/*
 * 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.rest.client;

import static org.apache.juneau.commons.utils.ThrowableUtils.*;
import static org.apache.juneau.commons.utils.Utils.*;
import static org.apache.juneau.httppart.HttpPartType.*;

import java.lang.reflect.*;
import java.time.*;
import java.util.*;
import java.util.regex.*;

import org.apache.http.*;
import org.apache.juneau.*;
import org.apache.juneau.assertions.*;
import org.apache.juneau.commons.lang.*;
import org.apache.juneau.commons.reflect.*;
import org.apache.juneau.http.header.*;
import org.apache.juneau.httppart.*;
import org.apache.juneau.oapi.*;
import org.apache.juneau.parser.ParseException;
import org.apache.juneau.rest.client.assertion.*;

/**
 * Represents a single header on an HTTP response.
 *
 * <p>
 * An extension of an HttpClient {@link Header} that provides various support for converting the header to POJOs and
 * other convenience methods.
 *
 * <h5 class='section'>See Also:</h5><ul>
 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/JuneauRestClientBasics">juneau-rest-client Basics</a>
 * </ul>
 */
public class ResponseHeader extends BasicHeader {

   private static final long serialVersionUID = 1L;

   static final Header NULL_HEADER = new Header() {

      @Override /* Overridden from Header */
      public HeaderElement[] getElements() throws org.apache.http.ParseException { return new HeaderElement[0]; }

      @Override /* Overridden from Header */
      public String getName() { return null; }

      @Override /* Overridden from Header */
      public String getValue() { return null; }
   };

   private final HeaderElement[] elements;
   private final RestRequest request;
   private final RestResponse response;
   private HttpPartParserSession parser;
   private HttpPartSchema schema;

   /**
    * Constructor.
    * @param name The header name.
    * @param request The request object.
    * @param response The response object.
    * @param header The wrapped header.  Can be <jk>null</jk>.
    * @throws IllegalArgumentException If name is <jk>null</jk> or empty.
    */
   public ResponseHeader(String name, RestRequest request, RestResponse response, Header header) {
      super(name, header == null ? null : header.getValue());
      this.request = request;
      this.response = response;
      this.elements = header == null ? new HeaderElement[0] : header.getElements();
      parser(null);
   }

   /**
    * Converts this header to the specified type.
    *
    * @param <T> The type to convert to.
    * @param type The type to convert to.
    * @return The converted type, or <jk>null</jk> if header is not present.
    */
   public <T> Optional<T> as(Class<T> type) {
      return as(request.getClassMeta(type));
   }

   /**
    * Converts this header to the specified type.
    *
    * @param <T> The type to convert to.
    * @param type The type to convert to.
    * @return The converted type, or <jk>null</jk> if header is not present.
    */
   public <T> Optional<T> as(ClassMeta<T> type) {
      try {
         return opt(parser.parse(HEADER, schema, getValue(), type));
      } catch (ParseException e) {
         throw rex(e, "Could not parse response header {0}.", getName());
      }
   }

   /**
    * Converts this header to the specified type.
    *
    * <p>
    * See <a class="doclink" href="https://juneau.apache.org/docs/topics/ComplexDataTypes">Complex Data Types</a> for information on defining complex generic types of {@link Map Maps} and {@link Collection Collections}.
    *
    * @param <T> The type to convert to.
    * @param type The type to convert to.
    * @param args The type parameters.
    * @return The converted type, or <jk>null</jk> if header is not present.
    */
   public <T> Optional<T> as(Type type, Type...args) {
      return as(request.getClassMeta(type, args));
   }

   /**
    * Same as {@link #as(Class)} but sets the value in a mutable for fluent calls.
    *
    * @param value The mutable to set the parsed header value in.
    * @param <T> The type to convert to.
    * @param type The type to convert to.
    * @return This object.
    */
   public <T> RestResponse as(Value<T> value, Class<T> type) {
      value.set(as(type).orElse(null));
      return response;
   }

   /**
    * Same as {@link #as(ClassMeta)} but sets the value in a mutable for fluent calls.
    *
    * @param value The mutable to set the parsed header value in.
    * @param <T> The type to convert to.
    * @param type The type to convert to.
    * @return This object.
    */
   public <T> RestResponse as(Value<T> value, ClassMeta<T> type) {
      value.set(as(type).orElse(null));
      return response;
   }

