/* -*- coding: utf-8; c-file-style: "ruby" -*- */
/*
  Copyright (C) 2011  Haruka Yoshihara <yoshihara@clear-code.com>
  Copyright (C) 2012  Kouhei Sutou <kou@clear-code.com>

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License version 2.1 as published by the Free Software Foundation.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include "rb-grn.h"

#define SELF(object) ((RbGrnIndexCursor *)DATA_PTR(object))

VALUE rb_cGrnIndexCursor;

VALUE
rb_grn_index_cursor_to_ruby_object (grn_ctx *context,
				    grn_obj *cursor,
				    VALUE rb_table,
				    VALUE rb_lexicon,
				    grn_bool owner)
{
    VALUE rb_cursor;

    rb_cursor = GRNOBJECT2RVAL(rb_cGrnIndexCursor, context, cursor, owner);
    rb_iv_set(rb_cursor, "@table", rb_table);
    rb_iv_set(rb_cursor, "@lexicon", rb_lexicon);

    return rb_cursor;
}

void
rb_grn_index_cursor_deconstruct (RbGrnIndexCursor *rb_grn_index_cursor,
				 grn_obj **cursor,
				 grn_ctx **context,
				 grn_id *domain_id,
				 grn_obj **domain,
				 grn_id *range_id,
				 grn_obj **range)
{
    RbGrnObject *rb_grn_object;

    rb_grn_object = RB_GRN_OBJECT(rb_grn_index_cursor);
    rb_grn_object_deconstruct(rb_grn_object, cursor, context,
			      domain_id, domain,
			      range_id, range);
}

static VALUE
next_value (grn_ctx *context, grn_obj *cursor, VALUE rb_table, VALUE rb_lexicon)
{
    grn_posting *posting;
    grn_id term_id;

    posting = grn_index_cursor_next(context, cursor, &term_id);
    if (!posting) {
	return Qnil;
    }

    return rb_grn_posting_new(posting, term_id, rb_table, rb_lexicon);
}

static VALUE
rb_grn_index_cursor_next (VALUE self)
{
    VALUE rb_posting = Qnil;
    grn_obj *cursor;
    grn_ctx *context;

    rb_grn_index_cursor_deconstruct(SELF(self), &cursor, &context,
				    NULL, NULL, NULL, NULL);
    if (context && cursor) {
	VALUE rb_table;
	VALUE rb_lexicon;
	rb_table = rb_iv_get(self, "@table");
	rb_lexicon = rb_iv_get(self, "@lexicon");
	rb_posting = next_value(context, cursor, rb_table, rb_lexicon);
    }

    return rb_posting;

}

static VALUE
rb_grn_index_cursor_each (VALUE self)
{
    grn_obj *cursor;
    grn_ctx *context;
    VALUE rb_table;
    VALUE rb_lexicon;

    RETURN_ENUMERATOR(self, 0, NULL);

    rb_grn_index_cursor_deconstruct(SELF(self), &cursor, &context,
				    NULL, NULL, NULL, NULL);

    if (!context) {
	return Qnil;
    }

    if (!cursor) {
	return Qnil;
    }

    rb_table = rb_iv_get(self, "@table");
    rb_lexicon = rb_iv_get(self, "@lexicon");
    while (GRN_TRUE) {
	VALUE rb_posting;
	rb_posting = next_value(context, cursor, rb_table, rb_lexicon);
	if (NIL_P(rb_posting)) {
	    break;
	}
	rb_yield(rb_posting);
    }

    return Qnil;
}

void
rb_grn_init_index_cursor (VALUE mGrn)
{
    rb_cGrnIndexCursor =
	rb_define_class_under(mGrn, "IndexCursor", rb_cGrnObject);
    rb_define_alloc_func(rb_cGrnIndexCursor, rb_grn_object_alloc);
    rb_include_module(rb_cGrnIndexCursor, rb_mEnumerable);

    rb_define_method(rb_cGrnIndexCursor, "next", rb_grn_index_cursor_next, 0);
    rb_define_method(rb_cGrnIndexCursor, "each", rb_grn_index_cursor_each, 0);
}