/*
 *  Roo/E, the Kangaroo Punch Portable GUI Toolkit
 *  Copyright (C) 2022 Scott Duensing
 *
 *  http://kangaroopunch.com
 *
 *
 *  This file is part of Roo/E.
 *
 *  Roo/E 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.
 *
 *  Roo/E 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 Affero General Public License
 *  along with Roo/E. If not, see <https://www.gnu.org/licenses/>.
 *
 */


#include "../wmwindow.h"
#include "../font.h"

#include "vscroll.h"


uint8_t  __MAGIC_VSCROLL = 0;


static void vscrollClick(WidgetT *widget, uint16_t x, uint16_t y, uint8_t event, void *data);
static void vscrollDestroy(struct WidgetS *widget, ...);
static void vscrollPaint(struct WidgetS *widget, ...);


static void vscrollClick(WidgetT *widget, uint16_t x, uint16_t y, uint8_t event, void *data) {
	VscrollT       *v = (VscrollT *)widget;

	(void)data;

	// Clicking in up arrow?
	if (y <= GADGET_SIZE) {
		// Move content up.
		v->value -= SCROLL_SPEED_SLOW;
		// Clip.
		if (v->value < v->min) v->value = v->min;
		// Update.
		widgetDirtySet(widget, 1);
		// Call the actual click event.
		if (v->handler) v->handler(widget, x, y, event, v->base.data);
		return;
	}

	// Clicking in down arrow?
	if (y >= v->base.r.h - GADGET_SIZE) {
		// Move content down.
		v->value += SCROLL_SPEED_SLOW;
		// Clip.
		if (v->value > v->max - v->base.r.h) v->value = v->max - v->base.r.h;
		// Update.
		widgetDirtySet(widget, 1);
		// Call the actual click event.
		if (v->handler) v->handler(widget, x, y, event, v->base.data);
		return;
	}

	// Clicking above thumb?  Also fakes dragging.
	if (y < v->thumb.y) {
		// Move content up.
		v->value -= SCROLL_SPEED_FAST;
		// Clip.
		if (v->value < v->min) v->value = v->min;
		// Update.
		widgetDirtySet(widget, 1);
		// Call the actual click event.
		if (v->handler) v->handler(widget, x, y, event, v->base.data);
		return;
	}

	// Clicking below thumb?  Also fakes dragging.
	if (y > v->thumb.y2) {
		// Move content down.
		v->value += SCROLL_SPEED_FAST;
		// Clip.
		if (v->value > v->max - v->base.r.h) v->value = v->max - v->base.r.h;
		// Update.
		widgetDirtySet(widget, 1);
		// Call the actual click event.
		if (v->handler) v->handler(widget, x, y, event, v->base.data);
		return;
	}
}


void vscrollClickSet(VscrollT *vscroll, ClickHandlerT handler, void *data) {
	vscroll->handler   = handler;
	vscroll->base.data = data;
}


VscrollT *vscrollCreate(int16_t h, ClickHandlerT handler, void *data, ...) {
	VscrollT *v = NULL;

	NEW(VscrollT, v);
	memset(v, 0, sizeof(VscrollT));

	v->min   = 1;
	v->max   = 100;
	v->value = 1;

	if (h < GADGET_SIZE * 3) h = GADGET_SIZE * 3;

	widgetBaseSet(W(v), __MAGIC_VSCROLL, GADGET_SIZE, h);

	v->handler   = handler;
	v->base.data = data;

	widgetInputSetRaw(W(v), 1);

	return v;
}


static void vscrollDestroy(struct WidgetS *widget, ...) {
	VscrollT *v = (VscrollT *)widget;

	DEL(v);
}


static void vscrollPaint(struct WidgetS *widget, ...) {
	VscrollT *v = (VscrollT *)widget;
	ColorT    scrollBackgroundColor;
	ColorT    widgetColor;
	RectT     r;
	int16_t   i;
	double    d;

	if (widgetDirtyGet(widget)) {
		widgetDirtySet(widget, 0);
		// Find some colors.
		if (widgetIsInWidget(widget, W(wmWindowOnTopGet()))) {
			scrollBackgroundColor = GUI_DARKGRAY;
			widgetColor           = GUI_LIGHTGRAY;
		} else {
			scrollBackgroundColor = GUI_LIGHTGRAY;
			widgetColor           = GUI_DARKGRAY;
		}
		// Find coordinates.
		r    = v->base.r;
		r.x2 = r.x + v->base.r.w - 1;
		r.y2 = r.y + v->base.r.h - 1;
		// Paint scrollbar.
		surfaceBoxFilled(r.x + 1, r.y + 1, r.x2 - 1, r.y2 - 1, scrollBackgroundColor);
		surfaceBoxHighlight(r.x, r.y, r.x2, r.y2, GUI_WHITE, GUI_BLACK);
		surfaceLineH(r.x + 1, r.x2, r.y  + (GADGET_SIZE - 1), GUI_BLACK);
		surfaceLineH(r.x + 1, r.x2, r.y2 - (GADGET_SIZE - 1), GUI_WHITE);
		// Prepare font.
		fontSet(__guiFontVGA8x8);
		fontColorSet(widgetColor, scrollBackgroundColor);
		// Draw arrows.
		fontRender("\x1e", r.x + 7, r.y + 7);
		fontRender("\x1f", r.x + 7, r.y2 - 12);
		// Distance between arrow buttons on scroll bar.
		i = r.y2 - r.y - (GADGET_SIZE * 2 - 2) - 2;
		// Percentage to scale content height to scroll bar height.
		d = (double)i / (double)(v->max - v->min);
		// Find position and size of thumb.
		v->thumb.x  = r.x  + 1;
		v->thumb.x2 = r.x2 - 1;
		v->thumb.y  = r.y + GADGET_SIZE + (v->value * d);
		v->thumb.y2 = v->thumb.y + (v->base.r.h * d);
		// Clamp overflow due to doubles and my off-by-one brain.
		if (v->thumb.y2 >= v->thumb.y + i - 1) v->thumb.y2 = v->thumb.y + i - 1;
		// Draw thumb.
		surfaceBoxFilled(v->thumb.x + 1, v->thumb.y + 1, v->thumb.x2 - 1, v->thumb.y2 - 1, GUI_LIGHTGRAY);
		surfaceBoxHighlight(v->thumb.x, v->thumb.y, v->thumb.x2, v->thumb.y2, GUI_WHITE, GUI_BLACK);
		// Adjust thumb values from window space to widget space for click handler.
		v->thumb.x  -= v->base.r.x;
		v->thumb.x2 -= v->base.r.x;
		v->thumb.y  -= v->base.r.y;
		v->thumb.y2 -= v->base.r.y;
	}
}


void vscrollRangeSet(VscrollT *vscroll, int32_t min, int32_t max) {
	vscroll->min = min;
	vscroll->max = max;
	vscrollValueSet(vscroll, min);
}


RegisterT *vscrollRegister(uint8_t magic) {
	static RegisterT reg = {
		"Vscroll",
		vscrollClick,
		vscrollDestroy,
		vscrollPaint,
		NULL           // No unregister handler.
	};

	// One-time widget startup code.
	__MAGIC_VSCROLL = magic;

	return &reg;
}


int32_t vscrollValueGet(VscrollT *vscroll) {
	return vscroll->value;
}


void vscrollValueSet(VscrollT *vscroll, int32_t value) {
	if (value < vscroll->min) value = vscroll->min;
	if (value > vscroll->max) value = vscroll->max;
	if (vscroll->value != value) {
		vscroll->value = value;
		widgetDirtySet(W(vscroll), 1);
	}
}