// Copyright (C) 2014 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.gerrit.client.change;

import com.google.gerrit.client.Gerrit;
import com.google.gerrit.client.changes.ChangeApi;
import com.google.gerrit.client.info.ChangeInfo;
import com.google.gerrit.client.rpc.GerritCallback;
import com.google.gerrit.client.rpc.Natives;
import com.google.gerrit.common.PageLinks;
import com.google.gerrit.reviewdb.client.Change;
import com.google.gwt.core.client.GWT;
import com.google.gwt.core.client.JavaScriptObject;
import com.google.gwt.core.client.JsArrayString;
import com.google.gwt.dom.client.Element;
import com.google.gwt.dom.client.NativeEvent;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.KeyCodes;
import com.google.gwt.event.dom.client.KeyDownEvent;
import com.google.gwt.event.dom.client.KeyDownHandler;
import com.google.gwt.uibinder.client.UiBinder;
import com.google.gwt.uibinder.client.UiField;
import com.google.gwt.uibinder.client.UiHandler;
import com.google.gwt.user.client.DOM;
import com.google.gwt.user.client.rpc.StatusCodeException;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.Composite;
import com.google.gwt.user.client.ui.HTMLPanel;
import com.google.gwt.user.client.ui.UIObject;
import com.google.gwtexpui.globalkey.client.NpTextBox;
import com.google.gwtexpui.safehtml.client.SafeHtmlBuilder;

import java.util.Iterator;

public class Hashtags extends Composite {

  interface Binder extends UiBinder<HTMLPanel, Hashtags> {}
  private static final int VISIBLE_LENGTH = 55;
  private static final Binder uiBinder = GWT.create(Binder.class);
  private static final String REMOVE;
  private static final String DATA_ID = "data-id";

  private boolean canEdit;

  static {
    REMOVE = DOM.createUniqueId().replace('-', '_');
    init(REMOVE);
  }

  private static final native void init(String r) /*-{
    $wnd[r] = $entry(function(e) {
      @com.google.gerrit.client.change.Hashtags::onRemove(Lcom/google/gwt/dom/client/NativeEvent;)(e)
    });
  }-*/;

  private static void onRemove(NativeEvent event) {
    String hashtags = getDataId(event);
    if (hashtags != null) {
      final ChangeScreen screen = ChangeScreen.get(event);
      ChangeApi.hashtags(screen.getChangeId().get()).post(
          PostInput.create(null, hashtags), new GerritCallback<JavaScriptObject>() {
            @Override
            public void onSuccess(JavaScriptObject result) {
              if (screen.isCurrentView()) {
                Gerrit.display(PageLinks.toChange(screen.getChangeId()));
              }
            }
          });
    }
  }

  private static String getDataId(NativeEvent event) {
    Element e = event.getEventTarget().cast();
    while (e != null) {
      String v = e.getAttribute(DATA_ID);
      if (!v.isEmpty()) {
        return v;
      }
      e = e.getParentElement();
    }
    return null;
  }

  @UiField Element hashtagsText;
  @UiField Button openForm;
  @UiField Element form;
  @UiField Element error;
  @UiField NpTextBox hashtagTextBox;

  private ChangeScreen.Style style;
  private Change.Id changeId;

  public Hashtags() {

    initWidget(uiBinder.createAndBindUi(this));

    hashtagTextBox.setVisibleLength(VISIBLE_LENGTH);
    hashtagTextBox.addKeyDownHandler(new KeyDownHandler() {
      @Override
      public void onKeyDown(KeyDownEvent e) {
        if (e.getNativeEvent().getKeyCode() == KeyCodes.KEY_ESCAPE) {
          onCancel(null);
        } else if (e.getNativeEvent().getKeyCode() == KeyCodes.KEY_ENTER) {
          onAdd(null);
        }
      }
    });
  }

  void init(ChangeScreen.Style style){
    this.style = style;
  }

  void set(ChangeInfo info) {
    canEdit = info.hasActions() && info.actions().containsKey("hashtags");
    this.changeId = info.legacyId();
    display(info);
    openForm.setVisible(canEdit);
  }

