/* Radar.cpp
Copyright (c) 2014 by Michael Zahniser

Endless Sky 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 3 of the License, or (at your option) any later version.

Endless Sky 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. If not, see <https://www.gnu.org/licenses/>.
*/

#include "Radar.h"

#include "GameData.h"
#include "LineShader.h"
#include "PointerShader.h"
#include "RingShader.h"

#include <cmath>

using namespace std;

const int Radar::PLAYER = 0;
const int Radar::FRIENDLY = 1;
const int Radar::UNFRIENDLY = 2;
const int Radar::HOSTILE = 3;
const int Radar::INACTIVE = 4;
const int Radar::SPECIAL = 5;
const int Radar::ANOMALOUS = 6;
const int Radar::BLINK = 7;
const int Radar::VIEWPORT = 8;
const int Radar::STAR = 9;



void Radar::Clear()
{
	objects.clear();
	pointers.clear();
	lines.clear();
}



void Radar::SetCenter(const Point &center)
{
	this->center = center;
}



// Add an object. If "inner" is 0 it is a dot; otherwise, it is a ring. The
// given position should be in world units (not shrunk to radar units).
void Radar::Add(int type, Point position, double outer, double inner)
{
	objects.emplace_back(GetColor(type).Opaque(), position - center, outer, inner);
}



// Add a pointer, pointing in the direction of the given vector.
void Radar::AddPointer(int type, const Point &position)
{
	pointers.emplace_back(GetColor(type), position.Unit());
}



// Create a "corner" from a vertical and horizontal leg.
void Radar::AddViewportBoundary(const Point &vertex)
{
	Point start(vertex.X() - copysign(200., vertex.X()), vertex.Y());
	Point end(vertex.X(), vertex.Y() - copysign(200., vertex.Y()));

	// Add the horizontal leg, pointing from start to vertex.
	lines.emplace_back(GetColor(VIEWPORT), start, vertex - start);
	// Add the vertical leg, pointing from end to vertex.
	lines.emplace_back(GetColor(VIEWPORT), end, vertex - end);
}



// Draw the radar display at the given coordinates.
void Radar::Draw(const Point &center, double scale, double radius, double pointerRadius) const
{
	// Draw any desired line vectors.
	for(const Line &line : lines)
	{
		Point start = line.base * scale;
		Point v = line.vector * scale;

		// At least one endpoint must be within the radar display.
		double startExcess = start.Length() - radius;
		double endExcess = (start + v).Length() - radius;
		if(startExcess > 0 && endExcess > 0)
			continue;
		else if(startExcess > 0)
		{
			// Move "start" along "v" until it is within the radius.
			start += startExcess * v.Unit();
			// Shorten "v" to keep the desired length.
			v -= startExcess * v.Unit();
		}
		else if(endExcess > 0)
			v -= endExcess * v.Unit();

		LineShader::Draw(start + center, start + v + center, 1.f, line.color);
	}

	// Draw StellarObjects and ships.
	RingShader::Bind();
	for(const Object &object : objects)
	{
		Point position = object.position * scale;
		double length = position.Length();
		if(length > radius)
			position *= radius / length;
		position += center;

		RingShader::Add(position, object.outer, object.inner, object.color);
	}
	RingShader::Unbind();

	// Draw neighboring system indicators.
	PointerShader::Bind();
	for(const Pointer &pointer : pointers)
		PointerShader::Add(center, pointer.unit, 10.f, 10.f, pointerRadius, pointer.color);
	PointerShader::Unbind();
}



const Color &Radar::GetColor(int type)
{
	static const vector<Color> color = {
		*GameData::Colors().Get("radar player"),
		*GameData::Colors().Get("radar friendly"),
		*GameData::Colors().Get("radar unfriendly"),
		*GameData::Colors().Get("radar hostile"),
		*GameData::Colors().Get("radar inactive"),
		*GameData::Colors().Get("radar special"),
		*GameData::Colors().Get("radar anomalous"),
		*GameData::Colors().Get("radar blink"),
		*GameData::Colors().Get("radar viewport"),
		*GameData::Colors().Get("radar star")
	};

	if(static_cast<size_t>(type) >= color.size())
		type = INACTIVE;

	return color[type];
}



Radar::Object::Object(const Color &color, const Point &pos, double out, double in)
	: color(color), position(pos), outer(out), inner(in)
{
}



Radar::Pointer::Pointer(const Color &color, const Point &unit)
	: color(color), unit(unit)
{
}



// Create a line starting from "base" with length and angle described by "vector."
Radar::Line::Line(const Color &color, const Point &base, const Point &vector)
	: color(color), base(base), vector(vector)
{
}
