/**************************************************************************/
/*  range.cpp                                                             */
/**************************************************************************/
/*                         This file is part of:                          */
/*                             GODOT ENGINE                               */
/*                        https://godotengine.org                         */
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/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
/*                                                                        */
/* Permission is hereby granted, free of charge, to any person obtaining  */
/* a copy of this software and associated documentation files (the        */
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/* distribute, sublicense, and/or sell copies of the Software, and to     */
/* permit persons to whom the Software is furnished to do so, subject to  */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,        */
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#include "range.h"

#include "core/object/callable_mp.h"
#include "core/object/class_db.h"
#include "servers/display/accessibility_server.h"

#include <thirdparty/misc/r128.h>

double Range::_snapped_r128(double p_value, double p_step) {
	if (p_step == 0.0) {
		return p_value;
	}
	if (p_value > (1e18 * p_step) || p_value < -(1e18 * p_step)) {
		// If the value goes outside of the range R128 supports, fallback to normal snapping.
		return Math::snapped(p_value, p_step);
	}
	// Rescale values to better utilize R128's range before snapping.
	// R128 is fixed-precision with 64 bits after the decimal point, but double already uses 53 of those,
	// so a step size finer than 2^-11 will lose precision, and in practice even 1e-3 can be problematic.
	// By rescaling the value and step, we can shift precision into the higher bits (effectively turning R128 into a makeshift float).
	const int decimals = MIN(18, 14 - Math::floor(std::log10(MAX(Math::abs(p_value), p_step))));
	const double scale = Math::pow(10.0, decimals);
	p_value *= scale;
	p_step *= scale;
	// All these lines are the equivalent of: p_value = Math::floor(p_value / p_step + 0.5) * p_step;
	// Convert to String to force rounding to a decimal value (not a binary one).
	String step_str = String::num(p_step);
	String value_str = String::num(p_value);
	R128 step_r128;
	R128 value_r128;
	const R128 half_r128 = R128(0.5);
	r128FromString(&step_r128, step_str.ascii().get_data(), nullptr);
	r128FromString(&value_r128, value_str.ascii().get_data(), nullptr);
	r128Div(&value_r128, &value_r128, &step_r128);
	r128Add(&value_r128, &value_r128, &half_r128);
	r128Floor(&value_r128, &value_r128);
	r128Mul(&value_r128, &value_r128, &step_r128);
	if (scale != 1.0) {
		const R128 scale_r128 = R128(scale);
		r128Div(&value_r128, &value_r128, &scale_r128);
	}
	p_value = (double)value_r128;
	return p_value;
}

PackedStringArray Range::get_configuration_warnings() const {
	PackedStringArray warnings = Control::get_configuration_warnings();

	if (shared->exp_ratio && shared->min < 0) {
		warnings.push_back(RTR("If \"Exp Edit\" is enabled, \"Min Value\" must be greater or equal to 0."));
	}

	return warnings;
}

void Range::_value_changed(double p_value) {
	GDVIRTUAL_CALL(_value_changed, p_value);
}

void Range::_value_changed_notify() {
	_value_changed(shared->val);
	emit_signal(SceneStringName(value_changed), shared->val);
	queue_accessibility_update();
	queue_redraw();
}

void Range::_accessibility_action_inc(const Variant &p_data) {
	double step = ((shared->step > 0) ? shared->step : 1);
	set_value(shared->val + step);
}

void Range::_accessibility_action_dec(const Variant &p_data) {
	double step = ((shared->step > 0) ? shared->step : 1);
	set_value(shared->val - step);
}

void Range::_accessibility_action_set_value(const Variant &p_data) {
	double new_val = p_data;
	set_value(new_val);
}

void Range::_notification(int p_what) {
	ERR_MAIN_THREAD_GUARD;
	switch (p_what) {
		case NOTIFICATION_ACCESSIBILITY_UPDATE: {
			RID ae = get_accessibility_element();
			ERR_FAIL_COND(ae.is_null());

