package model.x501;

import annotations.Assoc;
import model.asn1.ASN1Object;
import model.asn1.ObjectIdentifier;
import model.asn1.Tag;
import model.asn1.exceptions.ParseException;
import model.asn1.parsing.BytesReader;

import java.util.Arrays;
import java.util.Collection;
import java.util.stream.Stream;

/**
 * Implements the following:
 * <pre>
 *   AttributeTypeAndValue ::= SEQUENCE {
 *       type ATTRIBUTE.&id({SupportedAttributes}),
 *       value ATTRIBUTE.&Type({SupportedAttributes}{@type}),
 *   ... }
 * </pre>
 */
public class AttributeTypeAndValue extends ASN1Object {
    /**
     * The type of that attribute. For example, <pre>2.5.4.10</pre> is OU.
     * It determines the format of the value.
     */
    @Assoc(partOf = true)
    private final ObjectIdentifier type;

    /**
     * Value corresponding to type.
     */
    @Assoc(partOf = true)
    private final ASN1Object value;

    /**
     * EFFECT: Init the object with tag, parentTag, type, and values. For tag and parentTag, see {@link ASN1Object}.
     * REQUIRES: The values must match the type. Type tag should be UNIVERSAL OID.
     */
    public AttributeTypeAndValue(Tag tag, Tag parentTag,
                                 ObjectIdentifier type, ASN1Object value) {
        super(tag, parentTag);
        this.type = type;
        this.value = value;
    }

    /**
     * EFFECTS: Parse input DER. Value is not checked against the type.
     * Throws {@link ASN1Object} if invalid:
     * - Any fields missing
     * - Any fields having an incorrect tag (as seen in the ASN.1 definition)
     * - Any fields with encoding instructions that violate implicit / explicit encoding rules
     * - Other issues found during parsing the object, like early EOF (see {@link ASN1Object})
     * MODIFIES: this, encoded
     */
    public AttributeTypeAndValue(BytesReader encoded, boolean hasParentTag) throws ParseException {
        super(encoded, hasParentTag);
        this.type = new ObjectIdentifier(encoded, false);
        this.type.getTag().enforce(ObjectIdentifier.TAG);

        this.value = ASN1Object.parse(encoded, false);
    }

    /**
     * EFFECTS: Encode the fields into DER, in the order.
     */
    @Override
    public Byte[] encodeValueDER() {
        return Stream.of(Arrays.asList(type.encodeDER()),
                        Arrays.asList(value.encodeDER()))
                .flatMap(Collection::stream)
                .toArray(Byte[]::new);
    }

    /**
     * EFFECTS: Return in TYPE=Value format. Type will be either x.x.x.x.x or human-readable strings like CN. Value is
     * input-defined. ',' '+' '=' will be escaped.
     */
    @Override
    public String toString() {
        return type.toString().replace(",", "\\,")
                .replace("=", "\\=")
                .replace("+", "\\+")
                + "=" + value.toString().replace(",", "\\,")
                .replace("=", "\\=")
                .replace("+", "\\+");
    }

    public ObjectIdentifier getType() {
        return type;
    }

    public ASN1Object getValue() {
        return value;
    }
}