package org.briarproject.android;

import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.TextInputLayout;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.KeyEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.TextView.OnEditorActionListener;

import org.briarproject.R;
import org.briarproject.android.util.AndroidUtils;
import org.briarproject.android.util.StrengthMeter;
import org.briarproject.api.android.ReferenceManager;
import org.briarproject.api.crypto.CryptoComponent;
import org.briarproject.api.crypto.CryptoExecutor;
import org.briarproject.api.crypto.KeyPair;
import org.briarproject.api.crypto.PasswordStrengthEstimator;
import org.briarproject.api.crypto.SecretKey;
import org.briarproject.api.db.DatabaseConfig;
import org.briarproject.api.identity.AuthorFactory;
import org.briarproject.api.identity.LocalAuthor;
import org.briarproject.util.StringUtils;

import java.util.concurrent.Executor;
import java.util.logging.Logger;

import javax.inject.Inject;

import static android.content.Intent.FLAG_ACTIVITY_NEW_TASK;
import static android.view.View.INVISIBLE;
import static android.view.View.VISIBLE;
import static android.view.WindowManager.LayoutParams.FLAG_SECURE;
import static java.util.logging.Level.INFO;
import static org.briarproject.android.TestingConstants.PREVENT_SCREENSHOTS;
import static org.briarproject.api.crypto.PasswordStrengthEstimator.WEAK;
import static org.briarproject.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;

public class SetupActivity extends BaseActivity implements OnClickListener,
		OnEditorActionListener {

	private static final Logger LOG =
			Logger.getLogger(SetupActivity.class.getName());

	@Inject @CryptoExecutor protected Executor cryptoExecutor;
	@Inject protected PasswordStrengthEstimator strengthEstimator;

	// Fields that are accessed from background threads must be volatile
	@Inject protected volatile CryptoComponent crypto;
	@Inject protected volatile DatabaseConfig databaseConfig;
	@Inject protected volatile AuthorFactory authorFactory;
	@Inject protected volatile ReferenceManager referenceManager;

	TextInputLayout nicknameEntryWrapper;
	TextInputLayout passwordEntryWrapper;
	TextInputLayout passwordConfirmationWrapper;
	EditText nicknameEntry;
	EditText passwordEntry;
	EditText passwordConfirmation;
	StrengthMeter strengthMeter;
	Button createAccountButton;
	ProgressBar progress;

	@Override
	public void onCreate(Bundle state) {
		super.onCreate(state);
		setContentView(R.layout.activity_setup);

		nicknameEntryWrapper = (TextInputLayout)findViewById(R.id.nickname_entry_wrapper);
		passwordEntryWrapper = (TextInputLayout)findViewById(R.id.password_entry_wrapper);
		passwordConfirmationWrapper = (TextInputLayout)findViewById(R.id.password_confirm_wrapper);
		nicknameEntry = (EditText)findViewById(R.id.nickname_entry);
		passwordEntry = (EditText)findViewById(R.id.password_entry);
		passwordConfirmation = (EditText)findViewById(R.id.password_confirm);
		strengthMeter = (StrengthMeter)findViewById(R.id.strength_meter);
		createAccountButton = (Button)findViewById(R.id.create_account);
		progress = (ProgressBar)findViewById(R.id.progress_wheel);

		if (PREVENT_SCREENSHOTS) getWindow().addFlags(FLAG_SECURE);

		TextWatcher tw = new TextWatcher() {
			@Override
			public void beforeTextChanged(CharSequence s, int start, int count,
					int after) {
			}

			@Override
			public void onTextChanged(CharSequence s, int start, int before,
					int count) {
				enableOrDisableContinueButton();
			}

			@Override
			public void afterTextChanged(Editable s) {
			}
		};

		nicknameEntry.addTextChangedListener(tw);
		passwordEntry.addTextChangedListener(tw);
		passwordConfirmation.addTextChangedListener(tw);
		passwordConfirmation.setOnEditorActionListener(this);
		createAccountButton.setOnClickListener(this);
	}

