/*
XOWA: the XOWA Offline Wiki Application
Copyright (C) 2012 gnosygnu@gmail.com

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as
published by the Free Software Foundation, either version 3 of the
License, or (at your option) any later version.

This program 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 Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/
package gplx.core.stores; import gplx.*; import gplx.core.*;
import gplx.core.criterias.*; import gplx.dbs.*; import gplx.core.gfo_ndes.*;
public class DbMaprRdr extends DataRdr_base implements SrlMgr {
	@Override public String NameOfNode() {return "DbMaprRdr";}
	@Override public Object StoreRoot(SrlObj subProto, String key) {
		mgr = (DbMaprMgr)this.EnvVars().Get_by_or_fail(DbMaprWtr.Key_Mgr);
		DbMaprItm rootMapr = mgr.Root();

		GfoNde tbl = GetTbl(rootMapr, rootCrt); int subsCount = tbl.Subs().Count(); if (subsCount == 0) return null; if (subsCount > 1) throw Err_.new_wo_type("criteria returned > 1 row", "criteria", rootCrt.To_str(), "subsCount", subsCount);
		SrlObj root = subProto.SrlObj_New(null);
		mgr.EnvStack_add(rootMapr, root); RowStack_add(tbl, 0);
		root.SrlObj_Srl(this);
		mgr.Clear(); rowStack.Clear();
		return root;
	}
	@Override public void SrlList(String subPropKey, List_adp list, SrlObj subProto, String itmKey) {
		DbMaprItm curMapr = (DbMaprItm)mgr.MaprStack().Get_at_last();
		DbMaprItm subMapr = curMapr.Subs_get(subPropKey);
		list.Clear();

		Criteria crit = MakeCrt(mgr, subMapr);
		GfoNde tbl = GetTbl(subMapr, crit);
		int tblLen = tbl.Subs().Count();
		for (int i = 0; i < tblLen; i++) {
			SrlObj sub = (SrlObj)subProto.SrlObj_New(null);
			GfoNde subRow = tbl.Subs().FetchAt_asGfoNde(i);
			mgr.EnvStack_add(subMapr, sub); rowStack.Add(subRow);
			sub.SrlObj_Srl(this); list.Add(sub);
			mgr.EnvStack_del(subMapr, sub); List_adp_.DelAt_last(rowStack);
		}
	}
	Criteria MakeCrt(DbMaprMgr mgr, DbMaprItm mapr) {
		Criteria rv = null, cur = null;
		List_adp list = GetIdxFlds(mgr, mapr);
		for (Object kvObj : list) {
			KeyVal kv = (KeyVal)kvObj;
			cur = Db_crt_.New_eq(kv.Key(), kv.Val());
			rv = (rv == null) ? cur : Criteria_.And(rv, cur);
		}
		return rv;
	}
	List_adp GetIdxFlds(DbMaprMgr mgr, DbMaprItm curMapr) {
		List_adp rv = List_adp_.new_();
		int maprStackCount = mgr.MaprStack().Count() - 0; // -1 b/c current is added to stack
		for (int i = 0; i < maprStackCount; i ++) {
			DbMaprItm mapr = (DbMaprItm)mgr.MaprStack().Get_at(i);
			SrlObj gobj = (SrlObj)mgr.OwnerStack().Get_at(i);
			for (Object argObj : mapr.ContextFlds()) {
				DbMaprArg arg = (DbMaprArg)argObj;
				Object propVal = GfoInvkAble_.InvkCmd((GfoInvkAble)gobj, arg.ObjProp());
				rv.Add(KeyVal_.new_(arg.DbFld(), propVal));
			}					
		}
		for (Object argObj : curMapr.ConstantFlds()) {
			KeyVal arg = (KeyVal)argObj;
			rv.Add(arg);
		}
		return rv;
	}
	GfoNde GetTbl(DbMaprItm mapr, Criteria crit) {
		String key = mapr.TableName();			
		GfoNde tblByRootCrt = GfoNde_.as_(tables.Get_by(key));
		if (tblByRootCrt == null) {
			DataRdr dbRdr = null;
			try {
				dbRdr = conn.Exec_qry_as_old_rdr(Db_qry_.select_().From_(mapr.TableName()).Where_(rootCrt));
				tblByRootCrt = GfoNde_.rdr_(dbRdr);
			}
			finally {dbRdr.Rls();}
			tables.Add(key, tblByRootCrt);
		}
		GfoNde rv = GfoNde_.tbl_(mapr.TableName(), tblByRootCrt.Flds());
		for (int i = 0; i < tblByRootCrt.Subs().Count(); i++) {
			GfoNde row = tblByRootCrt.Subs().FetchAt_asGfoNde(i);
			if (crit.Matches(row)) rv.Subs().Add(row);
		}
		return rv;
	}
	void RowStack_add(GfoNde tbl, int i) {
		GfoNdeList ndeList = tbl.Subs(); if (i >= ndeList.Count()) throw Err_.new_missing_idx(i, ndeList.Count());
		rowStack.Add(tbl.Subs().FetchAt_asGfoNde(i));
	}
	@Override public Object Read(String key) {
		DbMaprItm mapr = (DbMaprItm)mgr.MaprStack().Get_at_last();
		GfoNde row = (GfoNde)rowStack.Get_at_last();
		DbMaprArg arg = mapr.Flds_get(key);
		Object dbVal = null; try {dbVal = row.Read(arg.DbFld());} catch (Exception e) {throw Err_.new_exc(e, "db", "failed to read dbVal from row", "key", key, "fld", arg.DbFld());}
		return dbVal;
	}
	@Override public DataRdr Subs_byName_moveFirst(String name) {throw Err_.new_unimplemented();}
	@Override public DataRdr Subs() {throw Err_.new_unimplemented();}
	@Override public int FieldCount() {throw Err_.new_unimplemented();}
	@Override public String KeyAt(int i) {throw Err_.new_unimplemented();}
	@Override public Object ReadAt(int i) {throw Err_.new_unimplemented();}
	@Override public KeyVal KeyValAt(int i) {throw Err_.new_unimplemented();}
	@Override public SrlMgr SrlMgr_new(Object o) {return new DbMaprRdr();}
	Hash_adp tables = Hash_adp_.new_();
	Db_conn conn; Criteria rootCrt;
	DbMaprMgr mgr; List_adp rowStack = List_adp_.new_();
	public static DbMaprRdr new_(Db_conn_info dbInfo, Criteria rootCrt) {
		DbMaprRdr rv = new DbMaprRdr();
		rv.conn = Db_conn_pool.Instance.Get_or_new(dbInfo); rv.rootCrt = rootCrt;
		return rv;
	}	DbMaprRdr() {}
}