/**
 * @file
 *
 * Fool's Shell
 * =========
 *
 * A minimalsitic and naive shell developed along the Fool OS kernel.
 * TODO: Free tokenizer / dynamic size!
 * TODO: & with pipes
 * TODO: > <
 * TODO: tab complete
 * TODO: multiple PATH vars
 * TODO: history
 */

#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include <errno.h>
#include <string.h>
#include "interface/fs.h"

extern char **environ;

bool process(char *buf);
bool metaprocess(char *buf);
bool cd(char *path);

void version()
{
    puts("Fool's Shell version git-commit:" GIT_REVISION "\ncompiled on " __DATE__ " at " __TIME__);
}

void help()
{
    puts(   "\nfoolshell: supported built-in commands/functions:\n\n" 

	    "'env'                       - show all environment variables\n"
	    "'getenv [var]'              - show environment variable\n"
	    "'setenv [var] [val]'        - set environemnet variable\n"

	    "'cd [dir]'                  - change directory (set $PWD)\n"
	    "'[binary] [params...]'      - run a binary\n"
	    "'[binary] [params...] &'    - run a binary in background\n"
	    " |                          - pipes\n"

	    "'help'                      - show this message\n"
	    "'exit'                      - exit running foolshell\n\n");

}

void prompt() 
{
    printf("\033[36mfool\033[37m@\033[32mhill\033[33m:%s%s\033[37m",getenv("PWD"),getenv("PS1"));
}

int main(int argc, char **argv) 
{
    for(int i=0;i<argc;i++)
    {
	if(!strcmp(argv[i],"--version"))
	{
	    version();
	    return 0;
	}

	if(!strcmp(argv[i],"--help"))
	{
	    help();
	    return 0;
	}
    }

    char *buf=calloc(sizeof(char),256);

    // input and output without buffering
    setvbuf(stdin,NULL,_IONBF,0);
    setvbuf(stdout,NULL,_IONBF,0);

    printf("\033c"); // clear screen

    while(1) // process commands until exit
    {
	prompt();
	int bl=0;

	while(1)
	{
            _gui_rect();
	    char c=fgetc(stdin);

	    if(c=='\b')
	    {
		if(bl==0)continue;
		buf[--bl]='\0';
		putc(c,stdout);
	    }
	    else
	    {
		putc(c,stdout);
		if(c=='\n')break;
		buf[bl]=c;
		buf[++bl]='\0';
	    }
	}

	if(!metaprocess(buf))break; // process input and return if exit
    }

    return 0;
}

// break the input in tokens on spaces
char **tokenize(char *buf,char chr)
{
    char **token;
    token=malloc(10*sizeof(char*));
    token=realloc(token,20*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]==chr&&i<l)i++;
	if(i==l)break;

	//get token
	int t=0;

	while(buf[i]!=chr&&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;
}

bool metaprocess2(char *buf);
bool metaprocess(char *buf)
{
    char **token=tokenize(buf,'|');
    if(token[0]==0 || token[1]==0)return process(buf); // no pipes

    int pid=_fork();

    if(pid==0)
    {
	metaprocess2(buf);
	exit(1);
    }

    _wait(pid);
    return true;
}

bool metaprocess2(char *buf)
{
    char **token=tokenize(buf,'|');
    if(token[0]==0 || token[1]==0)return process(buf); // no pipes

    int fds[2];
    _pipe(fds);

    int pid=_fork();

    if(pid==0)
    {
	// first child shall write to the pipe
	_close(fds[0]);
	_dup2(fds[1],1); // replace stdout with the write-end of our pipe
	process(token[0]);
	exit(1);
    }

    _close(fds[1]); // and we read from it
    _dup2(fds[0],0); 
    metaprocess2(strchr(buf,'|')+1);

    _wait(pid);

    return true;
}

bool process(char *buf)
{
    char **token=tokenize(buf,' ');
    char *command=token[0];

    if(!strcmp(command,"help"))help();
    else if(!strcmp(command,"cd"))cd(token[1]);
    else if(!strcmp(command,"exit")) return false;
    //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,"getenv"))printf("%s\n",getenv(token[1]));
    else if(!strcmp(command,"setenv"))
    {
	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]);
	    printf("%s\n" ,environ[i]);
	    i++;
	}
    }

    else // otherwise treat command as exectutable and send to execve
    {
        int last=0;
        for(last=0;token[last+1]!=NULL;last++);
        bool branch=!strcmp(token[last],"&");
        if(branch)token[last]=NULL;

	int pid=_fork();

	if(pid==0)
	{
	    if(token[0][0]=='/')sprintf(buf,"%s",token[0]);
	    else sprintf(buf,"%s/%s",getenv("PATH"),token[0]);
	    _execve(buf,token,environ);
	    printf("foolshell: %s (errno: %d)\n",strerror(errno),errno);
	    exit(1);
	}
	

        //printf("last: %s\n",token[last]);
	if(!branch)_wait(pid);

    }
    return true;
}

bool setpwd(char *path)
{
    if(!strcmp(path,"/"))
    {
	putenv("PWD=/");
	return true;
    }
    char buf[255];
    buf[0]=0;
    strcat(buf,"PWD="); 

    char **t=tokenize(path,'/');

    char *p[100];
    int pp=0;

    while(*t!=NULL)
    {
	if(!strcmp(*t,"..")){
	    pp--;
	    t++;
	    if(pp<0)pp=0;
	    continue;
	}
	if(!strcmp(*t,".")){t++; continue;}
	if(**t!=0)
	{
	    p[pp]=*t;
	    //printf("> %s\n",p[pp]);
	    pp++;
	}
	t++;
    }

    if(pp==0)
    {
        strcat(buf,"/"); 
    }

    for(int i=0;i<pp;i++)
    {
        strcat(buf,"/"); 
	strcat(buf,p[i]);
    }

    putenv(buf);
    return true; // TODO check if dir exists at all.
}

bool cd(char *path)
{
    char buf[256];
    // home
    if(path==NULL)
    {
	sprintf(buf,"%s",getenv("HOME"));
    }
    // absolute
    else if(path[0]=='/')
    {
	sprintf(buf,"%s",path);
    }
    // relative
    else
    {
	sprintf(buf,"%s/%s",getenv("PWD"),path);
    }

    // check if exists
    fs_dirent dirs;
    if(-1==_readdir(buf,&dirs,0))
    {
	    printf("directory not found!\n");
	    return false;
    }

    return setpwd(buf);
}