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package cdc.applic.expressions.content;

import java.util.List;

import cdc.applic.expressions.literals.LiteralUtils;
import cdc.graphs.PartialOrderPosition;
import cdc.graphs.PartiallyComparable;

/**
 * Class representing a single boolean value.
 *
 * @author Damien Carbonne
 */
public final class BooleanValue implements BooleanSItem, Value, Comparable, PartiallyComparable {
    private final boolean value;

    public static final BooleanValue FALSE = new BooleanValue(false);
    public static final BooleanValue TRUE = new BooleanValue(true);
    public static final List FALSE_TRUE = List.of(FALSE, TRUE);

    private BooleanValue(boolean value) {
        this.value = value;
    }

    /**
     * Creates a {@link BooleanValue} from a {@code boolean}.
     *
     * @param value The value.
     * @return A new {@link BooleanValue} from {@code value}.
     */
    public static BooleanValue of(boolean value) {
        return value ? TRUE : FALSE;
    }

    /**
     * Creates a {@link BooleanValue} from a its String representation.
     *
     * @param literal The boolean literal.
     * @return A new {@link BooleanValue} from {@code literal}.
     * @throws IllegalArgumentException When {@code literal} can not be recognized as a {@code boolean}.
     */
    public static BooleanValue of(String literal) {
        if (!LiteralUtils.isBooleanLiteral(literal)) {
            throw new IllegalArgumentException("Illegal boolean literal (" + literal + ")");
        }
        return of(Boolean.parseBoolean(literal));
    }

    public BooleanValue negate() {
        return this == TRUE ? FALSE : TRUE;
    }

    @Override
    public String getNonEscapedLiteral() {
        return value ? "true" : "false";
    }

    @Override
    public String getProtectedLiteral() {
        return getNonEscapedLiteral();
    }

    public boolean getValue() {
        return value;
    }

    @Override
    public int compareTo(BooleanValue o) {
        if (this == o) {
            return 0;
        }
        if (o == null) {
            return 1;
        } else {
            return this == FALSE ? -1 : 1;
        }
    }

    @Override
    public PartialOrderPosition partialCompareTo(BooleanValue o) {
        return PartiallyComparable.partialCompare(this, o);
    }

    @Override
    public boolean equals(Object object) {
        // Booleans are cached and there are only 2 values.
        // So we can use this simple approach
        return this == object;
    }

    @Override
    public int hashCode() {
        return Boolean.hashCode(value);
    }

    @Override
    public String toString() {
        return getProtectedLiteral();
    }
}