package ch.asynk.tankontank.engine;

import java.util.Set;
import java.util.List;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedHashSet;

import com.badlogic.gdx.Gdx;

import com.badlogic.gdx.utils.Disposable;

import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.Batch;
import com.badlogic.gdx.graphics.glutils.ShapeRenderer;

import com.badlogic.gdx.utils.Pool;
import com.badlogic.gdx.math.Vector2;
import com.badlogic.gdx.math.Vector3;
import com.badlogic.gdx.math.GridPoint2;
import com.badlogic.gdx.math.Matrix4;

import ch.asynk.tankontank.engine.gfx.Image;
import ch.asynk.tankontank.engine.gfx.Animation;
import ch.asynk.tankontank.engine.gfx.animations.AnimationSequence;
import ch.asynk.tankontank.engine.gfx.animations.RunnableAnimation;

public abstract class Board implements Disposable
{
    private final Tile neighbours[] = new Tile[6];
    protected List<ArrayList<SearchBoard.Node>> paths;

    public interface TileBuilder
    {
        public Tile getNewTile(float x, float y, int col, int row);
    }

    public static class Config
    {
        public int cols;
        public int rows;
        public int x0;          // bottom left x offset
        public int y0;          // bottom left y offset
        public int w;           // hex width
        public int dw;          // half hex : w/2
        public int s;           // hex side
        public float dh;        // hex top : s/2
        public float h;         // square height : s + dh
        public float slope;     // north-west side slope : (dh / (float) dw)
    }

    private final Pool<GridPoint2> gridPoint2Pool = new Pool<GridPoint2>() {
        @Override
        protected GridPoint2 newObject() {
            return new GridPoint2();
        }
    };

    private final Pool<Vector3> vector3Pool = new Pool<Vector3>() {
        @Override
        protected Vector3 newObject() {
            return new Vector3();
        }
    };

    private Config cfg;
    private Tile[] tiles;
    private SearchBoard searchBoard;
    private Image image;

    private boolean transform;
    private Matrix4 prevTransform;
    private Matrix4 nextTransform;

    private int tileCount = 0;
    private int pawnCount = 0;
    private int animationCount = 0;
    private final ArrayList<Animation> animations = new ArrayList<Animation>(2);
    private final ArrayList<Animation> nextAnimations = new ArrayList<Animation>(2);
    private final LinkedHashSet<Tile> tilesToDraw = new LinkedHashSet<Tile>();

    protected Board(int cols, int rows)
    {
        searchBoard = new SearchBoard(this, cols, rows);
    }

    public Board(TileBuilder tileBuilder, Config cfg, Texture texture)
    {
        image = new Image(texture);
        this.cfg = cfg;
        this.tiles = new Tile[cfg.cols * cfg.rows];
        searchBoard = new SearchBoard(this, cfg.cols, cfg.rows);

        int idx = 0;
        boolean evenRow = true;
        float y = cfg.y0 - cfg.dh + cfg.s;
        for (int i = 0; i < cfg.rows; i++) {
            float x = cfg.x0 + cfg.dw;
            if (!evenRow) x += cfg.dw;
            for ( int j = 0; j < cfg.cols; j ++) {
                this.tiles[idx] = tileBuilder.getNewTile(x, y, (j + ((i + 1) / 2)), i);
                idx += 1;
                x += cfg.w;
            }
            y += cfg.h;
            evenRow = !evenRow;
        }
    }

    @Override
    public void dispose()
    {
        image.dispose();
        for (int i = 0; i < (cfg.cols * cfg.rows); i++)
            tiles[i].dispose();
        tilesToDraw.clear();
        for (int i = 0, n = nextAnimations.size(); i < n; i++)
            nextAnimations.get(i).dispose();
        animations.clear();
        for (int i = 0, n = animations.size(); i < n; i++)
            animations.get(i).dispose();
        animations.clear();
    }

    public float getWidth()
    {
        return image.getWidth();
    }

    public float getHeight()
    {
        return image.getHeight();
    }

    public void setPosition(float x, float y)
    {
        image.setPosition(x, y);
        if ((x != 0.0f) || (y != 0.0f)) {
            transform = true;
            prevTransform = new Matrix4();
            nextTransform = new Matrix4();
            nextTransform.translate(x, y, 0);
        } else
            transform = false;
    }

