/*
 * ebusd - daemon for communication with eBUS heating systems.
 * Copyright (C) 2014-2017 John Baier <ebusd@ebusd.eu>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef LIB_EBUS_MESSAGE_H_
#define LIB_EBUS_MESSAGE_H_

#include <stdint.h>
#include <string>
#include <vector>
#include <deque>
#include <map>
#include <queue>
#include <functional>
#include "lib/ebus/data.h"
#include "lib/ebus/result.h"
#include "lib/ebus/symbol.h"

/** @file message.h
 * Classes and functions for decoding and encoding of complete messages on the
 * eBUS to and from readable values.
 *
 * A @a Message has a unique numeric key (see Message#getKey()) as well as a
 * unique name and circuit (see Message#getCircuit() and Message#getName()).
 * The numeric key is built from the message type (active/passive, read/write),
 * the source and destination address, the primary and secondary command byte,
 * as well as additional command ID bytes (see Message#getId()).
 *
 * Whenever a @a Message gets decoded from a master and slave @a SymbolString
 * (see Message#decode()), it stores these strings for later retrieval from
 * cache (see Message#decodeLastData()).
 *
 * In order to make a @a Message available (see Message#isAvailable()) under
 * certain conditions only, it may have assigned a @a Condition instance.
 *
 * A @a Condition is either a @a SimpleCondition referencing another
 * @a Message, numeric field, and field value, or a @a CombinedCondition
 * applying a logical AND on two or more other @a Condition instances.
 *
 * The @a MessageMap stores all @a Message and @a Condition instances by their
 * unique keys, and also keeps track of messages with polling enabled. It reads
 * the instances from configuration files by inheriting the @a FileReader
 * template class.
 */

namespace ebusd {

using std::binary_function;
using std::priority_queue;
using std::deque;

class Condition;
class SimpleCondition;
class CombinedCondition;
class MessageMap;

/** the column index in @a Message::dump() for the message type. */
#define COLUMN_TYPE 0

/** the column index in @a Message::dump() for the circuit name. */
#define COLUMN_CIRCUIT 1

/** the column index in @a Message::dump() for the message name. */
#define COLUMN_NAME 2

/** the column index in @a Message::dump() for the message comment. */
#define COLUMN_COMMENT 3

/** the column index in @a Message::dump() for the source address QQ. */
#define COLUMN_QQ 4

/** the column index in @a Message::dump() for the destination address QQ. */
#define COLUMN_ZZ 5

/** the column index in @a Message::dump() for the PBSB bytes. */
#define COLUMN_PBSB 6

/** the column index in @a Message::dump() for the ID columns (after the PBSB bytes). */
#define COLUMN_ID 7

/** the column index in @a Message::dump() for the field(s). */
#define COLUMN_FIELDS 8

/**
 * Defines parameters of a message sent or received on the bus.
 */
class Message {
  friend class MessageMap;
 public:
  /**
   * Construct a new instance.
   * @param circuit the optional circuit name.
   * @param name the message name (unique within the same circuit and type).
   * @param isWrite whether this is a write message.
   * @param isPassive true if message can only be initiated by a participant other than us,
   * false if message can be initiated by any participant.
   * @param comment the comment.
   * @param srcAddress the source address, or @a SYN for any (only relevant if passive).
   * @param dstAddress the destination address, or @a SYN for any (set later).
   * @param id the primary, secondary, and optional further ID bytes.
   * @param data the @a DataField for encoding/decoding the message.
   * @param deleteData whether to delete the @a DataField during destruction.
   * @param pollPriority the priority for polling, or 0 for no polling at all.
   * @param condition the @a Condition for this message, or NULL.
   */
  Message(const string circuit, const string name,
      const bool isWrite, const bool isPassive, const string comment,
      const unsigned char srcAddress, const unsigned char dstAddress,
      const vector<unsigned char> id,
      DataField* data, const bool deleteData,
      const unsigned char pollPriority = 0,
      Condition* condition = NULL);


 private:
  /**
   * Construct a new scan @a Message instance.
   * @param circuit the circuit name, or empty for not storing by name.
   * @param name the message name (unique within the same circuit and type), or empty for not storing by name.
   * @param isWrite whether this is a write message.
   * @param isPassive true if message can only be initiated by a participant other than us,
   * false if message can be initiated by any participant.
   * @param pb the primary ID byte.
   * @param sb the secondary ID byte.
   * @param data the @a DataField for encoding/decoding the message.
   * @param deleteData whether to delete the @a DataField during destruction.
   */
  Message(const string circuit, const string name,
      const bool isWrite, const bool isPassive,
      const unsigned char pb, const unsigned char sb,
      DataField* data, const bool deleteData);


 public:
  /**
   * Destructor.
   */
  virtual ~Message() { if (m_deleteData) { delete m_data; } }

  /**
   * Calculate the key for the ID.
   * @param id the primary, secondary, and optional further ID bytes.
   * @param isWrite whether this is a write message.
   * @param isPassive true if message can only be initiated by a participant other than us,
   * false if message can be initiated by any participant.
   * @param srcAddress the source address, or @a SYN for any (only relevant if passive).
   * @param dstAddress the destination address, or @a SYN for any (set later).
   * @return the key for the ID.
   */
  static uint64_t createKey(const vector<unsigned char> id,
    const bool isWrite, const bool isPassive,
    const unsigned char srcAddress, const unsigned char dstAddress);

