// SPDX-License-Identifier: MIT

#include <stdio.h>
#include "util.h"
#include "slider.h"


extern Pattern gSliderPattern;
RGBColor gLightGrey = {
	60000, 60000, 60000
};

#define kDragHeight 13

/** Custom slider control
 *
 * Pre-OS8 Mac OS has no builtin slider control. One exists
 * in Appearance Manager (OS 8), but we would like to stay
 * compatible with System 7. Therefore, we define a custom
 * control.
 */
pascal long
slider_proc(short /* varCode */, ControlHandle ctl,
 			short message, long param)
{
	Rect ctlRect, filledRect, dragRect, indicatorRect;
	short ctlValue, ctlMax, variableHeight, filledHeight;
	short topDist, botDist, offset, newValue;
	Point testPt;
	IndicatorDragConstraint* dragConstraint;
	RgnHandle cntlRgn;
	long retval = 0;
	
recalc:
	ctlRect = (**ctl).contrlRect;
	ctlValue = GetControlValue(ctl);
	ctlMax = GetControlMaximum(ctl);
	variableHeight = rect_height(&ctlRect) - kDragHeight;
	filledHeight = variableHeight * ctlValue / ctlMax;
	
	/* Set up drawing rects */
	filledRect = ctlRect;
	filledRect.top = filledRect.bottom - kDragHeight - filledHeight;
	dragRect = filledRect;
	dragRect.bottom = dragRect.top + kDragHeight;
	indicatorRect = filledRect;
	indicatorRect.top += 5;
	indicatorRect.bottom = indicatorRect.top + 3;
	indicatorRect.left += 5;
	indicatorRect.right -= 5;
	
	switch (message)
	{
	case drawCntl:
		EraseRoundRect(&ctlRect, 15, 15);
		
		// unfilled slider background
		RGBBackColor(&gLightGrey);
		FillRoundRect(&ctlRect, 15, 15, &gSliderPattern);
		BackColor(whiteColor);
		FrameRoundRect(&ctlRect, 13, 13);
		
		// contrast rings (white then black)
		ForeColor(whiteColor);
		rect_expand(&ctlRect, 1);
		FrameRoundRect(&ctlRect, 15, 15);
		
		ForeColor(blackColor);
		rect_expand(&ctlRect, 1);
		FrameRoundRect(&ctlRect, 18, 18);
		
		// filled slider part
		PaintRoundRect(&filledRect, 15, 15);
		
		// drag element
		if ((**ctl).contrlHilite == 129)
		{
			FillRoundRect(&dragRect, 15, 15, &qd.white);
			FillRoundRect(&indicatorRect, 8, 8, &qd.black);
		}
		else
			FillRoundRect(&indicatorRect, 8, 8, &qd.white);
		break;
	case testCntl:
		testPt.v = HiWord(param);
		testPt.h = LoWord(param);
		if (PtInRect(testPt, &dragRect))
			retval = 129;
		else if (PtInRect(testPt, &ctlRect))
			retval = 1;
		break;
	case thumbCntl:
		dragConstraint = (void*)param;
		topDist = dragConstraint->limitRect.top - dragRect.top;
		botDist = dragRect.bottom - dragConstraint->limitRect.top;
		dragConstraint->axis = 2; // vertical movement only
		dragConstraint->limitRect = ctlRect;
		dragConstraint->limitRect.top += topDist;
		dragConstraint->limitRect.bottom -= botDist - 1;
		dragConstraint->slopRect = ctlRect;
		rect_expand(&dragConstraint->slopRect, 40);
		break;
	case calcCntlRgn:
		cntlRgn = (RgnHandle)param;
		OpenRgn();
		FrameRoundRect(&ctlRect,15, 15);
		CloseRgn(cntlRgn);
		break;
	case calcThumbRgn:
		cntlRgn = (RgnHandle)param;
		OpenRgn();
		FrameRoundRect(&dragRect, 15, 15);
		CloseRgn(cntlRgn);
		break;
	case posCntl:
		offset = HiWord(param);
		newValue = (filledHeight - offset) * ctlMax / variableHeight;
		SetControlValue(ctl, newValue);
		param = 0;
		message = drawCntl;
		goto recalc;
		break;
	default:
		break;
	}
	
	return retval;
}