package model.asn1;

import model.asn1.exceptions.ParseException;
import model.asn1.parsing.BytesReader;
import org.junit.jupiter.api.Test;

import java.time.ZoneId;
import java.time.ZonedDateTime;

import static org.junit.jupiter.api.Assertions.*;

public class ASN1ObjectTest {
    @Test
    void testParseType() throws ParseException {
        assertEquals(Bool.class,
                ASN1Object.parse(new BytesReader(new Bool(Bool.TAG, null, true).encodeDER()),
                        false).getClass());
        assertEquals(Int.class,
                ASN1Object.parse(new BytesReader(new Int(Int.TAG, null, 1).encodeDER()),
                        false).getClass());
        assertEquals(BitString.class,
                ASN1Object.parse(new BytesReader(new BitString(BitString.TAG,
                                null, 0, new Byte[]{1}).encodeDER()),
                        false).getClass());
        assertEquals(OctetString.class,
                ASN1Object.parse(new BytesReader(new OctetString(OctetString.TAG, null, new Byte[]{1}).encodeDER()),
                        false).getClass());
        assertEquals(Null.class,
                ASN1Object.parse(new BytesReader(new Null(Null.TAG, null).encodeDER()),
                        false).getClass());
        assertEquals(ObjectIdentifier.class,
                ASN1Object.parse(new BytesReader(new ObjectIdentifier(ObjectIdentifier.TAG, null,
                                new Integer[]{1, 2, 3}).encodeDER()),
                        false).getClass());
        assertEquals(UTF8String.class,
                ASN1Object.parse(new BytesReader(new UTF8String(UTF8String.TAG, null,
                                "qwq").encodeDER()),
                        false).getClass());
        assertEquals(PrintableString.class,
                ASN1Object.parse(new BytesReader(new PrintableString(PrintableString.TAG, null,
                                "qwq").encodeDER()),
                        false).getClass());
        assertEquals(IA5String.class,
                ASN1Object.parse(new BytesReader(new IA5String(IA5String.TAG, null,
                                "qwq").encodeDER()),
                        false).getClass());
        assertEquals(UtcTime.class,
                ASN1Object.parse(new BytesReader(new UtcTime(UtcTime.TAG, null,
                                ZonedDateTime.now(ZoneId.of("UTC"))).encodeDER()),
                        false).getClass());
        assertEquals(GeneralizedTime.class,
                ASN1Object.parse(new BytesReader(new GeneralizedTime(GeneralizedTime.TAG, null,
                                ZonedDateTime.now(ZoneId.of("UTC"))).encodeDER()),
                        false).getClass());
        assertEquals(ASN1Object.class,
                ASN1Object.parse(new BytesReader(new Byte[]{0x30, 1, 0x0}), false)
                        .getClass());
    }

    @Test
    void testConstructor() {
        assertEquals(0, new ASN1Object(Null.TAG, null).getLength());
        assertNull(new ASN1Object(Null.TAG, null).encodeValueDER());
        assertEquals(0x5,
                new ASN1Object(new Tag(TagClass.UNIVERSAL, false, 0x5),
                        null).getTag().getNumber());
        assertEquals(0x6,
                new ASN1Object(new Tag(TagClass.UNIVERSAL, false, 0x5),
                        new Tag(TagClass.UNIVERSAL, false, 0x6)).getParentTag().getNumber());
    }

    @Test
    void testParseSuccess() throws ParseException {
        // No parent tag
        assertEquals(0x5,
                new ASN1Object(new BytesReader(new Byte[]{0x5, 0x0}), false)
                        .getTag().getNumber());
        assertEquals(TagClass.UNIVERSAL,
                new ASN1Object(new BytesReader(new Byte[]{0x5, 0x0}), false)
                        .getTag().getCls());
        assertFalse(new ASN1Object(new BytesReader(new Byte[]{0x5, 0x0}), false)
                .getTag().isConstructive());
        assertNull(new ASN1Object(new BytesReader(new Byte[]{0x5, 0x0}), false)
                .getParentTag());

        assertEquals(0, new ASN1Object(new BytesReader(new Byte[]{0x5, 0x0}), false)
                .encodeValueDER().length);
        assertEquals(0, new ASN1Object(new BytesReader(new Byte[]{0x5, 0x0}), false)
                .getLength());