    public Tile getTile(GridPoint2 coords)
    {
        return getTile(coords.x, coords.y);
    }

    public Tile getTile(int col, int row)
    {
        int idx = ((col - ((row + 1) / 2))) + (row * cfg.cols);
        // Gdx.app.debug("Board", " getTile: " + col + " ; " + row + " -> " + idx);
        return tiles[idx];
    }

    public Tile getTileSafe(GridPoint2 coords)
    {
        return getTileSafe(coords.x, coords.y);
    }

    public Tile getTileSafe(int col, int row)
    {
        int colOffset = ((row + 1) / 2);
        if ((col < colOffset) || (row < 0) || (row >= cfg.rows) || ((col - colOffset) >= cfg.cols))
            return null;

        return tiles[((col - colOffset)) + (row * cfg.cols)];
    }

    private void getAdjacentTiles(GridPoint2 coords, Tile tiles[])
    {
        tiles[0] = getTileSafe((coords.x - 1), (coords.y));
        tiles[1] = getTileSafe((coords.x),     (coords.y + 1));
        tiles[2] = getTileSafe((coords.x + 1), (coords.y + 1));
        tiles[3] = getTileSafe((coords.x + 1), (coords.y));
        tiles[4] = getTileSafe((coords.x),     (coords.y - 1));
        tiles[5] = getTileSafe((coords.x - 1), (coords.y - 1));
    }

    public void addAnimation(Animation a)
    {
        nextAnimations.add(a);
    }

    private void stats()
    {
        boolean print = false;

        if (tileCount != tilesToDraw.size()) {
            tileCount = tilesToDraw.size();
            print = true;
        }

        if (animationCount != animations.size()) {
            animationCount = animations.size();
            print = true;
        }

        if (print)
            Gdx.app.debug("Board", " tiles:" + tileCount + " pawns:" + pawnCount + " animations:" + animationCount);
    }

    public void animate(float delta)
    {

        Iterator<Animation> iter = animations.iterator();
        while (iter.hasNext()) {
            Animation a = iter.next();
            if (a.animate(delta))
                iter.remove();
        }

        for (int i = 0, n = nextAnimations.size(); i < n; i++)
            animations.add(nextAnimations.get(i));
        nextAnimations.clear();
    }

    public void draw(Batch batch)
    {
        image.draw(batch);

        if (transform) {
            prevTransform.set(batch.getTransformMatrix());
            batch.setTransformMatrix(nextTransform);
        }

        Iterator<Tile> tileIter = tilesToDraw.iterator();
        while (tileIter.hasNext())
            tileIter.next().draw(batch);

        Iterator<Animation> animationIter = animations.iterator();
        while (animationIter.hasNext())
            animationIter.next().draw(batch);

        if (transform)
            batch.setTransformMatrix(prevTransform);
    }

    public void drawDebug(ShapeRenderer debugShapes)
    {
        stats();
        if (transform) {
            prevTransform.set(debugShapes.getTransformMatrix());
            debugShapes.setTransformMatrix(nextTransform);
        }

        Iterator<Tile> iter = tilesToDraw.iterator();
        while (iter.hasNext())
            iter.next().drawDebug(debugShapes);

        Iterator<Animation> animationIter = animations.iterator();
        while (animationIter.hasNext())
            animationIter.next().drawDebug(debugShapes);

        if (transform)
            debugShapes.setTransformMatrix(prevTransform);
    }

    protected void clearPointVector(ArrayList<GridPoint2> points)
    {
        for (GridPoint2 point : points)
            gridPoint2Pool.free(point);
        points.clear();
    }

    private void nodesToPoints(List<SearchBoard.Node> nodes, ArrayList<GridPoint2> points)
    {
        int ns = nodes.size();
        int ps = points.size();

        if (ps > ns) {
            for (int i = (ps - 1); i >= ns; i--)
                gridPoint2Pool.free(points.remove(i));
        } else
            points.ensureCapacity(ns);

