// Copyright (C) 2012 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;

import com.google.gwt.user.client.ui.SuggestOracle;
import com.google.gwtexpui.safehtml.client.HighlightSuggestOracle;

import java.util.ArrayList;
import java.util.TreeSet;

public class SearchSuggestOracle extends HighlightSuggestOracle {
  private static final TreeSet<String> suggestions = new TreeSet<String>();

  static {
    suggestions.add("age:");
    suggestions.add("age:1week"); // Give an example age

    suggestions.add("change:");

    suggestions.add("owner:");
    suggestions.add("owner:self");
    suggestions.add("ownerin:");

    suggestions.add("reviewer:");
    suggestions.add("reviewer:self");
    suggestions.add("reviewerin:");

    suggestions.add("commit:");
    suggestions.add("project:");
    suggestions.add("branch:");
    suggestions.add("topic:");
    suggestions.add("ref:");
    suggestions.add("tr:");
    suggestions.add("bug:");
    suggestions.add("label:");
    suggestions.add("message:");
    suggestions.add("file:");

    suggestions.add("has:");
    suggestions.add("has:draft");
    suggestions.add("has:star");

    suggestions.add("is:");
    suggestions.add("is:starred");
    suggestions.add("is:watched");
    suggestions.add("is:reviewed");
    suggestions.add("is:owner");
    suggestions.add("is:reviewer");
    suggestions.add("is:open");
    suggestions.add("is:draft");
    suggestions.add("is:closed");
    suggestions.add("is:submitted");
    suggestions.add("is:merged");
    suggestions.add("is:abandoned");

    suggestions.add("status:");
    suggestions.add("status:open");
    suggestions.add("status:reviewed");
    suggestions.add("status:submitted");
    suggestions.add("status:closed");
    suggestions.add("status:merged");
    suggestions.add("status:abandoned");

    suggestions.add("AND");
    suggestions.add("OR");
    suggestions.add("NOT");
  }

  @Override
  public void requestDefaultSuggestions(Request request, Callback done) {
    final ArrayList<SearchSuggestion> r = new ArrayList<SearchSuggestOracle.SearchSuggestion>();
    // No text - show some default suggestions.
    r.add(new SearchSuggestion("status:open", "status:open"));
    r.add(new SearchSuggestion("age:1week", "age:1week"));
    if (Gerrit.isSignedIn()) {
      r.add(new SearchSuggestion("owner:self", "owner:self"));
    }
    done.onSuggestionsReady(request, new Response(r));
  }

  @Override
  protected void onRequestSuggestions(Request request, Callback done) {
    final String query = request.getQuery();
    int lastSpace = query.lastIndexOf(' ');
    final String lastWord;
    // NOTE: this method is not called if the query is empty.
    if (lastSpace == query.length() - 1) {
      // Starting a new word - don't show suggestions yet.
      done.onSuggestionsReady(request, null);
      return;
    } else if (lastSpace == -1) {
      lastWord = query;
    } else {
      lastWord = query.substring(lastSpace + 1);
    }

    final ArrayList<SearchSuggestion> r = new ArrayList<SearchSuggestOracle.SearchSuggestion>();
    for (String suggestion : suggestions.tailSet(lastWord)) {
      if ((lastWord.length() < suggestion.length()) && suggestion.startsWith(lastWord)) {
        if (suggestion.contains("self") && !Gerrit.isSignedIn()) {
          continue;
        }
        r.add(new SearchSuggestion(suggestion, query + suggestion.substring(lastWord.length())));
      }
    }
    done.onSuggestionsReady(request, new Response(r));
  }

  private static class SearchSuggestion implements SuggestOracle.Suggestion {
    private final String suggestion;
    private final String fullQuery;
    public SearchSuggestion(String suggestion, String fullQuery) {
      this.suggestion = suggestion;
      // Add a space to the query if it is a complete operation (e.g.
      // "status:open") so the user can keep on typing.
      this.fullQuery = fullQuery.endsWith(":") ? fullQuery : fullQuery + " ";
    }
    @Override
    public String getDisplayString() {
      return suggestion;
    }

    @Override
    public String getReplacementString() {
      return fullQuery;
    }
  }
}