  /**
   * Calculate the key for the master @a SymbolString.
   * @param master the master @a SymbolString.
   * @param maxIdLength the maximum ID length to use
   * @param anyDestination @p true to use the special @a SYN as destination address in the key.
   * @return the key for the ID, or -1LL if the data is invalid.
   */
  static uint64_t createKey(SymbolString& master,
    unsigned char maxIdLength, bool anyDestination = false);

  /**
   * Get the length field from the key.
   * @param key the key.
   * @return the length field from the key.
   */
  static unsigned char getKeyLength(uint64_t key) { return (unsigned char)(key >> (8 * 7 + 5)); }

  /**
   * Parse an ID part from the input @a string.
   * @param input the input @a string, hex digits optionally separated by space.
   * @param id the vector to which to add the parsed values.
   * @return @a RESULT_OK on success, or an error code.
   */
  static result_t parseId(string input, vector<unsigned char>& id);

  /**
   * Factory method for creating new instances.
   * @param it the iterator to traverse for the definition parts.
   * @param end the iterator pointing to the end of the definition parts.
   * @param defaultsRows a @a vector with rows containing defaults, or NULL.
   * @param condition the @a Condition instance for the message, or NULL.
   * @param filename the name of the file being read.
   * @param templates the @a DataFieldTemplates to be referenced by name, or NULL.
   * @param messages the @a vector to which to add created instances.
   * @return @a RESULT_OK on success, or an error code.
   * Note: the caller needs to free the created instances.
   */
  static result_t create(vector<string>::iterator& it, const vector<string>::iterator end,
      vector< vector<string> >* defaultsRows, Condition* condition, const string& filename,
      DataFieldTemplates* templates, vector<Message*>& messages);

  /**
   * Create a new scan @a Message instance.
   */
  static Message* createScanMessage();

  /**
   * Set that this is a special scanning @a Message instance.
   */
  void setScanMessage() { m_isScanMessage = true; }

  /**
   * Return whether this is a special scanning @a Message instance.
   * @return whether this is a special scanning @a Message instance.
   */
  bool isScanMessage() { return m_isScanMessage; }

  /**
   * Derive a new @a Message from this message.
   * @param dstAddress the new destination address.
   * @param srcAddress the new source address, or @a SYN to keep the current source address.
   * @param circuit the new circuit name, or empty to use the current circuit name.
   * @return the derived @a Message instance.
   */
  virtual Message* derive(const unsigned char dstAddress, const unsigned char srcAddress = SYN,
      const string circuit = "");

  /**
   * Derive a new @a Message from this message.
   * @param dstAddress the new destination address.
   * @param extendCircuit whether to extend the current circuit name with a dot and the new destination address in hex.
   * @return the derived @a ScanMessage instance.
   */
  Message* derive(const unsigned char dstAddress, const bool extendCircuit);

  /**
   * Get the optional circuit name.
   * @return the optional circuit name.
   */
  string getCircuit() const { return m_circuit; }

  /**
   * Get the message name (unique within the same circuit and type).
   * @return the message name (unique within the same circuit and type).
   */
  string getName() const { return m_name; }

  /**
   * Get the specified field name.
   * @param fieldIndex the index of the field.
   * @return the field name, or the index as string if not unique or not available.
   */
  virtual string getFieldName(signed char fieldIndex) const { return m_data->getName(fieldIndex); }

  /**
   * Get whether this is a write message.
   * @return whether this is a write message.
   */
  bool isWrite() const { return m_isWrite; }

  /**
   * Get whether message can be initiated only by a participant other than us.
   * @return true if message can only be initiated by a participant other than us,
   * false if message can be initiated by any participant.
   */
  bool isPassive() const { return m_isPassive; }

  /**
   * Get the comment.
   * @return the comment.
   */
  string getComment() const { return m_comment; }

  /**
   * Get the source address.
   * @return the source address, or @a SYN for any.
   */
  unsigned char getSrcAddress() const { return m_srcAddress; }

  /**
   * Get the destination address.
   * @return the destination address, or @a SYN for any.
   */
  unsigned char getDstAddress() const { return m_dstAddress; }

  /**
   * Get the primary command byte.
   * @return the primary command byte.
   */
  unsigned char getPrimaryCommand() const { return m_id[0]; }

  /**
   * Get the secondary command byte.
   * @return the secondary command byte.
   */
  unsigned char getSecondaryCommand() const { return m_id[1]; }

  /**
   * Get the length of the ID bytes (without primary and secondary command bytes).
   * @return the length of the ID bytes (without primary and secondary command bytes).
   */
  virtual unsigned char getIdLength() const { return (unsigned char)(m_id.size() - 2); }

  /**
   * Check if the full command ID starts with the given value.
   * @param id the ID bytes to check against.
   * @return true if the full command ID starts with the given value.
   */
  bool checkIdPrefix(vector<unsigned char>& id);

  /**
   * Check the ID against the master @a SymbolString data.
   * @param master the master @a SymbolString to check against.
   * @param index the variable in which to store the message part index, or NULL to ignore.
   * @return true if the ID matches, false otherwise.
   */
  virtual bool checkId(SymbolString& master, unsigned char* index = NULL);

  /**
   * Check the ID against the other @a Message.
   * @param other the other @a Message to check against.
   * @return true if the ID matches, false otherwise.
   */
  virtual bool checkId(Message& other);

  /**
   * Return the key for storing in @a MessageMap.
   * @return the key for storing in @a MessageMap.
   */
  uint64_t getKey() { return m_key; }

  /**
   * Return the derived key for storing in @a MessageMap.
   * @param dstAddress the destination address for the derivation.
   * @return the derived key for storing in @a MessageMap.
   */
  uint64_t getDerivedKey(const unsigned char dstAddress);