			AccessibilityServer::get_singleton()->update_set_role(ae, AccessibilityServerEnums::AccessibilityRole::ROLE_SPIN_BUTTON);
			AccessibilityServer::get_singleton()->update_set_num_value(ae, shared->val);
			AccessibilityServer::get_singleton()->update_set_num_range(ae, shared->min, shared->max);
			if (shared->step > 0) {
				AccessibilityServer::get_singleton()->update_set_num_step(ae, shared->step);
			} else {
				AccessibilityServer::get_singleton()->update_set_num_step(ae, 1);
			}
			AccessibilityServer::get_singleton()->update_add_action(ae, AccessibilityServerEnums::AccessibilityAction::ACTION_DECREMENT, callable_mp(this, &Range::_accessibility_action_dec));
			AccessibilityServer::get_singleton()->update_add_action(ae, AccessibilityServerEnums::AccessibilityAction::ACTION_INCREMENT, callable_mp(this, &Range::_accessibility_action_inc));
			AccessibilityServer::get_singleton()->update_add_action(ae, AccessibilityServerEnums::AccessibilityAction::ACTION_SET_VALUE, callable_mp(this, &Range::_accessibility_action_set_value));
		} break;
	}
}

void Range::Shared::emit_value_changed() {
	for (Range *E : owners) {
		Range *r = E;
		if (!r->is_inside_tree()) {
			continue;
		}
		r->_value_changed_notify();
	}
}

void Range::_changed_notify() {
	emit_signal(CoreStringName(changed));
	queue_redraw();
}

void Range::Shared::emit_changed() {
	for (Range *E : owners) {
		Range *r = E;
		if (!r->is_inside_tree()) {
			continue;
		}
		r->_changed_notify();
	}
}

void Range::Shared::redraw_owners() {
	for (Range *E : owners) {
		Range *r = E;
		if (!r->is_inside_tree()) {
			continue;
		}

		r->_value_changed(val);
		r->queue_accessibility_update();
		r->queue_redraw();
	}
}

void Range::set_value(double p_val) {
	double prev_val = shared->val;
	_set_value_no_signal(p_val);

	if (shared->val != prev_val && !(Math::is_nan(shared->val) && Math::is_nan(prev_val))) {
		shared->emit_value_changed();
	}
	queue_accessibility_update();
}

void Range::_set_value_no_signal(double p_val) {
	shared->val = _calc_value(p_val, shared->step);
}

double Range::_calc_value(double p_val, double p_step) const {
	if (Math::is_nan(p_val)) {
		return p_val;
	}

	if (p_step > 0) {
		if (Math::abs(shared->min) > p_step * 1e14) {
			// Min is too big to use for snapping offset, so snap without it.
			p_val = _snapped_r128(p_val, p_step);
		} else {
			// Subtract min to support cases like min = 0.1, step = 0.2, snaps to 0.1, 0.3, 0.5, etc.
			p_val = _snapped_r128(p_val - shared->min, p_step) + shared->min;
		}
	}

	if (_rounded_values) {
		p_val = Math::round(p_val);
	}

	if (!shared->allow_greater && p_val > shared->max - shared->page) {
		p_val = shared->max - shared->page;
	}

	if (!shared->allow_lesser && p_val < shared->min) {
		p_val = shared->min;
	}
	return p_val;
}

void Range::set_value_no_signal(double p_val) {
	double prev_val = shared->val;
	_set_value_no_signal(p_val);

	if (shared->val != prev_val) {
		shared->redraw_owners();
	}
}

void Range::set_min(double p_min) {
	if (shared->min == p_min) {
		return;
	}

	shared->min = p_min;
	shared->max = MAX(shared->max, shared->min);
	shared->page = CLAMP(shared->page, 0, shared->max - shared->min);
	set_value(shared->val);

	shared->emit_changed();

	update_configuration_warnings();

	queue_accessibility_update();
}

void Range::set_max(double p_max) {
	double max_validated = MAX(p_max, shared->min);
	if (shared->max == max_validated) {
		return;
	}

	shared->max = max_validated;
	shared->page = CLAMP(shared->page, 0, shared->max - shared->min);
	set_value(shared->val);

