/* TreyfCGI: a non-Kosher (optionally) FastCGI C web framework for when you're
 * sick of everything else.
 *
 * My first slightly interesting C project. It's probably pretty terrible.
 *
 * Released into the public domain by Teran McKinney.
 * If public domain is not an option for you, it's also released under the CC0
 * license.
 *
 * http://creativecommons.org/publicdomain/zero/1.0/
 *
 * Building:
 *
 * Something like this works for me, using GCC 4.4.2:
 * gcc -O2 -D fastcgi -std=c99 treyfcgi.c -lfcgi -o /usr/local/bin/treyfcgi
 *
 * -D options are fastcgi and debug at this time. If you want fastcgi, be sure
 * to have the appropriate FastCGI headers installed: http://www.fastcgi.com/A
 *
 * Usage:
 *
 * Typical FastCGI socket setup, or you can argv[1] a file to test it on.
 *
 * For example: treyfcgi test.tf
 *
 * Version history:
 * (two bytes representec in hex, for major and minor)
 * 00.00 - 2011-06-01
 * 00.01 - 2011-06-03 - First public release
 * 00.02 - 2011-06-15 - Fixed a buffer overflow, fixed source view, new tags.
 * 00.03 - 2011-12-25 - dirlist() did not ASCII sort on newer environment/libc
 * 00.04 - 2012-02-09 - <tt> to set font to monospaced.
 */

#define _SVID_SOURCE

#ifdef fastcgi
// FastCGI
#include <fcgi_stdio.h>
#else
// No FastCGI
#include <stdio.h>
#endif

// Environment variables
#include <stdlib.h>

// open
#include <fcntl.h>

// read
#include <unistd.h>

// Sensible int declaration
#include <stdint.h>

// Directory functions
#include <dirent.h>

extern char **environ;

typedef uint32_t u32;
typedef uint16_t u16;
typedef uint8_t u8;

// puts without the newline
void p (char *text) {
	fputs(text, stdout);
}

void e (char *text) {
	fputs(text, stderr);
}

void sc (char *dst, char *src) {
	u8 i=0;
	// Thanks to Mark L. for finding this obvious bugger overflow. I've
	// since added range checking on i.
	for ( ; src[i] != 0 && i != 0xFF; i++ ) {
		dst[i] = src[i];
	}
	// Null at the end of dst so we don't get contamination.
	dst[i] = 0;
//	return i; // Length until null byte.
}

char endtag[512];

void end(char *t) {
	sc(endtag, t);
}

void dirlist() {
	u16 n;
	u16 c = 0;
	extern char envpath[0x100];
	struct dirent **listing;
	n = scandir(envpath, &listing, 0, alphasort);
	while (c < n) {
		printf("<li><a href=\"%s\">%s</a>",
				listing[c]->d_name,listing[c]->d_name);
		c++;
	}
	free(listing);
}

void parse(char c) {
	extern u16 pos;
	switch (c) {
		// Title
		case 't': 
			p ("<title>");
			pos++; // Skip the space or newline
			end("</title>");
			break;
		// Bold
		case 'b':
			p ("<b>");
			pos++; // Skip the space or newline
			end("</b>");
			break;
		// Link
		case 'l':
			p ("<a href=\"");
			pos++; // Skip the space or newline
			end("\">");
			break;
		// End link
		case 'e':
			p ("</a>");
			end("");
			break;
		// Image
		case 'i':
			p ("<img src=\"images/");
			pos++; // Skip the space or newline
			end("\"/>");
			break;
		// Directory listing
		case 'd':
			dirlist();
			end("");
			break;
		//  p for prettyI really mean li, but l is already in use.
		case 'p':
			p ("<li>");
			pos++; // Skip the space or newline
			// No </li> because I'm terrible like that.
			end("");
			break;
	}
}

// I believe that technically this is a signed int that can be 32 or 64b
// depending on the libc build. Probably won't be happy if I force pass it a
// smaller or larger bitwidth.

char envpath[0x100];
char scriptpath[0x100];
char buf[0xFFFF];
u16 pos;

int main (u8 uberargc, char *uberargv[]) {
	#ifdef debug
	char **envp;
	#endif

	extern char endtag[512];

	#ifdef fastcgi
	u32 count = 0;
	while (FCGI_Accept() >= 0) {
	#endif
		char *script = getenv("SCRIPT_FILENAME");
		extern char scriptpath[0x100];
		char *env = getenv("DOCUMENT_ROOT");
		extern char envpath[0x100];
		char *query = getenv("QUERY_STRING");
		char querystring[0x100];

		if (env != NULL) {
			sc(envpath, env);
		} else {
			sc(envpath, ".");
		}

		if (query != NULL) {
			sc(querystring, query);
		} else {
			sc(querystring, "");
		}

		if (script != NULL) {
			sc(scriptpath, script);
		} else if (uberargc == 2) {
			sc(scriptpath, uberargv[1]);
		} else {
			e("You got treyfed!\n");
		}
		if (scriptpath != NULL) {
			#ifdef debug
			printf ("\n%s\n", scriptpath);
			#endif
			// Probably another int with potentially mixed
			// definition between libcs.
			int fd = open(scriptpath, O_RDONLY);
			if (fd == -1) {
				e("You got treyfed!\n");
				//return 1;
			}
			extern char buf[0xFFFF];
			extern u16 pos;
			u16 fdlength = read(fd, buf, 0xFFFF);
			close(fd);
			// Prevent buffer corruption.
			buf[fdlength]=0;
			#ifdef debug
			printf ("%d\n", fdlength);
			#endif
			#ifdef fastcgi
			// Source view mode
			if (querystring[0] == 's') {
				p("Content-type: text/plain\r\n\r\n");

				// Stripped whitespace to fit into 80 colums.
				for (pos=0;pos!=0xFFFF&&buf[pos]!=0;pos++)
					printf ("%c", buf[pos]);
				continue; // Don't do return 0!
			}
			printf("Content-type: text/html\r\n"
			       "TreyfCGI-Hits: %d\r\n"
			       "Cache-Control: max-age=120\r\n" // Two minute
			       "\r\n", ++count);		// simple cache
			p("<tt>");
			#endif
			for ( pos = 0; pos != 0xFFFF && buf[pos] != 0; pos++) {
				switch (buf[pos]) {
					case '[':
						parse(buf[++pos]);
						break; // newline.

					case ']':
						p(endtag);
						end("");
						break;
				#ifdef fastcgi
					case '\n':
						p("<br/>");
						break;
				#endif
					default :
						printf ("%c", buf[pos]);
						break;
				}
			}
		}
		#ifdef debug
		envp = environ;
		for ( ; *envp != NULL; envp++)
			printf("%s\n", *envp);
		#endif
	#ifdef fastcgi
	}
	#endif

	return 0;
}