/*
 * Copyright 2008 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.msgs.restricted;

import static com.google.common.base.Preconditions.checkArgument;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.template.soy.base.SourceLocation;

import com.ibm.icu.util.ULocale;

import java.util.Objects;

import javax.annotation.Nullable;

/**
 * Represents a message in some language/locale. Contains information relevant to translation.
 *
 * <p>This class is heavily optimized for memory usage. In one major server using SoyTofu, Soy
 * messages comprised the single largest category of memory usage prior to optimization. Several
 * fields can be omitted entirely for render-only usage. ImmutableSet and ImmutableList are used
 * because their empty implementations are singletons.
 *
 */
public final class SoyMsg {


  /** A unique id for this message (same across all translations). */
  private final long id;

  /** An alternate unique id for this message. */
  private final long altId;

  /** The language/locale string. */
  private final String localeString;

  /** The meaning string if set, otherwise null (usually null). */
  private final String meaning;

  /** The description for translators. */
  private final String desc;

  /** Whether this message should be hidden. */
  private final boolean isHidden;

  /** Content type of the document that this message will appear in. */
  private final String contentType;

  /** Location(s) of the source file(s) that this message comes from. */
  private ImmutableSet<SourceLocation> sourceLocations;

  /** Whether this is a plural/select message. */
  private final boolean isPlrselMsg;

  /** The parts that make up the message content. */
  private final ImmutableList<SoyMsgPart> parts;


  /**
   * @param id A unique id for this message (same across all translations).
   * @param altId An alternate unique id for this message, or -1L if not applicable.
   * @param localeString The language/locale string, or null if unknown. Should only be null for
   *     messages newly extracted from source files. Should always be set for messages parsed from
   *     message files/resources.
   * @param meaning The meaning string, or null if not necessary (usually null). This is a string
   *     to create unique messages for two otherwise identical messages. This is usually done for
   *     messages used in different contexts. (For example, the same word can be used as a noun in
   *     one location and as a verb in another location, and the message texts would be the same
   *     but the messages would have meanings of "noun" and "verb".). May not be applicable to all
   *     message plugins.
   * @param desc The description for translators.
   * @param isHidden Whether this message should be hidden. May not be applicable to all message
   *     plugins.
   * @param contentType Content type of the document that this message will appear in
   *     (e.g. "{@code text/html}"). May not be applicable to all message plugins.
   * @param sourceLocation Location of a source file that this message comes from. More sources can
   *     be added using {@code addSourceLocation()}. May not be applicable to all message plugins.
   * @param isPlrselMsg Whether this is a plural/select message.
   * @param parts The parts that make up the message content.
   */
  public SoyMsg(
      long id, long altId, @Nullable String localeString, @Nullable String meaning,
      @Nullable String desc, boolean isHidden, @Nullable String contentType,
      @Nullable SourceLocation sourceLocation, boolean isPlrselMsg,
      Iterable<? extends SoyMsgPart> parts) {

    checkArgument(id >= 0L);
    checkArgument(altId >= -1L);
    this.id = id;
    this.altId = altId;
    this.localeString = localeString;
    this.meaning = meaning;
    this.desc = desc;
    this.isHidden = isHidden;
    this.contentType = contentType;
    this.sourceLocations = ImmutableSet.of();
    if (sourceLocation != null) {
      addSourceLocation(sourceLocation);
    }
    this.isPlrselMsg = isPlrselMsg;
    this.parts = ImmutableList.copyOf(parts);
  }


  /**
   * @param id A unique id for this message (same across all translations).
   * @param localeString The language/locale string, or null if unknown. Should only be null for
   *     messages newly extracted from source files. Should always be set for messages parsed from
   *     message files/resources.
   * @param meaning The meaning string, or null if not necessary (usually null). This is a string
   *     to create unique messages for two otherwise identical messages. This is usually done for
   *     messages used in different contexts. (For example, the same word can be used as a noun in
   *     one location and as a verb in another location, and the message texts would be the same
   *     but the messages would have meanings of "noun" and "verb".). May not be applicable to all
   *     message plugins.
   * @param desc The description for translators.
   * @param isHidden Whether this message should be hidden. May not be applicable to all message
   *     plugins.
   * @param contentType Content type of the document that this message will appear in
   *     (e.g. "{@code text/html}"). May not be applicable to all message plugins.
   * @param sourceLocation Location of a source file that this message comes from. More sources can
   *     be added using {@code addSourceLocation()}. May not be applicable to all message plugins.
   * @param parts The parts that make up the message content.
   */
  public SoyMsg(
      long id, @Nullable String localeString, @Nullable String meaning, @Nullable String desc,
      boolean isHidden, @Nullable String contentType, @Nullable SourceLocation sourceLocation,
      Iterable<? extends SoyMsgPart> parts) {
    this(id, -1L, localeString, meaning, desc, isHidden, contentType, sourceLocation, false, parts);
  }