	shared->emit_changed();

	queue_accessibility_update();
}

void Range::set_step(double p_step) {
	if (shared->step == p_step) {
		return;
	}

	shared->step = p_step;
	shared->emit_changed();

	queue_accessibility_update();
}

void Range::set_page(double p_page) {
	double page_validated = CLAMP(p_page, 0, shared->max - shared->min);
	if (shared->page == page_validated) {
		return;
	}

	shared->page = page_validated;
	set_value(shared->val);

	shared->emit_changed();

	queue_accessibility_update();
}

double Range::get_value() const {
	return shared->val;
}

double Range::get_min() const {
	return shared->min;
}

double Range::get_max() const {
	return shared->max;
}

double Range::get_step() const {
	return shared->step;
}

double Range::get_page() const {
	return shared->page;
}

void Range::set_as_ratio(double p_value) {
	double v;

	if (shared->exp_ratio && get_min() >= 0) {
		double exp_min = get_min() == 0 ? 0.0 : Math::log(get_min()) / Math::log((double)2);
		double exp_max = Math::log(get_max()) / Math::log((double)2);
		v = Math::pow(2, exp_min + (exp_max - exp_min) * p_value);
	} else {
		double percent = (get_max() - get_min()) * p_value;
		if (get_step() > 0) {
			double steps = std::round(percent / get_step());
			v = steps * get_step() + get_min();
		} else {
			v = percent + get_min();
		}
	}
	v = CLAMP(v, get_min(), get_max());
	set_value(v);
}

double Range::get_as_ratio() const {
	if (Math::is_equal_approx(get_max(), get_min())) {
		// Avoid division by zero.
		return 1.0;
	}

	if (shared->exp_ratio && get_min() >= 0) {
		double exp_min = get_min() == 0 ? 0.0 : Math::log(get_min()) / Math::log((double)2);
		double exp_max = Math::log(get_max()) / Math::log((double)2);
		double value = CLAMP(get_value(), shared->min, shared->max);
		double v = Math::log(value) / Math::log((double)2);

		return CLAMP((v - exp_min) / (exp_max - exp_min), 0, 1);
	} else {
		double value = CLAMP(get_value(), shared->min, shared->max);
		return CLAMP((value - get_min()) / (get_max() - get_min()), 0, 1);
	}
}

void Range::_share(Node *p_range) {
	Range *r = Object::cast_to<Range>(p_range);
	ERR_FAIL_NULL(r);
	share(r);
}

void Range::share(Range *p_range) {
	ERR_FAIL_NULL(p_range);

	p_range->_ref_shared(shared);
	p_range->_changed_notify();
	p_range->_value_changed_notify();
}

void Range::unshare() {
	Shared *nshared = memnew(Shared);
	nshared->min = shared->min;
	nshared->max = shared->max;
	nshared->val = shared->val;
	nshared->step = shared->step;
	nshared->page = shared->page;
	nshared->exp_ratio = shared->exp_ratio;
	nshared->allow_greater = shared->allow_greater;
	nshared->allow_lesser = shared->allow_lesser;
	_unref_shared();
	_ref_shared(nshared);
	queue_accessibility_update();
}

void Range::_ref_shared(Shared *p_shared) {
	if (shared && p_shared == shared) {
		return;
	}

	_unref_shared();
	shared = p_shared;
	shared->owners.insert(this);
}

void Range::_unref_shared() {
	if (shared) {
		shared->owners.erase(this);
		if (shared->owners.is_empty()) {
			memdelete(shared);
			shared = nullptr;
		}
	}
}

