/*
 * 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.cbor;

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

import java.io.*;
import java.math.*;
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.parser.*;
import org.apache.juneau.marshall.stream.*;

/**
 * Parses CBOR streams (RFC 8949) into POJO models.
 *
 * <h5 class='topic'>Media types</h5>
 *
 * Handles <c>Content-Type</c> types:  <bc>application/cbor</bc>
 *
 * <h5 class='topic'>Description</h5>
 * <p>
 * CBOR-to-Java type mapping:
 * <ul class='spaced-list'>
 *    <li>CBOR map (major type 5) → bean or {@link Map}
 *    <li>CBOR array (major type 4) → {@link Collection} or Java array
 *    <li>CBOR text string (major type 3) → {@link String}; coerced to types parseable from string
 *    <li>CBOR unsigned/negative integer (major types 0/1) → {@link Integer} or {@link Long}
 *    <li>CBOR float (major type 7, 0xFA/0xFB) → {@link Float} or {@link Double}
 *    <li>CBOR half-precision float (major type 7, 0xF9) → {@link Float} (converted)
 *    <li>CBOR boolean (major type 7, 0xF4/0xF5) → {@link Boolean}
 *    <li>CBOR null (major type 7, 0xF6) → {@code null}
 *    <li>CBOR byte string (major type 2) → {@code byte[]}
 *    <li>CBOR semantic tag (major type 6) → tag ignored; tagged value parsed normally
 * </ul>
 *
 * <h5 class='section'>Round-trip notes:</h5>
 * <ul class='spaced-list'>
 *    <li>Integers (major types 0/1) surface by target type: a {@link BigInteger} field carries the full
 *       unsigned-64-bit magnitude; any other numeric type keeps the raw 64-bit bits as a {@code long}.
 *    <li>{@link BigInteger} / {@link BigDecimal} round-trip losslessly (big integers decode from native
 *       CBOR integers or, beyond {@code ±2^64}, from their decimal string; {@link BigDecimal} decodes
 *       from its decimal string).
 *    <li>Indefinite-length CBOR (RFC 8949 §3.2) is supported: arrays, maps, and chunked text/byte
 *       strings all decode.
 *    <li>Semantic tags are read and discarded on the databind path; tag number does not affect parsed
 *       type.  Enable {@link Builder#nativeMode() nativeMode} to surface tags/simple values on the
 *       {@link TokenReader} cursor.
 * </ul>
 *
 * <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/Cbor">CBOR</a>
 *    <li class='link'><a class="doclink" href="https://www.rfc-editor.org/rfc/rfc8949.html">RFC 8949</a>
 * </ul>
 */
@SuppressWarnings({
   "java:S110", // Inheritance depth acceptable for this class hierarchy
   "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" // Closeable resources are owned by the caller's parser session; Eclipse JDT @Owning warning is by design.
})
public class CborParser extends InputStreamParser implements CborMetaProvider, TokenReadable, ArrayRecordReadable {

   private static final int DEFAULT_MAX_LENGTH = CborInputStream.DEFAULT_MAX_LENGTH;

   /** Default parser, string input encoded as BASE64. */
   public static class Base64 extends CborParser {

      /**
       * Constructor.
       *
       * @param builder The builder for this object.
       */
      public Base64(Builder builder) {
         super(builder.binaryFormat(BinaryFormat.BASE64));
      }
   }

   /**
    * Builder class.
    */
   public static class Builder extends InputStreamParser.Builder<Builder> {

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

      private boolean nativeMode;
      private int maxLength = DEFAULT_MAX_LENGTH;

      /**
       * Constructor, default settings.
       */
      protected Builder() {
         consumes("application/cbor");
         nativeMode = env("CborParser.nativeMode", false);
         maxLength = env("CborParser.maxLength", DEFAULT_MAX_LENGTH);
      }

      /**
       * Copy constructor.
       *
       * @param copyFrom The builder to copy from.
       */
      protected Builder(Builder copyFrom) {
         super(reqnn("copyFrom", copyFrom));
         nativeMode = copyFrom.nativeMode;
         maxLength = copyFrom.maxLength;
      }

      /**
       * Copy constructor.
       *
       * @param copyFrom The parser to copy from.
       */
      protected Builder(CborParser copyFrom) {
         super(reqnn("copyFrom", copyFrom));
         nativeMode = copyFrom.nativeMode;
         maxLength = copyFrom.maxLength;
      }

