Theming improvements (#502)

* Split theme definitions into day and night

* Add support for Night Mode in code

* Add theme chooser in preferences

* Fix translations

* Adjust IDs

* Adjust preferences for custom themes

* UI tweaks for custom theme support

* Added code for custom theme support 🍅

* Fixed resource display in Kotlin 🍅

* Restored styles

* Updated strings

* Fixed getIdentifier() to fit into setTheme()

* Removed redundant resources

* Reset default theme to "Dusky"

* Fixed night mode handler to maintain compatibility

* Refactor functions to use helper methods

* Added license block

* Added preview to theme selector

* Added color identifier getter helper method

* Fixed reference in AccountMediaFragment

* Cleanup

* Fixed navbar foreground not changing color

* Fix fallback theme switch(){}

* Enable location-based daylight trigger

* Cleanup

* Modified theming strategy to reduce clutter in preferences

* Updated translations for latest version

* Removed "Default" theme flavor from settings

* Updated Polish translations 🇵🇱

* Modified TwilightManager handling code to support Android M's UiModeManager features and moved it to its own function

* Updated Polish translations 🇵🇱

* Cleanup; Fixed hardcoded string

* Added missing escape in string

* Removed permission request dialog.

As we now use native UiModeManager APIs that don't need special permission for Android 6.0 and above, we no longer need to bother user with Android M+ specific location permission request dialog.

* Increased readability of ThemeUtil class

* Refactored ThemeUtils.setAppNightMode method

* Cleanup

app/src/main/java/com/keylesspalace/tusky/util/ThemeUtils.java

@@ -15,22 +15,35 @@
 
 package com.keylesspalace.tusky.util;
 
+import android.app.UiModeManager;
 import android.content.Context;
 import android.graphics.Color;
 import android.graphics.PorterDuff;
 import android.graphics.drawable.Drawable;
+import android.os.Build;
 import android.support.annotation.AttrRes;
 import android.support.annotation.ColorInt;
+import android.support.annotation.ColorRes;
 import android.support.annotation.DrawableRes;
 import android.support.v4.content.ContextCompat;
+import android.support.v7.app.AppCompatDelegate;
 import android.util.TypedValue;
 import android.widget.ImageView;
 
+import com.keylesspalace.tusky.TuskyApplication;
+
 /**
  * Provides runtime compatibility to obtain theme information and re-theme views, especially where
  * the ability to do so is not supported in resource files.
  */
 public class ThemeUtils {
+    public static final String THEME_MODE_PREFER = "prefer";
+    public static final String THEME_MODE_ONLY = "only";
+    public static final String THEME_FLAVOR_NIGHT = "night";
+    public static final String THEME_FLAVOR_DAY = "day";
+    public static final String THEME_FLAVOR_AUTO = "auto";
+    public static final String THEME_FLAVOR_DEFAULT = "preferred";
+
     public static Drawable getDrawable(Context context, @AttrRes int attribute,
             @DrawableRes int fallbackDrawable) {
         TypedValue value = new TypedValue();
@@ -62,6 +75,17 @@ public class ThemeUtils {
         }
     }
 
+    public static @ColorRes int getColorId(Context context, @AttrRes int attribute) {
+        TypedValue value = new TypedValue();
+        context.getTheme().resolveAttribute(attribute, value, true);
+        return value.resourceId;
+    }
+
+    public static @ColorInt int getColorById(Context context, String name) {
+        return getColor(context,
+                ResourcesUtils.getResourceIdentifier(context, "attr", name));
+    }
+
     public static void setImageViewTint(ImageView view, @AttrRes int attribute) {
         view.setColorFilter(getColor(view.getContext(), attribute), PorterDuff.Mode.SRC_IN);
     }
@@ -69,4 +93,29 @@ public class ThemeUtils {
     public static void setDrawableTint(Context context, Drawable drawable, @AttrRes int attribute) {
         drawable.setColorFilter(getColor(context, attribute), PorterDuff.Mode.SRC_IN);
     }
+
+    public static boolean setAppNightMode(String flavor) {
+        int mode;
+        switch (flavor) {
+            case THEME_FLAVOR_AUTO:
+                mode = UiModeManager.MODE_NIGHT_AUTO;
+                break;
+            case THEME_FLAVOR_NIGHT:
+                mode = UiModeManager.MODE_NIGHT_YES;
+                break;
+            case THEME_FLAVOR_DAY:
+                mode = UiModeManager.MODE_NIGHT_NO;
+                break;
+            default:
+                return false;
+        }
+
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+            TuskyApplication.getUiModeManager().setNightMode(mode);
+        } else {
+            AppCompatDelegate.setDefaultNightMode(mode);
+        }
+
+        return true;
+    }
 }