void Range::_bind_methods() {
	ClassDB::bind_method(D_METHOD("get_value"), &Range::get_value);
	ClassDB::bind_method(D_METHOD("get_min"), &Range::get_min);
	ClassDB::bind_method(D_METHOD("get_max"), &Range::get_max);
	ClassDB::bind_method(D_METHOD("get_step"), &Range::get_step);
	ClassDB::bind_method(D_METHOD("get_page"), &Range::get_page);
	ClassDB::bind_method(D_METHOD("get_as_ratio"), &Range::get_as_ratio);
	ClassDB::bind_method(D_METHOD("set_value", "value"), &Range::set_value);
	ClassDB::bind_method(D_METHOD("set_value_no_signal", "value"), &Range::set_value_no_signal);
	ClassDB::bind_method(D_METHOD("set_min", "minimum"), &Range::set_min);
	ClassDB::bind_method(D_METHOD("set_max", "maximum"), &Range::set_max);
	ClassDB::bind_method(D_METHOD("set_step", "step"), &Range::set_step);
	ClassDB::bind_method(D_METHOD("set_page", "pagesize"), &Range::set_page);
	ClassDB::bind_method(D_METHOD("set_as_ratio", "value"), &Range::set_as_ratio);
	ClassDB::bind_method(D_METHOD("set_use_rounded_values", "enabled"), &Range::set_use_rounded_values);
	ClassDB::bind_method(D_METHOD("is_using_rounded_values"), &Range::is_using_rounded_values);
	ClassDB::bind_method(D_METHOD("set_exp_ratio", "enabled"), &Range::set_exp_ratio);
	ClassDB::bind_method(D_METHOD("is_ratio_exp"), &Range::is_ratio_exp);
	ClassDB::bind_method(D_METHOD("set_allow_greater", "allow"), &Range::set_allow_greater);
	ClassDB::bind_method(D_METHOD("is_greater_allowed"), &Range::is_greater_allowed);
	ClassDB::bind_method(D_METHOD("set_allow_lesser", "allow"), &Range::set_allow_lesser);
	ClassDB::bind_method(D_METHOD("is_lesser_allowed"), &Range::is_lesser_allowed);

	ClassDB::bind_method(D_METHOD("share", "with"), &Range::_share);
	ClassDB::bind_method(D_METHOD("unshare"), &Range::unshare);

	ADD_SIGNAL(MethodInfo("value_changed", PropertyInfo(Variant::FLOAT, "value")));
	ADD_SIGNAL(MethodInfo("changed"));

	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "min_value"), "set_min", "get_min");
	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "max_value"), "set_max", "get_max");
	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "step"), "set_step", "get_step");
	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "page"), "set_page", "get_page");
	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "value"), "set_value", "get_value");
	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "ratio", PROPERTY_HINT_RANGE, "0,1,0.01", PROPERTY_USAGE_NONE), "set_as_ratio", "get_as_ratio");
	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "exp_edit"), "set_exp_ratio", "is_ratio_exp");
	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "rounded"), "set_use_rounded_values", "is_using_rounded_values");
	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "allow_greater"), "set_allow_greater", "is_greater_allowed");
	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "allow_lesser"), "set_allow_lesser", "is_lesser_allowed");

	GDVIRTUAL_BIND(_value_changed, "new_value");

	ADD_LINKED_PROPERTY("min_value", "value");
	ADD_LINKED_PROPERTY("min_value", "max_value");
	ADD_LINKED_PROPERTY("min_value", "page");
	ADD_LINKED_PROPERTY("max_value", "value");
	ADD_LINKED_PROPERTY("max_value", "page");
}

void Range::set_use_rounded_values(bool p_enable) {
	_rounded_values = p_enable;
}

bool Range::is_using_rounded_values() const {
	return _rounded_values;
}

void Range::set_exp_ratio(bool p_enable) {
	if (shared->exp_ratio == p_enable) {
		return;
	}

	shared->exp_ratio = p_enable;

	update_configuration_warnings();
}

bool Range::is_ratio_exp() const {
	return shared->exp_ratio;
}

void Range::set_allow_greater(bool p_allow) {
	shared->allow_greater = p_allow;
}

bool Range::is_greater_allowed() const {
	return shared->allow_greater;
}

void Range::set_allow_lesser(bool p_allow) {
	shared->allow_lesser = p_allow;
}

bool Range::is_lesser_allowed() const {
	return shared->allow_lesser;
}

Range::Range() {
	shared = memnew(Shared);
	shared->owners.insert(this);
}

Range::~Range() {
	_unref_shared();
}
