/*
 * 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.logger;

import static org.apache.juneau.collections.JsonMap.*;

import java.util.function.*;
import java.util.logging.*;

import org.apache.juneau.*;
import org.apache.juneau.cp.*;
import org.apache.juneau.internal.*;

import jakarta.servlet.http.*;

/**
 * Represents a logging rule used by {@link CallLogger}.
 *
 * <h5 class='section'>See Also:</h5><ul>
 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/RestServerLoggingAndDebugging">Logging / Debugging</a>
 * </ul>
 */
public class CallLoggerRule {

   //-----------------------------------------------------------------------------------------------------------------
   // Static
   //-----------------------------------------------------------------------------------------------------------------

   /**
    * Static creator.
    *
    * @param beanStore The bean store to use for creating beans.
    * @return A new builder for this object.
    */
   public static Builder create(BeanStore beanStore) {
      return new Builder(beanStore);
   }

   //-----------------------------------------------------------------------------------------------------------------
   // Builder
   //-----------------------------------------------------------------------------------------------------------------

   /**
    * Builder class.
    */
   public static class Builder extends BeanBuilder<CallLoggerRule> {

      Predicate<Integer> statusFilter;
      Predicate<HttpServletRequest> requestFilter;
      Predicate<HttpServletResponse> responseFilter;
      Predicate<Throwable> exceptionFilter;
      Enablement enabled;
      Predicate<HttpServletRequest> enabledTest;
      Level level;
      CallLoggingDetail requestDetail, responseDetail;
      boolean logStackTrace;

      /**
       * Constructor.
       *
       * @param beanStore The bean store to use for creating beans.
       */
      protected Builder(BeanStore beanStore) {
         super(CallLoggerRule.class, beanStore);
      }

      @Override /* BeanBuilder */
      protected CallLoggerRule buildDefault() {
         return new CallLoggerRule(this);
      }

      //-------------------------------------------------------------------------------------------------------------
      // Properties
      //-------------------------------------------------------------------------------------------------------------

      /**
       * Apply a status-based predicate check for this rule to match against.
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a logger rule that only matches if the status code is greater than or equal to 500.</jc>
       *    RestLogger
       *       .<jsm>createRule</jsm>()
       *       .statusFilter(<jv>x</jv> -&gt; <jv>x</jv> &gt;= 500)
       *       .build();
       * </p>
       *
       * @param value
       *    The predicate check, or <jk>null</jk> to not use any filtering based on status code.
       * @return This object.
       */
      public Builder statusFilter(Predicate<Integer> value) {
         this.statusFilter = value;
         return this;
      }

      /**
       * Apply a throwable-based predicate check for this rule to match against.
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a logger rule that only matches if a NotFound exception was thrown.</jc>
       *    RestLogger
       *       .<jsm>createRule</jsm>()
       *       .exceptionFilter(<jv>x</jv> -&gt; <jv>x</jv> <jk>instanceof</jk> NotFound)
       *       .build();
       * </p>
       *
       * <p>
       * This check is only performed if an actual throwable was thrown.  Therefore it's not necessary to perform a
       * null check in the predicate.
       *
       * @param value
       *    The predicate check, or <jk>null</jk> to not use any filtering based on exceptions.
       * @return This object.
       */
      public Builder exceptionFilter(Predicate<Throwable> value) {
         this.exceptionFilter = value;
         return this;
      }

      /**
       * Apply a request-based predicate check for this rule to match against.
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a logger rule that only matches if the servlet path contains "foobar".</jc>
       *    RestLogger
       *       .<jsm>createRule</jsm>()
       *       .requestFilter(<jv>x</jv> -&gt; <jv>x</jv>.getServletPath().contains(<js>"foobar"</js>))
       *       .build();
       * </p>
       *
       * @param value
       *    The predicate check, or <jk>null</jk> to not use any filtering based on the request.
       * @return This object.
       */
      public Builder requestFilter(Predicate<HttpServletRequest> value) {
         this.requestFilter = value;
         return this;
      }

