/*
 * Copyright 2009 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.jstestdriver;

import java.io.File;
import java.util.Collection;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;

import com.google.inject.Inject;
import com.google.inject.name.Named;
import com.google.jstestdriver.hooks.FileLoadPostProcessor;
import com.google.jstestdriver.hooks.FileLoadPreProcessor;
import com.google.jstestdriver.util.StopWatch;

/**
 * A simple loader for files.
 * @author corysmith@google.com (Cory Smith)
 */
public class ProcessingFileLoader implements FileLoader {
  private final JsTestDriverFileFilter filter;
  private final FileReader reader;
  private final Set<FileLoadPostProcessor> postprocessors;
  private final Set<FileLoadPreProcessor> preProcessors;
  private final File basePath;
  private final StopWatch stopWatch;

  @Inject
  public ProcessingFileLoader(JsTestDriverFileFilter filter,
                              FileReader reader,
                              Set<FileLoadPostProcessor> postprocessors,
                              Set<FileLoadPreProcessor> preProcessors,
                              @Named("basePath") File basePath,
                              StopWatch stopWatch) {
    this.filter = filter;
    this.reader = reader;
    this.postprocessors = postprocessors;
    this.preProcessors = preProcessors;
    this.basePath = basePath;
    this.stopWatch = stopWatch;
  }

  //TODO(corysmith): Remove shouldReset.
  public List<FileInfo> loadFiles(
  		Collection<FileInfo> filesToLoad, boolean shouldReset) {
    List<FileInfo> processed = new LinkedList<FileInfo>();
    List<FileInfo> loaded = new LinkedList<FileInfo>();
    try {
      stopWatch.start("preProcessFiles");
      final List<FileInfo> preProcessedFiles = preProcessFiles(filesToLoad);
      stopWatch.stop("preProcessFiles");

      stopWatch.start("loadFile");
      for (FileInfo file : preProcessedFiles) {
        loaded.add(loadFile(shouldReset, basePath, file));
      }
      stopWatch.stop("loadFile");

      stopWatch.start("postProcessFile");
      for (FileInfo file : loaded) {
        processed.add(postProcessFile(file));
      }
      stopWatch.stop("postProcessFile");
    } catch (RuntimeException e) {
      throw e;
    }
    return processed;
  }

  private FileInfo loadFile(boolean shouldReset, File basePath, FileInfo file) {
    if (!file.canLoad()) {
      return file;
    }
    StringBuilder fileContent = new StringBuilder();
    long timestamp = file.getTimestamp();
    fileContent.append(
    		filter.filterFile(reader.readFile(file.getAbsoluteFileName(basePath)), !shouldReset));
    List<FileInfo> patches = file.getPatches();
    if (patches != null) {
      for (FileInfo patch : patches) {
        fileContent.append(reader.readFile(patch.getAbsoluteFileName(basePath)));
      }
    }
    return new FileInfo(file.getFilePath(),
                        timestamp,
                        false,
                        file.isServeOnly(),
                        fileContent.toString());
  }

  private FileInfo postProcessFile(FileInfo processed) {
    for (FileLoadPostProcessor hook : postprocessors) {
      processed = hook.process(processed);
    }
    return processed;
  }

  private List<FileInfo> preProcessFiles(Collection<FileInfo> filesToLoad) {
    List<FileInfo> files = new LinkedList<FileInfo>(filesToLoad);
    for (FileLoadPreProcessor processor : preProcessors) {
      files = processor.process(files);
    }
    return files;
  }
}