/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.juneau.json;

import static org.apache.juneau.commons.utils.AssertionUtils.*;
import static org.apache.juneau.commons.utils.Utils.*;

import java.lang.annotation.*;
import java.nio.charset.*;
import java.util.*;
import java.util.concurrent.*;

import org.apache.juneau.*;
import org.apache.juneau.collections.*;
import org.apache.juneau.commons.collections.*;
import org.apache.juneau.commons.function.*;
import org.apache.juneau.commons.reflect.*;
import org.apache.juneau.parser.*;

/**
 * Parses any valid JSON text into a POJO model.
 *
 * <h5 class='topic'>Media types</h5>
 * <p>
 * Handles <c>Content-Type</c> types:  <bc>application/json, text/json</bc>
 *
 * <h5 class='topic'>Description</h5>
 * <p>
 * This parser uses a state machine, which makes it very fast and efficient.  It parses JSON in about 70% of the
 * time that it takes the built-in Java DOM parsers to parse equivalent XML.
 *
 * <p>
 * This parser handles all valid JSON syntax.
 * In addition, when strict mode is disable, the parser also handles the following:
 * <ul class='spaced-list'>
 *    <li>
 *       Javascript comments (both {@code /*} and {@code //}) are ignored.
 *    <li>
 *       Both single and double quoted strings.
 *    <li>
 *       Automatically joins concatenated strings (e.g. <code><js>"aaa"</js> + <js>'bbb'</js></code>).
 *    <li>
 *       Unquoted attributes and values.
 * </ul>
 *
 * <p>
 * Also handles negative, decimal, hexadecimal, octal, and double numbers, including exponential notation.
 *
 * <p>
 * This parser handles the following input, and automatically returns the corresponding Java class.
 * <ul class='spaced-list'>
 *    <li>
 *       JSON objects (<js>"{...}"</js>) are converted to {@link JsonMap JsonMaps}.
 *       <b>Note:</b>  If a <code><xa>_type</xa>=<xs>'xxx'</xs></code> attribute is specified on the object, then an
 *       attempt is made to convert the object to an instance of the specified Java bean class.
 *       See the {@link org.apache.juneau.BeanContext.Builder#typePropertyName(String)} setting for more information about parsing
 *       beans from JSON.
 *    <li>
 *       JSON arrays (<js>"[...]"</js>) are converted to {@link JsonList JsonLists}.
 *    <li>
 *       JSON string literals (<js>"'xyz'"</js>) are converted to {@link String Strings}.
 *    <li>
 *       JSON numbers (<js>"123"</js>, including octal/hexadecimal/exponential notation) are converted to
 *       {@link Integer Integers}, {@link Long Longs}, {@link Float Floats}, or {@link Double Doubles} depending on
 *       whether the number is decimal, and the size of the number.
 *    <li>
 *       JSON booleans (<js>"false"</js>) are converted to {@link Boolean Booleans}.
 *    <li>
 *       JSON nulls (<js>"null"</js>) are converted to <jk>null</jk>.
 *    <li>
 *       Input consisting of only whitespace or JSON comments are converted to <jk>null</jk>.
 * </ul>
 *
 * <p>
 * Input can be any of the following:
 * <ul class='spaced-list'>
 *    <li>
 *       <js>"{...}"</js> - Converted to an {@link JsonMap} or an instance of a Java bean if a <xa>_type</xa>
 *       attribute is present.
 *    <li>
 *       <js>"[...]"</js> - Converted to an {@link JsonList}.
 *    <li>
 *       <js>"123..."</js> - Converted to a {@link Number} (either {@link Integer}, {@link Long}, {@link Float},
 *       or {@link Double}).
 *    <li>
 *       <js>"true"</js>/<js>"false"</js> - Converted to a {@link Boolean}.
 *    <li>
 *       <js>"null"</js> - Returns <jk>null</jk>.
 *    <li>
 *       <js>"'xxx'"</js> - Converted to a {@link String}.
 *    <li>
 *       <js>"\"xxx\""</js> - Converted to a {@link String}.
 *    <li>
 *       <js>"'xxx' + \"yyy\""</js> - Converted to a concatenated {@link String}.
 * </ul>
 *
 * <p>
 * TIP:  If you know you're parsing a JSON object or array, it can be easier to parse it using the
 * {@link JsonMap#JsonMap(CharSequence) JsonMap(CharSequence)} or {@link JsonList#JsonList(CharSequence)
 * JsonList(CharSequence)} constructors instead of using this class.
 * The end result should be the same.
 *
 * <h5 class='section'>Notes:</h5><ul>
 *    <li class='note'>This class is thread safe and reusable.
 * </ul>
 *
 * <h5 class='section'>See Also:</h5><ul>
 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/JsonBasics">JSON Basics</a>

