind] && newl_ind < newsize)
	{
		if(orig[oldl_ind] == '$')
		{
			if(orig[++oldl_ind] == '{') { if(expEnvVars(orig, new, &oldl_ind, &newl_ind)) return 1; }
			else if(orig[oldl_ind] == '(') { if(expCmdOutput(orig, new, &oldl_ind, &newl_ind)) return 1; }
			else if(orig[oldl_ind] == '$') { if(expShPid(orig, new, &oldl_ind, &newl_ind)) return 1; }
			else if(isdigit(orig[oldl_ind])) { if(expMainArgs(orig, new, &oldl_ind, &newl_ind)) return 1; } //, mainargc, mainargv, shiftedMArgV)) return 1; }
			else if(orig[oldl_ind] == '#') {
				if(expMainCount(new, &newl_ind)) return 1;
				oldl_ind++;
			}
			else if(orig[oldl_ind] == '?') {
				if(expLastExitS(new, &newl_ind)) return 1;
				oldl_ind++;
			}
			else
			{
				new[newl_ind] = orig[oldl_ind - 1];
				newl_ind++;
			}
		}
		else if(orig[oldl_ind] == '*')
		{
			if(orig[oldl_ind-1] == ' ' || orig[oldl_ind-1] == '"' || oldl_ind == 0)
			{
				if(orig[oldl_ind+1] == ' ' || orig[oldl_ind+1] == '"' || orig[oldl_ind+1] == 0)
				{
					if(expWildCard(orig, new, &oldl_ind, &newl_ind, 0)) return 1;
				}
				else
				{
					if(expWildCard(orig, new, &oldl_ind, &newl_ind, 1)) return 1;
				}
			}
			else if(orig[oldl_ind-1] == '\\')
			{
				new[newl_ind-1] = '*';
				oldl_ind++;
			}
			else
			{
				/*new[newl_ind] = '*';
				newl_ind++;
				oldl_ind++;*/
				if(expLiteralChars(orig, new, &oldl_ind, &newl_ind, &insideQuoteFlag)) return 1;
			}
		}
		else if(orig[oldl_ind] == '#' && !insideQuoteFlag) break;
		else if(orig[oldl_ind] == '~' && orig[oldl_ind-1] == ' ')
		{
			if(expHomeDir(orig, new, &oldl_ind, &newl_ind)) return 1;
		}
		else
		{
			/*if(orig[oldl_ind] == '"') insideQuoteFlag = !insideQuoteFlag;
			new[newl_ind] = orig[oldl_ind];
			newl_ind++;
			oldl_ind++;*/
			if(expLiteralChars(orig, new, &oldl_ind, &newl_ind, &insideQuoteFlag)) return 1;
		}
	}
	new[newl_ind] = 0;
	return 0;
}