/*
 * Copyright 2011 Google Inc.
 *
 * 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.gwt.dev.codeserver;

import com.google.gwt.core.ext.UnableToCompleteException;
import com.google.gwt.dev.json.JsonArray;
import com.google.gwt.dev.json.JsonObject;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.concurrent.atomic.AtomicReference;

/**
 * An in-memory directory of all the modules available on this code server. The {@link WebServer}
 * uses this directory to find the {@link ModuleState} associated with a URL and to list all the
 * modules on the front page.
 */
class Modules implements Iterable<String> {
  private final Map<String, ModuleState> moduleStateMap =
      new HashMap<String, ModuleState>();

  private AtomicReference<Progress> progress = new AtomicReference<Progress>(Progress.IDLE);

  /**
   * Adds a {@link ModuleState} to the map.
   * @param state the module state to map
   */
  public void addModuleState(ModuleState state) {
    moduleStateMap.put(state.getModuleName(), state);
  }

  /**
   * Retrieves a {@link ModuleState} corresponding to a given module name.
   * @param moduleName the module name to look up
   */
  public ModuleState get(String moduleName) {
    return moduleStateMap.get(moduleName);
  }

  /**
   * Iterates over the list of modules.
   */
  @Override
  public Iterator<String> iterator() {
    return moduleStateMap.keySet().iterator();
  }

  void defaultCompileAll(boolean noPrecompile) throws UnableToCompleteException {
    for (ModuleState m: moduleStateMap.values()) {
      m.defaultCompile(noPrecompile);
    }
  }

  /**
   * Returns a configuration object containing the names of all the modules.
   */
  JsonObject getConfig() {
    JsonObject config = JsonObject.create();
    JsonArray moduleNames = new JsonArray();
    for (String module : this) {
      moduleNames.add(module);
    }
    config.put("moduleNames", moduleNames);
    return config;
  }

  /**
   * Returns the recompiler's current state.
   */
  JsonObject getProgress() {
    return progress.get().toJsonObject();
  }

  /**
   * Compiles a module.
   *
   * <p>Updates progress and ensures that only one compile happens at a time.
   */
  synchronized boolean recompile(ModuleState module, Map<String, String> bindingProperties) {
    try {
      return module.recompile(bindingProperties, progress);
    } finally {
      progress.set(Progress.IDLE);
    }
  }
}