	@Override
	public void injectActivity(AndroidComponent component) {
		component.inject(this);
	}

	private void enableOrDisableContinueButton() {
		if (progress == null) return; // Not created yet
		if (passwordEntry.getText().length() > 0 && passwordEntry.hasFocus())
			strengthMeter.setVisibility(VISIBLE);
		else strengthMeter.setVisibility(INVISIBLE);
		String nickname = nicknameEntry.getText().toString();
		int nicknameLength = StringUtils.toUtf8(nickname).length;
		String firstPassword = passwordEntry.getText().toString();
		String secondPassword = passwordConfirmation.getText().toString();
		boolean passwordsMatch = firstPassword.equals(secondPassword);
		float strength = strengthEstimator.estimateStrength(firstPassword);
		strengthMeter.setStrength(strength);
		AndroidUtils.setError(nicknameEntryWrapper,
				getString(R.string.name_too_long),
				nicknameLength > MAX_AUTHOR_NAME_LENGTH);
		AndroidUtils.setError(passwordEntryWrapper,
				getString(R.string.password_too_weak),
				firstPassword.length() > 0 && strength < WEAK);
		AndroidUtils.setError(passwordConfirmationWrapper,
				getString(R.string.passwords_do_not_match),
				secondPassword.length() > 0 && !passwordsMatch);
		createAccountButton.setEnabled(nicknameLength > 0
				&& nicknameLength <= MAX_AUTHOR_NAME_LENGTH
				&& passwordsMatch && strength >= WEAK);
	}

	public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
		hideSoftKeyboard(v);
		return true;
	}

	public void onClick(View view) {
		// Replace the button with a progress bar
		createAccountButton.setVisibility(INVISIBLE);
		progress.setVisibility(VISIBLE);
		final String nickname = nicknameEntry.getText().toString();
		final String password = passwordEntry.getText().toString();
		// Store the DB key and create the identity in a background thread
		cryptoExecutor.execute(new Runnable() {
			public void run() {
				SecretKey key = crypto.generateSecretKey();
				databaseConfig.setEncryptionKey(key);
				String hex = encryptDatabaseKey(key, password);
				storeEncryptedDatabaseKey(hex);
				LocalAuthor localAuthor = createLocalAuthor(nickname);
				showDashboard(referenceManager.putReference(localAuthor,
						LocalAuthor.class));
			}
		});
	}

	private String encryptDatabaseKey(SecretKey key, String password) {
		long now = System.currentTimeMillis();
		byte[] encrypted = crypto.encryptWithPassword(key.getBytes(), password);
		long duration = System.currentTimeMillis() - now;
		if (LOG.isLoggable(INFO))
			LOG.info("Key derivation took " + duration + " ms");
		return StringUtils.toHexString(encrypted);
	}

	private LocalAuthor createLocalAuthor(String nickname) {
		long now = System.currentTimeMillis();
		KeyPair keyPair = crypto.generateSignatureKeyPair();
		byte[] publicKey = keyPair.getPublic().getEncoded();
		byte[] privateKey = keyPair.getPrivate().getEncoded();
		LocalAuthor localAuthor = authorFactory.createLocalAuthor(nickname,
				publicKey, privateKey);
		long duration = System.currentTimeMillis() - now;
		if (LOG.isLoggable(INFO))
			LOG.info("Identity creation took " + duration + " ms");
		return localAuthor;
	}

	private void showDashboard(final long handle) {
		runOnUiThread(new Runnable() {
			public void run() {
				Intent i = new Intent(SetupActivity.this,
						NavDrawerActivity.class);
				i.putExtra(BriarActivity.KEY_LOCAL_AUTHOR_HANDLE, handle);
				i.setFlags(FLAG_ACTIVITY_NEW_TASK);
				startActivity(i);
				finish();
			}
		});
	}
}