package org.thoughtcrime.securesms.stickers;

import android.arch.lifecycle.ViewModelProviders;
import android.content.Context;
import android.content.res.Configuration;
import android.graphics.Point;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.annotation.Px;
import android.support.v4.app.Fragment;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;

import org.thoughtcrime.securesms.R;
import org.thoughtcrime.securesms.database.DatabaseFactory;
import org.thoughtcrime.securesms.database.model.StickerRecord;
import org.thoughtcrime.securesms.logging.Log;
import org.thoughtcrime.securesms.mms.GlideApp;
import org.thoughtcrime.securesms.mms.GlideRequests;
import org.thoughtcrime.securesms.stickers.StickerKeyboardPageAdapter.StickerKeyboardPageViewHolder;
import org.thoughtcrime.securesms.util.ViewUtil;

/**
 * An individual page of stickers in the {@link StickerKeyboardProvider}.
 */
public final class StickerKeyboardPageFragment extends Fragment implements StickerKeyboardPageAdapter.EventListener {

  private static final String TAG = Log.tag(StickerKeyboardPageFragment.class);

  private static final String KEY_PACK_ID = "pack_id";

  public static final String RECENT_PACK_ID = StickerKeyboardPageViewModel.RECENT_PACK_ID;

  private RecyclerView               list;
  private StickerKeyboardPageAdapter adapter;
  private GridLayoutManager          layoutManager;

  private StickerKeyboardPageViewModel viewModel;
  private EventListener                eventListener;
  private ListTouchListener            listTouchListener;

  private String                       packId;

  public static StickerKeyboardPageFragment newInstance(@NonNull String packId) {
    Bundle args = new Bundle();
    args.putString(KEY_PACK_ID, packId);

    StickerKeyboardPageFragment fragment = new StickerKeyboardPageFragment();
    fragment.setArguments(args);
    fragment.packId = packId;

    return fragment;
  }

  @Override
  public @Nullable View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    return inflater.inflate(R.layout.sticker_keyboard_page, container, false);
  }

  @Override
  public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
    GlideRequests glideRequests = GlideApp.with(this);

    this.list              = view.findViewById(R.id.sticker_keyboard_list);
    this.adapter           = new StickerKeyboardPageAdapter(glideRequests, this);
    this.layoutManager     = new GridLayoutManager(requireContext(), 2);
    this.listTouchListener = new ListTouchListener(requireContext(), glideRequests);
    this.packId            = getArguments().getString(KEY_PACK_ID);

    list.setLayoutManager(layoutManager);
    list.setAdapter(adapter);
    list.addOnItemTouchListener(listTouchListener);

    initViewModel(packId);
    onScreenWidthChanged(getScreenWidth());
  }

  @Override
  public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);
    onScreenWidthChanged(getScreenWidth());
  }

  @Override
  public void onStickerClicked(@NonNull StickerRecord sticker) {
    if (eventListener != null) {
      eventListener.onStickerSelected(sticker);
    }
  }

  @Override
  public void onStickerLongClicked(@NonNull View targetView) {
    if (listTouchListener != null) {
      listTouchListener.enterHoverMode(list, targetView);
    }
  }

  public void setEventListener(@NonNull EventListener eventListener) {
    this.eventListener = eventListener;
  }

  public @NonNull String getPackId() {
    return packId;
  }

  private void initViewModel(@NonNull String packId) {
    StickerKeyboardRepository repository = new StickerKeyboardRepository(DatabaseFactory.getStickerDatabase(requireContext()));
    viewModel = ViewModelProviders.of(this, new StickerKeyboardPageViewModel.Factory(requireActivity().getApplication(), repository)).get(StickerKeyboardPageViewModel.class);

    viewModel.getStickers(packId).observe(getViewLifecycleOwner(), stickerRecords -> {
      if (stickerRecords == null) return;

      adapter.setStickers(stickerRecords, calculateStickerSize(getScreenWidth()));
    });
  }

  private void onScreenWidthChanged(@Px int newWidth) {
    if (layoutManager != null) {
      layoutManager.setSpanCount(calculateColumnCount(newWidth));
      adapter.setStickerSize(calculateStickerSize(newWidth));
    }
  }

  private int getScreenWidth() {
    Point size = new Point();
    requireActivity().getWindowManager().getDefaultDisplay().getSize(size);
    return size.x;
  }

  private int calculateColumnCount(@Px int screenWidth) {
    float modifier = getResources().getDimensionPixelOffset(R.dimen.sticker_page_item_padding);
    float divisor  = getResources().getDimensionPixelOffset(R.dimen.sticker_page_item_divisor);
    return (int) ((screenWidth - modifier) / divisor);
  }

  private int calculateStickerSize(@Px int screenWidth) {
    float multiplier  = getResources().getDimensionPixelOffset(R.dimen.sticker_page_item_multiplier);
    int   columnCount = calculateColumnCount(screenWidth);

    return (int) ((screenWidth - ((columnCount + 1) * multiplier)) / columnCount);
  }

  private final class ListTouchListener implements RecyclerView.OnItemTouchListener {

    private final StickerPreviewPopup popup;

    private boolean hoverMode;

    ListTouchListener(@NonNull Context context, @NonNull GlideRequests glideRequests) {
      this.popup = new StickerPreviewPopup(context, glideRequests);
      popup.setAnimationStyle(R.style.StickerPopupAnimation);
    }

    @Override
    public boolean onInterceptTouchEvent(@NonNull RecyclerView recyclerView, @NonNull MotionEvent motionEvent) {
      return hoverMode;
    }

    @Override
    public void onTouchEvent(@NonNull RecyclerView recyclerView, @NonNull MotionEvent motionEvent) {
      switch (motionEvent.getAction()) {
        case MotionEvent.ACTION_UP:
        case MotionEvent.ACTION_CANCEL:
          hoverMode = false;
          popup.dismiss();
          eventListener.onStickerPopupEnded();
          break;
        default:
          for (int i = 0, len = recyclerView.getChildCount(); i < len; i++) {
            View child = recyclerView.getChildAt(i);

            if (ViewUtil.isPointInsideView(recyclerView, motionEvent.getRawX(), motionEvent.getRawY()) &&
                ViewUtil.isPointInsideView(child, motionEvent.getRawX(), motionEvent.getRawY()))
            {
              showStickerForView(recyclerView, child);
            }
          }
      }
    }

    @Override
    public void onRequestDisallowInterceptTouchEvent(boolean b) {
    }

    void enterHoverMode(@NonNull RecyclerView recyclerView, View targetView) {
      this.hoverMode = true;
      showStickerForView(recyclerView, targetView);
    }

    private void showStickerForView(@NonNull RecyclerView recyclerView, @NonNull View view) {
      StickerKeyboardPageViewHolder holder = (StickerKeyboardPageViewHolder) recyclerView.getChildViewHolder(view);

      if (holder != null && holder.getCurrentSticker() != null) {
        if (!popup.isShowing()) {
          popup.showAtLocation(recyclerView, Gravity.NO_GRAVITY, 0, 0);
          eventListener.onStickerPopupStarted();
        }
        popup.presentSticker(holder.getCurrentSticker());
      }
    }
  }

  interface EventListener {
    void onStickerSelected(@NonNull StickerRecord sticker);
    void onStickerPopupStarted();
    void onStickerPopupEnded();
  }
}