Improve password protection

app/src/main/java/org/koitharu/kotatsu/settings/MainSettingsFragment.kt

@@ -1,6 +1,7 @@
 package org.koitharu.kotatsu.settings
 
 import android.content.DialogInterface
+import android.content.Intent
 import android.content.SharedPreferences
 import android.os.Bundle
 import android.text.InputType
@@ -17,6 +18,7 @@ import org.koitharu.kotatsu.base.ui.dialog.TextInputDialog
 import org.koitharu.kotatsu.core.model.MangaSource
 import org.koitharu.kotatsu.core.prefs.AppSettings
 import org.koitharu.kotatsu.core.prefs.ListMode
+import org.koitharu.kotatsu.settings.protect.ProtectSetupActivity
 import org.koitharu.kotatsu.utils.ext.*
 import java.io.File
 
@@ -77,6 +79,10 @@ class MainSettingsFragment : BasePreferenceFragment(R.string.settings),
 						?: getString(R.string.not_available)
 				}
 			}
+			AppSettings.KEY_APP_PASSWORD -> {
+				findPreference<SwitchPreference>(AppSettings.KEY_PROTECT_APP)
+					?.isChecked = !settings.appPassword.isNullOrEmpty()
+			}
 		}
 	}
 
@@ -102,8 +108,10 @@ class MainSettingsFragment : BasePreferenceFragment(R.string.settings),
 				true
 			}
 			AppSettings.KEY_PROTECT_APP -> {
-				if ((preference as? SwitchPreference ?: return false).isChecked) {
-					enableAppProtection(preference)
+				val pref = (preference as? SwitchPreference ?: return false)
+				if (pref.isChecked) {
+					pref.isChecked = false
+					startActivity(Intent(preference.context, ProtectSetupActivity::class.java))
 				} else {
 					settings.appPassword = null
 				}

app/src/main/java/org/koitharu/kotatsu/settings/SettingsModule.kt

@@ -9,6 +9,7 @@ import org.koitharu.kotatsu.core.backup.RestoreRepository
 import org.koitharu.kotatsu.core.prefs.AppSettings
 import org.koitharu.kotatsu.settings.backup.BackupViewModel
 import org.koitharu.kotatsu.settings.backup.RestoreViewModel
+import org.koitharu.kotatsu.settings.protect.ProtectSetupViewModel
 
 val settingsModule
 	get() = module {
@@ -19,4 +20,5 @@ val settingsModule
 
 		viewModel { BackupViewModel(get(), androidContext()) }
 		viewModel { (uri: Uri?) -> RestoreViewModel(uri, get(), androidContext()) }
+		viewModel { ProtectSetupViewModel(get()) }
 	}

