/* ------------- listbox.c ------------ */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "dflat.h"

static void near writeselection(WINDOW, int, int, RECT *);
static void near change_selection(WINDOW, int);
static int near selection_in_window(WINDOW, int);


int ListBoxProc(WINDOW wnd, MESSAGE msg, PARAM p1, PARAM p2)
{
	int rtn;
	static int py = -1;
	int my = (int) p2 - GetTop(wnd);

	if (my >= wnd->wlines-wnd->wtop)
		my = wnd->wlines - wnd->wtop;

	switch (msg)	{
		case CREATE_WINDOW:
			rtn = BaseWndProc(LISTBOX, wnd, msg, p1, p2);
			wnd->selection = -1;
			return rtn;
		case ADDTEXT:
			p2 = wnd->wlines == wnd->selection;
			break;
		case CLEARTEXT:
			wnd->selection = -1;
			break;
		case SCROLL:
			rtn = BaseWndProc(LISTBOX, wnd, msg, p1, p2);
			if (!selection_in_window(wnd, wnd->selection))	{
				if (p1)
					PostMessage(wnd, LB_SELECTION, wnd->selection+1, FALSE);
				else
					PostMessage(wnd, LB_SELECTION, wnd->selection-1, FALSE);
			}
			else
				writeselection(wnd, wnd->selection, TRUE, NULL);
			return rtn;
		case KEYBOARD:
			if (WindowMoving || WindowSizing)
				break;
			switch ((int) p1)	{
				case UP:
					if (wnd->selection > 0)	{
						if (wnd->selection == wnd->wtop)	{
							writeselection(wnd, wnd->selection, FALSE, NULL);
							--wnd->selection;
							rtn = BaseWndProc(LISTBOX, wnd, msg, p1, p2);
							PostMessage(wnd, LB_SELECTION, wnd->selection, FALSE);
						}
						else	{
							int newsel = wnd->selection-1;
							if (wnd->wlines == ClientHeight(wnd))
								while (*TextLine(wnd, newsel) == LINE)
									--newsel;
							PostMessage(wnd, LB_SELECTION, newsel, FALSE);
						}
					}
					return TRUE;
				case DN:
					if (wnd->selection < wnd->wlines-1)	{
						if (wnd->selection == wnd->wtop+ClientHeight(wnd)-1)	{
							writeselection(wnd, wnd->selection, FALSE, NULL);
							wnd->selection++;
							rtn = BaseWndProc(LISTBOX, wnd, msg, p1, p2);
							PostMessage(wnd, LB_SELECTION, wnd->selection, FALSE);
						}
						else	{
							int newsel = wnd->selection+1;
							if (wnd->wlines == ClientHeight(wnd))
								while (*TextLine(wnd, newsel) == LINE)
									newsel++;
							PostMessage(wnd, LB_SELECTION, newsel, FALSE);
						}
					}
					return TRUE;
				case PGUP:
				case PGDN:
					rtn = BaseWndProc(LISTBOX, wnd, msg, p1, p2);
					PostMessage(wnd, LB_SELECTION, wnd->wtop, FALSE);
					return rtn;
				case HOME:
					rtn = BaseWndProc(LISTBOX, wnd, msg, p1, p2);
					PostMessage(wnd, LB_SELECTION, 0, FALSE);
					return rtn;
				case END:
					rtn = BaseWndProc(LISTBOX, wnd, msg, p1, p2);
					PostMessage(wnd, LB_SELECTION, wnd->wlines-1, FALSE);
					return rtn;
				case '\r':
					if (wnd->selection != -1)	{
						WINDOW pwnd = GetParent(wnd);
						int sel = wnd->selection;
						SendMessage(wnd, LB_SELECTION, sel, TRUE);
						SendMessage(pwnd, LB_CHOOSE, sel, 0);
					}
					return TRUE;
				default:
					break;
			}
			break;
		case BUTTON_RELEASED:
			py = -1;
			break;
		case LEFT_BUTTON:
			if (!(WindowMoving || WindowSizing))	{
				RECT rc = ClientRect(wnd);
				if (!InsideRect(p1, p2, rc))
					break;
				if (my != py)	{
					int newsel = wnd->wtop+my-1;
					if (*TextLine(wnd, newsel) != LINE)
						SendMessage(wnd, LB_SELECTION, newsel, TRUE);
					py = my;
				}
				return TRUE;
			}
			break;
		case DOUBLE_CLICK:
			BaseWndProc(LISTBOX, wnd, msg, p1, p2);
			if (!(WindowMoving || WindowSizing))
				SendMessage(GetParent(wnd), LB_CHOOSE, wnd->selection, 0);
			return TRUE;
		case LB_SETSELECTION:
			change_selection(wnd, (int) p1);
			return TRUE;
		case LB_SELECTION:	{
			WINDOW pwnd = GetParent(wnd);
			CLASS class = GetClass(pwnd);
			change_selection(wnd, (int) p1);
			if (class != LISTBOX && DerivedClass(class) != LISTBOX)
				SendMessage(GetParent(wnd), LB_SELECTION, wnd->selection, 0);
			return TRUE;
		}
		case LB_CURRENTSELECTION:
			return wnd->selection;
		case LB_GETTEXT:
			if ((int)p2 != -1)	{
				char *cp1 = (char *)p1;
				char *cp2 = TextLine(wnd, (int)p2);
				while (cp2 && *cp2 && *cp2 != '\n')
					*cp1++ = *cp2++;
				*cp1 = '\0';
			}
			return TRUE;
		case PAINT:
			if (isVisible(wnd))	{
				rtn = BaseWndProc(LISTBOX, wnd, msg, p1, p2);
				writeselection(wnd, wnd->selection, TRUE, (RECT *)p1);
				return rtn;
			}
			break;
		default:
			break;
	}
	return BaseWndProc(LISTBOX, wnd, msg, p1, p2);
}

static int near selection_in_window(WINDOW wnd, int sel)
{
	return (wnd->wlines && sel >= wnd->wtop && sel < wnd->wtop+ClientHeight(wnd));
}

static void near writeselection(WINDOW wnd, int sel, int reverse, RECT *rc)
{
	if (selection_in_window(wnd, sel))
		WriteTextLine(wnd, rc, sel-wnd->wtop, reverse);
}

static void near change_selection(WINDOW wnd, int sel)
{
	if (sel != wnd->selection)	{
		writeselection(wnd, wnd->selection, FALSE, NULL);
		wnd->selection = sel;
		writeselection(wnd, sel, TRUE, NULL);
	}
}