android-calculatorpp/app/src/main/java/org/solovyev/android/calculator/AppModule.java

package org.solovyev.android.calculator;

import android.app.Application;
import android.content.Context;
import android.content.SharedPreferences;
import android.graphics.Typeface;
import android.os.Handler;
import android.os.Looper;
import android.preference.PreferenceManager;
import android.util.Log;

import androidx.annotation.NonNull;

import com.squareup.otto.Bus;
import com.squareup.otto.GeneratedHandlerFinder;

import org.solovyev.android.calculator.language.Languages;
import org.solovyev.android.calculator.wizard.CalculatorWizards;
import org.solovyev.android.plotter.Plot;
import org.solovyev.android.plotter.Plotter;
import org.solovyev.android.wizard.Wizards;

import java.io.File;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.atomic.AtomicInteger;

import javax.annotation.Nonnull;
import javax.inject.Named;
import javax.inject.Singleton;

import dagger.Module;
import dagger.Provides;
import jscl.JsclMathEngine;

@Module
public class AppModule {

    // single thread, should be used during the startup
    public static final String THREAD_INIT = "thread-init";
    // UI application thread
    public static final String THREAD_UI = "thread-ui";
    // multiple threads
    public static final String THREAD_BACKGROUND = "thread-background";
    public static final String DIR_FILES = "dir-files";
    public static final String PREFS_FLOATING = "prefs-floating";
    public static final String PREFS_TABS = "prefs-tabs";
    public static final String PREFS_UI = "prefs-ui";

    @NonNull
    private final Application application;
    @NonNull
    private final Languages languages;

    public AppModule(@NonNull Application application, @NonNull Languages languages) {
        this.application = application;
        this.languages = languages;
    }

    @Provides
    @Singleton
    Handler provideHandler() {
        return new Handler(Looper.getMainLooper());
    }

    @Provides
    @Singleton
    Application provideApplication() {
        return application;
    }

    @Provides
    @Singleton
    Bus provideBus(Handler handler) {
        return new AppBus(handler);
    }

    @Provides
    @Singleton
    SharedPreferences providePreferences() {
        return PreferenceManager.getDefaultSharedPreferences(application);
    }

    @Provides
    @Singleton
    @Named(PREFS_FLOATING)
    SharedPreferences provideFloatingPreferences() {
        return application.getSharedPreferences("floating-calculator", Context.MODE_PRIVATE);
    }

    @Provides
    @Singleton
    @Named(PREFS_TABS)
    SharedPreferences provideTabsPreferences() {
        return application.getSharedPreferences("tabs", Context.MODE_PRIVATE);
    }

    @Provides
    @Singleton
    @Named(PREFS_UI)
    SharedPreferences provideUiPreferences() {
        return provideUiPreferences(application);
    }

    @NonNull
    public static SharedPreferences provideUiPreferences(@NonNull Application application) {
        return application.getSharedPreferences("ui", Context.MODE_PRIVATE);
    }

    @Provides
    @Singleton
    @Named(THREAD_INIT)
    Executor provideInitThread() {
        return Executors.newSingleThreadExecutor(new ThreadFactory() {
            @Override
            public Thread newThread(@Nonnull Runnable r) {
                return new Thread(r, "Init");
            }
        });
    }

    @Provides
    @Singleton
    @Named(THREAD_BACKGROUND)
    Executor provideBackgroundThread() {
        return Executors.newFixedThreadPool(5, new ThreadFactory() {
            @NonNull
            private final AtomicInteger counter = new AtomicInteger();

            @Override
            public Thread newThread(@Nonnull Runnable r) {
                return new Thread(r, "Background #" + counter.getAndIncrement());
            }
        });
    }

    @Provides
    @Singleton
    ErrorReporter provideErrorReporter() {
        return new ErrorReporter() {
            @Override
            public void onException(@Nonnull Throwable e) {
            }

            @Override
            public void onError(@Nonnull String message) {
            }
        };
    }

    @Provides
    @Singleton
    Wizards provideWizards(@Nonnull Application application) {
        return new CalculatorWizards(application);
    }

    @Provides
    @Singleton
    @Named(THREAD_UI)
    Executor provideUiThread(@NonNull final Handler handler) {
        return new Executor() {
            @Override
            public void execute(@NonNull Runnable command) {
                if (App.isUiThread()) {
                    command.run();
                } else {
                    handler.post(command);
                }
            }
        };
    }

    @Provides
    @Singleton
    JsclMathEngine provideJsclMathEngine() {
        return JsclMathEngine.getInstance();
    }

    @Singleton
    @Provides
    Typeface provideTypeface() {
        return Typeface.createFromAsset(application.getAssets(), "fonts/Roboto-Regular.ttf");
    }

    @Singleton
    @Provides
    @Named(DIR_FILES)
    File provideFilesDir(@Named(THREAD_INIT) Executor initThread) {
        final File filesDir = makeFilesDir();
        initThread.execute(new Runnable() {
            @Override
            public void run() {
                if (!filesDir.exists() && !filesDir.mkdirs()) {
                    Log.e(App.TAG, "Can't create files dirs");
                }
            }
        });
        return filesDir;
    }

    @Provides
    @Singleton
    Plotter providePlotter() {
        return Plot.newPlotter(application);
    }

    @Provides
    @Singleton
    @NonNull
    public Languages provideLanguages() {
        return languages;
    }

    @Nonnull
    private File makeFilesDir() {
        final File filesDir = application.getFilesDir();
        if (filesDir == null) {
            return new File(application.getApplicationInfo().dataDir, "files");
        }
        return filesDir;
    }

    private static class AppBus extends Bus {

        @NonNull
        private final Handler handler;

        public AppBus(@Nonnull Handler handler) {
            super(new GeneratedHandlerFinder());
            this.handler = handler;
        }

        @Override
        public void post(final Object event) {
            if (Looper.myLooper() == Looper.getMainLooper()) {
                super.post(event);
                return;
            }
            handler.post(new Runnable() {
                @Override
                public void run() {
                    AppBus.super.post(event);
                }
            });
        }
    }
}