app/src/main/java/org/koitharu/kotatsu/settings/protect/ProtectSetupActivity.kt

@@ -0,0 +1,97 @@
+package org.koitharu.kotatsu.settings.protect
+
+import android.os.Bundle
+import android.text.Editable
+import android.text.TextWatcher
+import android.view.KeyEvent
+import android.view.View
+import android.view.inputmethod.EditorInfo
+import android.widget.TextView
+import androidx.core.graphics.Insets
+import androidx.core.view.isGone
+import org.koin.androidx.viewmodel.ext.android.viewModel
+import org.koitharu.kotatsu.R
+import org.koitharu.kotatsu.base.ui.BaseActivity
+import org.koitharu.kotatsu.databinding.ActivitySetupProtectBinding
+
+class ProtectSetupActivity : BaseActivity<ActivitySetupProtectBinding>(), TextWatcher,
+	View.OnClickListener, TextView.OnEditorActionListener {
+
+	private val viewModel by viewModel<ProtectSetupViewModel>()
+
+	override fun onCreate(savedInstanceState: Bundle?) {
+		super.onCreate(savedInstanceState)
+		setContentView(ActivitySetupProtectBinding.inflate(layoutInflater))
+		binding.editPassword.addTextChangedListener(this)
+		binding.editPassword.setOnEditorActionListener(this)
+		binding.buttonNext.setOnClickListener(this)
+		binding.buttonCancel.setOnClickListener(this)
+
+		viewModel.isSecondStep.observe(this, this::onStepChanged)
+		viewModel.onPasswordSet.observe(this) {
+			finishAfterTransition()
+		}
+		viewModel.onPasswordMismatch.observe(this) {
+			binding.editPassword.error = getString(R.string.passwords_mismatch)
+		}
+		viewModel.onClearText.observe(this) {
+			binding.editPassword.text?.clear()
+		}
+	}
+
+	override fun onWindowInsetsChanged(insets: Insets) {
+		val basePadding = resources.getDimensionPixelOffset(R.dimen.screen_padding)
+		binding.root.setPadding(
+			basePadding + insets.left,
+			basePadding + insets.top,
+			basePadding + insets.right,
+			basePadding + insets.bottom
+		)
+	}
+
+	override fun onClick(v: View) {
+		when (v.id) {
+			R.id.button_cancel -> finish()
+			R.id.button_next -> viewModel.onNextClick(
+				password = binding.editPassword.text?.toString() ?: return
+			)
+		}
+	}
+
+	override fun onEditorAction(v: TextView?, actionId: Int, event: KeyEvent?): Boolean {
+		return if (actionId == EditorInfo.IME_ACTION_DONE && binding.buttonNext.isEnabled) {
+			binding.buttonNext.performClick()
+			true
+		} else {
+			false
+		}
+	}
+
+	override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, after: Int) = Unit
+
+	override fun onTextChanged(s: CharSequence?, start: Int, before: Int, count: Int) = Unit
+
+	override fun afterTextChanged(s: Editable?) {
+		binding.editPassword.error = null
+		val isEnoughLength = (s?.length ?: 0) >= MIN_PASSWORD_LENGTH
+		binding.buttonNext.isEnabled = isEnoughLength
+		binding.layoutPassword.isHelperTextEnabled =
+			!isEnoughLength || viewModel.isSecondStep.value == true
+	}
+
+	private fun onStepChanged(isSecondStep: Boolean) {
+		binding.buttonCancel.isGone = isSecondStep
+		if (isSecondStep) {
+			binding.layoutPassword.helperText = getString(R.string.repeat_password)
+			binding.buttonNext.setText(R.string.confirm)
+		} else {
+			binding.layoutPassword.helperText = getString(R.string.password_length_hint)
+			binding.buttonNext.setText(R.string.next)
+		}
+	}
+
+	private companion object {
+
+		const val MIN_PASSWORD_LENGTH = 4
+	}
+}

app/src/main/java/org/koitharu/kotatsu/settings/protect/ProtectSetupViewModel.kt

@@ -0,0 +1,38 @@
+package org.koitharu.kotatsu.settings.protect
+
+import androidx.lifecycle.viewModelScope
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.map
+import org.koitharu.kotatsu.base.ui.BaseViewModel
+import org.koitharu.kotatsu.core.prefs.AppSettings
+import org.koitharu.kotatsu.utils.SingleLiveEvent
+import org.koitharu.kotatsu.utils.ext.asLiveDataDistinct
+import org.koitharu.kotatsu.utils.ext.md5
+
+class ProtectSetupViewModel(
+	private val settings: AppSettings
+) : BaseViewModel() {
+
+	private val firstPassword = MutableStateFlow<String?>(null)
+
+	val isSecondStep = firstPassword.map {
+		it != null
+	}.asLiveDataDistinct(viewModelScope.coroutineContext)
+	val onPasswordSet = SingleLiveEvent<Unit>()
+	val onPasswordMismatch = SingleLiveEvent<Unit>()
+	val onClearText = SingleLiveEvent<Unit>()
+
+	fun onNextClick(password: String) {
+		if (firstPassword.value == null) {
+			firstPassword.value = password
+			onClearText.call(Unit)
+		} else {
+			if (firstPassword.value == password) {
+				settings.appPassword = password.md5()
+				onPasswordSet.call(Unit)
+			} else {
+				onPasswordMismatch.call(Unit)
+			}
+		}
+	}
+}