  /**
   * Get the polling priority, or 0 for no polling at all.
   * @return the polling priority, or 0 for no polling at all.
   */
  unsigned char getPollPriority() const { return m_pollPriority; }

  /**
   * Set the polling priority.
   * @param priority the polling priority, or 0 for no polling at all.
   * @return true when the priority was changed and polling was not enabled before, false otherwise.
   */
  bool setPollPriority(unsigned char priority);

  /**
   * Set the poll priority suitable for resolving a @a Condition.
   */
  void setUsedByCondition();

  /**
   * Return whether this @a Message depends on a @a Condition.
   * @return true when this @a Message depends on a @a Condition.
   */
  bool isConditional() const { return m_condition != NULL; }

  /**
   * Return whether this @a Message is available (optionally depending on a @a Condition evaluation).
   * @return true when this @a Message is available.
   */
  bool isAvailable();

  /**
   * Return whether the field is available.
   * @param fieldName the name of the field to find, or NULL for any.
   * @param numeric true for a numeric field, false for a string field.
   * @return true if the field is available.
   */
  bool hasField(const char* fieldName, bool numeric = true);

  /**
   * @return the number of parts this message is composed of.
   */
  virtual unsigned char getCount() { return 1; }

  /**
   * Prepare the master @a SymbolString for sending a query or command to the bus.
   * @param srcAddress the source address to set.
   * @param masterData the master data @a SymbolString for writing symbols to.
   * @param input the @a istringstream to parse the formatted value(s) from.
   * @param separator the separator character between multiple fields.
   * @param dstAddress the destination address to set, or @a SYN to keep the address defined during construction.
   * @param index the index of the part to prepare.
   * @return @a RESULT_OK on success, or an error code.
   */
  result_t prepareMaster(const unsigned char srcAddress, SymbolString& masterData,
      istringstream& input, char separator = UI_FIELD_SEPARATOR,
      const unsigned char dstAddress = SYN, unsigned char index = 0);


 protected:
  /**
   * Prepare a part of the master data @a SymbolString for sending (everything including NN).
   * @param master the master data @a SymbolString for writing symbols to.
   * @param input the @a istringstream to parse the formatted value(s) from.
   * @param separator the separator character between multiple fields.
   * @param index the index of the part to prepare.
   * @return @a RESULT_OK on success, or an error code.
   */
  virtual result_t prepareMasterPart(SymbolString& master, istringstream& input, char separator, unsigned char index);


 public:
  /**
   * Prepare the slave @a SymbolString for sending an answer to the bus.
   * @param input the @a istringstream to parse the formatted value(s) from.
   * @param slaveData the slave data @a SymbolString for writing symbols to.
   * @return @a RESULT_OK on success, or an error code.
   */
  virtual result_t prepareSlave(istringstream& input, SymbolString& slaveData);

  /**
   * Store the last seen master and slave data.
   * @param master the last seen master data.
   * @param slave the last seen slave data.
   * @return @a RESULT_OK on success, or an error code.
   */
  virtual result_t storeLastData(SymbolString& master, SymbolString& slave);

  /**
   * Store last seen master or slave data.
   * @param partType the @a PartType of the data.
   * @param data the last seen data.
   * @param index the index of the part to store.
   * @return @a RESULT_OK on success, or an error code.
   */
  virtual result_t storeLastData(const PartType partType, SymbolString& data, unsigned char index);

  /**
   * Decode the value from the last stored data.
   * @param partType the @a PartType of the data.
   * @param output the @a ostringstream to append the formatted value to.
   * @param outputFormat the @a OutputFormat options to use.
   * @param leadingSeparator whether to prepend a separator before the formatted value.
   * @param fieldName the optional name of a field to limit the output to.
   * @param fieldIndex the optional index of the named field to limit the output to, or -1.
   * @return @a RESULT_OK on success, or an error code.
   */
  virtual result_t decodeLastData(const PartType partType,
      ostringstream& output, OutputFormat outputFormat = 0,
      bool leadingSeparator = false, const char* fieldName = NULL, signed char fieldIndex = -1);

  /**
   * Decode the value from the last stored data.
   * @param output the @a ostringstream to append the formatted value to.
   * @param outputFormat the @a OutputFormat options to use.
   * @param leadingSeparator whether to prepend a separator before the formatted value.
   * @param fieldName the optional name of a field to limit the output to.
   * @param fieldIndex the optional index of the named field to limit the output to, or -1.
   * @return @a RESULT_OK on success, or an error code.
   */
  virtual result_t decodeLastData(ostringstream& output, OutputFormat outputFormat = 0,
      bool leadingSeparator = false, const char* fieldName = NULL, signed char fieldIndex = -1);

  /**
   * Decode a particular numeric field value from the last stored data.
   * @param output the variable in which to store the value.
   * @param fieldName the name of the field to decode, or NULL for the first field.
   * @param fieldIndex the optional index of the named field, or -1.
   * @return @a RESULT_OK on success, or an error code.
   */
  virtual result_t decodeLastDataNumField(unsigned int& output, const char* fieldName, signed char fieldIndex = -1);

  /**
   * Get the last seen master data.
   * @return the last seen master @a SymbolString.
   */
  SymbolString& getLastMasterData() { return m_lastMasterData; }

  /**
   * Get the last seen slave data.
   * @return the last seen slave @a SymbolString.
   */
  SymbolString& getLastSlaveData() { return m_lastSlaveData; }

