(*
    Copyright 2021 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 Tabs;

IMPORT List, K := KolibriOS, RW;

CONST

    btnID* = 100;
    tabHeight* = 22;
    curTabHeight = 26;
    scrWidth = 15;

TYPE

    tItem = POINTER TO RECORD (List.tItem)

        val: RW.tFileName

    END;

    tTabs* = POINTER TO RECORD

        strings: List.tList;
        first, current: INTEGER;
        width, height: INTEGER;
        x, y: INTEGER

    END;


PROCEDURE drawTab (t: tTabs; id, x, y, width, height: INTEGER; s: ARRAY OF CHAR);
VAR
    x2, y2, color: INTEGER;
BEGIN
    IF id = t.current THEN
        INC(height, curTabHeight - tabHeight);
        DEC(y, curTabHeight - tabHeight);
        color := K.lightColor
    ELSE
        color := K.winColor
    END;
    DEC(x); INC(width);
    x2 := x + width - 1;
    y2 := y + height - 1;

    K.DrawRect(x, y, width, height,color);
    K.DrawLine(x, y, x2, y, K.borderColor);
    K.DrawLine(x2, y, x2, y2, K.borderColor);
    IF id # t.current THEN
        K.DrawLine(x2 - 1, y2, x, y2, K.borderColor);
    END;
    K.DrawLine(x, y2, x, y, K.borderColor);
    K.DrawText866bk(x + K.fontWidth, y + (height - K.fontHeight) DIV 2, K.textColor, color, s);
    K.CreateButton(id + ORD({30}) + btnID, x + 1, y - 1, width - 1, height - 1, color, "");
END drawTab;


PROCEDURE tabWidth (tab: tItem): INTEGER;
    RETURN (LENGTH(tab.val) + 2)*K.fontWidth
END tabWidth;


PROCEDURE Width (t: tTabs; pos, n: INTEGER): INTEGER;
VAR
    res, i: INTEGER;
    item: List.tItem;
BEGIN
    res := 0;
    i := pos;
    item := List.getItem(t.strings, i);
    WHILE (item # NIL) & (i <= n) DO
        INC(res, tabWidth(item(tItem)));
        item := item.next;
        INC(i)
    END
    RETURN res
END Width;


PROCEDURE draw* (t: tTabs);
VAR
    x, y, xmax, n, width: INTEGER;
    item: List.tItem;
    scroll: BOOLEAN;
BEGIN
    y := t.y;
    x := t.x;
    K.DrawRect(x, y - (curTabHeight - tabHeight), t.width + (2*scrWidth + 2), t.height + (curTabHeight - tabHeight) - 1, K.winColor);
    IF Width(t, 0, t.strings.count - 1) > t.width THEN
        INC(x, 2*scrWidth);
        K.CreateButton(btnID - 1, t.x, t.y, scrWidth, t.height - 1, K.btnColor, "<");
        K.CreateButton(btnID - 2, t.x + scrWidth, t.y, scrWidth, t.height - 1, K.btnColor, ">");
        scroll := TRUE
    ELSE
        t.first := 0;
        scroll := FALSE
    END;
    xmax := x + t.width - 1;

    n := t.strings.count - 1;
    WHILE (n >= 0) & (Width(t, n, t.strings.count - 1) <= t.width) DO
        DEC(n)
    END;
    IF n < 0 THEN
        n := 0
    ELSE
        INC(n)
    END;
    IF n < t.first THEN
        t.first := n
    END;

    K.DrawRect(x, y, t.width, t.height - 1, K.winColor);
    K.DrawLine(x, y + tabHeight - 1, x + t.width - 1 + 2*scrWidth*(1 - ORD(scroll)), y + tabHeight - 1, K.borderColor);
    item := List.getItem(t.strings, t.first);
    n := t.first;
    WHILE (item # NIL) & (x <= xmax) DO
        width := tabWidth(item(tItem));
        IF x + width - 1 <= xmax THEN
            drawTab(t, n, x + 1, y, width, t.height, item(tItem).val)
        END;
        INC(n);
        INC(x, width);
        item := item.next
    END
END draw;


PROCEDURE add* (t: tTabs; s: ARRAY OF CHAR);
VAR
    item: tItem;
BEGIN
    NEW(item);
    item.val := s;
    List.append(t.strings, item);
END add;


PROCEDURE rename* (t: tTabs; n: INTEGER; s: ARRAY OF CHAR);
VAR
    item: List.tItem;
BEGIN
    item := List.getItem(t.strings, n);
    item(tItem).val := s
END rename;


PROCEDURE delete* (t: tTabs; n: INTEGER);
VAR
    item: List.tItem;
BEGIN
    item := List.getItem(t.strings, n);
    List.delete(t.strings, item)
END delete;


PROCEDURE scroll* (t: tTabs; n: INTEGER);
VAR
    pos: INTEGER;
BEGIN
    pos := t.first + n;
    IF pos < 0 THEN
        pos := 0
    ELSIF pos >= t.strings.count THEN
        pos := t.strings.count - 1
    END;
    t.first := pos
END scroll;


PROCEDURE switch* (t: tTabs; n: INTEGER);
BEGIN
    IF (0 <= n) & (n < t.strings.count) THEN
        t.current := n;
        IF n < t.first THEN
            t.first := 0
        END;
        WHILE Width(t, t.first, n) > t.width DO
            INC(t.first)
        END
    END
END switch;


PROCEDURE setArea* (t: tTabs; x, y, width, height: INTEGER);
BEGIN
    t.x := x;
    t.y := y;
    t.width := width - 2*scrWidth;
    t.height := height
END setArea;


PROCEDURE create* (): tTabs;
VAR
    res: tTabs;
BEGIN
    NEW(res);
    res.strings := List.create(NIL);
    res.current := 0;
    res.first := 0
    RETURN res
END create;


END Tabs.