        int i = 0;
        for (SearchBoard.Node node : nodes) {
            if (i < ps) {
                points.get(i).set(node.col, node.row);
            } else {
                GridPoint2 point = gridPoint2Pool.obtain();
                point.set(node.col, node.row);
                points.add(point);
            }
            i += 1;
        }
    }

    protected int buildPossibleMovesFrom(Pawn pawn, GridPoint2 coords, ArrayList<GridPoint2> moves)
    {
        List<SearchBoard.Node> nodes = searchBoard.possibleMovesFrom(pawn, coords.x, coords.y);
        nodesToPoints(nodes, moves);
        return moves.size();
    }

    protected int buildPossibleTargetsFrom(Pawn pawn, GridPoint2 coords, ArrayList<GridPoint2> targets)
    {
        List<SearchBoard.Node> nodes = searchBoard.possibleTargetsFrom(pawn, coords.x, coords.y);
        nodesToPoints(nodes, targets);
        return targets.size();
    }

    protected int buildPossibleTargetsFrom(Pawn pawn, GridPoint2 coords, Iterator<Pawn> units, ArrayList<GridPoint2> targets)
    {
        clearPointVector(targets);

        GridPoint2 to = gridPoint2Pool.obtain();
        while (units.hasNext()) {
            Pawn target = units.next();
            getHexUnder(target, to);
            if (searchBoard.buildAttack(pawn, true, target, coords.x, coords.y, to.x, to.y)) {
                targets.add(to);
                to = gridPoint2Pool.obtain();
            }
        }

        int s = targets.size();
        if ((s > 0) && (to != targets.get(s - 1)))
            gridPoint2Pool.free(to);

        return s;
    }

    protected int buildMoveAssists(Pawn pawn, GridPoint2 coords, List<GridPoint2> assists)
    {
        assists.clear();
        getAdjacentTiles(coords, neighbours);
        for (int i = 0; i < 6; i++) {
            Tile t = neighbours[i];
            if (t != null) {
                // FIXME should support may pawns per tile
                Pawn p = t.getTopPawn();
                if ((p != null) && p.canMove() && !pawn.isEnemy(p)) {
                    GridPoint2 assist = gridPoint2Pool.obtain();
                    assist.set(t.getCol(), t.getRow());
                    assists.add(assist);
                }
            }
        }
        return assists.size();
    }

    protected int buildAttackAssists(Pawn pawn, Pawn target, GridPoint2 coords, Iterator<Pawn> units, ArrayList<GridPoint2> assists)
    {
        clearPointVector(assists);

        GridPoint2 from = gridPoint2Pool.obtain();
        while (units.hasNext()) {
            Pawn p = units.next();
            if ((p == pawn) || !p.canAttack()) continue;
            getHexUnder(p, from);
            if (searchBoard.buildAttack(p, !p.canAssistAttackWithoutLos(), target, from.x, from.y, coords.x, coords.y)) {
                if (p != pawn) {
                    assists.add(from);
                    from = gridPoint2Pool.obtain();
                }
            }
        }

        int s = assists.size();
        if ((s > 0) && (from != assists.get(s- 1)))
            gridPoint2Pool.free(from);

        return s;
    }

    protected void clearPointSet(Set<GridPoint2> points)
    {
        for (GridPoint2 point : points)
            gridPoint2Pool.free(point);
        points.clear();
    }

    private int nodesToSet(List<ArrayList<SearchBoard.Node>> nodes, Set<GridPoint2> points)
    {
        for (GridPoint2 point : points)
            gridPoint2Pool.free(point);
        points.clear();

        for (ArrayList<SearchBoard.Node> path : nodes) {
            for (int i = 1, n = (path.size() - 1); i < n; i++) {
                SearchBoard.Node node = path.get(i);
                GridPoint2 point = gridPoint2Pool.obtain();
                point.set(node.col, node.row);
                if (!points.add(point))
                    gridPoint2Pool.free(point);
            }
        }

        return nodes.size();
    }

    protected int buildPossiblePaths(Pawn pawn, GridPoint2 from, GridPoint2 to, Set<GridPoint2> points)
    {
        paths = searchBoard.possiblePaths(pawn, from.x, from.y, to.x, to.y);
        return nodesToSet(paths, points);
    }