      /**
       * Apply a response-based predicate check for this rule to match against.
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a logger rule that only matches if the servlet path contains "foobar".</jc>
       *    RestLogger
       *       .<jsm>createRule</jsm>()
       *       .responseFilter(<jv>x</jv> -&gt; <jv>x</jv>.getStatus() &gt;= 500)
       *       .build();
       * </p>
       *
       * <p>
       * Note that the {@link #statusFilter(Predicate)} and {@link #exceptionFilter(Predicate)} methods are simply
       * convenience response filters.
       *
       * @param value
       *    The predicate check, or <jk>null</jk> to not use any filtering based on the response.
       * @return This object.
       */
      public Builder responseFilter(Predicate<HttpServletResponse> value) {
         this.responseFilter = value;
         return this;
      }

      /**
       * Specifies whether logging is enabled when using this rule.
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a logger rule where logging is only enabled if the query string contains "foobar".</jc>
       *    RestLogger
       *       .<jsm>createRule</jsm>()
       *       .enabled(<jsf>CONDITIONALLY</jsf>)
       *       .enabledPredicate(<jv>x</jv> -&gt; <jv>x</jv>.getQueryString().contains(<js>"foobar"</js>))
       *       .build();
       * </p>
       *
       * <ul class='values'>
       *    <li>{@link Enablement#ALWAYS ALWAYS} - Logging is enabled.
       *    <li>{@link Enablement#NEVER NEVER} - Logging is disabled.
       *    <li>{@link Enablement#CONDITIONAL CONDITIONALLY} - Logging is enabled if it passes the {@link #enabledPredicate(Predicate)} test.
       * </ul>
       *
       * @param value
       *    The enablement flag value, or <jk>null</jk> to inherit from the call logger whose default value is {@link Enablement#ALWAYS ALWAYS}
       *    unless overridden via a <js>"juneau.restCallLogger.enabled"</js> system property or <js>"JUNEAU_RESTCALLLOGGER_ENABLED"</js> environment variable.
       * @return This object.
       */
      public Builder enabled(Enablement value) {
         this.enabled = value;
         return this;
      }

      /**
       * Specifies the predicate test to use when the enabled setting is set to {@link Enablement#CONDITIONAL CONDITIONALLY}.
       *
       * <p>
       * This setting has no effect if the enablement value is not {@link Enablement#CONDITIONAL CONDITIONALLY}.
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    <jc>// Create a logger rule where logging is only enabled if the query string contains "foobar".</jc>
       *    RestLogger
       *       .<jsm>createRule</jsm>()
       *       .enabled(<jsf>CONDITIONALLY</jsf>)
       *       .enabledPredicate(<jv>x</jv> -&gt; <jv>x</jv>.getQueryString().contains(<js>"foobar"</js>))
       *       .build();
       * </p>
       *
       * @param value
       *    The enablement predicate test, or <jk>null</jk> to inherit from the call logger whose default value is <c><jv>x</jv> -&gt; <jk>false</jk></c>.
       * @return This object.
       */
      public Builder enabledPredicate(Predicate<HttpServletRequest> value) {
         this.enabledTest = value;
         return this;
      }

      /**
       * Shortcut for calling <c>enabled(<jsf>NEVER</jsf>)</c>.
       *
       * @return This object.
       */
      public Builder disabled() {
         return this.enabled(Enablement.NEVER);
      }

      /**
       * The level of detail to log on a request.
       *
       * <ul class='values'>
       *    <li>{@link CallLoggingDetail#STATUS_LINE STATUS_LINE} - Log only the status line.
       *    <li>{@link CallLoggingDetail#HEADER HEADER} - Log the status line and headers.
       *    <li>{@link CallLoggingDetail#ENTITY ENTITY} - Log the status line and headers and content if available.
       * </ul>
       *
       * @param value
       *    The new value for this property, or <jk>null</jk> to inherit from the call logger.
       * @return This object.
       */
      public Builder requestDetail(CallLoggingDetail value) {
         this.requestDetail = value;
         return this;
      }

      /**
       * The level of detail to log on a response.
       *
       * <ul class='values'>
       *    <li>{@link CallLoggingDetail#STATUS_LINE STATUS_LINE} - Log only the status line.
       *    <li>{@link CallLoggingDetail#HEADER HEADER} - Log the status line and headers.
       *    <li>{@link CallLoggingDetail#ENTITY ENTITY} - Log the status line and headers and content if available.
       * </ul>
       *
       * @param value
       *    The new value for this property, or <jk>null</jk> to inherit from the call logger.
       * @return This object.
       */
      public Builder responseDetail(CallLoggingDetail value) {
         this.responseDetail = value;
         return this;
      }

