// Copyright (C) 2013 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.api;

import com.google.gerrit.client.Gerrit;
import com.google.gerrit.client.info.ActionInfo;
import com.google.gerrit.client.info.ChangeInfo;
import com.google.gerrit.client.rpc.GerritCallback;
import com.google.gerrit.client.rpc.NativeString;
import com.google.gerrit.client.rpc.RestApi;
import com.google.gerrit.common.PageLinks;
import com.google.gerrit.reviewdb.client.Project;
import com.google.gwt.core.client.JavaScriptObject;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.Window.Location;
import com.google.gwt.user.client.rpc.AsyncCallback;

class DefaultActions {
  static void invoke(ChangeInfo change, ActionInfo action, RestApi api) {
    invoke(action, api, callback(PageLinks.toChange(change.projectNameKey(), change.legacyId())));
  }

  static void invoke(Project.NameKey project, ActionInfo action, RestApi api) {
    invoke(action, api, callback(PageLinks.toProject(project)));
  }

  private static AsyncCallback<JavaScriptObject> callback(String target) {
    return new GerritCallback<JavaScriptObject>() {
      @Override
      public void onSuccess(JavaScriptObject in) {
        UiResult result = asUiResult(in);
        if (result == null) {
          Gerrit.display(target);
          return;
        }

        if (result.alert() != null) {
          Window.alert(result.alert());
        }

        if (result.redirectUrl() != null && result.openWindow()) {
          Window.open(result.redirectUrl(), "_blank", null);
        } else if (result.redirectUrl() != null) {
          Location.assign(result.redirectUrl());
        } else {
          Gerrit.display(target);
        }
      }

      private UiResult asUiResult(JavaScriptObject in) {
        if (NativeString.is(in)) {
          String str = ((NativeString) in).asString();
          return str.isEmpty() ? UiResult.none() : UiResult.alert(str);
        }
        return in.cast();
      }
    };
  }

  private static void invoke(ActionInfo action, RestApi api, AsyncCallback<JavaScriptObject> cb) {
    if ("GET".equalsIgnoreCase(action.method())) {
      api.get(cb);
    } else if ("PUT".equalsIgnoreCase(action.method())) {
      api.put(JavaScriptObject.createObject(), cb);
    } else if ("DELETE".equalsIgnoreCase(action.method())) {
      api.delete(cb);
    } else {
      api.post(JavaScriptObject.createObject(), cb);
    }
  }

  private DefaultActions() {}

  private static class UiResult extends JavaScriptObject {
    static native UiResult alert(String m) /*-{ return {'alert':m} }-*/;

    static native UiResult none() /*-{ return {} }-*/;

    final native String alert() /*-{ return this.alert }-*/;

    final native String redirectUrl() /*-{ return this.url }-*/;

    final native boolean openWindow() /*-{ return this.open_window || false }-*/;

    protected UiResult() {}
  }
}