(*
    Copyright 2021-2023 Anton Krotov

    This file is part of CEdit.

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

    CEdit 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 General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with CEdit. If not, see <http://www.gnu.org/licenses/>.
*)

MODULE Search;

IMPORT
	CB := Clipboard, List, Utils, SYSTEM;

CONST
	itemSize = 64;

TYPE
	tBuffer = CB.tBuffer;

	tIdxTable = ARRAY 65536, 2 OF INTEGER;

	tPos* = POINTER TO RECORD (List.tItem)
		cnt*: INTEGER;
		pos*: ARRAY itemSize OF INTEGER
	END;

VAR
	table: POINTER TO RECORD data: tIdxTable END;


PROCEDURE _index (text: tBuffer; cs: BOOLEAN; VAR table: tIdxTable): tBuffer;
VAR
	pChar, cnt, i: INTEGER;
	c: WCHAR;
	res: tBuffer;
BEGIN
	pChar := text.dataPtr;
	cnt := CB.bufSize(text) DIV SYSTEM.SIZE(WCHAR);

	FOR i := 0 TO 65535 DO
		table[i, 1] := 0
	END;

	i := cnt;
	WHILE i > 0 DO
		SYSTEM.GET(pChar, c);
		IF ~cs & Utils.lower(c) THEN
			SYSTEM.PUT(pChar, c)
		END;
		INC(table[ORD(c), 1]);
		INC(pChar, SYSTEM.SIZE(WCHAR));
		DEC(i)
	END;

	res := CB.create(cnt*SYSTEM.SIZE(INTEGER));

	table[0, 0] := res.dataPtr;
	FOR i := 1 TO 65535 DO
		table[i, 0] := table[i - 1, 0] + table[i - 1, 1]*SYSTEM.SIZE(INTEGER)
	END;

	pChar := text.dataPtr;
	i := 0;
	WHILE i < cnt DO
		SYSTEM.GET(pChar, c);
		SYSTEM.PUT(table[ORD(c), 0], i);
		INC(table[ORD(c), 0], SYSTEM.SIZE(INTEGER));
		INC(pChar, SYSTEM.SIZE(WCHAR));
		INC(i)
	END;

	FOR i := 0 TO 65535 DO
		DEC(table[i, 0], table[i, 1]*SYSTEM.SIZE(INTEGER))
	END

	RETURN res
END _index;


PROCEDURE index* (text: tBuffer; cs: BOOLEAN): tBuffer;
BEGIN
	IF table = NIL THEN
		NEW(table)
	END
	RETURN _index(text, cs, table.data)
END index;


PROCEDURE next* (VAR item: tPos; VAR i: INTEGER): INTEGER;
VAR
	res: INTEGER;
BEGIN
	IF (item # NIL) & (i >= item.cnt) THEN
		item := item.next(tPos);
		i := 0;
	END;
	IF (item # NIL ) & (i < item.cnt) THEN
		res := item.pos[i];
		INC(i)
	ELSE
		res := -1
	END
	RETURN res
END next;


PROCEDURE add* (list: List.tList; pos: INTEGER);
VAR
	item: tPos;
BEGIN
	item := list.last(tPos);
	IF (item = NIL) OR (item.cnt = itemSize) THEN
		NEW(item);
		item.cnt := 0;
		List.append(list, item)
	END;
	item.pos[item.cnt] := pos;
	INC(item.cnt)
END add;


PROCEDURE find* (text: tBuffer; s: ARRAY OF WCHAR; whole: BOOLEAN; list: List.tList; offset: INTEGER);
VAR
	k, pos, n, i, x, prev_item_pos: INTEGER;
	c1, c2: WCHAR;
	flag: BOOLEAN;
BEGIN
	ASSERT(table # NIL);
	n := LENGTH(s);
	i := 0;
	WHILE (i < n) & whole DO
		whole := Utils.isWordChar(s[i]);
		INC(i)
	END;
	k := table.data[ORD(s[0]), 1];
	pos := table.data[ORD(s[0]), 0];
	prev_item_pos := 0;
	WHILE k > 0 DO
		SYSTEM.GET(pos, x);
		IF Utils.streq(text.dataPtr + x*SYSTEM.SIZE(WCHAR), SYSTEM.ADR(s[0]), n) THEN
			flag := whole;
			IF flag THEN
				IF x > 0 THEN
					SYSTEM.GET(text.dataPtr + (x - 1)*SYSTEM.SIZE(WCHAR), c1);
				ELSE
					c1 := 0X
				END;
				SYSTEM.GET(text.dataPtr + (x + n)*SYSTEM.SIZE(WCHAR), c2);
				flag := Utils.isWordChar(c1) OR Utils.isWordChar(c2)
			END;
			IF ~flag & (x >= prev_item_pos) THEN
				prev_item_pos := x + n;
				add(list, x + offset)
			END
		END;
		INC(pos, SYSTEM.SIZE(INTEGER));
		DEC(k)
	END
END find;


PROCEDURE close*;
BEGIN
	IF table # NIL THEN
		DISPOSE(table)
	END
END close;


BEGIN
	table := NIL
END Search.