package eu.siacs.conversations.crypto;

import android.app.PendingIntent;
import android.content.Intent;
import android.util.Log;
import androidx.annotation.StringRes;
import com.google.common.base.Joiner;
import com.google.common.base.Splitter;
import com.google.common.base.Strings;
import eu.siacs.conversations.Config;
import eu.siacs.conversations.R;
import eu.siacs.conversations.entities.Account;
import eu.siacs.conversations.entities.Contact;
import eu.siacs.conversations.entities.Conversation;
import eu.siacs.conversations.entities.DownloadableFile;
import eu.siacs.conversations.entities.Message;
import eu.siacs.conversations.persistance.FileBackend;
import eu.siacs.conversations.services.XmppConnectionService;
import eu.siacs.conversations.ui.UiCallback;
import eu.siacs.conversations.utils.AsciiArmor;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import org.openintents.openpgp.OpenPgpError;
import org.openintents.openpgp.OpenPgpSignatureResult;
import org.openintents.openpgp.util.OpenPgpApi;
import org.openintents.openpgp.util.OpenPgpApi.IOpenPgpCallback;

public class PgpEngine {
    private final OpenPgpApi api;
    private final XmppConnectionService mXmppConnectionService;

    public PgpEngine(OpenPgpApi api, XmppConnectionService service) {
        this.api = api;
        this.mXmppConnectionService = service;
    }

    private static void logError(Account account, OpenPgpError error) {
        if (error != null) {
            error.describeContents();
            Log.d(
                    Config.LOGTAG,
                    account.getJid().asBareJid().toString()
                            + ": OpenKeychain error '"
                            + error.getMessage()
                            + "' code="
                            + error.getErrorId()
                            + " class="
                            + error.getClass().getName());
        } else {
            Log.d(
                    Config.LOGTAG,
                    account.getJid().asBareJid().toString()
                            + ": OpenKeychain error with no message");
        }
    }

    public void encrypt(final Message message, final UiCallback<Message> callback) {
        Intent params = new Intent();
        params.setAction(OpenPgpApi.ACTION_ENCRYPT);
        final Conversation conversation = (Conversation) message.getConversation();
        if (conversation.getMode() == Conversation.MODE_SINGLE) {
            long[] keys = {
                conversation.getContact().getPgpKeyId(), conversation.getAccount().getPgpId()
            };
            params.putExtra(OpenPgpApi.EXTRA_KEY_IDS, keys);
        } else {
            params.putExtra(OpenPgpApi.EXTRA_KEY_IDS, conversation.getMucOptions().getPgpKeyIds());
        }

        if (!message.needsUploading()) {
            params.putExtra(OpenPgpApi.EXTRA_REQUEST_ASCII_ARMOR, true);
            String body;
            if (message.hasFileOnRemoteHost()) {
                body = message.getFileParams().url;
            } else {
                body = message.getBody();
            }
            InputStream is = new ByteArrayInputStream(body.getBytes());
            final OutputStream os = new ByteArrayOutputStream();
            api.executeApiAsync(
                    params,
                    is,
                    os,
                    result -> {
                        switch (result.getIntExtra(
                                OpenPgpApi.RESULT_CODE, OpenPgpApi.RESULT_CODE_ERROR)) {
                            case OpenPgpApi.RESULT_CODE_SUCCESS:
                                try {
                                    os.flush();
                                    final ArrayList<String> encryptedMessageBody =
                                            new ArrayList<>();
                                    final String[] lines = os.toString().split("\n");
                                    for (int i = 2; i < lines.length - 1; ++i) {
                                        if (!lines[i].contains("Version")) {
                                            encryptedMessageBody.add(lines[i].trim());
                                        }
                                    }
                                    message.setEncryptedBody(
                                            Joiner.on('\n').join(encryptedMessageBody));
                                    message.setEncryption(Message.ENCRYPTION_DECRYPTED);
                                    mXmppConnectionService.sendMessage(message);
                                    callback.success(message);
                                } catch (IOException e) {
                                    callback.error(R.string.openpgp_error, message);
                                }