  /**
   * Get the time when this message was last seen with reasonable data.
   * @return the time when this message was last seen, or 0.
   */
  time_t getLastUpdateTime() { return m_lastUpdateTime; }

  /**
   * Get the time when the message data was last changed.
   * @return the time when the message data was last changed, or 0 if this message was not decoded yet.
   */
  time_t getLastChangeTime() { return m_lastChangeTime; }

  /**
   * Get the time when this message was last polled for.
   * @return the time when this message was last polled for, or 0 for never.
   */
  time_t getLastPollTime() { return m_lastPollTime; }

  /**
   * Return whether this @a Message needs to be polled after the other one.
   * @param other the other @a Message to compare with.
   * @return true if this @a Message needs to be polled after the other one.
   */
  bool isLessPollWeight(const Message* other);

  /**
   * Write the message definition or parts of it to the @a ostream.
   * @param output the @a ostream to append the formatted value to.
   * @param columns the list of column indexes to write, or NULL for all (see @p COLUMN_TYPE index constants).
   * @param withConditions whether to include the optional conditions prefix.
   */
  void dump(ostream& output, vector<size_t>* columns = NULL, bool withConditions = false);

  /**
   * Write the specified column to the @a ostream.
   * @param output the @a ostream to append the formatted value to.
   * @param column the column index to write (see @p COLUMN_TYPE index constants).
   * @param withConditions whether to include the optional conditions prefix.
   */
  virtual void dumpColumn(ostream& output, size_t column, bool withConditions = false);


 protected:
  /** the optional circuit name. */
  const string m_circuit;

  /** the message name (unique within the same circuit and type). */
  const string m_name;

  /** whether this is a write message. */
  const bool m_isWrite;

  /** true if message can only be initiated by a participant other than us,
   * false if message can be initiated by any participant. */
  const bool m_isPassive;

  /** the comment. */
  const string m_comment;

  /** the source address, or @a SYN for any (only relevant if passive). */
  const unsigned char m_srcAddress;

  /** the destination address, or @a SYN for any (only for temporary scan messages). */
  const unsigned char m_dstAddress;

  /** the primary, secondary, and optionally further command ID bytes. */
  vector<unsigned char> m_id;

  /**
   * the key for storing in @a MessageMap.
   * <ul>
   * <li>byte 7:
   *  <ul>
   *   <li>bits 5-7: length of ID bytes (without PB/SB)</li>
   *   <li>bits 0-4:
   *    <ul>
   *     <li>master number (1..25) of sender for passive message</li>
   *     <li>0x00 for passive message with any sender</li>
   *     <li>0x1f for active write</li>
   *     <li>0x1e for active read</li>
   *    </ul>
   *  </ul>
   * </li>
   * <li>byte 6: ZZ or SYN for any</li>
   * <li>byte 5: PB</li>
   * <li>byte 4: SB</li>
   * <li>bytes 3-0: ID bytes (with cyclic xor if more than 4)</li>
   * </ul>
   */
  uint64_t m_key;

  /** the @a DataField for encoding/decoding the message. */
  DataField* m_data;

  /** whether to delete the @a DataField during destruction. */
  const bool m_deleteData;

  /** the priority for polling, or 0 for no polling at all. */
  unsigned char m_pollPriority;

  /** whether this message is used by a @a Condition. */
  bool m_usedByCondition;

  /** whether this is a special scanning @a Message instance. */
  bool m_isScanMessage;

  /** the @a Condition for this message, or NULL. */
  Condition* m_condition;

  /** the last seen master data. */
  SymbolString m_lastMasterData;

  /** the last seen slave data. */
  SymbolString m_lastSlaveData;

  /** the system time when the message was last updated, 0 for never. */
  time_t m_lastUpdateTime;

  /** the system time when the message content was last changed, 0 for never. */
  time_t m_lastChangeTime;

  /** the number of times this messages was already polled for. */
  unsigned int m_pollCount;

  /** the system time when this message was last polled for, 0 for never. */
  time_t m_lastPollTime;
};


/**
 * A chained @a Message that needs more than one read/write on the bus to collect/send the data.
 */
class ChainedMessage : public Message {
 public:
  /**
   * Construct a new instance.
   * @param circuit the optional circuit name.
   * @param name the message name (unique within the same circuit and type).
   * @param isWrite whether this is a write message.
   * @param comment the comment.
   * @param srcAddress the source address, or @a SYN for any (only relevant if passive).
   * @param dstAddress the destination address, or @a SYN for any (set later).
   * @param id the primary, secondary, and optional further ID bytes common to each part of the chain.
   * @param ids the primary, secondary, and optional further ID bytes for each part of the chain.
   * @param lengths the data length for each part of the chain.
   * @param data the @a DataField for encoding/decoding the chained message.
   * @param deleteData whether to delete the @a DataField during destruction.
   * @param pollPriority the priority for polling, or 0 for no polling at all.
   * @param condition the @a Condition for this message, or NULL.
   */
  ChainedMessage(const string circuit, const string name,
      const bool isWrite, const string comment,
      const unsigned char srcAddress, const unsigned char dstAddress,
      const vector<unsigned char> id,
      vector< vector<unsigned char> > ids, vector<unsigned char> lengths,
      DataField* data, const bool deleteData,
      const unsigned char pollPriority,
      Condition* condition = NULL);

  virtual ~ChainedMessage();

  // @copydoc
  virtual Message* derive(const unsigned char dstAddress, const unsigned char srcAddress = SYN,
      const string circuit = "");

  // @copydoc
  virtual unsigned char getIdLength() const { return (unsigned char)(m_ids[0].size() - 2); }

