/*
 * Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
 *
 * This file is part of PortaPack.
 *
 * This program 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 2, or (at your option)
 * any later version.
 *
 * This program 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 this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#include "ui_widget.hpp"
#include "ui_painter.hpp"

#include <cstdint>
#include <cstddef>
#include <algorithm>

namespace ui {

static bool ui_dirty = true;

void dirty_set() {
	ui_dirty = true;
}

void dirty_clear() {
	ui_dirty = false;
}

bool is_dirty() {
	return ui_dirty;
}

constexpr size_t to_string_max_length = 16;

static char* to_string_dec_uint_internal(
	char* p,
	uint32_t n
) {
	*p = 0;
	auto q = p;

	do {
		const uint32_t d = n % 10;
		const char c = d + 48;
		*(--q) = c;
		n /= 10;
	} while( n != 0 );

	return q;
}

static char* to_string_dec_uint_pad_internal(
	char* const term,
	const uint32_t n,
	const int32_t l,
	const char fill
) {
	auto q = to_string_dec_uint_internal(term, n);

	if( fill ) {
		while( (term - q) < l ) {
			*(--q) = fill;
		}
	}

	return q;
}

std::string to_string_dec_uint(
	const uint32_t n,
	const int32_t l,
	const char fill
) {
	char p[16];
	auto term = p + sizeof(p) - 1;
	auto q = to_string_dec_uint_pad_internal(term, n, l, fill);

	// Right justify.
	while( (term - q) < l ) {
		*(--q) = ' ';
	}

	return q;
}

std::string to_string_dec_int(
	const int32_t n,
	const int32_t l,
	const char fill
) {
	const size_t negative = (n < 0) ? 1 : 0;
	uint32_t n_abs = negative ? -n : n;

	char p[16];
	auto term = p + sizeof(p) - 1;
	auto q = to_string_dec_uint_pad_internal(term, n_abs, l - negative, fill);

	// Add sign.
	if( negative ) {
		*(--q) = '-';
	}

	// Right justify.
	while( (term - q) < l ) {
		*(--q) = ' ';
	}

	return q;
}

static void to_string_hex_internal(char* p, const uint32_t n, const int32_t l) {
	const uint32_t d = n & 0xf;
	p[l] = (d > 9) ? (d + 87) : (d + 48);
	if( l > 0 ) {
		to_string_hex_internal(p, n >> 4, l - 1);
	}
}

std::string to_string_hex(const uint32_t n, const int32_t l) {
	char p[16];
	to_string_hex_internal(p, n, l - 1);
	p[l] = 0;
	return p;
}

/* Widget ****************************************************************/

Point Widget::screen_pos() {
	return parent() ? (parent()->screen_pos() + parent_rect.pos) : parent_rect.pos;
}

Size Widget::size() const {
	return parent_rect.size;
}

Rect Widget::screen_rect() {
	return parent() ? (parent_rect + parent()->screen_pos()) : parent_rect;
}

void Widget::set_parent_rect(const Rect new_parent_rect) {
	parent_rect = new_parent_rect;
	set_dirty();
}

Widget* Widget::parent() const {
	return parent_;
}

void Widget::set_parent(Widget* const widget) {
	if( parent_ && !widget ) {
		// We have a parent, but are losing it. Update visible status.
		visible(false);
	}

	parent_ = widget;
}

void Widget::set_dirty() {
	flags.dirty = true;
	dirty_set();
}

bool Widget::dirty() const {
	return flags.dirty;
}

void Widget::set_clean() {
	flags.dirty = false;
}

void Widget::hidden(bool hide) {
	if( hide != flags.hidden ) {
		flags.hidden = hide;