        // With parent tag
        // -95 is the 2's complement represent of 0b10100001
        assertEquals(0x5,
                new ASN1Object(new BytesReader(new Byte[]{-95, 2, 0x5, 0x0}), true)
                        .getTag().getNumber());
        assertEquals(TagClass.UNIVERSAL,
                new ASN1Object(new BytesReader(new Byte[]{-95, 2, 0x5, 0x0}), true)
                        .getTag().getCls());
        assertFalse(new ASN1Object(new BytesReader(new Byte[]{-95, 2, 0x5, 0x0}), true)
                .getTag().isConstructive());
        assertEquals(0x1,
                new ASN1Object(new BytesReader(new Byte[]{-95, 2, 0x5, 0x0}), true)
                        .getParentTag().getNumber());
        assertEquals(TagClass.CONTEXT_SPECIFIC,
                new ASN1Object(new BytesReader(new Byte[]{-95, 2, 0x5, 0x0}), true)
                        .getParentTag().getCls());
        assertTrue(new ASN1Object(new BytesReader(new Byte[]{-95, 2, 0x5, 0x0}), true)
                .getParentTag().isConstructive());

        // Test index
        BytesReader reader = new BytesReader(new Byte[]{0xE, 5, 1, 2, 3, 4, 5});
        ASN1Object obj = new ASN1Object(reader, false);
        // Contents should not be read.
        assertEquals(2, reader.getIndex());
        // But is copied
        assertArrayEquals(new Byte[]{1, 2, 3, 4, 5}, obj.encodeValueDER());
        // If we parse an unknown type
        reader = new BytesReader(new Byte[]{0xE, 5, 1, 2, 3, 4, 5});
        obj = ASN1Object.parse(reader, false);
        // Contents should be read now
        assertEquals(7, reader.getIndex());
    }

    @Test
    void testParseFail() {
        // Value early EOF
        assertThrows(ParseException.class, () ->
                new ASN1Object(new BytesReader(new Byte[]{0x5, 0x1}), false));
        // Tag early EOF
        assertThrows(ParseException.class, () ->
                new ASN1Object(new BytesReader(new Byte[]{-95, 2}), true));
        // Length not found
        assertThrows(ParseException.class, () ->
                new ASN1Object(new BytesReader(new Byte[]{0x5}), false));
        assertThrows(ParseException.class, () ->
                new ASN1Object(new BytesReader(new Byte[]{-95, 2, 0x5}), true));
        // Parent tag is not CONTEXT_SPECIFIC
        // UNIVERSAL
        assertThrows(ParseException.class, () ->
                new ASN1Object(new BytesReader(new Byte[]{33, 2, 0x5, 0x0}), true));
        // APPLICATION
        assertThrows(ParseException.class, () ->
                new ASN1Object(new BytesReader(new Byte[]{97, 2, 0x5, 0x0}), true));
        // PRIVATE
        assertThrows(ParseException.class, () ->
                new ASN1Object(new BytesReader(new Byte[]{-31, 2, 0x5, 0x0}), true));
        // Parent tag is not constructive
        assertThrows(ParseException.class, () ->
                new ASN1Object(new BytesReader(new Byte[]{-127, 2, 0x5, 0x0}), true));
        // Parent tag length incorrect
        assertThrows(ParseException.class, () ->
                new ASN1Object(new BytesReader(new Byte[]{-95, 0, 0x5, 0x0}), true));
        assertThrows(ParseException.class, () ->
                new ASN1Object(new BytesReader(new Byte[]{-95, 1, 0x5, 0x0}), true));
        assertThrows(ParseException.class, () ->
                new ASN1Object(new BytesReader(new Byte[]{-95, 3, 0x5, 0x0}), true));
    }

    @Test
    void testEncode() {
        // No parent tag
        assertArrayEquals(new Byte[]{
                0x5, 0x0
        }, new Null(Null.TAG, null).encodeDER());
        // Custom tag
        assertArrayEquals(new Byte[]{
                0x72, 0x0
        }, new Null(new Tag(TagClass.APPLICATION, true, 0x12), null)
                .encodeDER());
        // With parent tag
        assertArrayEquals(new Byte[]{
                -95, 2,
                0x72, 0x0
        }, new Null(new Tag(TagClass.APPLICATION, true, 0x12),
                new Tag(TagClass.CONTEXT_SPECIFIC, true, 0x1))
                .encodeDER());
    }
}