Passed
Pull Request — master (#281)
by Vincent
15:23
created

generate(AI,AiActionFactory)   B

Complexity

Conditions 6

Size

Total Lines 36
Code Lines 21

Duplication

Lines 0
Ratio 0 %

Code Coverage

Tests 16
CRAP Score 6.0493

Importance

Changes 0
Metric Value
eloc 21
dl 0
loc 36
ccs 16
cts 18
cp 0.8889
rs 8.4426
c 0
b 0
f 0
cc 6
crap 6.0493
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/*
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 * This file is part of Araknemu.
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 *
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 * Araknemu is free software: you can redistribute it and/or modify
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 * it under the terms of the GNU Lesser General Public License as published by
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 * the Free Software Foundation, either version 3 of the License, or
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 * (at your option) any later version.
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 *
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 * Araknemu is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * GNU Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public License
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 * along with Araknemu.  If not, see <https://www.gnu.org/licenses/>.
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 *
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 * Copyright (c) 2017-2021 Vincent Quatrevieux
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 */
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package fr.quatrevieux.araknemu.game.fight.ai.action.util;
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import fr.arakne.utils.maps.CoordinateCell;
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import fr.arakne.utils.maps.path.Decoder;
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import fr.arakne.utils.maps.path.Path;
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import fr.arakne.utils.maps.path.PathException;
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import fr.arakne.utils.maps.path.Pathfinder;
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import fr.quatrevieux.araknemu.game.fight.ai.AI;
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import fr.quatrevieux.araknemu.game.fight.ai.action.ActionGenerator;
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import fr.quatrevieux.araknemu.game.fight.ai.action.AiActionFactory;
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import fr.quatrevieux.araknemu.game.fight.fighter.ActiveFighter;
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import fr.quatrevieux.araknemu.game.fight.map.BattlefieldCell;
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import fr.quatrevieux.araknemu.game.fight.turn.action.Action;
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import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
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import org.checkerframework.checker.nullness.util.NullnessUtil;
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import java.util.ArrayList;
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import java.util.List;
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import java.util.Optional;
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import java.util.function.Predicate;
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import java.util.function.ToDoubleFunction;
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/**
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 * Try to select the best move action
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 *
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 * - Select reachable (i.e. walkable cells in MP range) cells. Note : pathfinding is not performed, so it's not warranty that cells are really reachable
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 * - Sort cell by the score (ascending, lower score cells selected first)
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 * - Iterates selected cells
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 * - Filter cells (using filter predicate)
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 * - Try to find the path
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 * - If a path is found, and can be performed by the current number of MPs, return the move action
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 */
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public final class Movement<F extends ActiveFighter> implements ActionGenerator<F> {
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    private final ToDoubleFunction<CoordinateCell<BattlefieldCell>> scoreFunction;
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    private final Predicate<ScoredCell> filter;
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    private @MonotonicNonNull Pathfinder<BattlefieldCell> pathfinder;
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    /**
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     * Creates the Movement action generator
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     *
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     * @param scoreFunction The score function. The returned score is used for select the best cell. Higher score are selected first.
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     * @param filter The selection cell filter
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     */
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    public Movement(ToDoubleFunction<CoordinateCell<BattlefieldCell>> scoreFunction, Predicate<ScoredCell> filter) {
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        this.scoreFunction = scoreFunction;
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        this.filter = filter;
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    }
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    @Override
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    public void initialize(AI<F> ai) {
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        this.pathfinder = new Decoder<>(ai.map()).pathfinder();
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    }
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    @Override
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    public Optional<Action> generate(AI<F> ai, AiActionFactory actions) {
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        final Pathfinder<BattlefieldCell> pathfinder = NullnessUtil.castNonNull(this.pathfinder);
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        final int movementPoints = ai.turn().points().movementPoints();
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        final List<ScoredCell> selectedCells = selectCells(ai, movementPoints);
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        final CoordinateCell<BattlefieldCell> currentCell = ai.fighter().cell().coordinate();
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        final ScoredCell currentCellScore = new ScoredCell(currentCell, scoreFunction.applyAsDouble(currentCell));
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        final boolean currentCellIsValid = filter.test(currentCellScore);
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        selectedCells.sort(ScoredCell::compareTo);
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        for (ScoredCell cell : selectedCells) {
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            if ((currentCellIsValid && currentCellScore.score() >= cell.score()) || !filter.test(cell)) {
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                continue;
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            }
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            final Path<BattlefieldCell> path;
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            try {
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                path = pathfinder.findPath(ai.fighter().cell(), cell.coordinates.cell());
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            } catch (PathException e) {
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                // No valid path can be found
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                continue;
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            }
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            // The path contains, as first step, the current cell.
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            // So this steps must not be considered in MPs
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            if (path.size() - 1 > movementPoints) {
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                continue;
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            }
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            return Optional.of(actions.move(path));
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        }
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        return Optional.empty();
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    }
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    /**
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     * Select all reachable cells for movement
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     */
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    private List<ScoredCell> selectCells(AI<F> ai, int movementPoints) {
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        final CoordinateCell<BattlefieldCell> currentCell = ai.fighter().cell().coordinate();
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        final List<ScoredCell> selectedCells = new ArrayList<>();
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        for (BattlefieldCell cell : ai.map()) {
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            if (!cell.walkable()) {
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                continue;
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            }
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            final CoordinateCell<BattlefieldCell> coordinates = cell.coordinate();
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            if (coordinates.distance(currentCell) > movementPoints) {
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                continue;
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            }
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            selectedCells.add(new ScoredCell(coordinates, scoreFunction.applyAsDouble(coordinates)));
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        }
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        return selectedCells;
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    }
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    public static final class ScoredCell implements Comparable<ScoredCell> {
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        private final CoordinateCell<BattlefieldCell> coordinates;
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        private final double score;
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        public ScoredCell(CoordinateCell<BattlefieldCell> coordinates, double score) {
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            this.coordinates = coordinates;
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            this.score = score;
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        }
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        /**
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         * Get the cell coordinates
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         */
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        public CoordinateCell<BattlefieldCell> coordinates() {
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            return coordinates;
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        }
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        /**
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         * Get the cell score
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         * Higher score are prioritized
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         */
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        public double score() {
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            return score;
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        }
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        @Override
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        public int compareTo(ScoredCell o) {
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            return Double.compare(o.score, score);
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        }
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    }
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}
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