                                break;
                            case OpenPgpApi.RESULT_CODE_USER_INTERACTION_REQUIRED:
                                callback.userInputRequired(
                                        result.getParcelableExtra(OpenPgpApi.RESULT_INTENT),
                                        message);
                                break;
                            case OpenPgpApi.RESULT_CODE_ERROR:
                                OpenPgpError error =
                                        result.getParcelableExtra(OpenPgpApi.RESULT_ERROR);
                                String errorMessage = error != null ? error.getMessage() : null;
                                @StringRes final int res;
                                if (errorMessage != null
                                        && errorMessage.startsWith("Bad key for encryption")) {
                                    res = R.string.bad_key_for_encryption;
                                } else {
                                    res = R.string.openpgp_error;
                                }
                                logError(conversation.getAccount(), error);
                                callback.error(res, message);
                                break;
                        }
                    });
        } else {
            try {
                DownloadableFile inputFile =
                        this.mXmppConnectionService.getFileBackend().getFile(message, true);
                DownloadableFile outputFile =
                        this.mXmppConnectionService.getFileBackend().getFile(message, false);
                outputFile.getParentFile().mkdirs();
                outputFile.createNewFile();
                final InputStream is = new FileInputStream(inputFile);
                final OutputStream os = new FileOutputStream(outputFile);
                api.executeApiAsync(
                        params,
                        is,
                        os,
                        result -> {
                            switch (result.getIntExtra(
                                    OpenPgpApi.RESULT_CODE, OpenPgpApi.RESULT_CODE_ERROR)) {
                                case OpenPgpApi.RESULT_CODE_SUCCESS:
                                    try {
                                        os.flush();
                                    } catch (IOException ignored) {
                                        // ignored
                                    }
                                    FileBackend.close(os);
                                    mXmppConnectionService.sendMessage(message);
                                    callback.success(message);
                                    break;
                                case OpenPgpApi.RESULT_CODE_USER_INTERACTION_REQUIRED:
                                    callback.userInputRequired(
                                            result.getParcelableExtra(OpenPgpApi.RESULT_INTENT),
                                            message);
                                    break;
                                case OpenPgpApi.RESULT_CODE_ERROR:
                                    logError(
                                            conversation.getAccount(),
                                            result.getParcelableExtra(OpenPgpApi.RESULT_ERROR));
                                    callback.error(R.string.openpgp_error, message);
                                    break;
                            }
                        });
            } catch (final IOException e) {
                callback.error(R.string.openpgp_error, message);
            }
        }
    }

    public long fetchKeyId(final Account account, final String status, final String signature) {
        if (signature == null || api == null) {
            return 0;
        }
        final Intent params = new Intent();
        params.setAction(OpenPgpApi.ACTION_DECRYPT_VERIFY);
        try {
            params.putExtra(OpenPgpApi.RESULT_DETACHED_SIGNATURE, AsciiArmor.decode(signature));
        } catch (final Exception e) {
            Log.d(Config.LOGTAG, "unable to parse signature", e);
            return 0;
        }
        final InputStream is = new ByteArrayInputStream(Strings.nullToEmpty(status).getBytes());
        final ByteArrayOutputStream os = new ByteArrayOutputStream();
        final Intent result = api.executeApi(params, is, os);
        switch (result.getIntExtra(OpenPgpApi.RESULT_CODE, OpenPgpApi.RESULT_CODE_ERROR)) {
            case OpenPgpApi.RESULT_CODE_SUCCESS:
                final OpenPgpSignatureResult sigResult =
                        result.getParcelableExtra(OpenPgpApi.RESULT_SIGNATURE);
                // TODO unsure that sigResult.getResult() is either 1, 2 or 3
                if (sigResult != null) {
                    return sigResult.getKeyId();
                } else {
                    return 0;
                }
            case OpenPgpApi.RESULT_CODE_USER_INTERACTION_REQUIRED:
                return 0;
            case OpenPgpApi.RESULT_CODE_ERROR:
                logError(account, result.getParcelableExtra(OpenPgpApi.RESULT_ERROR));
                return 0;
        }
        return 0;
    }

    public void chooseKey(final Account account, final UiCallback<Account> callback) {
        Intent p = new Intent();
        p.setAction(OpenPgpApi.ACTION_GET_SIGN_KEY_ID);
        api.executeApiAsync(
                p,
                null,
                null,
                result -> {
                    switch (result.getIntExtra(OpenPgpApi.RESULT_CODE, 0)) {
                        case OpenPgpApi.RESULT_CODE_SUCCESS:
                            callback.success(account);
                            return;
                        case OpenPgpApi.RESULT_CODE_USER_INTERACTION_REQUIRED:
                            callback.userInputRequired(
                                    result.getParcelableExtra(OpenPgpApi.RESULT_INTENT), account);
                            return;
                        case OpenPgpApi.RESULT_CODE_ERROR:
                            logError(account, result.getParcelableExtra(OpenPgpApi.RESULT_ERROR));
                            callback.error(R.string.openpgp_error, account);
                    }
                });
    }

