/*
 * 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.template.soy.shared;

import static java.nio.charset.StandardCharsets.UTF_8;

import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableMap;
import com.google.common.io.Files;
import com.google.common.io.Resources;
import com.google.template.soy.SoyUtils;
import com.google.template.soy.basetree.SyntaxVersion;
import com.google.template.soy.data.internalutils.InternalValueUtils;
import com.google.template.soy.data.restricted.PrimitiveData;

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.Map;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;


/**
 * Compilation options applicable to the Soy frontend and/or to multiple Soy backends.
 *
 */
public final class SoyGeneralOptions implements Cloneable {

  /** User-declared syntax version, or null if not set. */
  @Nullable private SyntaxVersion declaredSyntaxVersion;

  /** Whether to allow external calls (calls to undefined templates). Null if not explicitly set. */
  private Boolean allowExternalCalls;

  /** Whether Strict autoescaping is required. */
  private boolean strictAutoescapingRequired;

  /** Map from compile-time global name to value. */
  private ImmutableMap<String, PrimitiveData> compileTimeGlobals;

  public SoyGeneralOptions() {}

  private SoyGeneralOptions(SoyGeneralOptions orig) {
    this.declaredSyntaxVersion = orig.declaredSyntaxVersion;
    this.allowExternalCalls = orig.allowExternalCalls;
    this.strictAutoescapingRequired = orig.strictAutoescapingRequired;
    this.compileTimeGlobals = orig.compileTimeGlobals;
  }

  /**
   * Sets the user-declared syntax version name for the Soy file bundle.
   * @param versionName The syntax version name, e.g. "1.0", "2.0", "2.3".
   */
  public SoyGeneralOptions setDeclaredSyntaxVersionName(@Nonnull String versionName) {
    this.declaredSyntaxVersion = SyntaxVersion.forName(versionName);
    return this;
  }

  /**
   * Returns the user-declared syntax version, or the given default value if the user did not
   * declare a syntax version.
   *
   * <p> Important: Do not use outside of Soy code (treat as superpackage-private).
   *
   * @param defaultSyntaxVersion The default value to return if the user did not declare a syntax
   *     version.
   */
  public SyntaxVersion getDeclaredSyntaxVersion(SyntaxVersion defaultSyntaxVersion) {
    return (declaredSyntaxVersion != null) ? declaredSyntaxVersion : defaultSyntaxVersion;
  }

  /**
   * Sets whether to allow external calls (calls to undefined templates).
   * @param allowExternalCalls The value to set.
   */
  public SoyGeneralOptions setAllowExternalCalls(boolean allowExternalCalls) {
    this.allowExternalCalls = allowExternalCalls;
    return this;
  }

  /**
   * Returns whether to allow external calls (calls to undefined templates). If this option was
   * never explicitly set, then returns null.
   */
  public Boolean allowExternalCalls() {
    return allowExternalCalls;
  }

  /**
   * Sets whether strict autoescaping is required.
   * @param strictAutoescapingRequired Whether autoescaping is required.
   */
  public SoyGeneralOptions setStrictAutoescapingRequired(boolean strictAutoescapingRequired) {
    this.strictAutoescapingRequired = strictAutoescapingRequired;
    return this;
  }

  /**
   * Returns whether strict autoescaping is required.
   */
  public boolean isStrictAutoescapingRequired() {
    return strictAutoescapingRequired;
  }

  /**
   * Sets the map from compile-time global name to value.
   *
   * <p> The values can be any of the Soy primitive types: null, boolean, integer, float (Java
   * double), or string.
   *
   * @param compileTimeGlobalsMap Map from compile-time global name to value. The values can be
   *     any of the Soy primitive types: null, boolean, integer, float (Java double), or string.
   * @throws com.google.template.soy.base.SoySyntaxException If one of the values is not a valid
   *        Soy primitive type.
   */
  public SoyGeneralOptions setCompileTimeGlobals(Map<String, ?> compileTimeGlobalsMap) {
    setCompileTimeGlobalsInternal(
        InternalValueUtils.convertCompileTimeGlobalsMap(compileTimeGlobalsMap));
    return this;
  }

  /**
   * Sets the map from compile-time global name to value using Soy primitive types.
   *
   * @param compileTimeGlobalsMap Map from compile-time global name to value.
   */
  private void setCompileTimeGlobalsInternal(
      ImmutableMap<String, PrimitiveData> compileTimeGlobalsMap) {
    Preconditions.checkState(compileTimeGlobals == null, "Compile-time globals already set.");
    compileTimeGlobals = compileTimeGlobalsMap;
  }

  /**
   * Sets the file containing compile-time globals.
   *
   * <p> Each line of the file should have the format
   * <pre>
   *     &lt;global_name&gt; = &lt;primitive_data&gt;
   * </pre>
   * where primitive_data is a valid Soy expression literal for a primitive type (null, boolean,
   * integer, float, or string). Empty lines and lines beginning with "//" are ignored. The file
   * should be encoded in UTF-8.
   *
   * <p> If you need to generate a file in this format from Java, consider using the utility
   * {@code SoyUtils.generateCompileTimeGlobalsFile()}.
   *
   * @param compileTimeGlobalsFile The file containing compile-time globals.
   * @throws IOException If there is an error reading the compile-time globals file.
   */
  public SoyGeneralOptions setCompileTimeGlobals(File compileTimeGlobalsFile) throws IOException {
    setCompileTimeGlobalsInternal(SoyUtils.parseCompileTimeGlobals(
        Files.asCharSource(compileTimeGlobalsFile, UTF_8)));
    return this;
  }

  /**
   * Sets the resource file containing compile-time globals.
   *
   * <p> Each line of the file should have the format
   * <pre>
   *     &lt;global_name&gt; = &lt;primitive_data&gt;
   * </pre>
   * where primitive_data is a valid Soy expression literal for a primitive type (null, boolean,
   * integer, float, or string). Empty lines and lines beginning with "//" are ignored. The file
   * should be encoded in UTF-8.
   *
   * <p> If you need to generate a file in this format from Java, consider using the utility
   * {@code SoyUtils.generateCompileTimeGlobalsFile()}.
   *
   * @param compileTimeGlobalsResource The resource file containing compile-time globals.
   * @throws IOException If there is an error reading the compile-time globals file.
   */
  public SoyGeneralOptions setCompileTimeGlobals(URL compileTimeGlobalsResource)
      throws IOException {
    setCompileTimeGlobalsInternal(SoyUtils.parseCompileTimeGlobals(
        Resources.asCharSource(compileTimeGlobalsResource, UTF_8)));
    return this;
  }

  /**
   * Returns the map from compile-time global name to value.
   */
  public ImmutableMap<String, PrimitiveData> getCompileTimeGlobals() {
    return compileTimeGlobals == null
        ? ImmutableMap.<String, PrimitiveData>of()
        : compileTimeGlobals;
  }

  @Override public final SoyGeneralOptions clone() {
    return new SoyGeneralOptions(this);
  }
}