   /**
    * Same as {@link #as(Type,Type...)} but sets the value in a mutable for fluent calls.
    *
    * <p>
    * See <a class="doclink" href="https://juneau.apache.org/docs/topics/ComplexDataTypes">Complex Data Types</a> for information on defining complex generic types of {@link Map Maps} and {@link Collection Collections}.
    *
    * @param value The mutable to set the parsed header value in.
    * @param <T> The type to convert to.
    * @param type The type to convert to.
    * @param args The type parameters.
    * @return This object.
    */
   @SuppressWarnings("unchecked")
   public <T> RestResponse as(Value<T> value, Type type, Type...args) {
      value.set((T)as(type, args).orElse(null));
      return response;
   }

   /**
    * Returns the value of this header as a boolean.
    *
    * @return The value of this header as a boolean, or {@link Optional#empty()} if the header was not present.
    */
   public Optional<Boolean> asBoolean() {
      return asBooleanHeader().asBoolean();
   }

   /**
    * Returns the value of this header as an boolean header.
    *
    * @return The value of this header as an boolean header, never <jk>null</jk>.
    */
   public BasicBooleanHeader asBooleanHeader() {
      return new BasicBooleanHeader(getName(), getValue());
   }

   /**
    * Returns the value of this header as a list from a comma-delimited string.
    *
    * @return The value of this header as a list from a comma-delimited string, or {@link Optional#empty()} if the header was not present.
    */
   public Optional<String[]> asCsvArray() {
      return asCsvHeader().asArray();
   }

   /**
    * Returns the value of this header as a CSV array header.
    *
    * @return The value of this header as a CSV array header, never <jk>null</jk>.
    */
   public BasicCsvHeader asCsvHeader() {
      return new BasicCsvHeader(getName(), getValue());
   }

   /**
    * Returns the value of this header as a date.
    *
    * @return The value of this header as a date, or {@link Optional#empty()} if the header was not present.
    */
   public Optional<ZonedDateTime> asDate() {
      return asDateHeader().asZonedDateTime();
   }

   /**
    * Returns the value of this header as a date header.
    *
    * @return The value of this header as a date header, never <jk>null</jk>.
    */
   public BasicDateHeader asDateHeader() {
      return new BasicDateHeader(getName(), getValue());
   }

   /**
    * Returns the value of this header as an entity validator header.
    *
    * @return The value of this header as an entity validator array, never <jk>null</jk>.
    */
   public BasicEntityTagHeader asEntityTagHeader() {
      return new BasicEntityTagHeader(getName(), getValue());
   }

   /**
    * Returns the value of this header as an entity validator array header.
    *
    * @return The value of this header as an entity validator array header, never <jk>null</jk>.
    */
   public BasicEntityTagsHeader asEntityTagsHeader() {
      return new BasicEntityTagsHeader(getName(), getValue());
   }

   /**
    * Returns the value of this header as a {@link BasicHeader}.
    *
    * @param c The subclass of {@link BasicHeader} to instantiate.
    * @param <T> The subclass of {@link BasicHeader} to instantiate.
    * @return The value of this header as a string, never <jk>null</jk>.
    */
   public <T extends BasicHeader> T asHeader(Class<T> c) {
      try {
         var ci = ClassInfo.of(c);
         var cc = ci.getPublicConstructor(x -> x.hasParameterTypes(String.class)).orElse(null);
         if (nn(cc))
            return cc.newInstance(getValue());
         cc = ci.getPublicConstructor(x -> x.hasParameterTypes(String.class, String.class)).orElse(null);
         if (nn(cc))
            return cc.newInstance(getName(), getValue());
      } catch (Throwable e) {
         if (e instanceof ExecutableException)
            e = e.getCause();
         throw toRex(e);
      }
      throw rex("Could not determine a method to construct type {0}", cn(c));
   }

   /**
    * Returns the value of this header as an integer.
    *
    * @return The value of this header as an integer, or {@link Optional#empty()} if the header was not present.
    */
   public Optional<Integer> asInteger() {
      return asIntegerHeader().asInteger();
   }

   /**
    * Returns the value of this header as an integer header.
    *
    * @return The value of this header as an integer header, never <jk>null</jk>.
    */
   public BasicIntegerHeader asIntegerHeader() {
      return new BasicIntegerHeader(getName(), getValue());
   }