      /**
       * The logging level to use for logging the request/response.
       *
       * <p>
       * The default value is {@link Level#INFO}.
       *
       * @param value
       *    The new value for this property, or <jk>null</jk> to inherit from the call logger.
       * @return This object.
       */
      public Builder level(Level value) {
         this.level = value;
         return this;
      }

      /**
       * Log a stack trace as part of the log entry.
       *
       * <p>
       * The default value is <jk>false</jk>.
       *
       * @return This object.
       */
      public Builder logStackTrace() {
         this.logStackTrace = true;
         return this;
      }
      @Override /* Overridden from BeanBuilder */
      public Builder impl(Object value) {
         super.impl(value);
         return this;
      }

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

   //-----------------------------------------------------------------------------------------------------------------
   // Instance
   //-----------------------------------------------------------------------------------------------------------------

   private final Predicate<Integer> statusFilter;
   private final Predicate<HttpServletRequest> requestFilter;
   private final Predicate<HttpServletResponse> responseFilter;
   private final Predicate<Throwable> exceptionFilter;
   private final Level level;
   private final Enablement enabled;
   private final Predicate<HttpServletRequest> enabledTest;
   private final CallLoggingDetail requestDetail, responseDetail;

   /**
    * Constructor.
    *
    * @param b Builder
    */
   CallLoggerRule(Builder b) {
      this.statusFilter = b.statusFilter;
      this.exceptionFilter = b.exceptionFilter;
      this.requestFilter = b.requestFilter;
      this.responseFilter = b.responseFilter;
      this.level = b.level;
      this.enabled = b.enabled;
      this.enabledTest = b.enabledTest;
      this.requestDetail = b.requestDetail;
      this.responseDetail = b.responseDetail;
   }

   /**
    * Returns <jk>true</jk> if this rule matches the specified parameters.
    *
    * @param req The HTTP request being logged.  Never <jk>null</jk>.
    * @param res The HTTP response being logged.  Never <jk>null</jk>.
    * @return <jk>true</jk> if this rule matches the specified parameters.
    */
   public boolean matches(HttpServletRequest req, HttpServletResponse res) {

      if ((requestFilter != null && ! requestFilter.test(req)) || (responseFilter != null && ! responseFilter.test(res)))
         return false;

      if (statusFilter != null && ! statusFilter.test(res.getStatus()))
         return false;

      Throwable e = (Throwable)req.getAttribute("Exception");
      if (e != null && exceptionFilter != null && ! exceptionFilter.test(e))
         return false;

      return true;
   }

   /**
    * Returns the detail level for HTTP requests.
    *
    * @return the detail level for HTTP requests, or <jk>null</jk> if it's not set.
    */
   public CallLoggingDetail getRequestDetail() {
      return requestDetail;
   }

   /**
    * Returns the detail level for HTTP responses.
    *
    * @return the detail level for HTTP responses, or <jk>null</jk> if it's not set.
    */
   public CallLoggingDetail getResponseDetail() {
      return responseDetail;
   }

   /**
    * Returns the log level on this rule.
    *
    * @return The log level on this rule, or <jk>null</jk> if it's not set.
    */
   public Level getLevel() {
      return level;
   }

   /**
    * Returns the enablement flag value on this rule.
    *
    * @return The enablement flag value on this rule, or <jk>null</jk> if it's not set.
    */
   public Enablement getEnabled() {
      return enabled;
   }

   /**
    * Returns the enablement predicate test on this rule.
    *
    * @return The enablement predicate test on this rule, or <jk>null</jk> if it's not set.
    */
   public Predicate<HttpServletRequest> getEnabledTest() {
      return enabledTest;
   }

   @Override /* Object */
   public String toString() {
      return filteredMap()
         .append("codeFilter", statusFilter)
         .append("exceptionFilter", exceptionFilter)
         .append("requestFilter", requestFilter)
         .append("responseFilter", responseFilter)
         .append("level", level)
         .append("requestDetail", requestDetail)
         .append("responseDetail", responseDetail)
         .append("enabled", enabled)
         .append("enabledTest", enabledTest)
         .asReadableString();
   }
}