#include "terrain_primitive.h"
#include "core/error/error_list.h"
#include "core/math/expression.h"
#include "core/math/math_funcs.h"
#include "terrain_editor/macros.h"

void TerrainPrimitive::_bind_methods() {
	BIND_HPROPERTY(Variant::INT, blend_mode, PROPERTY_HINT_ENUM, BlendMode_hint());
	BIND_PROPERTY(Variant::FLOAT, blend_range);
	BIND_HPROPERTY(Variant::STRING, expression, PROPERTY_HINT_EXPRESSION);
	ClassDB::bind_method(D_METHOD("get_expression_error"), &self_type::get_expression_error);
}

// by default does not modify height
void TerrainPrimitive::evaluate(Vector2, float &) const {}

float TerrainPrimitive::blend(float under, float over) const {
	float const difference{ under - over };
	float const distance{ Math::abs(difference) };
	// .25 because we need half of each half of the blend range to be used
	float const center_distance{ this->blend_range == 0.f ? 0.f : this->blend_range * 0.25f - distance / this->blend_range };
	if (center_distance < 0.f) {
		if (this->blend_mode == Both) {
			return over;
		} else if (this->blend_mode == Peak) {
			return under > over ? under : over;
		} else {
			return under > over ? over : under;
		}
	}
	float const smooth_center_distance{ center_distance * center_distance };
	if (this->blend_mode == Both) {
		return over + smooth_center_distance;
	} else {
		return (this->blend_mode == Peak
						? (under > over ? under : over) + smooth_center_distance
						: (under > over ? over : under) - smooth_center_distance);
	}
}

void TerrainPrimitive::set_blend_mode(BlendMode mode) {
	this->blend_mode = mode;
	emit_changed();
}

TerrainPrimitive::BlendMode TerrainPrimitive::get_blend_mode() const {
	return this->blend_mode;
}

void TerrainPrimitive::set_blend_range(float value) {
	this->blend_range = value;
	emit_changed();
}

float TerrainPrimitive::get_blend_range() const {
	return this->blend_range;
}

void TerrainPrimitive::set_expression(String expression) {
	this->expr_text = expression;
	if (expression.is_empty()) {
		this->expression_valid = false;
	} else {
		_parse_new_expression(expression);
	}
	emit_changed();
}

String TerrainPrimitive::get_expression() const {
	return this->expr_text;
}

String TerrainPrimitive::get_expression_error() const {
	if (this->expression_valid) {
		return "Valid Expression";
	} else {
		return this->expression->get_error_text();
	}
}

void PlanePrimitive::_bind_methods() {
	BIND_PROPERTY(Variant::FLOAT, baseline);
}

void PlanePrimitive::_parse_new_expression(String expression) {
	this->expression_valid = this->expression->parse(expression, { "previous_height", "at", "baseline" }) == OK;
}

void PlanePrimitive::evaluate(Vector2 at, float &io_height) const {
	float height{ this->baseline };
	if (this->expression_valid) {
		height = this->expression->execute({ io_height, at, this->baseline }, nullptr, false, true);
	}
	io_height = blend(io_height, height);
}

void PlanePrimitive::set_baseline(float value) {
	this->baseline = value;
	emit_changed();
}

float PlanePrimitive::get_baseline() const {
	return this->baseline;
}

void PointPrimitive::_bind_methods() {
	BIND_PROPERTY(Variant::VECTOR2, center);
	BIND_PROPERTY(Variant::FLOAT, slope);
	BIND_PROPERTY(Variant::FLOAT, height);
}

void PointPrimitive::_parse_new_expression(String expression) {
	this->expression_valid = this->expression->parse(expression, { "previous_height", "at", "center", "height", "sloped_height", "distance", "slope" }) == OK;
}

void PointPrimitive::evaluate(Vector2 at, float &io_height) const {
	float distance{ at.distance_to(this->center) };
	float height{ this->height + distance * this->slope };
	if (this->expression_valid) {
		height = this->expression->execute({ io_height, at, this->center, this->height, height, distance, this->slope }, nullptr, false, true);
	}
	io_height = blend(io_height, height);
}

void PointPrimitive::set_center(Vector2 center) {
	this->center = center;
	emit_changed();
}

Vector2 PointPrimitive::get_center() const {
	return this->center;
}

void PointPrimitive::set_slope(float radius) {
	this->slope = radius;
	emit_changed();
}

float PointPrimitive::get_slope() const {
	return this->slope;
}

void PointPrimitive::set_height(float height) {
	this->height = height;
	emit_changed();
}

float PointPrimitive::get_height() const {
	return this->height;
}

void NoisePrimitive::_bind_methods() {
	BIND_HPROPERTY(Variant::OBJECT, noise, PROPERTY_HINT_RESOURCE_TYPE, "Noise");
	BIND_PROPERTY(Variant::FLOAT, noise_scale);
	BIND_PROPERTY(Variant::FLOAT, noise_amplitude);
}

void NoisePrimitive::_parse_new_expression(String expression) {
	this->expression_valid = this->expression->parse(expression, { "previous_height", "at", "noise", "amplitude", "scale" }) == OK;
}

void NoisePrimitive::evaluate(Vector2 at, float &io_height) const {
	if (this->noise.is_valid()) {
		if (Math::is_nan(io_height) || Math::is_inf(io_height)) {
			io_height = 0;
		}
		float noise_sample{ this->noise->get_noise_2dv(at / this->noise_scale) };
		noise_sample *= this->noise_amplitude;
		float height{ noise_sample + io_height };
		if (this->expression_valid) {
			height = this->expression->execute({ io_height, at, noise_sample, this->noise_amplitude, this->noise_scale }, nullptr, false, true);
		}
		io_height = blend(io_height, height);
	}
}

void NoisePrimitive::set_noise(Ref<Noise> noise) {
	if (this->noise.is_valid()) {
		this->noise->disconnect_changed(callable_mp(cast_to<Resource>(this), &Resource::emit_changed));
	}
	this->noise = noise;
	if (this->noise.is_valid()) {
		this->noise->connect_changed(callable_mp(cast_to<Resource>(this), &Resource::emit_changed));
	}
	emit_changed();
}

Ref<Noise> NoisePrimitive::get_noise() const {
	return this->noise;
}

void NoisePrimitive::set_noise_scale(float value) {
	this->noise_scale = value;
	emit_changed();
}

float NoisePrimitive::get_noise_scale() const {
	return this->noise_scale;
}

void NoisePrimitive::set_noise_amplitude(float value) {
	this->noise_amplitude = value;
	emit_changed();
}

float NoisePrimitive::get_noise_amplitude() const {
	return this->noise_amplitude;
}