package model.csr;

import model.asn1.ASN1Object;
import model.asn1.Encodable;
import model.asn1.Tag;
import model.asn1.exceptions.ParseException;
import model.asn1.parsing.BytesReader;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Stream;

/**
 * Represents a CSR attribute values list.
 * <pre>
 *   Attribute { ATTRIBUTE:IOSet } ::= SEQUENCE {
 *       type   ATTRIBUTE.&id({IOSet}),
 *       values SET SIZE(1..MAX) OF ATTRIBUTE.&Type({IOSet}{@type})
 *   }
 * </pre>
 * Values can be none or any length. Parsing and decoding the values are handled in specific types.
 */
public class Values extends ASN1Object {
    private final ASN1Object[] array;

    /**
     * EFFECT: Initialize the list with the given tag, parentTag, and array. For tag and parentTag, consult
     * {@link ASN1Object}.
     * REQUIRES: All elements in the array shall be the same ASN.1 type.
     */
    public Values(Tag tag, Tag parentTag, ASN1Object[] array) {
        super(tag, parentTag);
        this.array = array;
    }

    /**
     * EFFECT: Parse the list from input DER bytes. For details on parsing, refer to {@link ASN1Object}.
     *   Throws {@link ParseException} for invalid input.
     * MODIFIES: this, encoded
     */
    public Values(BytesReader encoded, boolean hasParentTag) throws ParseException {
        super(encoded, hasParentTag);
        final List<ASN1Object> list = new ArrayList<>();
        for (int i = 0; i < getLength();) {
            int index = encoded.getIndex();
            final ASN1Object value = ASN1Object.parse(encoded, false);
            list.add(value);
            index = encoded.getIndex() - index;
            i += index;
        }
        this.array = list.toArray(new ASN1Object[0]);
    }

    /**
     * EFFECTS: Encode the SET OF into DER, keep order. Values will be encoded one-by-one.
     */
    @Override
    public Byte[] encodeValueDER() {
        return Stream.of(array)
                .map(Encodable::encodeDER)
                .flatMap(Arrays::stream)
                .toArray(Byte[]::new);
    }

    public ASN1Object[] getArray() {
        return array;
    }
}