 * </ul>
 */
public class JsonParser extends ReaderParser implements JsonMetaProvider {
   /**
    * Builder class.
    */
   public static class Builder extends ReaderParser.Builder {

      private static final Cache<HashKey,JsonParser> CACHE = Cache.of(HashKey.class, JsonParser.class).build();

      private boolean validateEnd;

      /**
       * Constructor, default settings.
       */
      protected Builder() {
         consumes("application/json,text/json");
         validateEnd = env("JsonParser.validateEnd", false);
      }

      /**
       * Copy constructor.
       *
       * @param copyFrom The builder to copy from.
       *    <br>Cannot be <jk>null</jk>.
       */
      protected Builder(Builder copyFrom) {
         super(assertArgNotNull("copyFrom", copyFrom));
         validateEnd = copyFrom.validateEnd;
      }

      /**
       * Copy constructor.
       *
       * @param copyFrom The bean to copy from.
       *    <br>Cannot be <jk>null</jk>.
       */
      protected Builder(JsonParser copyFrom) {
         super(assertArgNotNull("copyFrom", copyFrom));
         validateEnd = copyFrom.validateEnd;
      }

      @Override /* Overridden from Builder */
      public Builder annotations(Annotation...values) {
         super.annotations(values);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder apply(AnnotationWorkList work) {
         super.apply(work);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder applyAnnotations(Class<?>...from) {
         super.applyAnnotations(from);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder applyAnnotations(Object...from) {
         super.applyAnnotations(from);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder autoCloseStreams() {
         super.autoCloseStreams();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder autoCloseStreams(boolean value) {
         super.autoCloseStreams(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanClassVisibility(Visibility value) {
         super.beanClassVisibility(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanConstructorVisibility(Visibility value) {
         super.beanConstructorVisibility(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanContext(BeanContext value) {
         super.beanContext(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanContext(BeanContext.Builder value) {
         super.beanContext(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanDictionary(java.lang.Class<?>...values) {
         super.beanDictionary(values);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanFieldVisibility(Visibility value) {
         super.beanFieldVisibility(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanInterceptor(Class<?> on, Class<? extends org.apache.juneau.swap.BeanInterceptor<?>> value) {
         super.beanInterceptor(on, value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanMapPutReturnsOldValue() {
         super.beanMapPutReturnsOldValue();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanMethodVisibility(Visibility value) {
         super.beanMethodVisibility(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanProperties(Class<?> beanClass, String properties) {
         super.beanProperties(beanClass, properties);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanProperties(Map<String,Object> values) {
         super.beanProperties(values);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanProperties(String beanClassName, String properties) {
         super.beanProperties(beanClassName, properties);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanPropertiesExcludes(Class<?> beanClass, String properties) {
         super.beanPropertiesExcludes(beanClass, properties);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanPropertiesExcludes(Map<String,Object> values) {
         super.beanPropertiesExcludes(values);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanPropertiesExcludes(String beanClassName, String properties) {
         super.beanPropertiesExcludes(beanClassName, properties);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanPropertiesReadOnly(Class<?> beanClass, String properties) {
         super.beanPropertiesReadOnly(beanClass, properties);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanPropertiesReadOnly(Map<String,Object> values) {
         super.beanPropertiesReadOnly(values);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanPropertiesReadOnly(String beanClassName, String properties) {
         super.beanPropertiesReadOnly(beanClassName, properties);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanPropertiesWriteOnly(Class<?> beanClass, String properties) {
         super.beanPropertiesWriteOnly(beanClass, properties);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanPropertiesWriteOnly(Map<String,Object> values) {
         super.beanPropertiesWriteOnly(values);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beanPropertiesWriteOnly(String beanClassName, String properties) {
         super.beanPropertiesWriteOnly(beanClassName, properties);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beansRequireDefaultConstructor() {
         super.beansRequireDefaultConstructor();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beansRequireSerializable() {
         super.beansRequireSerializable();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder beansRequireSettersForGetters() {
         super.beansRequireSettersForGetters();
         return this;
      }