		// If parent is hidden, either of these is a no-op.
		if( hide ) {
			parent()->set_dirty();
			/* TODO: Notify self and all non-hidden children that they're
			 * now effectively hidden?
			 */
		} else {
			set_dirty();
			/* TODO: Notify self and all non-hidden children that they're
			 * now effectively shown?
			 */
		}
	}
}

void Widget::focus() {
	context().focus_manager().set_focus_widget(this);
}

void Widget::on_focus() {
	//set_dirty();
}

void Widget::blur() {
	context().focus_manager().set_focus_widget(nullptr);
}

void Widget::on_blur() {
	//set_dirty();
}

bool Widget::focusable() const {
	return flags.focusable;
}

bool Widget::has_focus() {
	return (context().focus_manager().focus_widget() == this);
}

Widget* Widget::last_child_focus() const {
	return nullptr;
}

void Widget::set_last_child_focus(Widget* const child) {
	// Ignore.
	(void)child;
}

bool Widget::on_key(const KeyEvent event) {
	(void)event;
	return false;
}

bool Widget::on_encoder(const EncoderEvent event) {
	(void)event;
	return false;
}

bool Widget::on_touch(const TouchEvent event) {
	(void)event;
	return false;
}

const std::vector<Widget*> Widget::children() const {
	return { };
}

Context& Widget::context() const {
	return parent()->context();
}

void Widget::set_style(const Style* new_style) {
	if( new_style != style_ ) {
		style_ = new_style;
		set_dirty();
	}
}

const Style& Widget::style() const {
	return style_ ? *style_ : parent()->style();
}

void Widget::visible(bool v) {
	if( v != flags.visible ) {
		flags.visible = v;

		/* TODO: This on_show/on_hide implementation seems inelegant.
		 * But I need *some* way to take/configure resources when
		 * a widget becomes visible, and reverse the process when the
		 * widget becomes invisible, whether the widget (or parent) is
		 * hidden, or the widget (or parent) is removed from the tree.
		 */
		if( v ) {
			on_show();
		} else {
			on_hide();

			// Set all children invisible too.
			for(const auto child : children()) {
				child->visible(false);
			}
		}
	}
}

/* View ******************************************************************/

void View::set_parent_rect(const Rect new_parent_rect) {
	Widget::set_parent_rect(new_parent_rect);
	dirty_screen_rect += screen_rect();
}

void View::paint(Painter& painter) {
	painter.fill_rectangle(
		screen_rect(),
		style().background
	);
}

void View::add_child(Widget* const widget) {
	if( widget ) {
		if( widget->parent() == nullptr ) {
			widget->set_parent(this);
			children_.push_back(widget);
			widget->set_dirty();
		}
	}
}

void View::add_children(const std::vector<Widget*>& children) {
	for(auto child : children) {
		add_child(child);
	}
}

void View::remove_child(Widget* const widget) {
	if( widget ) {
		children_.erase(std::remove(children_.begin(), children_.end(), widget), children_.end());
		dirty_screen_rect += widget->screen_rect();
		widget->set_parent(nullptr);
		if( dirty_screen_rect ) {
			set_dirty();
		}
	}
}

const std::vector<Widget*> View::children() const {
	return children_;
}

Widget* View::initial_focus() {
	return nullptr;
}

/* Rectangle *************************************************************/

void Rectangle::set_color(const Color c) {
	color = c;
	set_dirty();
}

void Rectangle::paint(Painter& painter) {
	painter.fill_rectangle(
		screen_rect(),
		color
	);
}

/* Text ******************************************************************/

void Text::set(const std::string value) {
	text = value;
	set_dirty();
}

void Text::paint(Painter& painter) {
	painter.draw_string(
		screen_pos(),
		style(),
		text
	);
}

