#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include <string.h>

extern char **environ;
//
void hello()
{
    // ascci art: http://patorjk.com/software/taag/#p=testall&f=Cards&t=Fool%20OS
    puts(
                    
    "       ______            __   ____  _____      \n"
    "      / ____/___  ____  / /  / __ \\/ ___/     \n"
    "     / /_  / __ \\/ __ \\/ /  / / / /\\__ \\   \n"
    "    / __/ / /_/ / /_/ / /  / /_/ /___/ /       \n"
    "   /_/    \\____/\\____/_/   \\____//____/     \n"
    "                                               \n"
    "Welcome to FoolShell v0.4 (Compiled on " __DATE__ " at " __TIME__ "\n"
    "------------------------------------------------------------------\n\n"
    "Please type 'help' anytime, to show shell \"built-ins\" or execute \n"
    "user programms that are in you $PATH directory by simply typing \n"
    "their filenames. You can get additional information for many commands\n"
    "by invking them with the --help or -h flag (e.g. ls --help) \n"
    );

    printf("Your $PATH is currently set to: %s\n\n",getenv("PATH"));
}

void prompt() 
{
    printf("%s%s",getenv("PWD"),getenv("PS1"));
}

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

    bool silent=false;
    for(int i=0;i<argc;i++)
    {
	if(!strcmp(argv[i],"--silent"))silent=true;
    }
    
    if(!silent)hello();

    char *buf=malloc(256);

    while(1)
    {
	prompt();
        fgets(buf,255,stdin);
	buf[strlen(buf)-1]=0; // remove \n
	process(buf);
    }

    return 0;
}

char **tokenize(char *buf)
{

    char **token;
    token=malloc(10*sizeof(char*));

    int l=strlen(buf);

    int i;
    int c=0;

    for(i=0;i<l;i++)
    {  
	// init space for next token
	token[c]=malloc(256);

	//skip all the whitespace
	while(buf[i]==' '&&i<l)i++;
	if(i==l)break;

	//get token
	int t=0;

	while(buf[i]!=' '&&i<l)
	{
	    token[c][t]=buf[i];
	    t++;
	    i++;
	}
	token[c][t]=0;
	


//	printf("token %i : <%s>\n",c, token[c]);
	c++;
	token[c]=NULL;

    }

    return token;

}

int process(char *buf)
{
    
    char **token=tokenize(buf);
    char *command=token[0];
  //  puts(command);
    // copied from trottelshell

    if(!strcmp(command,"help"))
    {
	puts("foolshell: supported built-in commands: 'help', 'echo [string]', 'malloc [bytes]', 'free [address]', 'getenv [var]', 'putenv/setenv [var] [val]', 'env' 'cd [dir]'");
    }
    else if(!strcmp(command,"cd"))
    {
	char *dir=getenv("PWD");

	char buf[256];

	if(token[1][0]!='/')
	{
	    sprintf(buf,"%s%s%s",dir,dir[0]=='/'&&dir[1]==0?"":"/",token[1]);
	}
	else
	{
	    sprintf(buf,"%s",token[1]);
	}

	char token[10];

	//adjust pwd (resolve '..' and '.')
////	printf("adjusting pwd: '%s'\n",buf);
	int left=1;
	int right=0;

	do{

	    int t=0;
	    do
	    {
		right++;
		token[t]=buf[right];

		t++;
	    }
	    while(buf[right]!=0&&buf[right]!='/');
	    token[t-1]=0;
	    
//	    printf("path token: '%s'\n",token);

	    

	    if(!strcmp(token,".."))
	    {
		left--;
		while(buf[left]!='/')left--;
	    }
	    else if(!strcmp(token,"."))
	    {
	    }
	    else
	    {
		int i=0;
		if(left!=1)buf[left++]='/';
		do{buf[left++]=token[i++];}while(token[i]!=0);

	    }

	}while(buf[right]!=0);
	buf[left]=0;
//	printf("adjusted: '%s'\n",buf);
	
	setenv("PWD",buf,1);

    }
    else if(!strcmp(command,"echo"))
    {
	printf("\"%s\"\n",token[1]);

    }
    else if(!strcmp(command,"malloc"))
    {
	uint8_t *mall=malloc(atoi(token[1]));
	printf("allocated %d bytes at 0x%08X (%i).\n",atoi(token[1]),mall,mall);
    }
    else if(!strcmp(command,"free"))
    {
	free(atoi(token[1]));
	printf("called free(0x%08X).\n",atoi(token[1]));
    }
    else if(!strcmp(command,"getenv"))
    {
	printf("(0x%08X) get: '%s' = '%s'(0x%08X) \n",environ,token[1],getenv(token[1]),getenv(token[1]));
    }
    else if(!strcmp(command,"putenv")||!strcmp(command,"setenv"))
    {
	char buf[256];
	sprintf(buf,"%s=%s",token[1],token[2]);
	putenv(buf);
	printf("(0x%08X) set: '%s' = '%s' \n",environ,token[1],getenv(token[1]));
    }
    else if(!strcmp(command,"env"))
    {
	int i=0;
	printf("env: 0x%08X\n",environ);
	while(environ[i]!=NULL)
	{
	    printf("envvar %s (0x%08X)\n" ,environ[i],environ[i]);
	    i++;
	}
    }
    else
    {
	char buf[256];
	sprintf(buf,"%s/%s",getenv("PATH"),token[0]);

	asm("mov $0x05bff,%esp"); // set stack pointer
	execve(buf,token,environ);
	asm("mov $0x07000,%esp"); // set stack pointer

	puts("foolshell: command not found");

	asm("mov $0x05bff,%esp"); // set stack pointer
	static char *argv[]={"shell","--silent",NULL};
	execve("/bin/foolshell",argv,environ); // start shell
	


    }
    return 0;

}