#ifndef PL_H
#define PL_H

#include <windows.h>
#include <SWI-Prolog.h>

int PL_get_tchars(term_t t, TCHAR** pTsz, int iFlags);
int Plx(const char* szMod, const char* szPred);

struct Query
{
	Query(module_t ctx, predicate_t p, term_t t0);
	~Query(void);
	int Cut(void);
	int Close(void);
	int NextSolution(void);
private:
	qid_t m_q;
};

/* Polymorphic aliases for PL_put_*, PL_get_*. */
inline int PlPut(const term_t t, const int x) { return PL_put_integer(t, x); }
inline int PlPut(const term_t t, const long x) { return PL_put_integer(t, x); }
inline int PlPut(const term_t t, const long long x) { return PL_put_integer(t, x); }
inline int PlPut(const term_t t, const atom_t x) { return PL_put_atom(t, x); }
inline int PlPut(const term_t t, char* const x) { return PL_put_atom(t, PL_new_atom(x)); }
inline int PlPut(const term_t t, const char* const x) { return PL_put_atom(t, PL_new_atom(x)); }
inline int PlPut(const term_t t, wchar_t* const x) { return PL_put_atom(t, PL_new_atom_wchars(-1, x)); }
inline int PlPut(const term_t t, const wchar_t* const x) { return PL_put_atom(t, PL_new_atom_wchars(-1, x)); }
inline int PlPut(const term_t, int* const) { return -1; }
inline int PlPut(const term_t, long* const) { return -1; }
inline int PlPut(const term_t, long long* const) { return -1; }
inline int PlPut(const term_t, atom_t* const) { return -1; }
inline int PlPut(const term_t, char** const) { return -1; }
inline int PlPut(const term_t, wchar_t** const) { return -1; }

inline int PlGet(const term_t, const int) { return -1; }
inline int PlGet(const term_t, const long) { return -1; }
inline int PlGet(const term_t, const long long) { return -1; }
inline int PlGet(const term_t, const atom_t) { return -1; }
inline int PlGet(const term_t, char* const) { return -1; }
inline int PlGet(const term_t, const char* const) { return -1; }
inline int PlGet(const term_t t, int* const x) { return PL_get_integer(t, x); }
inline int PlGet(const term_t t, long* const x) { return PL_get_long(t, x); }
inline int PlGet(const term_t t, long long* const x) { return PL_get_int64(t, x); }
inline int PlGet(const term_t t, atom_t* const x) { return PL_get_atom(t, x); }
inline int PlGet(const term_t t, char** const x) { return PL_get_atom_chars(t, x); }
inline int PlGet(const term_t t, wchar_t** const x)
{
	atom_t a;
	size_t len;
	if (!PL_get_atom(t, &a)) return 0;
	*x = (wchar_t*)PL_atom_wchars(a, &len);
	return *x != NULL;
}

/* Helper templates for Plx, Pl. */
template <typename T>
int PlPutv(const term_t t, T arg) { return PlPut(t, arg); }
template <typename T, typename ...R>
int PlPutv(const term_t t, T arg, R... rest) { return PlPut(t, arg)? PlPutv(t+1, rest...): 0; }
template <typename T>
int PlGetv(const term_t t, T arg) { return PlGet(t, arg); }
template <typename T, typename ...R>
int PlGetv(const term_t t, T arg, R... rest) { return PlGet(t, arg)? PlGetv(t+1, rest...): 0; }
template <typename T>
int Countv(const int i, T arg) { return i+1; }
template <typename T, typename ...R>
int Countv(const int i, T arg, R... rest) { return Countv(i+1, rest...); }

/* Call Prolog predicate, propagating Prolog exceptions. */
template <typename ...T>
int Plx(const char* const szMod, const char* const szPred, T... args)
{
	const int iArity = Countv(0, args...);
	const term_t t = PL_new_term_refs(iArity);
	if (!PlPutv(t, args...)) return 0;
	Query q(NULL, PL_predicate(szPred, iArity, szMod), t);
	if (!q.NextSolution()) return 0;
	if (!PlGetv(t, args...)) return 0;
	return 1;
}

/* Call Prolog predicate, ignoring Prolog exceptions. */
inline int Pl(const char* const szMod, const char* const szPred)
{
	try {
		return Plx(szMod, szPred);
	} catch (term_t& t) {
		return 0;
	}
}
template <typename ...T>
int Pl(const char* const szMod, const char* const szPred, T... args)
{
	try {
		return Plx(szMod, szPred, args...);
	} catch (term_t& t) {
		return 0;
	}
}

#endif