/* Button ****************************************************************/

void Button::set_text(const std::string value) {
	text_ = value;
	set_dirty();
}

std::string Button::text() const {
	return text_;
}

void Button::paint(Painter& painter) {
	const auto r = screen_rect();

	const auto paint_style = (has_focus() || flags.highlighted) ? style().invert() : style();

	painter.draw_rectangle(r, style().foreground);

	painter.fill_rectangle(
		{
			static_cast<Coord>(r.pos.x + 1), static_cast<Coord>(r.pos.y + 1),
			static_cast<Dim>(r.size.w - 2), static_cast<Dim>(r.size.h - 2)
		},
		paint_style.background
	);

	const auto label_r = paint_style.font.size_of(text_);
	painter.draw_string(
		{
			static_cast<Coord>(r.pos.x + (r.size.w - label_r.w) / 2),
			static_cast<Coord>(r.pos.y + (r.size.h - label_r.h) / 2)
		},
		paint_style,
		text_
	);
}

bool Button::on_key(const KeyEvent key) {
	if( key == KeyEvent::Select ) {
		if( on_select ) {
			on_select(*this);
			return true;
		}
	}

	return false;
}

bool Button::on_touch(const TouchEvent event) {
	switch(event.type) {
	case TouchEvent::Type::Start:
		flags.highlighted = true;
		set_dirty();
		return true;


	case TouchEvent::Type::End:
		flags.highlighted = false;
		set_dirty();
		if( on_select ) {
			on_select(*this);
		}
		return true;

	default:
		return false;
	}
#if 0
	switch(event.type) {
	case TouchEvent::Type::Start:
		flags.highlighted = true;
		set_dirty();
		return true;

	case TouchEvent::Type::Move:
		{
			const bool new_highlighted = screen_rect().contains(event.point);
			if( flags.highlighted != new_highlighted ) {
				flags.highlighted = new_highlighted;
				set_dirty();
			}
		}
		return true;

	case TouchEvent::Type::End:
		if( flags.highlighted ) {
			flags.highlighted = false;
			set_dirty();
			if( on_select ) {
				on_select(*this);
			}
		}
		return true;

	default:
		return false;
	}
#endif
}

/* OptionsField **********************************************************/

size_t OptionsField::selected_index() const {
	return selected_index_;
}

void OptionsField::set_selected_index(const size_t new_index) {
	if( new_index < options.size() ) {
		if( new_index != selected_index() ) {
			selected_index_ = new_index;
			if( on_change ) {
				on_change(selected_index(), options[selected_index()].second);
			}
			set_dirty();
		}
	}
}

void OptionsField::set_by_value(value_t v) {
	size_t new_index { 0 };
	for(const auto& option : options) {
		if( option.second >= v ) {
			set_selected_index(new_index);
			break;
		}
		new_index++;
	}
}

void OptionsField::paint(Painter& painter) {
	const auto paint_style = has_focus() ? style().invert() : style();

	if( selected_index() < options.size() ) {
		const auto text = options[selected_index()].first;
		painter.draw_string(
			screen_pos(),
			paint_style,
			text
		);
	}
}

bool OptionsField::on_encoder(const EncoderEvent delta) {
	set_selected_index(selected_index() + delta);
	return true;
}

bool OptionsField::on_touch(const TouchEvent event) {
	if( event.type == TouchEvent::Type::Start ) {
		focus();
	}
	return true;
}

/* NumberField ***********************************************************/

int32_t NumberField::value() const {
	return value_;
}

void NumberField::set_value(int32_t new_value) {
	new_value = clip_value(new_value);

	if( new_value != value() ) {
		value_ = new_value;
		if( on_change ) {
			on_change(value_);
		}
		set_dirty();
	}
}

void NumberField::paint(Painter& painter) {
	const auto text = to_string_dec_int(value_, length_, fill_char);

	const auto paint_style = has_focus() ? style().invert() : style();

	painter.draw_string(
		screen_pos(),
		paint_style,
		text
	);
}

bool NumberField::on_encoder(const EncoderEvent delta) {
	set_value(value() + (delta * step));
	return true;
}

bool NumberField::on_touch(const TouchEvent event) {
	if( event.type == TouchEvent::Type::Start ) {
		focus();
	}
	return true;
}

int32_t NumberField::clip_value(int32_t value) {
	if( value > range.second ) {
		value = range.second;
	}
	if( value < range.first ) {
		value = range.first;
	}
	return value;
}

} /* namespace ui */