package model.x501;

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.Collectors;
import java.util.stream.Stream;

/**
 * Represents an X.501 directory Name (a.k.a. RDNSequence).
 * <pre>
 *     Name ::= CHOICE { -- only one possibility for now -- rdnSequence RDNSequence }
 *     RDNSequence ::= SEQUENCE OF RelativeDistinguishedName
 *     DistinguishedName ::= RDNSequence
 * </pre>
 */
public class Name extends ASN1Object {
    private final RelativeDistinguishedName[] rdnSequence;

    /**
     * EFFECT: Initialize the Name with the given tags and rdnSequence. For tag and parentTag, consult
     * {@link ASN1Object}.
     * REQUIRES: Items should have SET tag.
     */
    public Name(Tag tag, Tag parentTag, RelativeDistinguishedName[] rdnSequence) {
        super(tag, parentTag);
        this.rdnSequence = rdnSequence;
    }

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

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

    /**
     * EFFECT: Convert the name into directory string, like CN=yuuta,OU=users,DC=yuuta,DC=moe
     */
    @Override
    public String toString() {
        return Stream.of(rdnSequence)
                .map(RelativeDistinguishedName::toString)
                .collect(Collectors.joining(","));
    }

    public RelativeDistinguishedName[] getRdnSequence() {
        return rdnSequence;
    }
}