Merge branch '4-create-decompiler' into 'master'

Resolve "Create decompiler"

Closes #4

See merge request bartlomiej.pluta/esa-tool!4

src/main/java/com/bartek/esa/decompiler/decompiler/Decompiler.java

@@ -0,0 +1,50 @@
+package com.bartek.esa.decompiler.decompiler;
+
+import com.bartek.esa.error.EsaException;
+import com.bartek.esa.file.provider.FileProvider;
+import io.vavr.control.Try;
+
+import javax.inject.Inject;
+import java.io.File;
+
+public class Decompiler {
+    private final FileProvider fileProvider;
+
+    @Inject
+    public Decompiler(FileProvider fileProvider) {
+
+        this.fileProvider = fileProvider;
+    }
+
+    public File decompile(File inputApk) {
+        File target = provideTargetDirectory();
+        Process process = decompile(inputApk, target);
+        waitForProcess(process);
+        checkExitValue(process);
+        return target;
+    }
+
+    private void checkExitValue(Process process) {
+        if(process.exitValue() != 0) {
+            throw new EsaException("'apktool' process has finished with non-zero code. Interrupting...");
+        }
+    }
+
+    private void waitForProcess(Process process) {
+        Try.run(process::waitFor).getOrElseThrow(EsaException::new);
+    }
+
+    private Process decompile(File inputApk, File target) {
+        return Try.of(() -> Runtime.getRuntime().exec(provideCommandArray(inputApk, target)))
+                    .getOrElseThrow(EsaException::new);
+    }
+
+    private String[] provideCommandArray(File inputApk, File target) {
+        return new String[]{"apktool", "d", inputApk.getAbsolutePath(), "-o", target.getAbsolutePath()};
+    }
+
+    private File provideTargetDirectory() {
+        File tmp = fileProvider.createTemporaryDirectory();
+        return new File(tmp, "apktool_out");
+    }
+}

src/main/java/com/bartek/esa/decompiler/di/DecompilerModule.java

@@ -0,0 +1,15 @@
+package com.bartek.esa.decompiler.di;
+
+import com.bartek.esa.decompiler.decompiler.Decompiler;
+import com.bartek.esa.file.provider.FileProvider;
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class DecompilerModule {
+
+    @Provides
+    public Decompiler decompiler(FileProvider fileProvider) {
+        return new Decompiler(fileProvider);
+    }
+}

src/main/java/com/bartek/esa/di/DependencyInjector.java

@@ -2,6 +2,7 @@ package com.bartek.esa.di;
 
 import com.bartek.esa.EsaMain;
 import com.bartek.esa.cli.di.CliModule;
+import com.bartek.esa.decompiler.di.DecompilerModule;
 import com.bartek.esa.dispatcher.di.DispatcherModule;
 import com.bartek.esa.file.di.FileModule;
 import dagger.Component;
@@ -9,7 +10,8 @@ import dagger.Component;
 @Component(modules = {
         CliModule.class,
         DispatcherModule.class,
-        FileModule.class
+        FileModule.class,
+        DecompilerModule.class
 })
 public interface DependencyInjector {
     EsaMain esa();

src/main/java/com/bartek/esa/file/provider/FileProvider.java

@@ -18,6 +18,12 @@ public class FileProvider {
 
     }
 
+    public File createTemporaryDirectory() {
+        return Try.of(() -> Files.createTempDirectory(null))
+                .getOrElseThrow(EsaException::new)
+                .toFile();
+    }
+
     public String readFile(File file) {
         StringBuilder content = new StringBuilder();
         Try.run(() -> Files.lines(file.toPath())