// ***************************************************************************************************************************
// * 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;

import static org.apache.juneau.rest.Enablement.*;

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

import javax.servlet.http.*;

import org.apache.juneau.*;
import org.apache.juneau.collections.*;
import org.apache.juneau.json.*;

/**
 * Represents a set of logging rules for how to handle logging of HTTP requests/responses.
 */
public class RestCallLoggerConfig {

   /**
    * Default empty logging config.
    */
   public static final RestCallLoggerConfig DEFAULT_NOOP = RestCallLoggerConfig.create().build();

   /**
    * Default debug logging config.
    */
   public static final RestCallLoggerConfig DEFAULT_DEBUG =
      RestCallLoggerConfig
         .create()
         .useStackTraceHashing(false)
         .level(Level.WARNING)
         .rules(
            RestCallLoggerRule
               .create()
               .codes("*")
               .verbose()
               .build()
         )
         .build();

   private final RestCallLoggerRule[] rules;
   private final boolean useStackTraceHashing;
   private final Enablement disabled;
   private final int stackTraceHashingTimeout;
   private final Level level;

   RestCallLoggerConfig(Builder b) {
      RestCallLoggerConfig p = b.parent;

      this.disabled = b.disabled != null ? b.disabled : p != null ? p.disabled : FALSE;
      this.useStackTraceHashing = b.useStackTraceHashing != null ? b.useStackTraceHashing : p != null ? p.useStackTraceHashing : false;
      this.stackTraceHashingTimeout = b.stackTraceHashingTimeout != null ? b.stackTraceHashingTimeout : p != null ? p.stackTraceHashingTimeout : Integer.MAX_VALUE;
      this.level = b.level != null ? b.level : p != null ? p.level : Level.INFO;

      AList<RestCallLoggerRule> rules = AList.of();
      rules.addAll(b.rules);
      if (p != null)
         rules.a(p.rules);
      this.rules = rules.asArrayOf(RestCallLoggerRule.class);
   }

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

   /**
    * Builder for {@link RestCallLoggerConfig} objects.
    */
   public static class Builder {
      List<RestCallLoggerRule> rules = new ArrayList<>();
      RestCallLoggerConfig parent;
      Level level;
      Boolean useStackTraceHashing;
      Enablement disabled;
      Integer stackTraceHashingTimeout;

      /**
       * Sets the parent logging config.
       *
       * @param parent
       *    The parent logging config.
       *    <br>Can be <jk>null</jk>.
       * @return This object (for method chaining).
       */
      public Builder parent(RestCallLoggerConfig parent) {
         this.parent = parent;
         return this;
      }

      /**
       * Adds a new logging rule to this config.
       *
       * <p>
       *    The rule will be added to the END of list of current rules and thus checked last in the current list but
       *    before any parent rules.
       *
       * @param rule The logging rule to add to this config.
       * @return This object (for method chaining).
       */
      public Builder rule(RestCallLoggerRule rule) {
         this.rules.add(rule);
         return this;
      }

      /**
       * Adds new logging rules to this config.
       *
       * <p>
       *    The rules will be added in order to the END of list of current rules and thus checked last in the current list but
       *    before any parent rules.
       *
       * @param rules The logging rules to add to this config.
       * @return This object (for method chaining).
       */
      public Builder rules(RestCallLoggerRule...rules) {
         for (RestCallLoggerRule rule : rules)
            this.rules.add(rule);
         return this;
      }

      /**
       * Enables no-trace mode on this config.
       *
       * <p>
       * No-trace mode prevents logging of messages to the log file.
       *
       * <p>
       * Possible values (case-insensitive):
       * <ul>
       *    <li>{@link Enablement#TRUE TRUE} - No-trace mode enabled for all requests.
       *    <li>{@link Enablement#FALSE FALSE} - No-trace mode disabled for all requests.
       *    <li>{@link Enablement#PER_REQUEST PER_REQUEST} - No-trace mode enabled for requests that have a <js>"X-NoTrace: true"</js> header.
       * </ul>
       *
       * @param value
       *    The value for this property.
       *    <br>Can be <jk>null</jk> (inherit from parent or default to {@link Enablement#FALSE NEVER}).
       * @return This object (for method chaining).
       */
      public Builder disabled(Enablement value) {
         this.disabled = value;
         return this;
      }

      /**
       * Shortcut for calling <c>disabled(<jsf>TRUE</jsf>)</c>.
       *
       * @return This object (for method chaining).
       */
      public Builder disabled() {
         return disabled(TRUE);
      }

      /**
       * Enables the use of stacktrace hashing.
       *
       * <p>
       * When enabled, stacktraces will be replaced with hashes in the log file.
       *
       * @param value
       *    The value for this property.
       *    <br>Can be <jk>null</jk> (inherit from parent or default to <jk>false</jk>).
       * @return This object (for method chaining).
       */
      public Builder useStackTraceHashing(Boolean value) {
         this.useStackTraceHashing = value;
         return this;
      }

      /**
       * Shortcut for calling <c>useStackTraceHashing(<jk>true</jk>);</c>.
       *
       * @return This object (for method chaining).
       */
      public Builder useStackTraceHashing() {
         this.useStackTraceHashing = true;
         return this;
      }

