package eu.siacs.conversations.crypto;

import android.app.PendingIntent;
import android.content.Intent;
import androidx.annotation.StringRes;
import android.util.Log;

import org.openintents.openpgp.OpenPgpError;
import org.openintents.openpgp.OpenPgpSignatureResult;
import org.openintents.openpgp.util.OpenPgpApi;
import org.openintents.openpgp.util.OpenPgpApi.IOpenPgpCallback;

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 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;

public class PgpEngine {
	private OpenPgpApi api;
	private 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.toString();
			} 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();
							StringBuilder encryptedMessageBody = new StringBuilder();
							String[] lines = os.toString().split("\n");
							for (int i = 2; i < lines.length - 1; ++i) {
								if (!lines[i].contains("Version")) {
									encryptedMessageBody.append(lines[i].trim());
								}
							}
							message.setEncryptedBody(encryptedMessageBody.toString());
							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(Account account, String status, String signature) {
		if ((signature == null) || (api == null)) {
			return 0;
		}
		if (status == null) {
			status = "";
		}
		final StringBuilder pgpSig = new StringBuilder();
		pgpSig.append("-----BEGIN PGP SIGNED MESSAGE-----");
		pgpSig.append('\n');
		pgpSig.append('\n');
		pgpSig.append(status);
		pgpSig.append('\n');
		pgpSig.append("-----BEGIN PGP SIGNATURE-----");
		pgpSig.append('\n');
		pgpSig.append('\n');
		pgpSig.append(signature.replace("\n", "").trim());
		pgpSig.append('\n');
		pgpSig.append("-----END PGP SIGNATURE-----");
		Intent params = new Intent();
		params.setAction(OpenPgpApi.ACTION_DECRYPT_VERIFY);
		params.putExtra(OpenPgpApi.EXTRA_REQUEST_ASCII_ARMOR, true);
		InputStream is = new ByteArrayInputStream(pgpSig.toString().getBytes());
		ByteArrayOutputStream os = new ByteArrayOutputStream();
		Intent result = api.executeApi(params, is, os);
		switch (result.getIntExtra(OpenPgpApi.RESULT_CODE,
				OpenPgpApi.RESULT_CODE_ERROR)) {
			case OpenPgpApi.RESULT_CODE_SUCCESS:
				OpenPgpSignatureResult sigResult = result
						.getParcelableExtra(OpenPgpApi.RESULT_SIGNATURE);
				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:
					StringBuilder signatureBuilder = new StringBuilder();
					try {
						os.flush();
						String[] lines = os.toString().split("\n");
						boolean sig = false;
						for (String line : lines) {
							if (sig) {
								if (line.contains("END PGP SIGNATURE")) {
									sig = false;
								} else {
									if (!line.contains("Version")) {
										signatureBuilder.append(line.trim());
									}
								}
							}
							if (line.contains("BEGIN PGP SIGNATURE")) {
								sig = true;
							}
						}
					} catch (IOException e) {
						callback.error(R.string.openpgp_error, null);
						return;
					}
					callback.success(signatureBuilder.toString());
					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);
		Intent result = api.executeApi(params, null, null);
		return (PendingIntent) result.getParcelableExtra(OpenPgpApi.RESULT_INTENT);
	}
}