    public void generateSignature(
            Intent intent,
            final Account account,
            String status,
            final UiCallback<String> callback) {
        if (account.getPgpId() == 0) {
            return;
        }
        Intent params = intent == null ? new Intent() : intent;
        params.setAction(OpenPgpApi.ACTION_CLEARTEXT_SIGN);
        params.putExtra(OpenPgpApi.EXTRA_REQUEST_ASCII_ARMOR, true);
        params.putExtra(OpenPgpApi.EXTRA_SIGN_KEY_ID, account.getPgpId());
        InputStream is = new ByteArrayInputStream(status.getBytes());
        final OutputStream os = new ByteArrayOutputStream();
        Log.d(
                Config.LOGTAG,
                account.getJid().asBareJid() + ": signing status message \"" + status + "\"");
        api.executeApiAsync(
                params,
                is,
                os,
                result -> {
                    switch (result.getIntExtra(OpenPgpApi.RESULT_CODE, 0)) {
                        case OpenPgpApi.RESULT_CODE_SUCCESS:
                            final ArrayList<String> signature = new ArrayList<>();
                            try {
                                os.flush();
                                boolean sig = false;
                                for (final String line : Splitter.on('\n').split(os.toString())) {
                                    if (sig) {
                                        if (line.contains("END PGP SIGNATURE")) {
                                            sig = false;
                                        } else {
                                            if (!line.contains("Version")) {
                                                signature.add(line.trim());
                                            }
                                        }
                                    }
                                    if (line.contains("BEGIN PGP SIGNATURE")) {
                                        sig = true;
                                    }
                                }
                            } catch (IOException e) {
                                callback.error(R.string.openpgp_error, null);
                                return;
                            }
                            callback.success(Joiner.on('\n').join(signature));
                            return;
                        case OpenPgpApi.RESULT_CODE_USER_INTERACTION_REQUIRED:
                            callback.userInputRequired(
                                    result.getParcelableExtra(OpenPgpApi.RESULT_INTENT), status);
                            return;
                        case OpenPgpApi.RESULT_CODE_ERROR:
                            OpenPgpError error = result.getParcelableExtra(OpenPgpApi.RESULT_ERROR);
                            if (error != null
                                    && "signing subkey not found!".equals(error.getMessage())) {
                                callback.error(0, null);
                            } else {
                                logError(account, error);
                                callback.error(R.string.unable_to_connect_to_keychain, null);
                            }
                    }
                });
    }

    public void hasKey(final Contact contact, final UiCallback<Contact> callback) {
        Intent params = new Intent();
        params.setAction(OpenPgpApi.ACTION_GET_KEY);
        params.putExtra(OpenPgpApi.EXTRA_KEY_ID, contact.getPgpKeyId());
        api.executeApiAsync(
                params,
                null,
                null,
                new IOpenPgpCallback() {

                    @Override
                    public void onReturn(Intent result) {
                        switch (result.getIntExtra(OpenPgpApi.RESULT_CODE, 0)) {
                            case OpenPgpApi.RESULT_CODE_SUCCESS:
                                callback.success(contact);
                                return;
                            case OpenPgpApi.RESULT_CODE_USER_INTERACTION_REQUIRED:
                                callback.userInputRequired(
                                        result.getParcelableExtra(OpenPgpApi.RESULT_INTENT),
                                        contact);
                                return;
                            case OpenPgpApi.RESULT_CODE_ERROR:
                                logError(
                                        contact.getAccount(),
                                        result.getParcelableExtra(OpenPgpApi.RESULT_ERROR));
                                callback.error(R.string.openpgp_error, contact);
                        }
                    }
                });
    }

    public PendingIntent getIntentForKey(long pgpKeyId) {
        Intent params = new Intent();
        params.setAction(OpenPgpApi.ACTION_GET_KEY);
        params.putExtra(OpenPgpApi.EXTRA_KEY_ID, pgpKeyId);
        final ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        final ByteArrayInputStream inputStream = new ByteArrayInputStream(new byte[0]);
        Intent result = api.executeApi(params, inputStream, outputStream);
        return result.getParcelableExtra(OpenPgpApi.RESULT_INTENT);
    }
}