  // @copydoc
  virtual bool checkId(SymbolString& master, unsigned char* index = NULL);

  // @copydoc
  virtual bool checkId(Message& other);

  // @copydoc
  virtual unsigned char getCount() { return (unsigned char)m_ids.size(); }


 protected:
  // @copydoc
  virtual result_t prepareMasterPart(SymbolString& master, istringstream& input, char separator, unsigned char index);


 public:
  // @copydoc
  virtual result_t storeLastData(SymbolString& master, SymbolString& slave);

  // @copydoc
  virtual result_t storeLastData(const PartType partType, SymbolString& data, unsigned char index);


 protected:
  // @copydoc
  virtual void dumpColumn(ostream& output, size_t column, bool withConditions = false);


 private:
  /** the primary, secondary, and optional further ID bytes for each part of the chain. */
  const vector< vector<unsigned char> > m_ids;

  /** the data length for each part of the chain. */
  const vector<unsigned char> m_lengths;

  /** the maximum allowed time difference of any data pair. */
  const time_t m_maxTimeDiff;

  /** array of the last seen master datas. */
  SymbolString** m_lastMasterDatas;

  /** array of the last seen slave datas. */
  SymbolString** m_lastSlaveDatas;

  /** array of the system times when the corresponding master data was last updated, 0 for never. */
  time_t* m_lastMasterUpdateTimes;

  /** array of the system times when the corresponding slave data was last updated, 0 for never. */
  time_t* m_lastSlaveUpdateTimes;
};


/**
 * A function that compares the weighted poll priority of two @a Message instances.
 */
struct compareMessagePriority : binary_function<Message*, Message*, bool> {
  /**
   * Compare the weighted poll priority of the two @a Message instances.
   * @param x the first @a Message.
   * @param y the second @a Message.
   * @return whether @a x is smaller than @a y with regard to their weighted poll priority.
   */
  bool operator() (Message* x, Message* y) const { return x->isLessPollWeight(y); }
};


/**
 * Helper class extending @a priority_queue to hold distinct values only.
 */
class MessagePriorityQueue
  : public priority_queue<Message*, vector<Message*>, compareMessagePriority> {
 public:
  /**
   * Add data to the queue and ensure it is contained only once.
   * @param __x the element to add.
   */
  void push(const value_type& __x) {
    for (vector<Message*>::iterator it = c.begin(); it != c.end(); it++) {
      if (*it == __x) {
        c.erase(it);
        break;
      }
    }
    priority_queue<Message*, vector<Message*>, compareMessagePriority>::push(__x);
  }
};


/**
 * An abstract condition based on the value of one or more @a Message instances.
 */
class Condition {
 public:
  /**
   * Construct a new instance.
   */
  Condition()
    : m_lastCheckTime(0), m_isTrue(false) { }

  /**
   * Destructor.
   */
  virtual ~Condition() { }

  /**
   * Factory method for creating a new instance.
   * @param condName the name of the condition.
   * @param it the iterator to traverse for the definition parts.
   * @param end the iterator pointing to the end of the definition parts.
   * @param defaultDest the valid destination address extracted from the file name (from ZZ part), or empty.
   * @param defaultCircuit the valid circuit name extracted from the file name (from IDENT part), or empty.
   * @param returnValue the variable in which to store the created instance.
   * @return @a RESULT_OK on success, or an error code.
   */
  static result_t create(const string condName, vector<string>::iterator& it, const vector<string>::iterator end,
      string defaultDest, string defaultCircuit, SimpleCondition*& returnValue);

  /**
   * Derive a new @a SimpleCondition from this condition.
   * @param valueList the @a string with the new list of values.
   * @return the derived @a SimpleCondition instance, or NULL if the value list is invalid.
   */
  virtual SimpleCondition* derive(string valueList) { return NULL; }

  /**
   * Write the condition definition or resolved expression to the @a ostream.
   * @param output the @a ostream to append to.
   * @param matched true for dumping the matched value if the condition is true, false for dumping the definition.
   */
  virtual void dump(ostream& output, bool matched = false) = 0;

  /**
   * Combine this condition with another instance using a logical and.
   * @param other the @a Condition to combine with.
   * @return the @a CombinedCondition instance.
   */
  virtual CombinedCondition* combineAnd(Condition* other) = 0;

  /**
   * Resolve the referred @a Message instance(s) and field index(es).
   * @param messages the @a MessageMap instance for resolving.
   * @param errorMessage a @a ostringstream to which to add optional error messages.
   * @param readMessageFunc the function to call for immediate reading of a @a Message from the bus, or NULL.
   * @return @a RESULT_OK on success, or an error code.
   */
  virtual result_t resolve(MessageMap* messages, ostringstream& errorMessage,
      void (*readMessageFunc)(Message* message) = NULL) = 0;

  /**
   * Check and return whether this condition is fulfilled.
   * @return whether this condition is fulfilled.
   */
  virtual bool isTrue() = 0;


 protected:
  /** the system time when the condition was last checked, 0 for never. */
  time_t m_lastCheckTime;

  /** whether the condition was @a true during the last check. */
  bool m_isTrue;
};


