/*
 * Copyright 2015 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.template.soy.jbcsrc;

import static com.google.template.soy.jbcsrc.BytecodeUtils.SOY_RECORD_TYPE;

import com.google.auto.value.AutoValue;
import com.google.template.soy.jbcsrc.api.AdvisingAppendable;
import com.google.template.soy.jbcsrc.shared.CompiledTemplate;
import com.google.template.soy.jbcsrc.shared.Names;
import com.google.template.soy.jbcsrc.shared.RenderContext;
import com.google.template.soy.soytree.TemplateNode;

import org.objectweb.asm.Type;
import org.objectweb.asm.commons.Method;

/**
 * Information about a compiled template.
 *
 * <p>This should contain basic information about a single template that will be useful for
 * generating that template as well as calls to the template.
 */
@AutoValue abstract class CompiledTemplateMetadata {
  /**
   * The {@link Method} signature of all generated constructors for the {@link CompiledTemplate}
   * classes.
   */
  private static final Method GENERATED_CONSTRUCTOR =
      new Method(
          "<init>", Type.getMethodDescriptor(Type.VOID_TYPE, SOY_RECORD_TYPE, SOY_RECORD_TYPE));

  /** 
   * The {@link Method} signature of the 
   * {@link CompiledTemplate#render(AdvisingAppendable, RenderContext)}  
   * method. 
   */
  private static final Method RENDER_METHOD;

  /**
   * The {@link Method} signature of the {@link CompiledTemplate#kind()} method.
   */
  private static final Method KIND_METHOD;

  static {
    try {
      RENDER_METHOD =
          Method.getMethod(
              CompiledTemplate.class.getMethod(
                  "render", AdvisingAppendable.class, RenderContext.class));
      KIND_METHOD = Method.getMethod(CompiledTemplate.class.getMethod("kind"));
    } catch (NoSuchMethodException | SecurityException e) {
      throw new RuntimeException(e);
    }
  }

  static CompiledTemplateMetadata create(String templateName, TemplateNode node) {
    String className = Names.javaClassNameFromSoyTemplateName(templateName);
    TypeInfo type = TypeInfo.create(className);
    return new AutoValue_CompiledTemplateMetadata(
        ConstructorRef.create(type, GENERATED_CONSTRUCTOR),
        MethodRef.createInstanceMethod(type, RENDER_METHOD).asNonNullable(),
        MethodRef.createInstanceMethod(type, KIND_METHOD).asCheap(),
        type,
        node);
  }

  /** 
   * The template constructor.
   * 
   * <p>The constructor has the same interface as 
   * {@link com.google.template.soy.jbcsrc.shared.CompiledTemplate.Factory#create}
   */
  abstract ConstructorRef constructor();
  
  /** The {@link CompiledTemplate#render(AdvisingAppendable, RenderContext)} method. */
  abstract MethodRef renderMethod();

  /** The {@link CompiledTemplate#kind()} method. */
  abstract MethodRef kindMethod();

  /** The name of the compiled template. */
  abstract TypeInfo typeInfo();

  /** The actual template. */
  abstract TemplateNode node();
}