#pragma region License
/*
License (OLC-3)
~~~~~~~~~~~~~~~

Copyright 2024 Joshua Sigona <sigonasr2@gmail.com>

Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:

1. Redistributions or derivations of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.

2. Redistributions or derivative works in binary form must reproduce the above
copyright notice. This list of conditions and the following	disclaimer must be
reproduced in the documentation and/or other materials provided with the distribution.

3. Neither the name of the copyright holder nor the names of its contributors may
be used to endorse or promote products derived from this software without specific
prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS	"AS IS" AND ANY
EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
SHALL THE COPYRIGHT	HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL,	SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT	(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.

Portions of this software are copyright © 2023 The FreeType
Project (www.freetype.org). Please see LICENSE_FT.txt for more information.
All rights reserved.
*/
#pragma endregion
#include "Pathfinding.h"
#include "DEFINES.h"
#include "AdventuresInLestoria.h"

INCLUDE_game

const vi2d Pathfinding::gridSpacing=vf2d{12,12};

void Pathfinding::Initialize(){
    nodes.clear();
    sNode*lastNodeAdded=nullptr;
	for (int x = 0; x < game->GetCurrentMapData().width*24; x+=gridSpacing.x)
		for (int y = 0; y < game->GetCurrentMapData().height*24; y+=gridSpacing.y)
		{
            bool tileIsEmpty=true;
            for(const LayerTag&layer:game->GetCurrentMap().GetLayers()){
				int tileID=layer.tiles[y/24][x/24]-1;
				if(tileID!=-1){
                    tileIsEmpty=false;
					break;
				}
			}
            if(tileIsEmpty)continue; //Don't add the node since it's outside the map.

            sNode&node=nodes[{x,y}];
			node.x = x; // ...because we give each node its own coordinates
			node.y = y; // ...because we give each node its own coordinates
            geom2d::rect<float>tile=game->GetTileCollision(game->GetCurrentLevel(),{float(x),float(y)});
            if(tile==game->NO_COLLISION){
                node.bObstacle=false;
            }else{
			    node.bObstacle=geom2d::overlaps(vf2d{fmodf(x+gridSpacing.x/2,24),fmodf(y+gridSpacing.y/2,24)},tile);
            }
            tile=game->GetTileCollision(game->GetCurrentLevel(),{float(x),float(y)},true);
            if(tile==game->NO_COLLISION){
                node.bObstacleUpper=false;
            }else{
			    node.bObstacleUpper=geom2d::overlaps(vf2d{fmodf(x,24),fmodf(y,24)},tile);
            }
			node.parent = nullptr;
			node.bVisited = false;
            if(nodes.size()==1){//This is the first node added, set as the start node.
                nodeStart=&node;
            }
            nodeEnd=&node;
		}

	for (auto&[key,node]:nodes){
        if(nodes.find({node.x,node.y-gridSpacing.y})!=nodes.end()){
			node.vecNeighbours.push_back(&nodes[{node.x,node.y-gridSpacing.y}]);
        }
        if(nodes.find({node.x,node.y+gridSpacing.y})!=nodes.end()){
			node.vecNeighbours.push_back(&nodes[{node.x,node.y+gridSpacing.y}]);
        }
        if(nodes.find({node.x-gridSpacing.x,node.y})!=nodes.end()){
            node.vecNeighbours.push_back(&nodes[{node.x-gridSpacing.x,node.y}]);
        }
        if(nodes.find({node.x+gridSpacing.x,node.y})!=nodes.end()){
            node.vecNeighbours.push_back(&nodes[{node.x+gridSpacing.x,node.y}]);
        }
    }
}