    protected int possiblePathsFilterToggle(GridPoint2 coords, Set<GridPoint2> points)
    {
        paths = searchBoard.possiblePathsFilterToggle(coords.x, coords.y);
        return nodesToSet(paths, points);
    }

    protected void clearCoordinateVector(ArrayList<Vector3> points)
    {
        for (Vector3 point : points)
            vector3Pool.free(point);
        points.clear();
    }

    protected int getPathCost(Pawn pawn, int i)
    {
        return searchBoard.pathCost(pawn, paths.get(i));
    }

    protected int getCoordinatePath(Pawn pawn, int idx, ArrayList<Vector3> path, Orientation finalOrientation)
    {
        clearCoordinateVector(path);

        Vector2 tmpCoords = new Vector2();
        GridPoint2 tmpHex = gridPoint2Pool.obtain();

        Vector3 p = pawn.getPosition();
        Vector3 v = vector3Pool.obtain();
        v.set(p.x, p.y, 0f);
        Orientation prevOrientation = pawn.getOrientation();

        ArrayList<SearchBoard.Node> nodes = paths.get(idx);
        SearchBoard.Node prevNode = nodes.get(0);
        // Gdx.app.debug("Board", "getCoordinatePath()");
        // Gdx.app.debug("Board", "  " + prevNode);

        for (int i = 1, n = nodes.size(); i < n; i++) {
            SearchBoard.Node node = nodes.get(i);
            // Gdx.app.debug("Board", "  " + node);
            Orientation o = Orientation.fromMove(prevNode.col, prevNode.row, node.col, node.row);
            if ((o != Orientation.KEEP) && (o != prevOrientation)) {
                v.z = o.r();
                path.add(v);
                v = vector3Pool.obtain();
            }
            tmpHex.set(node.col, node.row);
            getPawnPosAt(pawn, tmpHex, tmpCoords);
            v.set(tmpCoords.x, tmpCoords.y, o.r());
            path.add(v);
            prevOrientation = o;
            v = vector3Pool.obtain();
            v.set(tmpCoords.x, tmpCoords.y, 0f);

            prevNode = node;
        }

        if (finalOrientation != prevOrientation) {
            v.z = finalOrientation.r();
            path.add(v);
        } else {
            vector3Pool.free(v);
        }

        gridPoint2Pool.free(tmpHex);

        // Gdx.app.debug("Board", " =>");
        // for (Vector3 vector :path)
        //     Gdx.app.debug("Board", "  " + vector);

        return path.size();
    }

    protected boolean hasUnits(GridPoint2 coords)
    {
        return getTile(coords).hasUnits();
    }

    public boolean isOffMap(GridPoint2 coords)
    {
        return getTile(coords).isOffMap();
    }

    protected boolean isOverlayEnabledOn(GridPoint2 coords, int i)
    {
        return getTile(coords).isOverlayEnabled(i);
    }

    public void enableOverlayOn(GridPoint2 coords, int i, boolean enable)
    {
        Tile tile = getTile(coords);
        if(tile.enableOverlay(i, enable))
            tilesToDraw.add(tile);
        else
            tilesToDraw.remove(tile);
    }

    public void enableOverlayOn(GridPoint2 coords, int i, boolean enable, Orientation o)
    {
        Tile tile = getTile(coords);
        if(tile.enableOverlay(i, enable, o.r()))
            tilesToDraw.add(tile);
        else
            tilesToDraw.remove(tile);
    }

    public Pawn getTopPawnAt(GridPoint2 coords)
    {
        return getTile(coords).getTopPawn();
    }

    private int pushPawnAt(Pawn pawn, GridPoint2 coords)
    {
        Tile tile = getTile(coords);
        tilesToDraw.add(tile);
        return tile.push(pawn);
    }

    public int removePawn(Pawn pawn)
    {
        return removePawnFrom(pawn, getHexUnder(pawn));
    }

    public int removePawnFrom(Pawn pawn, GridPoint2 coords)
    {
        Tile tile = getTile(coords);
        int n = tile.remove(pawn);
        if (!tile.mustBeDrawn())
            tilesToDraw.remove(tile);
        return n;
    }

