/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * The contents of this file are subject to the Netscape Public License
 * Version 1.0 (the "NPL"); you may not use this file except in
 * compliance with the NPL.  You may obtain a copy of the NPL at
 * http://www.mozilla.org/NPL/
 *
 * Software distributed under the NPL is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
 * for the specific language governing rights and limitations under the
 * NPL.
 *
 * The Initial Developer of this code under the NPL is Netscape
 * Communications Corporation.  Portions created by Netscape are
 * Copyright (C) 1998 Netscape Communications Corporation.  All Rights
 * Reserved.
 */

#ifndef query_h___
#define query_h___

/* the RDF Query API. */

#include "rdf.h"

typedef uint8 RDF_TermType; /* type of a term */

/* values of RDF_TermType */
#define RDF_VARIABLE_TERM_TYPE 1
#define RDF_RESOURCE_TERM_TYPE 2
#define RDF_CONSTANT_TERM_TYPE 3

typedef struct _RDF_VariableStruc {
	void* value;
	RDF_ValueType type;
	char* id;
	PRBool isResult;
	struct _RDF_QueryStruc* query;
} RDF_VariableStruc;

typedef RDF_VariableStruc* RDF_Variable;

typedef struct _RDF_VariableListStruc {
	RDF_Variable element;
	struct _RDF_VariableListStruc* next;
} RDF_VariableListStruc;

typedef RDF_VariableListStruc* RDF_VariableList;

PR_PUBLIC_API(PRBool) RDF_IsResultVariable(RDF_Variable var);
PR_PUBLIC_API(void) RDF_SetResultVariable(RDF_Variable var, PRBool isResult);
PR_PUBLIC_API(void*) RDF_GetVariableValue(RDF_Variable var);
PR_PUBLIC_API(void) RDF_SetVariableValue(RDF_Variable var, void* value, RDF_ValueType type);

typedef struct _Term {
	void* value;
	RDF_TermType type;
} TermStruc;

typedef struct TermStruc* RDF_Term;

typedef struct _LiteralStruc {
	TermStruc u;
	RDF_Resource s;
	TermStruc* v;
	uint8 valueCount; /* disjunction */
	RDF_Cursor c;
	PRBool tv;
	PRBool bt;
	RDF_Variable variable;
	RDF_ValueType valueType;
} LiteralStruc;

typedef LiteralStruc* RDF_Literal;

typedef struct _RDF_LiteralListStruc {
	RDF_Literal element;
	struct _RDF_LiteralListStruc* next;
} RDF_LiteralListStruc;

typedef RDF_LiteralListStruc* RDF_LiteralList;

typedef struct _RDF_QueryStruc {
  struct _RDF_VariableListStruc* variables;
  struct _RDF_LiteralListStruc* literals;
  uint16 numLiterals;
  uint16 index;
  PRBool conjunctsOrdered;
  PRBool queryRunning;
  RDF rdf;
} RDF_QueryStruc;

typedef RDF_QueryStruc* RDF_Query;

/* Note: the API assumes that the query parameter is non-NULL. */
PR_PUBLIC_API(RDF_Query) RDF_CreateQuery(RDF rdf);
PR_PUBLIC_API(void) RDF_DestroyQuery(RDF_Query q);
PR_PUBLIC_API(RDF_Variable) RDF_GetVariable(RDF_Query q, char* name);
PR_PUBLIC_API(PRBool) RDF_RunQuery (RDF_Query q);
PR_PUBLIC_API(PRBool) RDF_GetNextElement(RDF_Query q);
PR_PUBLIC_API(void) RDF_EndQuery (RDF_Query q);
PR_PUBLIC_API(RDF_VariableList) RDF_GetVariableList(RDF_Query q);
PR_PUBLIC_API(uint16) RDF_GetVariableListCount(RDF_Query q);
PR_PUBLIC_API(RDF_Variable) RDF_GetNthVariable(RDF_Query q, uint16 index);
PR_PUBLIC_API(RDF_Error) RDF_AddConjunctVRV(RDF_Query q, RDF_Variable arg1, RDF_Resource s, RDF_Variable arg2, RDF_ValueType type);
PR_PUBLIC_API(RDF_Error) RDF_AddConjunctVRO(RDF_Query q, RDF_Variable arg1, RDF_Resource s, void* arg2, RDF_ValueType type);
PR_PUBLIC_API(RDF_Error) RDF_AddConjunctRRO(RDF_Query q, RDF_Resource arg1, RDF_Resource s, void* arg2, RDF_ValueType type);
PR_PUBLIC_API(RDF_Error) RDF_AddConjunctVRR(RDF_Query q, RDF_Variable arg1, RDF_Resource s, RDF_Resource arg2);
PR_PUBLIC_API(RDF_Error) RDF_AddConjunctRRV(RDF_Query q, RDF_Resource arg1, RDF_Resource s, RDF_Variable arg2, RDF_ValueType type);
PR_PUBLIC_API(RDF_Error) RDF_AddConjunctVRL(RDF_Query q, RDF_Variable arg1, RDF_Resource s, RDF_Term arg2, RDF_ValueType type, uint8 count);

#endif /* query_h___ */