  /**
   * Constructor with just enough information for rendering only.
   *
   * <p>Using this constructor results in a working renderable message but uses much less memory
   * than providing all the information for the full constructor.
   *
   * @param id A unique id for this message (same across all translations).
   * @param localeString The language/locale string, or null if unknown. Should only be null for
   *     messages newly extracted from source files. Should always be set for messages parsed from
   *     message files/resources.
   * @param isPlrselMsg Whether this is a plural/select message.
   * @param parts The parts that make up the message content.
   */
  public SoyMsg(
      long id, @Nullable String localeString, boolean isPlrselMsg,
      Iterable<? extends SoyMsgPart> parts) {
    this(id, -1L, localeString, null, null, false, null, null, isPlrselMsg, parts);
  }


  /** Returns the language/locale string. */
  @Nullable
  public String getLocaleString() {
    return localeString;
  }

  @Nullable
  public ULocale getLocale() {
    // TODO(lukes): Consider storing this in preference to the localeString
    return localeString == null ? null : new ULocale(localeString);
  }

  /** Returns the unique id for this message (same across all translations). */
  public long getId() {
    return id;
  }

  /** Returns the alternate unique id for this message, or -1L if not applicable. */
  public long getAltId() {
    return altId;
  }

  /** Returns the meaning string if set, otherwise null (usually null). */
  public String getMeaning() {
    return meaning;
  }

  /** Returns the description for translators. */
  public String getDesc() {
    return desc;
  }

  /** Returns whether this message should be hiddens. */
  public boolean isHidden() {
    return isHidden;
  }

  /** Returns the content type of the document that this message will appear in. */
  public String getContentType() {
    return contentType;
  }

  /** @param sourceLocation Location of a source file that this message comes from. */
  public void addSourceLocation(SourceLocation sourceLocation) {
    sourceLocations = ImmutableSet.<SourceLocation>builder()
        .addAll(sourceLocations).add(sourceLocation).build();
  }

  /** Returns the location(s) of the source file(s) that this message comes from. */
  public ImmutableSet<SourceLocation> getSourceLocations() {
    return sourceLocations;
  }

  /** Returns whether this is a plural/select message. */
  public boolean isPlrselMsg() {
    return isPlrselMsg;
  }

  /** Returns the parts that make up the message content. */
  public ImmutableList<SoyMsgPart> getParts() {
    return parts;
  }

  @Override public boolean equals(Object otherObject) {
    if (!(otherObject instanceof SoyMsg)) {
      return false;
    }
    SoyMsg other = (SoyMsg) otherObject;
    // NOTE: Source locations are not considered part of the object's identity,
    // since they're mutable.
    return id == other.id
        && altId == other.altId
        && Objects.equals(localeString, other.localeString)
        && Objects.equals(meaning, other.meaning)
        && Objects.equals(desc, other.desc)
        && isHidden == other.isHidden
        && Objects.equals(contentType, other.contentType)
        && isPlrselMsg == other.isPlrselMsg
        && Objects.equals(parts, other.parts);
  }

  @Override public int hashCode() {
    // NOTE: Source paths are not considered part of the object's identity, since they're mutable.
    return Objects.hash(
        this.getClass(), id, altId, localeString, meaning, desc, contentType, isPlrselMsg, parts);
  }

  @Override public String toString() {
    return this.getClass() + "(" + id + ", " + altId + ", " + localeString + ", " + meaning
        + ", " + desc + ", " + isHidden + ", " + contentType + ", " + sourceLocations + ", "
        + isPlrselMsg + ", " + parts + ")";
  }
}