package model.asn1;

import model.asn1.exceptions.ParseException;
import model.asn1.parsing.BytesReader;

/**
 * Represents the ASN.1 BOOLEAN type. It always has one byte length. Its content is either 0xFF (true) or 0x00 (false).
 */
public class Bool extends ASN1Object {
    /**
     * The X.680 universal class tag assignment.
     */
    public static final Tag TAG = new Tag(TagClass.UNIVERSAL, false, 0x1);

    private final boolean value;

    /**
     * EFFECTS: Initiate the BOOLEAN with the given tag, an optional context-specific tag number for explicit
     * encoding, and its value. For more information, consult {@link ASN1Object}.
     * REQUIRES: Consult {@link ASN1Object}.
     */
    public Bool(Tag tag, Tag parentTag, boolean value) {
        super(tag, parentTag);
        this.value = value;
    }

    /**
     * EFFECTS: Parse input bytes. For more information on tags parsing, consult {@link ASN1Object}.
     * Throws {@link ParseException} if the input data is invalid:
     * - The length is not 1
     * - The value is neither 0x00 nor 0xFF
     * - Other cases as denoted in {@link ASN1Object}
     */
    public Bool(BytesReader encoded, boolean hasParentTag) throws ParseException {
        super(encoded, hasParentTag);
        if (getLength() != 1) {
            throw new ParseException("Invalid boolean length: " + getLength());
        }
        final Byte val = encoded.require(1, true)[0];
        if (val == 0) {
            this.value = false;
        } else if (val == -1) {
            this.value = true;
        } else {
            throw new ParseException("Unknown boolean value: " + val);
        }
    }

    /**
     * EFFECTS: Encode the boolean to either 0x00 or 0xFF.
     */
    @Override
    public Byte[] encodeValueDER() {
        return new Byte[]{value ? (byte) -1 : 0};
    }

    public boolean getValue() {
        return value;
    }
}