Confirm traffic consumption

app/src/main/java/org/koitharu/kotatsu/core/prefs/AppSettings.kt

@@ -37,6 +37,11 @@ class AppSettings private constructor(resources: Resources, private val prefs: S
 		setOf(PAGE_SWITCH_TAPS)
 	)
 
+	var isTrafficWarningEnabled by BoolPreferenceDelegate(
+		resources.getString(R.string.key_traffic_warning),
+		true
+	)
+
 	private var sourcesOrderStr by NullableStringPreferenceDelegate(resources.getString(R.string.key_sources_order))
 
 	var sourcesOrder: List<Int>

app/src/main/java/org/koitharu/kotatsu/ui/common/dialog/CheckBoxAlertDialog.kt

@@ -0,0 +1,84 @@
+package org.koitharu.kotatsu.ui.common.dialog
+
+import android.annotation.SuppressLint
+import android.content.Context
+import android.content.DialogInterface
+import android.view.LayoutInflater
+import androidx.annotation.DrawableRes
+import androidx.annotation.StringRes
+import androidx.appcompat.app.AlertDialog
+import com.google.android.material.checkbox.MaterialCheckBox
+import org.koitharu.kotatsu.R
+
+class CheckBoxAlertDialog private constructor(private val delegate: AlertDialog) :
+	DialogInterface by delegate {
+
+	fun show() = delegate.show()
+
+	class Builder(context: Context) {
+
+		@SuppressLint("InflateParams")
+		private val view = LayoutInflater.from(context)
+			.inflate(R.layout.dialog_checkbox, null, false)
+		private val checkBox = view.findViewById<MaterialCheckBox>(android.R.id.checkbox)
+
+		private val delegate = AlertDialog.Builder(context)
+			.setView(view)
+
+		fun setTitle(@StringRes titleResId: Int): Builder {
+			delegate.setTitle(titleResId)
+			return this
+		}
+
+		fun setTitle(title: CharSequence): Builder {
+			delegate.setTitle(title)
+			return this
+		}
+
+		fun setMessage(@StringRes messageId: Int): Builder {
+			delegate.setMessage(messageId)
+			return this
+		}
+
+		fun setMessage(message: CharSequence): Builder {
+			delegate.setMessage(message)
+			return this
+		}
+
+		fun setCheckBoxText(@StringRes textId: Int): Builder {
+			checkBox.setText(textId)
+			return this
+		}
+
+		fun setCheckBoxChecked(isChecked: Boolean): Builder {
+			checkBox.isChecked = isChecked
+			return this
+		}
+
+		fun setIcon(@DrawableRes iconId: Int): Builder {
+			delegate.setIcon(iconId)
+			return this
+		}
+
+		fun setPositiveButton(
+			@StringRes textId: Int,
+			listener: (DialogInterface, Boolean) -> Unit
+		): Builder {
+			delegate.setPositiveButton(textId) { dialog, _ ->
+				listener(dialog, checkBox.isChecked)
+			}
+			return this
+		}
+
+		fun setNegativeButton(
+			@StringRes textId: Int,
+			listener: DialogInterface.OnClickListener? = null
+		): Builder {
+			delegate.setNegativeButton(textId, listener)
+			return this
+		}
+
+		fun create() = CheckBoxAlertDialog(delegate.create())
+
+	}
+}

app/src/main/java/org/koitharu/kotatsu/ui/download/DownloadService.kt

@@ -2,7 +2,9 @@ package org.koitharu.kotatsu.ui.download
 
 import android.content.Context
 import android.content.Intent
+import android.net.ConnectivityManager
 import android.webkit.MimeTypeMap
+import androidx.appcompat.app.AlertDialog
 import androidx.core.content.ContextCompat
 import coil.Coil
 import coil.api.get
@@ -13,11 +15,14 @@ import kotlinx.coroutines.withContext
 import okhttp3.OkHttpClient
 import okhttp3.Request
 import org.koin.core.inject
+import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.core.local.PagesCache
 import org.koitharu.kotatsu.core.model.Manga
+import org.koitharu.kotatsu.core.prefs.AppSettings
 import org.koitharu.kotatsu.domain.MangaProviderFactory
 import org.koitharu.kotatsu.domain.local.MangaZip
 import org.koitharu.kotatsu.ui.common.BaseService
+import org.koitharu.kotatsu.ui.common.dialog.CheckBoxAlertDialog
 import org.koitharu.kotatsu.utils.CacheUtils
 import org.koitharu.kotatsu.utils.ext.await
 import org.koitharu.kotatsu.utils.ext.retryUntilSuccess
@@ -144,12 +149,34 @@ class DownloadService : BaseService() {
 		private const val EXTRA_CHAPTERS_IDS = "chapters_ids"
 
 		fun start(context: Context, manga: Manga, chaptersIds: Collection<Long>? = null) {
-			val intent = Intent(context, DownloadService::class.java)
-			intent.putExtra(EXTRA_MANGA, manga)
-			if (chaptersIds != null) {
-				intent.putExtra(EXTRA_CHAPTERS_IDS, chaptersIds.toLongArray())
+			confirmDataTransfer(context) {
+				val intent = Intent(context, DownloadService::class.java)
+				intent.putExtra(EXTRA_MANGA, manga)
+				if (chaptersIds != null) {
+					intent.putExtra(EXTRA_CHAPTERS_IDS, chaptersIds.toLongArray())
+				}
+				ContextCompat.startForegroundService(context, intent)
+			}
+		}
+
+		private fun confirmDataTransfer(context: Context, callback: () -> Unit) {
+			val cm = context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
+			val settings = AppSettings(context)
+			if (cm.isActiveNetworkMetered && settings.isTrafficWarningEnabled) {
+				CheckBoxAlertDialog.Builder(context)
+					.setTitle(R.string.warning)
+					.setMessage(R.string.network_consumption_warning)
+					.setCheckBoxText(R.string.dont_ask_again)
+					.setCheckBoxChecked(false)
+					.setNegativeButton(android.R.string.cancel, null)
+					.setPositiveButton(R.string._continue) { _, doNotAsk ->
+						settings.isTrafficWarningEnabled = !doNotAsk
+						callback()
+					}.create()
+					.show()
+			} else {
+				callback()
 			}
-			ContextCompat.startForegroundService(context, intent)
 		}
 	}
 }