std::vector<vf2d> Pathfinding::Solve_AStar(vf2d startPos,vf2d endPos,float maxRange,bool upperLevel){
    float dist=float(sqrt(pow(endPos.x-startPos.x,2)+pow(endPos.y-startPos.y,2)));
    if(dist>maxRange*game->GetCurrentMapData().tilewidth)return{};

    startPos=vi2d(startPos/gridSpacing.x)*gridSpacing.x;
    endPos=vi2d(endPos/gridSpacing.x)*gridSpacing.x;

    if(nodes.find(startPos)==nodes.end())return{};
    if(nodes.find(endPos)==nodes.end())return{};

    nodeStart=&nodes[startPos];
    nodeEnd=&nodes[endPos];
    
    geom2d::rect<int>posPerimeter{{int(std::min(startPos.x,endPos.x)),int(std::min(startPos.y,endPos.y))},{int(abs(endPos.x-startPos.x)),int(abs(endPos.y-startPos.y))}};
    posPerimeter.pos={int(std::clamp(posPerimeter.pos.x-maxRange*game->GetCurrentMapData().tilewidth,0.f,game->GetCurrentMapData().width*float(game->GetCurrentMapData().tilewidth))),int(std::clamp(posPerimeter.pos.y-maxRange*game->GetCurrentMapData().tilewidth,0.f,game->GetCurrentMapData().height*float(game->GetCurrentMapData().tilewidth)))};
    posPerimeter.size={int(std::clamp(posPerimeter.size.x+maxRange*game->GetCurrentMapData().tilewidth*2,0.f,game->GetCurrentMapData().width*float(game->GetCurrentMapData().tilewidth)-posPerimeter.pos.x)),int(std::clamp(posPerimeter.size.y+maxRange*game->GetCurrentMapData().tilewidth*2,0.f,game->GetCurrentMapData().height*float(game->GetCurrentMapData().tilewidth)-posPerimeter.pos.y))};

    for (auto&[key,node]:nodes){
        if(geom2d::overlaps(posPerimeter,vi2d{node.x,node.y})){
            node.bVisited = false;
        }else{
            node.bVisited = true;
        }
        node.fGlobalGoal = INFINITY;
        node.fLocalGoal = INFINITY;
        node.parent = nullptr;	// No parents
    }

    auto distance = [](sNode* a, sNode* b) // For convenience
    {
        return sqrtf(float((a->x - b->x)*(a->x - b->x) + (a->y - b->y)*(a->y - b->y)));
    };

    auto heuristic = [distance](sNode* a, sNode* b)
    {
        return distance(a, b);
    };

    sNode *nodeCurrent = nodeStart;
    nodeStart->fLocalGoal = 0.0f;
    nodeStart->fGlobalGoal = heuristic(nodeStart, nodeEnd);

    std::list<sNode*> listNotTestedNodes;
    //if((!upperLevel && nodeStart->bObstacle)||(upperLevel && nodeStart->bObstacleUpper))return {};
    listNotTestedNodes.push_back(nodeStart);

    while (!listNotTestedNodes.empty() && nodeCurrent != nodeEnd)
    {
        listNotTestedNodes.sort([](const sNode* lhs, const sNode* rhs){ return lhs->fGlobalGoal < rhs->fGlobalGoal; } );
        
        while(!listNotTestedNodes.empty() && listNotTestedNodes.front()->bVisited)
            listNotTestedNodes.pop_front();
        if (listNotTestedNodes.empty())
            break;

        nodeCurrent = listNotTestedNodes.front();
        nodeCurrent->bVisited = true;
        for (auto nodeNeighbour : nodeCurrent->vecNeighbours)
        {
            if (!nodeNeighbour->bVisited && ((!upperLevel && !nodeNeighbour->bObstacle)||(upperLevel && !nodeNeighbour->bObstacleUpper)))
                listNotTestedNodes.push_back(nodeNeighbour);

            float fPossiblyLowerGoal = nodeCurrent->fLocalGoal + distance(nodeCurrent, nodeNeighbour);

            if (fPossiblyLowerGoal < nodeNeighbour->fLocalGoal)
            {
                nodeNeighbour->parent = nodeCurrent;
                nodeNeighbour->fLocalGoal = fPossiblyLowerGoal;
                nodeNeighbour->fGlobalGoal = nodeNeighbour->fLocalGoal + heuristic(nodeNeighbour, nodeEnd);
            }
        }	
    } 

    if (nodeEnd != nullptr)
    {
        int pathLength=INFINITE;
