import android.app.Activity;
import android.app.Dialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.design.widget.BottomSheetBehavior;
import android.support.design.widget.CoordinatorLayout;
import android.support.v4.app.DialogFragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.widget.FrameLayout;

import butterknife.ButterKnife;

/**
 * Full screen {@link BaseFragment} with {@link BottomSheetBehavior} attached to its main content view.
 *
 * @author Leo
 */
public abstract class FullScreenBottomSheetDialogFragment extends DialogFragment {

    /** {@link BottomSheetBehavior} object that associates with this Fragment **/
    private BottomSheetBehavior mBottomSheetBehavior;

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setStyle(DialogFragment.STYLE_NORMAL, R.style.BottomSheetDialog);
    }

    @Nullable
    @Override
    public final View onCreateView(LayoutInflater inflater,
                                   @Nullable ViewGroup container,
                                   @Nullable Bundle savedInstanceState) {
        CoordinatorLayout coordinator = (CoordinatorLayout) inflater.inflate(
                R.layout.full_screen_bottom_sheet, container, false);
        FrameLayout bottomSheet = (FrameLayout) coordinator.findViewById(R.id.bottom_sheet);

        // create and add content view
        FrameLayout.LayoutParams layoutParams = new FrameLayout.LayoutParams(
                FrameLayout.LayoutParams.MATCH_PARENT, FrameLayout.LayoutParams.MATCH_PARENT);
        View contentView = onCreateBottomSheetContentView(inflater, bottomSheet, savedInstanceState);
        ButterKnife.inject(this, contentView);
        bottomSheet.addView(contentView, layoutParams);

        // behavior
        mBottomSheetBehavior = BottomSheetBehavior.from(bottomSheet);
        mBottomSheetBehavior.setBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {
            @Override
            public void onStateChanged(@NonNull View bottomSheet, int newState) {
                switch (newState) {
                    case BottomSheetBehavior.STATE_DRAGGING:
                    case BottomSheetBehavior.STATE_SETTLING:
                    case BottomSheetBehavior.STATE_EXPANDED:
                        break;
                    case BottomSheetBehavior.STATE_COLLAPSED:
                    case BottomSheetBehavior.STATE_HIDDEN:
                        if (isAdded()) {
                            dismissAllowingStateLoss();
                        }
                        break;
                }
            }

            @Override
            public void onSlide(@NonNull View bottomSheet, float slideOffset) {
                // do nothing
                // be careful when overriding this method since it hurts performance on old devices
            }
        });

        return coordinator;
    }

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        if (savedInstanceState == null) {
            // We need to use post here so we can prevent animation of setting STATE_EXPANDED from being swallowed in case
            // (probably) this method is run before layout pass is done.
            view.post(() -> mBottomSheetBehavior.setState(BottomSheetBehavior.STATE_EXPANDED));
        } else {
            // if this fragment is restored from saved state, so don't bother to play the fancy animation
            mBottomSheetBehavior.setState(BottomSheetBehavior.STATE_EXPANDED);
        }
    }

    @Override
    public void onStart() {
        super.onStart();
        // make this dialog fullscreen - these lines have to be called here in onStart()
        Dialog dialog = getDialog();
        if (dialog.getWindow() != null) {
            dialog.getWindow().setLayout(WindowManager.LayoutParams.MATCH_PARENT, WindowManager.LayoutParams.MATCH_PARENT);
        }
    }

    /** Get {@link BottomSheetBehavior} object that associates with this Fragment **/
    protected BottomSheetBehavior getBottomSheetBehavior() {
        return mBottomSheetBehavior;
    }

    @Override
    public void onDismiss(DialogInterface dialog) {
        super.onDismiss(dialog);
        // finish activity if necessary
        Activity activity;
        if (shouldFinishActivityOnDismiss()
                && (activity = getActivity()) != null
                && !activity.isFinishing()) {
            activity.finish();
        }
    }

    /**
     * Default returning {@code true}.<br/>
     * Override this method to return true to tell this Fragment not to finish its containing Activity on dismiss.
     */
    protected boolean shouldFinishActivityOnDismiss() {
        return true;
    }

    /** Provide content view for this fragment **/
    @NonNull
    protected abstract View onCreateBottomSheetContentView(LayoutInflater inflater,
                                                           @Nullable ViewGroup container,
                                                           @Nullable Bundle savedInstanceState);
}