package launcher.hasher;

import java.io.IOException;
import java.nio.file.Path;
import java.util.Arrays;

import launcher.LauncherAPI;
import launcher.helper.IOHelper;
import launcher.helper.SecurityHelper;
import launcher.helper.SecurityHelper.DigestAlgorithm;
import launcher.helper.VerifyHelper;
import launcher.serialize.HInput;
import launcher.serialize.HOutput;

public final class HashedFile extends HashedEntry {
    public static final DigestAlgorithm DIGEST_ALGO = DigestAlgorithm.MD5;

    // Instance
    @LauncherAPI public final long size;
    private final byte[] digest;

    @LauncherAPI
    public HashedFile(long size, byte[] digest) {
        this.size = VerifyHelper.verifyLong(size, VerifyHelper.L_NOT_NEGATIVE, "Illegal size: " + size);
        this.digest = DIGEST_ALGO.verify(digest).clone();
    }

    @LauncherAPI
    public HashedFile(Path file, long size, boolean digest) throws IOException {
        this(size, digest ? SecurityHelper.digest(DIGEST_ALGO, file) : null);
    }

    @LauncherAPI
    public HashedFile(HInput input) throws IOException {
        this(input.readVarLong(), input.readBoolean() ? input.readByteArray(-DIGEST_ALGO.bytes) : null);
    }

    @Override
    public Type getType() {
        return Type.FILE;
    }

    @Override
    public long size() {
        return size;
    }

    @Override
    public void write(HOutput output) throws IOException {
        output.writeVarLong(size);
        output.writeBoolean(digest != null);
        if (digest != null) {
            output.writeByteArray(digest, -DIGEST_ALGO.bytes);
        }
    }

    @LauncherAPI
    public boolean isSame(HashedFile o) {
        return size == o.size && (digest == null || o.digest == null || Arrays.equals(digest, o.digest));
    }

    @LauncherAPI
    public boolean isSame(Path file, boolean digest) throws IOException {
        if (size != IOHelper.readAttributes(file).size()) {
            return false;
        }
        if (!digest || this.digest == null) {
            return true;
        }

        // Create digest
        byte[] actualDigest = SecurityHelper.digest(DIGEST_ALGO, file);
        return Arrays.equals(this.digest, actualDigest);
    }

    @LauncherAPI
    public boolean isSameDigest(byte[] digest) {
        return this.digest == null || digest == null || Arrays.equals(this.digest, digest);
    }
}