import android.app.Activity;
import android.app.Dialog;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.GradientDrawable;
import android.os.Build;
import android.support.annotation.NonNull;
import android.support.design.widget.BottomSheetBehavior;
import android.support.design.widget.CoordinatorLayout;
import android.util.DisplayMetrics;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;

/*
    FiskBottomSheetDialog dialog = new FiskBottomSheetDialog(activity, R.layout.some_layout, R.style.AppTheme);
    View view = dialog.getContentView();
 */
public class FiskBottomSheetDialog {

    private final Dialog dialog;
    private View contentView;
    private boolean cancelable = true;

    private Dialog.OnDismissListener onDismissListener = null;

    public FiskBottomSheetDialog(Activity context, int layout, int theme){

        dialog  = new Dialog(context, theme);

        Window window = dialog.getWindow();

        if(window != null){
            window.setDimAmount(0);
            window.setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
            window.setLayout(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
        }

        contentView = context.getLayoutInflater().inflate (layout, null);

        //Curved top corners:
        GradientDrawable curvedBackground = new GradientDrawable();
        curvedBackground.setColor(Color.WHITE);

        float cornerRadius = 8 * ((float)context.getResources().getDisplayMetrics().densityDpi / DisplayMetrics.DENSITY_DEFAULT);

        curvedBackground.setCornerRadii(new float[]{cornerRadius, cornerRadius, cornerRadius, cornerRadius, 0, 0, 0, 0});
        contentView.setBackground(curvedBackground);

        //Full screen coordinator to hold the bottomsheet
        CoordinatorLayout coordinatorLayout = new CoordinatorLayout(context);
        coordinatorLayout.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
        coordinatorLayout.setBackgroundColor(Color.parseColor("#00000000"));

        BottomSheetBehavior bottomSheetBehavior = new BottomSheetBehavior();
        bottomSheetBehavior.setSkipCollapsed(true);
        bottomSheetBehavior.setHideable(true);
        bottomSheetBehavior.setState(BottomSheetBehavior.STATE_HIDDEN);

        CoordinatorLayout.LayoutParams params = new CoordinatorLayout.LayoutParams(CoordinatorLayout.LayoutParams.MATCH_PARENT, CoordinatorLayout.LayoutParams.WRAP_CONTENT);
        params.setBehavior(bottomSheetBehavior);

        contentView.setLayoutParams(params);

        coordinatorLayout.addView(contentView);

        //Any click on the dimmed coordinator in the background should dismiss the dialog (unless setCanceleable(false); has been called):
        coordinatorLayout.setOnClickListener(_view -> {
            if(cancelable) BottomSheetBehavior.from(contentView).setState(BottomSheetBehavior.STATE_HIDDEN);
        });

        bottomSheetBehavior.setBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {

            @Override
            public void onStateChanged(@NonNull View bottomSheet, int newState) {
                switch(newState){
                    case BottomSheetBehavior.STATE_HIDDEN:
                            dialog.dismiss();
                            if (onDismissListener != null) onDismissListener.onDismiss(dialog);
                            break;
                }
            }

            //slideOffset is float in range 0 to 1 - remapped to 0 to 153 (0x99000000)
            @Override
            public void onSlide(@NonNull View bottomSheet, float slideOffset) {
                int alpha = (int)map(slideOffset, 0f, 1f, 0f, 153f);
                int overlayColor = Color.argb(alpha, Color.red(Color.BLACK), Color.green(Color.BLACK), Color.blue(Color.BLACK));

                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP && window != null) {
                    window.setStatusBarColor(overlayColor);
                }

                coordinatorLayout.setBackgroundColor(overlayColor);
            }
        });

        dialog.setContentView(coordinatorLayout);

        //Without this the bottom sheet doesn't animate, despite the default state being hidden
        BottomSheetBehavior.from(contentView).setState(BottomSheetBehavior.STATE_HIDDEN);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) dialog.create();
    }

    public void show(){
        dialog.show();
        contentView.post(() -> BottomSheetBehavior.from(contentView).setState(BottomSheetBehavior.STATE_EXPANDED));
    }

    public void dismiss() {
        BottomSheetBehavior.from(contentView).setState(BottomSheetBehavior.STATE_HIDDEN);
    }

    public void setCancelable(boolean cancelable){
        this.cancelable = cancelable;
    }

    public View getContentView(){
        return contentView;
    }

    public void setOnDismissListener(Dialog.OnDismissListener onDismissListener){
        this.onDismissListener = onDismissListener;
    }

    private float map(float value, float start1, float stop1, float start2, float stop2) {
        return start2 + (stop2 - start2) * ((value - start1) / (stop1 - start1));
    }
}