/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.android.setupdesign.span;

import android.content.Context;
import android.content.ContextWrapper;
import android.os.Build;
import android.text.Selection;
import android.text.Spannable;
import android.text.TextPaint;
import android.text.style.ClickableSpan;
import android.util.Log;
import android.view.View;
import android.widget.TextView;
import androidx.annotation.Nullable;

/**
 * A clickable span that will listen for click events and send it back to the context. To use this
 * class, implement {@link OnLinkClickListener} in your TextView, or use {@link
 * com.google.android.setupdesign.view.RichTextView#setOnClickListener(View.OnClickListener)}.
 *
 * <p>Note on accessibility: For TalkBack to be able to traverse and interact with the links, you
 * should use {@code LinkAccessibilityHelper} in your {@code TextView} subclass. Optionally you can
 * also use {@code RichTextView}, which includes link support.
 */
public class LinkSpan extends ClickableSpan {

  /*
   * Implementation note: When the orientation changes, TextView retains a reference to this span
   * instead of writing it to a parcel (ClickableSpan is not Parcelable). If this class has any
   * reference to the containing Activity (i.e. the activity context, or any views in the
   * activity), it will cause memory leak.
   */

  /* static section */

  private static final String TAG = "LinkSpan";

  /** @deprecated Use {@link OnLinkClickListener} */
  @Deprecated
  public interface OnClickListener {
    void onClick(LinkSpan span);
  }

  /**
   * Listener that is invoked when a link span is clicked. If the containing view of this span
   * implements this interface, this will be invoked when the link is clicked.
   */
  public interface OnLinkClickListener {

    /**
     * Called when a link has been clicked.
     *
     * @param span The span that was clicked.
     * @return True if the click was handled, stopping further propagation of the click event.
     */
    boolean onLinkClick(LinkSpan span);
  }

  /* non-static section */

  private final String link;

  public LinkSpan(String link) {
    this.link = link;
  }

  @Override
  public void onClick(View view) {
    if (dispatchClick(view)) {
      if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
        // Prevent the touch event from bubbling up to the parent views.
        view.cancelPendingInputEvents();
      }
    } else {
      Log.w(TAG, "Dropping click event. No listener attached.");
    }
    if (view instanceof TextView) {
      // Remove the highlight effect when the click happens by clearing the selection
      CharSequence text = ((TextView) view).getText();
      if (text instanceof Spannable) {
        Selection.setSelection((Spannable) text, 0);
      }
    }
  }

  private boolean dispatchClick(View view) {
    boolean handled = false;
    if (view instanceof OnLinkClickListener) {
      handled = ((OnLinkClickListener) view).onLinkClick(this);
    }
    if (!handled) {
      final OnClickListener listener = getLegacyListenerFromContext(view.getContext());
      if (listener != null) {
        listener.onClick(this);
        handled = true;
      }
    }
    return handled;
  }

  /** @deprecated Deprecated together with {@link OnClickListener} */
  @Nullable
  @Deprecated
  private OnClickListener getLegacyListenerFromContext(@Nullable Context context) {
    while (true) {
      if (context instanceof OnClickListener) {
        return (OnClickListener) context;
      } else if (context instanceof ContextWrapper) {
        // Unwrap any context wrapper, in base the base context implements onClickListener.
        // ContextWrappers cannot have circular base contexts, so at some point this will
        // reach the one of the other cases and return.
        context = ((ContextWrapper) context).getBaseContext();
      } else {
        return null;
      }
    }
  }

  @Override
  public void updateDrawState(TextPaint drawState) {
    super.updateDrawState(drawState);
    drawState.setUnderlineText(false);
  }

  public String getLink() {
    return link;
  }

  /**
   * @deprecated Method's return type clashes with its superclass. Use {@link #getLink()} instead.
   * This will be removed in the future.
   */
  @Deprecated
  public String getId() {
    return link;
  }
}