// 
// library to be preloaded into Dwarf Fortress (linux)
// Yoann Guillot, 10/2010
// 
// gcc -W -Wall -o dfclone.so dfclone.c -shared -fPIC
// LD_PRELOAD=./dfclone.so libs/Dwarf_Fortress
// 
// load your save, then create a 'reveal_now' file in the current directory
//
// uses hardcoded offsets for the v0.31.16 linux version
//

#include <stdio.h>
#include <unistd.h>

static void dfclone(void) __attribute__((constructor));
static int cloneloop(void*);


#ifdef USE_CLONE

// XXX this makes DF segfault during startup in some pthread function
#define _GNU_SOURCE
#include <sched.h>
static void dfclone(void) {
	static char clone_stack[4096*16];
	void *stackptr = clone_stack + sizeof(clone_stack) - 4;

	clone(cloneloop, stackptr, CLONE_VM, 0);
}


#else

#include <pthread.h>
static void dfclone(void) {
	pthread_t fu;
	pthread_create(&fu, 0, (void*(*)(void*))cloneloop, 0);
}


#endif

static void cloneloop_poll(void);
static void reveal(void);

static int cloneloop(void* arg) {
	(void)arg;	// unused argument blablabla

	for (;;) {
		sleep(1);
		cloneloop_poll();
	}

	_exit(0);
}


static void cloneloop_poll(void)
{
	int *caret = (int*)0x8b33550;

	// display game cursor position
	printf("%d %d %d\n", caret[0], caret[1], caret[2]);

	// TODO more useful stuff here, like read the name of a .so in the file, dlopen it, and call some function in it
	if (unlink("reveal_now") == 0)
		reveal();
}


static void reveal(void) {
// XXX dont know how to find all the map_data structures, this seems to work (top row only)
// but 'bi' used to be a 'xi'+'yi', now when trying to access other bi game crashes
// also why do z start at 14 ?

	struct map_data {
		char foo[0x26c];
		int flags[16*16];
	};

	struct map_data ***md = *(void**)(0x933f320);
	int bi, z, xi, yi;

	for (bi=0 ; bi<12 ; bi++) {
		printf("b=%d %p\n", bi, md[bi]);
		if (!md[bi])
			continue;

		for (z=14 ; z<160 ; z++) {
			// looks like all z-level are already allocated
			if (!md[bi][z])
				continue;
			int *flags = md[bi][z]->flags;
			for (xi=0 ; xi<16 ; xi++)
				for (yi=0 ; yi<16 ; yi++)
					// remove 'hidden from view' flag
					flags[16*xi+yi] &= ~0x200;
		}
	}
}