package model.asn1.parsing;

import model.asn1.Tag;
import model.asn1.TagClass;
import model.asn1.exceptions.ParseException;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;

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

public class BytesReaderTest {
    private BytesReader target;

    @BeforeEach
    void setup() {
        target = new BytesReader(new Byte[]{ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 });
    }

    @Test
    void testConstructor() {
        assertEquals(0, target.getIndex());
        assertEquals(10, target.getRawInput().length);
        assertArrayEquals(new Byte[]{ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }, target.getRawInput());
    }

    @Test
    void testBytesRemaining() {
        assertEquals(10, target.bytesRemaining());
        target.read(5, true);
        assertEquals(5, target.bytesRemaining());
    }

    @Test
    void testRead() {
        assertEquals(10, target.bytesRemaining());
        assertEquals(0, target.getIndex());
        assertArrayEquals(new Byte[]{ 1, 2 }, target.read(2, true));
        assertEquals(8, target.bytesRemaining());
        assertEquals(2, target.getIndex());
        assertArrayEquals(new Byte[]{ 3 }, target.read(1, false));
        assertEquals(8, target.bytesRemaining());
        assertEquals(2, target.getIndex());
        assertArrayEquals(new Byte[]{ 3, 4, 5, 6, 7 }, target.read(5, true));
        assertEquals(3, target.bytesRemaining());
        assertEquals(7, target.getIndex());
        assertArrayEquals(new Byte[]{ 8, 9, 10 }, target.read(3, false));
        assertEquals(3, target.bytesRemaining());
        assertEquals(7, target.getIndex());
        assertArrayEquals(new Byte[]{ 8, 9, 10 }, target.read(3, true));
        assertEquals(0, target.bytesRemaining());
        assertEquals(10, target.getIndex());
    }

    @Test
    void testRequire() throws Exception { // TODO: Exception testing
        assertEquals(10, target.bytesRemaining());
        assertEquals(0, target.getIndex());
        assertArrayEquals(new Byte[]{ 1, 2 }, target.require(2, true));
        assertArrayEquals(new Byte[]{ 3, 4, 5, 6, 7, 8, 9 }, target.require(7, true));
        assertArrayEquals(new Byte[]{ 10 }, target.require(1, false));
        assertThrows(ParseException.class, () -> target.require(2, true));
        assertArrayEquals(new Byte[]{ 10 }, target.require(1, true));
        assertThrows(ParseException.class, () -> target.require(1, true));
    }

    @Test
    void testValidateSize() throws Exception { // TODO: Exception testing
        assertEquals(10, target.bytesRemaining());
        assertEquals(0, target.getIndex());
        assertArrayEquals(new Byte[]{ 1, 2 }, target.require(2, true));
        assertArrayEquals(new Byte[]{ 3, 4, 5, 6, 7, 8, 9 }, target.require(7, true));
        assertArrayEquals(new Byte[]{ 10 }, target.require(1, false));
        target.validateSize(1);
        assertThrows(ParseException.class, () -> target.validateSize(2));
        assertArrayEquals(new Byte[]{ 10 }, target.require(1, true));
        assertThrows(ParseException.class, () -> target.validateSize(1));
    }

    @Test
    void testDetectTag() throws Exception {
        final BytesReader reader = new BytesReader(new Byte[]{ -95, 0 });
        assertTrue(reader.detectTag(new Tag(TagClass.CONTEXT_SPECIFIC, true, 1)));
        assertFalse(reader.detectTag(new Tag(TagClass.CONTEXT_SPECIFIC, true, 0)));
        assertFalse(reader.detectTag(new Tag(TagClass.UNIVERSAL, true, 0)));
        assertFalse(reader.detectTag(new Tag(TagClass.CONTEXT_SPECIFIC, false, 0)));
    }

    @Test
    void testGetTag() throws Exception {
        BytesReader reader = new BytesReader(new Byte[]{ -95, 0 });
        assertEquals(1, reader.getTag(false).getNumber());
        reader = new BytesReader(new Byte[]{ -96, 0, -95, 0 });
        assertEquals(1, reader.getTag(true).getNumber());
    }
}