package tfg;

import org.jsfml.graphics.Drawable;
import org.jsfml.graphics.PrimitiveType;
import org.jsfml.graphics.RenderStates;
import org.jsfml.graphics.RenderTarget;
import org.jsfml.graphics.RenderWindow;
import org.jsfml.graphics.Texture;
import org.jsfml.graphics.Vertex;
import org.jsfml.graphics.VertexArray;
import org.jsfml.system.Vector2f;
import org.jsfml.system.Vector2i;

import java.io.IOException;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Iterator;

/**
 * A map or level for the player to interact in. Can be created
 * manually or procedurally.
 * @author Ritchie Cunningham
 */
public class Map implements Drawable {
    /**
     * The size (length, width) of the map.
     */
    private Vector2i dimensions = new Vector2i(0, 0);
    private Tile[][] tileArray;
    /**
     * The tilesheet texture.
     */
    private Texture tilesheetTexture = new Texture();
    /**
     * Vertex array for the tile map.
     * This is a streamlined way to draw many sprites at once.
     */
    private VertexArray vertexArray = new VertexArray();

    private final ArrayList<Entity> entitiesOnMap = new ArrayList<Entity>();

    /**
     * Create a new map of specified size and tile type.
     * @param l Map length.
     * @param w Map width.
     * @param t Default tile to auto-pupulate map.
     */
    public Map(int l, int w, Tile t) {
        dimensions = new Vector2i(l,w);
        tileArray = new Tile[dimensions.x][dimensions.y];
        try {
            tilesheetTexture.loadFromFile(Paths.get("res/terrain.png"));
        } catch(IOException ex) {
            ex.printStackTrace();
        }
        /* Set vertex array to use quads because the tiles are square. */
        vertexArray.setPrimitiveType(PrimitiveType.QUADS);
        initializeMap(t); /* Auto-populate the map with specified tile. */
    }

    /**
     * Create a new map of speceified size that default to grass.
     * @param l Map length.
     * @param w Map width.
     */
    public Map(int l, int w) {
        this(l,w,Tile.GRASS);
    }

    /**
     * Fill the entire map to the specified tile.
     * @param initialTile The tile to populate the map with.
     */
    public void initializeMap(Tile initialTile) {
        /**
         * Arrays.fill does not work with matrices,
         * therefore we have to loop through the outer level to fill the inner.
         */
        for(Tile[] row : tileArray) {
            /* Set each tile in the row to the specified tile. */
            Arrays.fill(row,initialTile);
        }
    }

    /**
     * Draw the map onto the window.
     */
    public void draw(RenderTarget target, RenderStates states) {
        vertexArray.clear(); /* empty array from previous draw. */
        final int tileSize = Tile.getSize();
        /* Iterate through every tile in the map. */
        for(int i = 0; i < dimensions.x; i++) {
            for(int j = 0; j < dimensions.y; j++) {
                Tile tileType = tileArray[i][j]; /* Grab current tile in the loop. */
                /* Grab texture coord to render the tile. */
                Vector2f textureCoords = Tile.getTextureCoords(tileType);

                /*
                 * Add each corner of the tile to the vertex array
                 * counter-clockwise.
                 */
                /* Top left. */
                vertexArray.add(new Vertex(
                    new Vector2f(i*tileSize, j* tileSize), textureCoords));
                
                /* Bottom left. */
                vertexArray.add(new Vertex(
                    new Vector2f(i*tileSize,(j*tileSize)+tileSize),
                    Vector2f.add(textureCoords, new Vector2f(tileSize,tileSize))));
                
                /* Bottom right. */
                vertexArray.add(new Vertex(
                    new Vector2f((i*tileSize)+tileSize, (j*tileSize)+tileSize),
                    Vector2f.add(textureCoords, new Vector2f(tileSize,tileSize))));

                /* Top right. */
                vertexArray.add(new Vertex(
                    new Vector2f((i*tileSize)+tileSize, j*tileSize),
                    Vector2f.add(textureCoords, new Vector2f(tileSize,0))));                
            }
        }
        /* Apply texture to the vertex array. */
        RenderStates newStates = new RenderStates(tilesheetTexture);
        vertexArray.draw(target, newStates); /* Draw vertex array. */
    }

    /**
     * Return the tile at specified location.
     * @param l Location of the tile to get.
     * @return Tile at the specified location.
     */
    public Tile getTile(Location l) {
        Vector2i position = l.getPosition(); /* Get pos from loc. */
        Tile t = tileArray[position.x][position.y]; /* Get tile at this pos. */
        return t;
    }

    /**
     * Determine whether or not the location fits within the map.
     * @param l Location to test.
     * @return If location is valid.
     */
    public boolean isValidLocation(Location l) {
        Vector2i coordinates = l.getPosition(); /* Pos from last location. */
        /* Return true if the location is greater than 0. */
        return ((coordinates.x >= 0) && (coordinates.y >=0) &&
            (coordinates.x < dimensions.x) &&
            (coordinates.y < dimensions.y) &&
            Tile.getCanWalkOn(getTile(l)) &&
            (getEntityatLocation(l) == null));
    }

    public Entity getEntityatLocation(Location l) {
        Iterator<Entity> it = entitiesOnMap.iterator();
        while(it.hasNext()) {
            Entity e = it.next();
            if(e.getLocation().equals(1)) {
                return e;
            }
        }
        return null;
    }

    public void addEntity(Entity e) {
        if(getEntityatLocation(e.getLocation()) == null) {
            e.setParentMap(this);
            entitiesOnMap.add(e);
        }
    }

    public void drawAllEntities(RenderWindow w) {
        for(Entity e : entitiesOnMap) {
            w.draw(e);
        }
    }

    public void updateAllEntities() {
        Collections.sort(entitiesOnMap);
        for(Entity e : entitiesOnMap) {
            e.update();
        }
    }    
}