        sNode *p = nodeEnd;
        std::vector<vf2d>finalPath;
        while (p->parent != nullptr)
        {
            if(pathLength==INFINITE){
                pathLength=1;
            } else {
                pathLength++;
            }
            finalPath.push_back({float((*p).x),float((*p).y)});
            p = p->parent;
        }
        std::reverse(finalPath.begin(),finalPath.end());
        return finalPath;
    } else {
        return {};
    }
}

Pathfinding::sSpline Pathfinding::Solve_WalkPath(vf2d startPos,vf2d endPos,float maxRange,bool upperLevel){
	maxRange*=(24/game->pathfinder.gridSpacing.x);
    Pathfinding::sSpline newSpline{};
    newSpline.Initialize(Solve_AStar(startPos,endPos,maxRange,upperLevel));
    return newSpline;
}

void Pathfinding::sSpline::Initialize(const std::vector<vf2d>&points){
	this->points.clear();
	for(const vf2d&point:points){
        this->points.push_back({vf2d{point}+gridSpacing/2});
	}
    fTotalSplineLength=0.f;
    for (int i = 0; i < this->points.size(); i++)
	{
		fTotalSplineLength += (this->points[i].length = CalculateSegmentLength(i, true));
    }
}

Pathfinding::sPoint2D Pathfinding::sSpline::GetSplinePoint(float t, bool bLooped){
	int p0, p1, p2, p3;
    float t1=t;
	if (!bLooped)
	{
		p1 = (int)t1 + 1;
		p2 = p1 + 1;
		p3 = p2 + 1;
		p0 = p1 - 1;
	}
	else
	{
		p1 = (int)t1;
		p2 = (p1 + 1) % points.size();
		p3 = (p2 + 1) % points.size();
		p0 = p1 >= 1 ? p1 - 1 : points.size() - 1;
	}

	t = t - (int)t;

	float tt = t * t;
	float ttt = tt * t;

	float q1 = -ttt + 2.0f*tt - t;
	float q2 = 3.0f*ttt - 5.0f*tt + 2.0f;
	float q3 = -3.0f*ttt + 4.0f*tt + t;
	float q4 = ttt - tt;

	float tx = 0.5f * (points[p0].pos.x * q1 + points[p1].pos.x * q2 + points[p2].pos.x * q3 + points[p3].pos.x * q4);
	float ty = 0.5f * (points[p0].pos.y * q1 + points[p1].pos.y * q2 + points[p2].pos.y * q3 + points[p3].pos.y * q4);

	return{ {tx, ty} };
}

Pathfinding::sPoint2D Pathfinding::sSpline::GetSplineGradient(float t, bool bLooped){
	int p0, p1, p2, p3;
    float t1=t;
	if (!bLooped)
	{
		p1 = (int)t1 + 1;
		p2 = p1 + 1;
		p3 = p2 + 1;
		p0 = p1 - 1;
	}
	else
	{
		p1 = (int)t1;
		p2 = (p1 + 1) % points.size();
		p3 = (p2 + 1) % points.size();
		p0 = p1 >= 1 ? p1 - 1 : points.size() - 1;
	}

	t = t - (int)t;

	float tt = t * t;
	float ttt = tt * t;

	float q1 = -3.0f * tt + 4.0f*t - 1;
	float q2 = 9.0f*tt - 10.0f*t;
	float q3 = -9.0f*tt + 8.0f*t + 1.0f;
	float q4 = 3.0f*tt - 2.0f*t;

	float tx = 0.5f * (points[p0].pos.x * q1 + points[p1].pos.x * q2 + points[p2].pos.x * q3 + points[p3].pos.x * q4);
	float ty = 0.5f * (points[p0].pos.y * q1 + points[p1].pos.y * q2 + points[p2].pos.y * q3 + points[p3].pos.y * q4);

	return{ {tx, ty} };
}

float Pathfinding::sSpline::CalculateSegmentLength(int node, bool bLooped){
    float fLength = 0.0f;
    float fStepSize = 0.005;

    sPoint2D old_point, new_point;
    old_point = GetSplinePoint((float)node, bLooped);

    for (float t = 0; t < 1.0f; t += fStepSize)
    {
	    new_point = GetSplinePoint(fmod((float)node + t,1.0f), bLooped);
	    fLength += sqrtf((new_point.pos.x - old_point.pos.x)*(new_point.pos.x - old_point.pos.x)
					    + (new_point.pos.y - old_point.pos.y)*(new_point.pos.y - old_point.pos.y));
	    old_point = new_point;
    }

    return fLength;
}

float Pathfinding::sSpline::GetNormalisedOffset(float p){
	// Which node is the base?
	int i = 0;
	while (p > points[i].length)
	{
		p -= points[i].length;
		i++;
	}

	// The fractional is the offset
	return (float)i + (p / points[i].length);
}