   /**
    * Returns the value of this header as a long.
    *
    * @return The value of this header as a long, or {@link Optional#empty()} if the header was not present.
    */
   public Optional<Long> asLong() {
      return asLongHeader().asLong();
   }

   /**
    * Returns the value of this header as a long header.
    *
    * @return The value of this header as a long header, never <jk>null</jk>.
    */
   public BasicLongHeader asLongHeader() {
      return new BasicLongHeader(getName(), getValue());
   }

   /**
    * Matches the specified pattern against this header value.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bjava'>
    *    <jc>// Parse header using a regular expression.</jc>
    *    Matcher <jv>matcher</jv> = <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .run()
    *       .getResponseHeader(<js>"Content-Type"</js>).asMatcher(Pattern.<jsm>compile</jsm>(<js>"application/(.*)"</js>));
    *
    *    <jk>if</jk> (<jv>matcher</jv>.matches()) {
    *       String <jv>mediaType</jv> = <jv>matcher</jv>.group(1);
    *    }
    * </p>
    *
    * @param pattern The regular expression pattern to match.
    * @return The matcher.
    */
   public Matcher asMatcher(Pattern pattern) {
      return pattern.matcher(orElse(""));
   }

   /**
    * Matches the specified pattern against this header value.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bjava'>
    *    <jc>// Parse header using a regular expression.</jc>
    *    Matcher <jv>matcher</jv> = <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .run()
    *       .getHeader(<js>"Content-Type"</js>).asMatcher(<js>"application/(.*)"</js>);
    *
    *    <jk>if</jk> (<jv>matcher</jv>.matches()) {
    *       String <jv>mediaType</jv> = <jv>matcher</jv>.group(1);
    *    }
    * </p>
    *
    * @param regex The regular expression pattern to match.
    * @return The matcher.
    */
   public Matcher asMatcher(String regex) {
      return asMatcher(regex, 0);
   }

   /**
    * Matches the specified pattern against this header value.
    *
    * <h5 class='section'>Example:</h5>
    * <p class='bjava'>
    *    <jc>// Parse header using a regular expression.</jc>
    *    Matcher <jv>matcher</jv> = <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .run()
    *       .getHeader(<js>"Content-Type"</js>).asMatcher(<js>"application/(.*)"</js>, <jsf>CASE_INSENSITIVE</jsf>);
    *
    *    <jk>if</jk> (<jv>matcher</jv>.matches()) {
    *       String <jv>mediaType</jv> = <jv>matcher</jv>.group(1);
    *    }
    * </p>
    *
    * @param regex The regular expression pattern to match.
    * @param flags Pattern match flags.  See {@link Pattern#compile(String, int)}.
    * @return The matcher.
    */
   public Matcher asMatcher(String regex, int flags) {
      return asMatcher(Pattern.compile(regex, flags));
   }

   /**
    * Shortcut for calling <c>assertValue().asInteger()</c>.
    *
    * @return A new fluent assertion.
    */
   public FluentIntegerAssertion<ResponseHeader> assertInteger() {
      return new FluentResponseHeaderAssertion<>(this, this).asInteger();
   }

   /**
    * Shortcut for calling <c>assertValue().asLong()</c>.
    *
    * @return A new fluent assertion.
    */
   public FluentLongAssertion<ResponseHeader> assertLong() {
      return new FluentResponseHeaderAssertion<>(this, this).asLong();
   }

   /**
    * Shortcut for calling <c>assertValue().asString()</c>.
    *
    * @return A new fluent assertion.
    */
   public FluentStringAssertion<ResponseHeader> assertString() {
      return new FluentResponseHeaderAssertion<>(this, this).asString();
   }