      /**
       * Surfaces CBOR semantic tags and simple values as token-level metadata on
       * {@link TokenReader} cursors returned by {@link CborParserSession#readTokens(Object)}.
       *
       * <p>
       * When enabled, tags accumulate on the cursor's tag stack (visible via
       * {@link TokenReader#getTagCount()} / {@link TokenReader#getTag(int)}) and simple values
       * surface their int via {@link TokenReader#getSimpleValue()} on
       * {@link TokenType#VALUE_NULL} tokens.  When disabled (default), tags are silently
       * unwrapped and simple values collapse to {@link TokenType#VALUE_NULL} with no metadata.
       *
       * <p>
       * This is a token-cursor-level setting and does not affect the high-level POJO databind
       * path ({@link CborParser#read(Object, Class)}); that path always discards tags.
       *
       * @return This object.
       */
      public Builder nativeMode() {
         return nativeMode(true);
      }

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

      /**
       * The maximum allowed wire-declared length for CBOR byte/text strings and array/map element counts.
       *
       * <p>
       * Guards against malformed or adversarial input where a small payload declares a huge length or
       * element count, which would otherwise trigger {@link OutOfMemoryError}.  Malformed lengths are
       * reported as a clean parse error instead.
       *
       * @param value The maximum length.  Default is 16 MiB.  Values &le; 0 disable the cap.
       * @return This object.
       */
      public Builder maxLength(int value) {
         maxLength = value;
         return this;
      }

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

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

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

   /** Default parser, string input encoded as spaced-hex. */
   public static class SpacedHex extends CborParser {

      /**
       * Constructor.
       *
       * @param builder The builder for this object.
       */
      public SpacedHex(Builder builder) {
         super(builder.binaryFormat(BinaryFormat.SPACED_HEX));
      }
   }

   /** Default parser, all default settings. */
   public static final CborParser DEFAULT = new CborParser(create());
   /** Default parser with binary-native opt-in mode enabled (CBOR tags / simple values surface as token-level metadata). */
   public static final CborParser DEFAULT_NATIVE = new CborParser(create().nativeMode());
   /** Default parser, string input encoded as spaced-hex. */
   public static final CborParser DEFAULT_SPACED_HEX = new SpacedHex(create());
   /** Default parser, string input encoded as BASE64. */
   public static final CborParser DEFAULT_BASE64 = new Base64(create());

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

   protected final boolean nativeMode;

   private final int maxLength;

   private final Map<ClassMeta<?>,CborClassMeta> cborClassMetas = new ConcurrentHashMap<>();
   private final Map<BeanPropertyMeta,CborBeanPropertyMeta> cborBeanPropertyMetas = new ConcurrentHashMap<>();

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

   /**
    * Returns <jk>true</jk> if token-cursor native mode is enabled.
    *
    * @return <jk>true</jk> if native mode is enabled, else <jk>false</jk>.
    */
   public boolean isNativeMode() {
      return nativeMode;
   }

   /**
    * Returns the maximum allowed wire-declared length for byte/text strings and array/map element counts.
    *
    * @return The maximum length.
    */
   public int getMaxLength() {
      return maxLength;
   }

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

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

   @Override /* Overridden from CborMetaProvider */
   public CborBeanPropertyMeta getCborBeanPropertyMeta(BeanPropertyMeta bpm) {
      if (bpm == null)
         return CborBeanPropertyMeta.DEFAULT;
      return cborBeanPropertyMetas.computeIfAbsent(bpm, k -> new CborBeanPropertyMeta(k.getDelegateFor(), this));
   }

   @Override /* Overridden from CborMetaProvider */
   public CborClassMeta getCborClassMeta(ClassMeta<?> cm) {
      return cborClassMetas.computeIfAbsent(cm, k -> new CborClassMeta(k, this));
   }

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

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

   /**
    * Convenience delegator for the streaming array-element {@link RecordReader} (uses default
    * session args; see {@link #readTokens(Object)}).  Real impl on
    * {@link CborParserSession#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);
   }

   @Override /* Overridden from InputStreamParser */
   protected FluentMap<String,Object> properties() {
      return super.properties()
         .a("nativeMode", nativeMode);
   }
}