      @Override /* Overridden from Context.Builder */
      public JsonParser build() {
         return cache(CACHE).build(JsonParser.class);
      }

      @Override /* Overridden from Builder */
      public Builder cache(Cache<HashKey,? extends org.apache.juneau.Context> value) {
         super.cache(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder consumes(String value) {
         super.consumes(value);
         return this;
      }

      @Override /* Overridden from Context.Builder */
      public Builder copy() {
         return new Builder(this);
      }

      @Override /* Overridden from Builder */
      public Builder debug() {
         super.debug();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder debug(boolean value) {
         super.debug(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder debugOutputLines(int value) {
         super.debugOutputLines(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder dictionaryOn(Class<?> on, java.lang.Class<?>...values) {
         super.dictionaryOn(on, values);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder disableBeansRequireSomeProperties() {
         super.disableBeansRequireSomeProperties();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder disableIgnoreMissingSetters() {
         super.disableIgnoreMissingSetters();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder disableIgnoreTransientFields() {
         super.disableIgnoreTransientFields();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder disableIgnoreUnknownNullBeanProperties() {
         super.disableIgnoreUnknownNullBeanProperties();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder disableInterfaceProxies() {
         super.disableInterfaceProxies();
         return this;
      }

      @Override /* Overridden from Builder */
      public <T> Builder example(Class<T> pojoClass, String json) {
         super.example(pojoClass, json);
         return this;
      }

      @Override /* Overridden from Builder */
      public <T> Builder example(Class<T> pojoClass, T o) {
         super.example(pojoClass, o);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder fileCharset(Charset value) {
         super.fileCharset(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder findFluentSetters() {
         super.findFluentSetters();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder findFluentSetters(Class<?> on) {
         super.findFluentSetters(on);
         return this;
      }

      @Override /* Overridden from Context.Builder */
      public HashKey hashKey() {
         return HashKey.of(super.hashKey(), validateEnd);
      }

      @Override /* Overridden from Builder */
      public Builder ignoreInvocationExceptionsOnGetters() {
         super.ignoreInvocationExceptionsOnGetters();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder ignoreInvocationExceptionsOnSetters() {
         super.ignoreInvocationExceptionsOnSetters();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder ignoreUnknownBeanProperties() {
         super.ignoreUnknownBeanProperties();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder ignoreUnknownEnumValues() {
         super.ignoreUnknownEnumValues();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder impl(Context value) {
         super.impl(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder implClass(Class<?> interfaceClass, Class<?> implClass) {
         super.implClass(interfaceClass, implClass);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder implClasses(Map<Class<?>,Class<?>> values) {
         super.implClasses(values);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder interfaceClass(Class<?> on, Class<?> value) {
         super.interfaceClass(on, value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder interfaces(java.lang.Class<?>...value) {
         super.interfaces(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder listener(Class<? extends org.apache.juneau.parser.ParserListener> value) {
         super.listener(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder locale(Locale value) {
         super.locale(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder mediaType(MediaType value) {
         super.mediaType(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder notBeanClasses(java.lang.Class<?>...values) {
         super.notBeanClasses(values);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder notBeanPackages(String...values) {
         super.notBeanPackages(values);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder propertyNamer(Class<?> on, Class<? extends org.apache.juneau.PropertyNamer> value) {
         super.propertyNamer(on, value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder propertyNamer(Class<? extends org.apache.juneau.PropertyNamer> value) {
         super.propertyNamer(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder sortProperties() {
         super.sortProperties();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder sortProperties(java.lang.Class<?>...on) {
         super.sortProperties(on);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder stopClass(Class<?> on, Class<?> value) {
         super.stopClass(on, value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder streamCharset(Charset value) {
         super.streamCharset(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder strict() {
         super.strict();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder strict(boolean value) {
         super.strict(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public <T,S> Builder swap(Class<T> normalClass, Class<S> swappedClass, ThrowingFunction<T,S> swapFunction) {
         super.swap(normalClass, swappedClass, swapFunction);
         return this;
      }

