/*
 * 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.gwt.uibinder.rebind;

import com.google.gwt.core.ext.UnableToCompleteException;
import com.google.gwt.core.ext.typeinfo.JClassType;
import com.google.gwt.core.ext.typeinfo.JMethod;
import com.google.gwt.core.ext.typeinfo.JType;
import com.google.gwt.core.ext.typeinfo.TypeOracle;
import com.google.gwt.resources.client.CssResource;
import com.google.gwt.uibinder.rebind.model.ImplicitCssResource;

import java.io.PrintWriter;
import java.util.Set;

/**
 * Writes the source to implement an {@link ImplicitCssResource} interface.
 */
public class CssResourceWriter {
  /**
   *
   */
  private static final JType[] NO_PARAMS = new JType[0];
  private final ImplicitCssResource css;
  private final IndentedWriter writer;
  private final JClassType cssResourceType;
  private final JClassType stringType;

  public CssResourceWriter(ImplicitCssResource css, TypeOracle oracle,
      PrintWriter writer) {
    this.css = css;
    this.writer = new IndentedWriter(writer);
    this.cssResourceType = oracle.findType(CssResource.class.getName());
    this.stringType = oracle.findType(String.class.getName());
  }

  public void write() throws UnableToCompleteException {
    // Package declaration
    String packageName = css.getPackageName();
    if (packageName.length() > 0) {
      writer.write("package %1$s;", packageName);
      writer.newline();
    }

    JClassType superType = css.getExtendedInterface();
    if (superType == null) {
      superType = cssResourceType;
    }

    writer.write("import %s;", superType.getQualifiedSourceName());
    writer.newline();

    // Open interface
    writer.write("public interface %s extends %s {", css.getClassName(),
        superType.getSimpleSourceName());
    writer.indent();

    writeCssMethods(superType);

    // Close interface.
    writer.outdent();
    writer.write("}");
  }

  private void writeCssMethods(JClassType superType) throws UnableToCompleteException {
    Set<String> classNames = css.getCssClassNames();

    /*
     * Only write names that we are not overriding from super, or else we'll
     * re-obfuscate any @Shared ones
     */
    for (String className : classNames) {
      JMethod method = superType.findMethod(className, NO_PARAMS);
      if (method == null || !stringType.equals(method.getReturnType())) {
        writer.write("String %s();", className);
      }
    }
  }
}