    protected Vector2 getPawnPosAt(Pawn pawn, GridPoint2 coords, Vector2 pos)
    {
        return pawn.getPosAt(getTile(coords.x, coords.y), pos);
    }

    public Pawn setPawnAt(Pawn pawn, GridPoint2 coords, Orientation o)
    {
        Vector2 pos = getPawnPosAt(pawn, coords, null);
        pawn.setPosition(pos.x, pos.y, o.r());
        pushPawnAt(pawn, coords);
        return pawn;
    }

    protected void movePawn(final Pawn pawn, int cost, ArrayList<Vector3> path, RunnableAnimation whenDone)
    {
        removePawnFrom(pawn, getHexUnder(pawn));

        AnimationSequence seq = pawn.getMoveAnimation(path);
        seq.addAnimation(RunnableAnimation.get(pawn, new Runnable() {
            @Override
            public void run() {
                pushPawnAt(pawn, getHexUnder(pawn));
            }
        }));
        seq.addAnimation(whenDone);
        addAnimation(seq);
        pawn.move(cost);
    }

    protected void rotatePawn(final Pawn pawn, Orientation o, RunnableAnimation whenDone)
    {
        Vector3 p = pawn.getPosition();
        Vector3 v = vector3Pool.obtain();
        v.set(p.x, p.y, o.r());
        AnimationSequence seq = pawn.getRotateAnimation(v);
        seq.addAnimation(whenDone);
        addAnimation(seq);
        vector3Pool.free(v);
        pawn.rotate(o);
    }

    protected void revertLastPawnMove(final Pawn pawn, RunnableAnimation whenDone)
    {
        removePawnFrom(pawn, getHexUnder(pawn));

        AnimationSequence seq = pawn.getRevertLastMoveAnimation();
        seq.addAnimation(RunnableAnimation.get(pawn, new Runnable() {
            @Override
            public void run() {
                pushPawnAt(pawn, getHexUnder(pawn));
            }
        }));
        seq.addAnimation(whenDone);
        addAnimation(seq);
        pawn.revertLastMove();
    }

    public GridPoint2 getHexUnder(Pawn pawn)
    {
        return getHexAt(pawn.getCenter(), null);
    }

    public GridPoint2 getHexUnder(Pawn pawn, GridPoint2 hex)
    {
        return getHexAt(pawn.getCenter(), hex);
    }

    public GridPoint2 getHexAt(Vector2 v, GridPoint2 hex)
    {
        return getHexAt(hex, v.x, v.y);
    }

    public GridPoint2 getHexAt(GridPoint2 hex, float mx, float my)
    {
        if (hex == null) hex = new GridPoint2();

        // compute row
        float y = (my - cfg.y0);
        int row = (int) (y / cfg.h);
        boolean oddRow = ((row % 2) == 1);
        if (y < 0.f) {
            row = -1;
            oddRow = true;
        }

        // compute col
        float x = (mx - cfg.x0);
        if (oddRow) x -= cfg.dw;
        int col = (int) (x / cfg.w);
        if (x < 0.f)
            col = -1;

        int colOffset = ((row +1) / 2);

        // check upper boundaries
        float dy = (y - (row * cfg.h));
        if (dy > cfg.s) {
            dy -= cfg.s;
            float dx = (x - (col * cfg.w));
            col += colOffset;
            if (dx < cfg.dw) {
                if ((dx * cfg.slope) < dy) {
                    // upper left corner
                    row += 1;
                    colOffset = ((row +1) / 2);
                }
            } else {
                if (((cfg.w - dx) * cfg.slope) < dy) {
                    // upper right corner
                    row += 1;
                    col += 1;
                    colOffset = ((row +1) / 2);
                }
            }
        } else
            col += colOffset;


        // validate hex
        if ((col < colOffset) || (row < 0) || (row >= cfg.rows) || ((col - colOffset) >= cfg.cols))
            hex.set(-1, -1);
        else
            hex.set(col, row);

        // Gdx.app.debug("Board", " hex: " + hex.x + " ; " + hex.y);
        return hex;
    }
}