      /**
       * Enables a timeout after which stack traces hashes are flushed.
       *
       * @param timeout
       *    Time in milliseconds to hash stack traces for.
       *    <br>Can be <jk>null</jk> (inherit from parent or default to {@link Integer#MAX_VALUE MAX_VALUE}).
       * @return This object (for method chaining).
       */
      public Builder stackTraceHashingTimeout(Integer timeout) {
         this.stackTraceHashingTimeout = timeout;
         return this;
      }

      /**
       * The default logging level.
       *
       * <p>
       * This defines the logging level for messages if they're not already defined on the matched rule.
       *
       * @param value
       *    The value for this property.
       *    <br>Can be <jk>null</jk> (inherit from parent or default to {@link Level#INFO INFO}).
       * @return This object (for method chaining).
       */
      public Builder level(Level value) {
         this.level = value;
         return this;
      }

      /**
       * Applies the properties in the specified object map to this builder.
       *
       * @param m The map containing properties to apply.
       * @return This object (for method chaining).
       */
      public Builder apply(OMap m) {
         for (String key : m.keySet()) {
            if ("useStackTraceHashing".equals(key))
               useStackTraceHashing(m.getBoolean("useStackTraceHashing"));
            else if ("stackTraceHashingTimeout".equals(key))
               stackTraceHashingTimeout(m.getInt("stackTraceHashingTimeout"));
            else if ("disabled".equals(key))
               disabled(m.get("disabled", Enablement.class));
            else if ("rules".equals(key))
               rules(m.get("rules", RestCallLoggerRule[].class));
            else if ("level".equals(key))
               level(m.get("level", Level.class));
         }
         return this;
      }

      /**
       * Creates the {@link RestCallLoggerConfig} object based on settings on this builder.
       *
       * @return A new {@link RestCallLoggerConfig} object.
       */
      public RestCallLoggerConfig build() {
         return new RestCallLoggerConfig(this);
      }
   }

   /**
    * Given the specified servlet request/response, find the rule that applies to it.
    *
    * @param req The servlet request.
    * @param res The servlet response.
    * @return The applicable logging rule, or <jk>null</jk> if a match could not be found.
    */
   public RestCallLoggerRule getRule(HttpServletRequest req, HttpServletResponse res) {

      int status = res.getStatus();
      Throwable e = (Throwable)req.getAttribute("Exception");
      boolean debug = isDebug(req);

      for (RestCallLoggerRule r : rules) {
         if (r.matches(status, debug, e)) {
            Enablement disabled = r.getDisabled();
            if (disabled == null)
               disabled = this.disabled;
            if (disabled == TRUE)
               return null;
            if (isNoTraceAttr(req))
               return null;
            if (disabled == FALSE)
               return r;
            if (isNoTraceHeader(req))
               return null;
            return r;
         }
      }

      return null;
   }

   /**
    * Returns <jk>true</jk> if logging is disabled for this request.
    *
    * @param req The HTTP request.
    * @return <jk>true</jk> if logging is disabled for this request.
    */
   public boolean isDisabled(HttpServletRequest req) {
      if (disabled == TRUE)
         return true;
      if (disabled == FALSE)
         return false;
      return isNoTraceAttr(req);
   }

   private boolean isDebug(HttpServletRequest req) {
      Boolean b = boolAttr(req, "Debug");
      return (b != null && b == true);
   }

   private boolean isNoTraceAttr(HttpServletRequest req) {
      Boolean b = boolAttr(req, "NoTrace");
      return (b != null && b == true);
   }

   private boolean isNoTraceHeader(HttpServletRequest req) {
      return "true".equalsIgnoreCase(req.getHeader("X-NoTrace"));
   }

   /**
    * Returns the default logging level.
    *
    * @return The default logging level.
    */
   public Level getLevel() {
      return level;
   }

   /**
    * Returns <jk>true</jk> if stack traces should be hashed.
    *
    * @return <jk>true</jk> if stack traces should be hashed.
    */
   public boolean isUseStackTraceHashing() {
      return useStackTraceHashing;
   }

   /**
    * Returns the time in milliseconds that stacktrace hashes should be persisted.
    *
    * @return The time in milliseconds that stacktrace hashes should be persisted.
    */
   public int getStackTraceHashingTimeout() {
      return stackTraceHashingTimeout;
   }

   /**
    * Returns the rules defined in this config.
    *
    * @return Thew rules defined in this config.
    */
   public List<RestCallLoggerRule> getRules() {
      return Collections.unmodifiableList(Arrays.asList(rules));
   }

   //-----------------------------------------------------------------------------------------------------------------
   // Other methods
   //-----------------------------------------------------------------------------------------------------------------

   private Boolean boolAttr(HttpServletRequest req, String name) {
      Object o = req.getAttribute(name);
      if (o == null || ! (o instanceof Boolean))
         return null;
      return (Boolean)o;
   }

   @Override /* Object */
   public String toString() {
      return SimpleJsonSerializer.DEFAULT_READABLE.toString(toMap());
   }

   /**
    * Returns the properties defined on this bean context as a simple map for debugging purposes.
    *
    * @return A new map containing the properties defined on this context.
    */
   public OMap toMap() {
      return new DefaultFilteringOMap()
         .append("useStackTraceHashing", useStackTraceHashing)
         .append("disabled", disabled == FALSE ? null : disabled)
         .append("stackTraceHashingTimeout", stackTraceHashingTimeout == Integer.MAX_VALUE ? null : stackTraceHashingTimeout)
         .append("level", level == Level.INFO ? null : level)
         .append("rules", rules.length == 0 ? null : rules)
      ;
   }
}