/*
 * 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.marshall.json;

import static org.apache.juneau.commons.utils.Shorts.*;
import static org.apache.juneau.commons.utils.SystemUtils.*;

import java.io.*;
import java.util.*;
import java.util.concurrent.*;

import org.apache.juneau.commons.bean.*;
import org.apache.juneau.commons.collections.*;
import org.apache.juneau.marshall.*;
import org.apache.juneau.marshall.collections.*;
import org.apache.juneau.marshall.json5.*;
import org.apache.juneau.marshall.parser.*;
import org.apache.juneau.marshall.stream.*;

/**
 * Parses any valid RFC 8259 JSON text into a POJO model.
 *
 * <p>
 * This parser strictly enforces RFC 8259 JSON syntax. Double-quoted strings only; single-quoted strings,
 * comments, trailing commas, and unquoted keys are rejected. For JSON5 syntax (single quotes, comments,
 * etc.), use {@link Json5Parser}.
 *
 * <h5 class='topic'>Media types</h5>
 * <p>
 * Handles <c>Content-Type</c> types:  <bc>application/json, text/json, application/jcs+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 RFC 8259 JSON syntax.
 *
 * <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.marshall.MarshallingContext.Builder#typePropertyName(String) MarshallingContext.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>.
 * </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} (double quotes only).
 * </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='figure'>Example input (Map of name/age):</h5>
 * <p class='bjson'>
 *    {<js>"name"</js>:<js>"Alice"</js>,<js>"age"</js>:30}
 * </p>
 *
 * <h5 class='figure'>Complex (nested object + array):</h5>
 * <p class='bjson'>
 *    {<js>"name"</js>:<js>"Alice"</js>,<js>"age"</js>:30,<js>"address"</js>:{<js>"street"</js>:<js>"123 Main St"</js>,<js>"city"</js>:<js>"Boston"</js>,<js>"state"</js>:<js>"MA"</js>},<js>"tags"</js>:[<js>"a"</js>,<js>"b"</js>,<js>"c"</js>]}
 * </p>
 *
 * <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/JsonSupport">JSON</a>
 *    <li class='link'>{@link Json5Parser} - For JSON5 syntax (single quotes, comments, etc.)
 * </ul>
 */
@SuppressWarnings({
   "java:S110", // Inheritance depth acceptable
   "java:S1192", // Duplicated literals (argument/property names) read more clearly inline than as constants
   "java:S9149", // Per-format static factories intentionally shadow the parent's.
   "resource" // readTokens(...) returns a Closeable owned by the caller; Eclipse JDT @Owning warning is by design.
})
public class JsonParser extends ReaderParser implements JsonMetaProvider, TokenReadable, ArrayRecordReadable {

   /**
    * Builder class.
    *
    * <p>
    * Unlike the abstract context builders, this builder is concrete <i>and</i> generic: it terminates the CRTP
    * recursion via the leaf-free {@code new Builder<>()} pattern (see {@link JsonParser#create()} /
    * {@link JsonParser#copy()}) rather than via a separate concrete {@code DefaultBuilder} leaf.
    */
   @SuppressWarnings({
      "java:S119" // 'SELF' (CRTP self-type) is intentional and clearer than a single-letter name.
   })
   public static class Builder<SELF extends Builder<SELF>> extends ReaderParser.Builder<SELF> {

      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,application/jcs+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(reqnn("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(reqnn("copyFrom", copyFrom));
         validateEnd = copyFrom.validateEnd;
      }

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

      @Override /* Overridden from Context.Builder<?> */
      @SuppressWarnings({
         "unchecked" // CRTP self-type cast on the leaf-free Builder copy is safe by construction.
      })
      public SELF copy() {
         return (SELF) new Builder<>(this);
      }

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


      /**
       * 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>.read(<jv>json</jv>, MyBean.<jk>class</jk>);
       * </p>
       *
       * <p>
       * <b>Token streams:</b> this setting is not honored by {@link #readTokens(Object) readTokens}
       * &mdash; the cursor leaves end-of-input checking to the caller.
       *
       * @return This object.
       */
      public SELF 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 SELF validateEnd(boolean value) {
         validateEnd = value;
         return self();
      }
   }

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

   /**
    * Creates a new builder for this object.
    *
    * @return A new builder.
    */
   @SuppressWarnings({
      "java:S1452" // Self-typed builder: Builder<?> is the only non-raw, leaf-free return; chaining + build() unaffected.
   })
   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;
      return jsonBeanPropertyMetas.computeIfAbsent(bpm, k -> new JsonBeanPropertyMeta(k.getDelegateFor(), this));
   }

   @Override /* Overridden from JsonMetaProvider */
   public JsonClassMeta getJsonClassMeta(ClassMeta<?> cm) {
      return jsonClassMetas.computeIfAbsent(cm, k -> new JsonClassMeta(k, this));
   }

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

   /**
    * Convenience delegator that opens a {@link JsonTokenReader} over the input using
    * <b>default session arguments</b> (mirrors {@link #read(Object, Class)}).
    *
    * <p>
    * The real implementation lives on {@link JsonParserSession#readTokens(Object)}.  Callers
    * that need request-derived configuration (locale, timezone, schema, swaps) should call
    * {@link #createSession()} and invoke {@link JsonParserSession#readTokens(Object)} on the
    * built session instead.
    *
    * @param input The input.  Accepts {@link Reader}, {@link CharSequence}, {@link InputStream},
    *    <code><jk>byte</jk>[]</code>, or {@link File}.
    * @return A new {@link JsonTokenReader}.
    * @throws IOException If a problem occurred opening the underlying input.
    */
   @Override /* TokenReadable */
   public TokenReader readTokens(Object input) throws IOException {
      return getSession().readTokens(input);
   }

   /**
    * 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; }

   /**
    * Convenience delegator for the streaming array-element {@link RecordReader} (uses default
    * session args; see {@link #readTokens(Object)}).  Real impl on
    * {@link JsonParserSession#readArrayRecords(Object)}.
    *
    * @param input The input.
    * @return A new element-streamed {@link RecordReader}.
    * @throws IOException If a problem occurred opening the underlying input.
    */
   @Override /* ArrayRecordReadable */
   public RecordReader readArrayRecords(Object input) throws IOException {
      return getSession().readArrayRecords(input);
   }
}