   /**
    * Provides the ability to perform fluent-style assertions on this response header.
    *
    * <h5 class='section'>Examples:</h5>
    * <p class='bjava'>
    *    <jc>// Validates the content type header is provided.</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .run()
    *       .getHeader(<js>"Content-Type"</js>).assertValue().exists();
    *
    *    <jc>// Validates the content type is JSON.</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .run()
    *       .getHeader(<js>"Content-Type"</js>).assertValue().equals(<js>"application/json"</js>);
    *
    *    <jc>// Validates the content type is JSON using test predicate.</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .run()
    *       .getHeader(<js>"Content-Type"</js>).assertValue().is(<jv>x</jv> -&gt; <jv>x</jv>.equals(<js>"application/json"</js>));
    *
    *    <jc>// Validates the content type is JSON by just checking for substring.</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .run()
    *       .getHeader(<js>"Content-Type"</js>).assertValue().contains(<js>"json"</js>);
    *
    *    <jc>// Validates the content type is JSON using regular expression.</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .run()
    *       .getHeader(<js>"Content-Type"</js>).assertValue().isPattern(<js>".*json.*"</js>);
    *
    *    <jc>// Validates the content type is JSON using case-insensitive regular expression.</jc>
    *    <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .run()
    *       .getHeader(<js>"Content-Type"</js>).assertValue().isPattern(<js>".*json.*"</js>, <jsf>CASE_INSENSITIVE</jsf>);
    * </p>
    *
    * <p>
    * The assertion test returns the original response object allowing you to chain multiple requests like so:
    * <p class='bjava'>
    *    <jc>// Validates the header and converts it to a bean.</jc>
    *    MediaType <jv>mediaType</jv> = <jv>client</jv>
    *       .get(<jsf>URI</jsf>)
    *       .run()
    *       .getHeader(<js>"Content-Type"</js>).assertValue().isNotEmpty()
    *       .getHeader(<js>"Content-Type"</js>).assertValue().isPattern(<js>".*json.*"</js>)
    *       .getHeader(<js>"Content-Type"</js>).as(MediaType.<jk>class</jk>);
    * </p>
    *
    * @return A new fluent assertion object.
    */
   public FluentResponseHeaderAssertion<ResponseHeader> assertValue() {
      return new FluentResponseHeaderAssertion<>(this, this);
   }

   /**
    * Shortcut for calling <c>assertValue().asZonedDateTime()</c>.
    *
    * @return A new fluent assertion.
    */
   public FluentZonedDateTimeAssertion<ResponseHeader> assertZonedDateTime() {
      return new FluentResponseHeaderAssertion<>(this, this).asZonedDateTime();
   }

   /**
    * Same as {@link #asString()} but sets the value in a mutable for fluent calls.
    *
    * @param value The mutable to set the header value in.
    * @return This object.
    */
   public RestResponse asString(Value<String> value) {
      value.set(orElse(null));
      return response;
   }

   /**
    * Returns the value of this header as a string header.
    *
    * @return The value of this header as a string header, never <jk>null</jk>.
    */
   public BasicStringHeader asStringHeader() {
      return new BasicStringHeader(getName(), getValue());
   }

   /**
    * Returns the value of this header as a range array header.
    *
    * @return The value of this header as a range array header, never <jk>null</jk>.
    */
   public BasicStringRangesHeader asStringRangesHeader() {
      return new BasicStringRangesHeader(getName(), getValue());
   }

   /**
    * Returns the value of this header as a URI header.
    *
    * @return The value of this header as a URI header, never <jk>null</jk>.
    */
   public BasicUriHeader asUriHeader() {
      return new BasicUriHeader(getName(), getValue());
   }

   /**
    * Parses the value.
    *
    * @return An array of {@link HeaderElement} entries, may be empty, but is never <jk>null</jk>.
    * @throws org.apache.http.ParseException In case of a parsing error.
    */
   @Override /* Overridden from Header */
   public HeaderElement[] getElements() throws org.apache.http.ParseException { return elements; }

   /**
    * Specifies the part parser to use for this header.
    *
    * <p>
    * If not specified, uses the part parser defined on the client by calling {@link RestClient.Builder#partParser(Class)}.
    *
    * @param value
    *    The new part parser to use for this header.
    *    <br>If <jk>null</jk>, {@link SimplePartParser#DEFAULT} will be used.
    * @return This object.
    */
   public ResponseHeader parser(HttpPartParserSession value) {
      this.parser = value == null ? SimplePartParser.DEFAULT_SESSION : value;
      return this;
   }

   /**
    * Returns the response that created this object.
    *
    * @return The response that created this object.
    */
   public RestResponse response() {
      return response;
   }

   /**
    * Specifies the part schema for this header.
    *
    * <p>
    * Used by schema-based part parsers such as {@link OpenApiParser}.
    *
    * @param value
    *    The part schema.
    * @return This object.
    */
   public ResponseHeader schema(HttpPartSchema value) {
      schema = value;
      return this;
   }
}