/**
 * A simple @a Condition based on the value of one @a Message.
 */
class SimpleCondition : public Condition {
 public:
  /**
   * Construct a new instance.
   * @param condName the name of the condition.
   * @param refName the reference name for dumping.
   * @param circuit the circuit name.
   * @param name the message name, or empty for scan message.
   * @param dstAddress the override destination address, or @a SYN (only for @a Message without specific destination
   * as well as scan message).
   * @param field the field name.
   * @param hasValues whether a value has to be checked against.
   */
  SimpleCondition(const string condName, const string refName, const string circuit, const string name,
      const unsigned char dstAddress, const string field, const bool hasValues = false)
    : Condition(),
      m_condName(condName), m_refName(refName), m_circuit(circuit), m_name(name), m_dstAddress(dstAddress),
      m_field(field), m_hasValues(hasValues), m_message(NULL) { }

  /**
   * Destructor.
   */
  virtual ~SimpleCondition() {}

  // @copydoc
  virtual SimpleCondition* derive(string valueList);

  // @copydoc
  virtual void dump(ostream& output, bool matched = false);

  // @copydoc
  virtual CombinedCondition* combineAnd(Condition* other);

  // @copydoc
  virtual result_t resolve(MessageMap* messages, ostringstream& errorMessage,
      void (*readMessageFunc)(Message* message) = NULL);

  // @copydoc
  virtual bool isTrue();

  /**
   * Return whether the condition is based on a numeric value.
   * @return whether the condition is based on a numeric value.
   */
  virtual bool isNumeric() { return true; }


 protected:
  /**
   * Check the values against the field in the @a Message.
   * @param message the @a Message to check against.
   * @param field the field name to check against, or empty for first field.
   * @return whether the field matches one of the valid values.
   */
  virtual bool checkValue(Message* message, const string field) { return true; }

  /** the value that matched in @a checkValue. */
  string m_matchedValue;


 private:
  /** the condition name. */
  const string m_condName;

  /** the reference name for dumping. */
  const string m_refName;

  /** the circuit name. */
  const string m_circuit;

  /** the message name, or empty for scan message. */
  const string m_name;

  /** the override destination address, or @a SYN (only for @a Message without specific destination as well as scan
   * message). */
  const unsigned char m_dstAddress;

  /** the field name, or empty for first field. */
  const string m_field;

  /** whether a value has to be checked against. */
  const bool m_hasValues;

  /** the resolved @a Message instance, or NULL. */
  Message* m_message;
};


/**
 * A simple @a Condition based on the numeric value of one @a Message.
 */
class SimpleNumericCondition : public SimpleCondition {
 public:
  /**
   * Construct a new instance.
   * @param condName the name of the condition.
   * @param refName the reference name for dumping.
   * @param circuit the circuit name.
   * @param name the message name, or empty for scan message.
   * @param dstAddress the override destination address, or @a SYN (only for @a Message without specific destination as well as scan message).
   * @param field the field name.
   * @param valueRanges the valid value ranges (pairs of from/to inclusive), empty for @a m_message seen check.
   */
  SimpleNumericCondition(const string condName, const string refName, const string circuit, const string name,
      const unsigned char dstAddress, const string field, const vector<unsigned int> valueRanges)
    : SimpleCondition(condName, refName, circuit, name, dstAddress, field, true),
      m_valueRanges(valueRanges) { }

  /**
   * Destructor.
   */
  virtual ~SimpleNumericCondition() {}


 protected:
  // @copydoc
  virtual bool checkValue(Message* message, const string field);


 private:
  /** the valid value ranges (pairs of from/to inclusive), empty for @a m_message seen check. */
  const vector<unsigned int> m_valueRanges;
};


/**
 * A simple @a Condition based on the string value of one @a Message.
 */
class SimpleStringCondition : public SimpleCondition {
 public:
  /**
   * Construct a new instance.
   * @param condName the name of the condition.
   * @param refName the reference name for dumping.
   * @param circuit the circuit name.
   * @param name the message name, or empty for scan message.
   * @param dstAddress the override destination address, or @a SYN (only for @a Message without specific destination as well as scan message).
   * @param field the field name.
   * @param values the valid values.
   */
  SimpleStringCondition(const string condName, const string refName, const string circuit, const string name,
      const unsigned char dstAddress, const string field, const vector<string> values)
    : SimpleCondition(condName, refName, circuit, name, dstAddress, field, true),
      m_values(values) { }

  /**
   * Destructor.
   */
  virtual ~SimpleStringCondition() {}

  // @copydoc
  virtual bool isNumeric() { return false; }


 protected:
  // @copydoc
  virtual bool checkValue(Message* message, const string field);


 private:
  /** the valid values. */
  const vector<string> m_values;
};


/**
 * A @a Condition combining two or more @a SimpleCondition instances with a logical and.
 */
class CombinedCondition : public Condition {
 public:
  /**
   * Construct a new instance.
   */
  CombinedCondition()
    : Condition() { }

  /**
   * Destructor.
   */
  virtual ~CombinedCondition() {}

  // @copydoc
  virtual void dump(ostream& output, bool matched = false);

  // @copydoc
  virtual CombinedCondition* combineAnd(Condition* other) { m_conditions.push_back(other); return this; }

  // @copydoc
  virtual result_t resolve(MessageMap* messages, ostringstream& errorMessage,
      void (*readMessageFunc)(Message* message) = NULL);

  // @copydoc
  virtual bool isTrue();


 private:
  /** the @a Condition instances used. */
  vector<Condition*> m_conditions;
};


