package de.einfachhans.emailcomposer;

import android.content.Context;
import android.content.res.AssetManager;
import android.content.res.Resources;
import android.net.Uri;
import android.util.Base64;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;

final class AssetUtil {

  // Path where to put tmp the attachments.
  private static final String ATTACHMENT_FOLDER = "/email_composer";

  // Application context
  private final Context ctx;

  AssetUtil(Context ctx) {
    this.ctx = ctx;
  }

  static void cleanupAttachmentFolder(Context ctx) {
    try {
      String path = ctx.getExternalCacheDir() + ATTACHMENT_FOLDER;
      File dir = new File(path);

      if (!dir.isDirectory()) return;

      File[] files = dir.listFiles();

      assert files != null;
      for (File file : files) {
        file.delete();
      }
    } catch (Exception ignored) {}
  }

  Uri parse(String path, String type, String name) {
    switch (type) {
      case "absolute":
        return this.getUriForAbsolutePath(path);
      case "resource":
        return this.getUriForResourcePath(path);
      case "asset":
        return this.getUriForAssetPath(path);
      case "base64":
        return this.getUriForBase64Content(path, name);
      default:
        throw new RuntimeException("Unknown Attachment Type");
    }
  }

  private Uri getUriForAbsolutePath(String path) {
    File file = new File(path);

    if (!file.exists()) {
      throw new RuntimeException("File does not exist at absolute path");
    }

    return getUriForFile(ctx, file);
  }

  private Uri getUriForAssetPath(String path) {
    String resPath = "public/assets" + path;
    String fileName = resPath.substring(resPath.lastIndexOf('/') + 1);
    File dir = ctx.getExternalCacheDir();

    if (dir == null) {
      return Uri.EMPTY;
    }

    String storage = dir.toString() + ATTACHMENT_FOLDER;
    File file = new File(storage, fileName);
    new File(storage).mkdir();

    try {
      AssetManager assets = ctx.getAssets();
      InputStream in = assets.open(resPath);
      FileOutputStream out = new FileOutputStream(file);
      copyStream(in, out);
    } catch (Exception e) {
      throw new RuntimeException("File does not exist at assets");
    }

    return getUriForFile(ctx, file);
  }

  private Uri getUriForResourcePath(String path) {
    String fileName = path.substring(path.lastIndexOf('/') + 1);
    String resName = fileName.substring(0, fileName.lastIndexOf('.'));
    String extension = path.substring(path.lastIndexOf('.'));
    File dir = ctx.getExternalCacheDir();
    int resId = getResId(path);

    if (dir == null) {
      return Uri.EMPTY;
    }

    if (resId == 0) {
      throw new RuntimeException("File does not exist at resources");
    }

    String storage = dir.toString() + ATTACHMENT_FOLDER;
    File file = new File(storage, resName + extension);
    new File(storage).mkdir();

    try {
      Resources res = ctx.getResources();
      InputStream in = res.openRawResource(resId);
      FileOutputStream out = new FileOutputStream(file);
      copyStream(in, out);
    } catch (Exception e) {
      throw new RuntimeException("File does not exist at resources");
    }

    return getUriForFile(ctx, file);
  }

  private Uri getUriForBase64Content(String base64, String name) {
    File dir = ctx.getExternalCacheDir();

    if (dir == null) {
      return Uri.EMPTY;
    }

    String storage = dir.toString() + ATTACHMENT_FOLDER;
    File file = new File(storage, name);
    new File(storage).mkdir();

    try {
      byte[] bytes = Base64.decode(base64, 0);
      InputStream in = new ByteArrayInputStream(bytes);
      FileOutputStream out = new FileOutputStream(file);
      copyStream(in, out);
    } catch (Exception e) {
      e.printStackTrace();
    }

    return getUriForFile(ctx, file);
  }

  private Uri getUriForFile(Context ctx, File file) {
    String authority = ctx.getPackageName() + ".fileprovider";

    try {
      return Provider.getUriForFile(ctx, authority, file);
    } catch (Exception e) {
      throw new RuntimeException("Failed to get uri for file");
    }
  }

  private void copyStream(InputStream in, FileOutputStream out) {
    byte[] buffer = new byte[1024];
    int read;

    try {
      while ((read = in.read(buffer)) != -1) {
        out.write(buffer, 0, read);
      }
      out.flush();
      out.close();
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

  private int getResId(String resPath) {
    Resources res = ctx.getResources();
    String pkgName = ctx.getPackageName();
    String dirName = "drawable";
    String fileName = resPath;

    if (resPath.contains("/")) {
      dirName = resPath.substring(0, resPath.lastIndexOf('/'));
      fileName = resPath.substring(resPath.lastIndexOf('/') + 1);
    }

    String resName = fileName.substring(0, fileName.lastIndexOf('.'));
    int resId = res.getIdentifier(resName, dirName, pkgName);

    if (resId == 0) {
      resId = res.getIdentifier(resName, "mipmap", pkgName);
    }

    if (resId == 0) {
      resId = res.getIdentifier(resName, "drawable", pkgName);
    }

    return resId;
  }
}