  @UiHandler("openForm")
  void onOpenForm(@SuppressWarnings("unused") ClickEvent e) {
    onOpenForm();
  }

  void onOpenForm() {
    UIObject.setVisible(form, true);
    UIObject.setVisible(error, false);
    openForm.setVisible(false);
    hashtagTextBox.setFocus(true);
  }

  private void display(ChangeInfo info) {
    hashtagsText.setInnerSafeHtml(formatHashtags(info));
  }
  private void display(JsArrayString hashtags) {
    hashtagsText.setInnerSafeHtml(formatHashtags(hashtags));
  }

  private SafeHtmlBuilder formatHashtags(ChangeInfo info) {
    if (info.hashtags() != null) {
      return formatHashtags(info.hashtags());
    }
    return new SafeHtmlBuilder();
  }

  private SafeHtmlBuilder formatHashtags(JsArrayString hashtags) {
    SafeHtmlBuilder html = new SafeHtmlBuilder();
    Iterator<String> itr = Natives.asList(hashtags).iterator();
    while (itr.hasNext()) {
      String hashtagName = itr.next();
      html.openSpan()
          .setAttribute(DATA_ID, hashtagName)
          .setStyleName(style.hashtagName())
          .openAnchor()
          .setAttribute("href",
              "#" + PageLinks.toChangeQuery("hashtag:\"" + hashtagName + "\""))
          .setAttribute("role", "listitem")
          .append("#").append(hashtagName)
          .closeAnchor();
      if (canEdit) {
        html.openElement("button")
            .setAttribute("title", "Remove hashtag")
            .setAttribute("onclick", REMOVE + "(event)")
            .append("×")
            .closeElement("button");
      }
      html.closeSpan();
      if (itr.hasNext()) {
        html.append(' ');
      }
    }
    return html;
  }

  @UiHandler("cancel")
  void onCancel(@SuppressWarnings("unused") ClickEvent e) {
    openForm.setVisible(true);
    UIObject.setVisible(form, false);
    hashtagTextBox.setFocus(false);
  }

  @UiHandler("add")
  void onAdd(@SuppressWarnings("unused") ClickEvent e) {
    String hashtag = hashtagTextBox.getText();
    if (!hashtag.isEmpty()) {
      addHashtag(hashtag);
    }
  }

  private void addHashtag(final String hashtags) {
    ChangeApi.hashtags(changeId.get()).post(
        PostInput.create(hashtags, null),
        new GerritCallback<JsArrayString>() {
          @Override
          public void onSuccess(JsArrayString result) {
            hashtagTextBox.setEnabled(true);
            UIObject.setVisible(error, false);
            error.setInnerText("");
            hashtagTextBox.setText("");

            if (result != null && result.length() > 0) {
              updateHashtagList(result);
            }
          }

          @Override
          public void onFailure(Throwable err) {
            UIObject.setVisible(error, true);
            error.setInnerText(err instanceof StatusCodeException
                ? ((StatusCodeException) err).getEncodedResponse()
                : err.getMessage());
            hashtagTextBox.setEnabled(true);
          }
        });
  }

  protected void updateHashtagList() {
    ChangeApi.detail(changeId.get(),
        new GerritCallback<ChangeInfo>() {
          @Override
          public void onSuccess(ChangeInfo result) {
            display(result);
          }
        });
  }

  protected void updateHashtagList(JsArrayString hashtags){
    display(hashtags);
  }

  public static class PostInput extends JavaScriptObject {
    public static PostInput create(String add, String remove) {
      PostInput input = createObject().cast();
      input.init(toJsArrayString(add), toJsArrayString(remove));
      return input;
    }
    private static JsArrayString toJsArrayString(String commaSeparated){
      if (commaSeparated == null || commaSeparated.equals("")) {
        return null;
      }
      JsArrayString array = JsArrayString.createArray().cast();
      for (String hashtag : commaSeparated.split(",")){
        array.push(hashtag.trim());
      }
      return array;
    }

    private native void init(JsArrayString add, JsArrayString remove) /*-{
      this.add = add;
      this.remove = remove;
    }-*/;

    protected PostInput() {
    }
  }

  public static class Result extends JavaScriptObject {
    public final native JsArrayString hashtags() /*-{ return this.hashtags; }-*/;
    public final native String error() /*-{ return this.error; }-*/;

    protected Result() {
    }
  }
}