      @Override /* Overridden from Builder */
      public <T,S> Builder swap(Class<T> normalClass, Class<S> swappedClass, ThrowingFunction<T,S> swapFunction, ThrowingFunction<S,T> unswapFunction) {
         super.swap(normalClass, swappedClass, swapFunction, unswapFunction);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder swaps(Class<?>...values) {
         super.swaps(values);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder swaps(Object...values) {
         super.swaps(values);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder timeZone(TimeZone value) {
         super.timeZone(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder trimStrings() {
         super.trimStrings();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder trimStrings(boolean value) {
         super.trimStrings(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder type(Class<? extends org.apache.juneau.Context> value) {
         super.type(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder typeName(Class<?> on, String value) {
         super.typeName(on, value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder typePropertyName(Class<?> on, String value) {
         super.typePropertyName(on, value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder typePropertyName(String value) {
         super.typePropertyName(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder unbuffered() {
         super.unbuffered();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder unbuffered(boolean value) {
         super.unbuffered(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder useEnumNames() {
         super.useEnumNames();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder useJavaBeanIntrospector() {
         super.useJavaBeanIntrospector();
         return this;
      }

      /**
       * Validate end.
       *
       * <p>
       * When enabled, after parsing a POJO from the input, verifies that the remaining input in
       * the stream consists of only comments or whitespace.
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a parser that validates that there's no garbage at the end of the input.</jc>
       *    ReaderParser <jv>parser</jv> = JsonParser.
       *       .<jsm>create</jsm>()
       *       .validateEnd()
       *       .build();
       *
       *    <jc>// Should fail because input has multiple POJOs.</jc>
       *    String <jv>json</jv> = <js>"{foo:'bar'}{baz:'qux'}"</js>;
       *    MyBean <jv>myBean</jv> =<jv>parser</jv>.parse(<jv>json</jv>, MyBean.<jk>class</jk>);
       * </p>
       *
       * @return This object.
       */
      public Builder validateEnd() {
         return validateEnd(true);
      }

      /**
       * Same as {@link #validateEnd()} but allows you to explicitly specify the value.
       *
       * @param value The value for this setting.
       * @return This object.
       */
      public Builder validateEnd(boolean value) {
         validateEnd = value;
         return this;
      }
   }

   /** Default parser, strict mode. */
   public static class Strict extends JsonParser {

      /**
       * Constructor.
       *
       * @param builder The builder for this object.
       */
      public Strict(Builder builder) {
         super(builder.strict().validateEnd());
      }
   }

   /** Default parser, all default settings.*/
   public static final JsonParser DEFAULT = new JsonParser(create());
   /** Default parser, all default settings.*/
   public static final JsonParser DEFAULT_STRICT = new JsonParser.Strict(create());

   /**
    * Creates a new builder for this object.
    *
    * @return A new builder.
    */
   public static Builder create() {
      return new Builder();
   }

   protected final boolean validateEnd;

   private final Map<BeanPropertyMeta,JsonBeanPropertyMeta> jsonBeanPropertyMetas = new ConcurrentHashMap<>();
   private final Map<ClassMeta<?>,JsonClassMeta> jsonClassMetas = new ConcurrentHashMap<>();

   /**
    * Constructor.
    *
    * @param builder The builder for this object.
    */
   public JsonParser(Builder builder) {
      super(builder);
      validateEnd = builder.validateEnd;
   }

   @Override /* Overridden from Context */
   public Builder copy() {
      return new Builder(this);
   }

   @Override /* Overridden from Context */
   public JsonParserSession.Builder createSession() {
      return JsonParserSession.create(this);
   }

   @Override /* Overridden from JsonMetaProvider */
   public JsonBeanPropertyMeta getJsonBeanPropertyMeta(BeanPropertyMeta bpm) {
      if (bpm == null)
         return JsonBeanPropertyMeta.DEFAULT;
      JsonBeanPropertyMeta m = jsonBeanPropertyMetas.get(bpm);
      if (m == null) {
         m = new JsonBeanPropertyMeta(bpm.getDelegateFor(), this);
         jsonBeanPropertyMetas.put(bpm, m);
      }
      return m;
   }

   @Override /* Overridden from JsonMetaProvider */
   public JsonClassMeta getJsonClassMeta(ClassMeta<?> cm) {
      JsonClassMeta m = jsonClassMetas.get(cm);
      if (m == null) {
         m = new JsonClassMeta(cm, this);
         jsonClassMetas.put(cm, m);
      }
      return m;
   }

   @Override /* Overridden from Context */
   public JsonParserSession getSession() { return createSession().build(); }

   /**
    * Validate end.
    *
    * @see Builder#validateEnd()
    * @return
    *    <jk>true</jk> if after parsing a POJO from the input, verifies that the remaining input in
    *    the stream consists of only comments or whitespace.
    */
   protected final boolean isValidateEnd() { return validateEnd; }
}