/**
 * An abstract instruction based on the value of one or more @a Message instances.
 */
class Instruction {
 public:
  /**
   * Construct a new instance.
   * @param condition the @a Condition this instruction requires, or null.
   * @param singleton whether this @a Instruction belongs to a set of instructions of which only the first one may be
   * executed for the same source file.
   * @param defaultDest the default destination address, or empty.
   * @param defaultCircuit the default circuit name, or empty.
   * @param defaultSuffix the default circuit name suffix (starting with a "."), or empty.
   */
  Instruction(Condition* condition, const bool singleton, const string& defaultDest, const string& defaultCircuit,
      const string& defaultSuffix)
    : m_condition(condition), m_singleton(singleton), m_defaultDest(defaultDest), m_defaultCircuit(defaultCircuit),
      m_defaultSuffix(defaultSuffix) { }

  /**
   * Destructor.
   */
  virtual ~Instruction() { }

  /**
   * Factory method for creating a new instance.
   * @param contextPath the path and/or filename context being loaded.
   * @param defaultDest the default destination address, or empty.
   * @param defaultCircuit the default circuit name, or empty.
   * @param defaultSuffix the default circuit name suffix (starting with a "."), or empty.
   * @param condition the @a Condition for the instruction, or NULL.
   * @param type the type of the instruction.
   * @param it the iterator to traverse for the definition parts.
   * @param end the iterator pointing to the end of the definition parts.
   * @param returnValue the variable in which to store the created instance.
   * @return @a RESULT_OK on success, or an error code.
   */
  static result_t create(const string contextPath, const string& defaultDest, const string& defaultCircuit,
      const string& defaultSuffix, Condition* condition, const string type, vector<string>::iterator& it,
      const vector<string>::iterator end, Instruction*& returnValue);

  /**
   * Return the @a Condition this instruction requires.
   * @return the @a Condition this instruction requires, or null.
   */
  Condition* getCondition() { return m_condition; }

  /**
   * Return whether this @a Instruction belongs to a set of instructions of which only the first one may be executed
   * for the same source file.
   * @return whether this @a Instruction belongs to a set of instructions of which only the first one may be executed
   * for the same source file.
   */
  bool isSingleton() { return m_singleton; }

  /**
   * Return a string describing the destination from the stored default values.
   * @return a string describing the destination.
   */
  string getDestination();

  /**
   * Execute the instruction.
   * @param messages the @a MessageMap.
   * @param log the @a ostringstream to log success messages to (if necessary).
   * @param condition the @a Condition that was successfully evaluated for execution, or NULL.
   * @return @a RESULT_OK on success, or an error code.
   */
  virtual result_t execute(MessageMap* messages, ostringstream& log, Condition* condition) = 0;


 private:
  /** the @a Condition this instruction requires, or null. */
  Condition* m_condition;

  /** whether this @a Instruction belongs to a set of instructions of which only the first one may be executed for the
   * same source file. */
  bool m_singleton;


 protected:
  /** the default destination address, or empty. */
  const string m_defaultDest;

  /** the default circuit name, or empty. */
  const string m_defaultCircuit;

  /** the default circuit name suffix (starting with a "."), or empty. */
  const string m_defaultSuffix;
};


/**
 * An @a Instruction allowing to load another file.
 */
class LoadInstruction : public Instruction {
 public:
  /**
   * Construct a new instance.
   * @param condition the @a Condition this instruction requires, or null.
   * @param singleton whether this @a Instruction belongs to a set of instructions of which only the first one may be
   * executed for the same source file.
   * @param defaultDest the default destination address (may be overwritten by file name), or empty.
   * @param defaultCircuit the default circuit name (may be overwritten by file name), or empty.
   * @param defaultSuffix the default circuit name suffix (starting with a ".", may be overwritten by file name), or
   * empty.
   * @param filename the name of the file to load.
   */
  LoadInstruction(Condition* condition, const bool singleton, const string& defaultDest, const string& defaultCircuit,
      const string& defaultSuffix, const string filename)
    : Instruction(condition, singleton, defaultDest, defaultCircuit, defaultSuffix), m_filename(filename) { }

  /**
   * Destructor.
   */
  virtual ~LoadInstruction() { }

  // @copydoc
  virtual result_t execute(MessageMap* messages, ostringstream& log, Condition* condition);


 private:
  /** the name of the file to load. */
  const string m_filename;
};


/**
 * Holds a map of all known @a Message instances.
 */
class MessageMap : public FileReader {
 public:
  /**
   * Construct a new instance.
   * @param addAll whether to add all messages, even if duplicate.
   */
  explicit MessageMap(const bool addAll = false) : FileReader::FileReader(true),
    m_addAll(addAll), m_maxIdLength(0), m_messageCount(0), m_conditionalMessageCount(0), m_passiveMessageCount(0) {
    m_scanMessage = Message::createScanMessage();
  }

  /**
   * Destructor.
   */
  virtual ~MessageMap() {
    clear();
    delete m_scanMessage;
  }

  /**
   * Add a @a Message instance to this set.
   * @param message the @a Message instance to add.
   * @param storeByName whether to store the @a Message by name.
   * @return @a RESULT_OK on success, or an error code.
   * Note: the caller may not free the added instance on success.
   */
  result_t add(Message* message, bool storeByName = true);

  // @copydoc
  virtual result_t addDefaultFromFile(vector< vector<string> >& defaults, vector<string>& row,
    vector<string>::iterator& begin, string defaultDest, string defaultCircuit, string defaultSuffix,
    const string& filename, unsigned int lineNo);

  /**
   * Read the @a Condition instance(s) from the types field.
   * @param types the field from which to read the @a Condition instance(s).
   * @param filename the name of the file being read.
   * @param condition the variable in which to store the result.
   * @return @a RESULT_OK on success, or an error code.
   */
  result_t readConditions(string& types, const string& filename, Condition*& condition);

  // @copydoc
  virtual result_t addFromFile(vector<string>::iterator& begin, const vector<string>::iterator end,
    vector< vector<string> >* defaults, const string& defaultDest, const string& defaultCircuit,
    const string& defaultSuffix, const string& filename, unsigned int lineNo);

  /**
   * Get the scan @a Message instance for the specified address.
   * @param dstAddress the destination address, or @a SYN for the base scan @a Message.
   * @return the scan @a Message instance, or NULL if the dstAddress is no slave.
   */
  Message* getScanMessage(const unsigned char dstAddress = SYN);

  /**
   * Resolve all @a Condition instances.
   * @param verbose whether to verbosely add all problems to the error message.
   * @return @a RESULT_OK on success, or an error code.
   */
  result_t resolveConditions(bool verbose = false);

  /**
   * Resolve a @a Condition.
   * @param condition the @a Condition to resolve.
   * @param readMessageFunc the function to call for immediate reading of a @a Message from the bus, or NULL.
   * @return @a RESULT_OK on success, or an error code.
   */
  result_t resolveCondition(Condition* condition, void (*readMessageFunc)(Message* message) = NULL);

  /**
   * Run all executable @a Instruction instances.
   * @param log the @a ostringstream to log success messages to (if necessary).
   * @param readMessageFunc the function to call for immediate reading of a
   * @a Message values from the bus required for singleton instructions, or NULL.
   * @return @a RESULT_OK on success, or an error code.
   */
  result_t executeInstructions(ostringstream& log, void (*readMessageFunc)(Message* message) = NULL);

  /**
   * Add a loaded file to a participant.
   * @param address the slave address.
   * @param file the name of the file from which a configuration part was loaded for the participant.
   * @param comment an optional comment.
   */
  void addLoadedFile(unsigned char address, string file, string comment);

  /**
   * Get the loaded files for a participant.
   * @param address the slave address.
   * @return the name of the file(s) loaded for the participant (separated by comma and enclosed in double quotes),
   * or empty.
   */
  string getLoadedFiles(unsigned char address);

  /**
   * Get the stored @a Message instances for the key.
   * @param key the key of the @a Message.
   * @return the found @a Message instances, or NULL.
   * Note: the caller may not free the returned instances.
   */
  vector<Message*>* getByKey(const uint64_t key);

  /**
   * Find the @a Message instance for the specified circuit and name.
   * @param circuit the optional circuit name.
   * @param name the message name.
   * @param isWrite whether this is a write message.
   * @param isPassive whether this is a passive message.
   * @return the @a Message instance, or NULL.
   * Note: the caller may not free the returned instance.
   */
  Message* find(const string& circuit, const string& name, const bool isWrite, const bool isPassive = false);

  /**
   * Find all active get @a Message instances for the specified circuit and name.
   * @param circuit the circuit name, or empty for any.
   * @param name the message name, or empty for any.
   * @param completeMatch false to also include messages where the circuit and name matches only a part of the given
   * circuit and name (default true).
   * @param withRead true to include read messages (default true).
   * @param withWrite true to include write messages (default false).
   * @param withPassive true to include passive messages (default false).
   * @return the found @a Message instances.
   * @param completeMatchIgnoreCircuitSuffix ignore different circuit suffixes (after "#") for completeMatch.
   * @param onlyAvailable true to include only available messages (default true), false to also include messages that
   * are currently not available (e.g. due to unresolved or false conditions).
   * @param since the start time from which to add updates (inclusive, also removes messages with unset destination
   * address), or 0 to ignore.
   * @param until the end time to which to add updates (exclusive, also removes messages with unset destination
   * address), or 0 to ignore.
   * Note: the caller may not free the returned instances.
   */
  deque<Message*> findAll(const string& circuit, const string& name, const bool completeMatch = true,
    const bool withRead = true, const bool withWrite = false, const bool withPassive = false,
    const bool completeMatchIgnoreCircuitSuffix = false, const bool onlyAvailable = true,
    const time_t since = 0, const time_t until = 0);

  /**
   * Find the @a Message instance for the specified master data.
   * @param master the master @a SymbolString for identifying the @a Message.
   * @param anyDestination true to only return messages without a particular destination.
   * @param withRead true to include read messages (default true).
   * @param withWrite true to include write messages (default true).
   * @param withPassive true to include passive messages (default true).
   * @return the @a Message instance, or NULL.
   * Note: the caller may not free the returned instance.
   */
  Message* find(SymbolString& master, bool anyDestination = false,
    const bool withRead = true, const bool withWrite = true, const bool withPassive = true);

  /**
   * Invalidate cached data of the @a Message and all other instances with a matching name key.
   * @param message the @a Message to invalidate.
   */
  void invalidateCache(Message* message);

  /**
   * Add a @a Message to the list of instances to poll.
   * @param message the @a Message to poll.
   * @param toFront whether to add the @a Message to the very front of the poll queue.
   */
  void addPollMessage(Message* message, bool toFront = false);

  /**
   * Removes all @a Message instances.
   */
  void clear();

  /**
   * Get the number of all stored @a Message instances.
   * @return the the number of all stored @a Message instances.
   */
  size_t size() { return m_messageCount; }

  /**
   * Get the number of stored conditional @a Message instances.
   * @return the the number of stored conditional @a Message instances.
   */
  size_t sizeConditional() { return m_conditionalMessageCount; }

  /**
   * Get the number of stored passive @a Message instances.
   * @return the the number of stored passive @a Message instances.
   */
  size_t sizePassive() { return m_passiveMessageCount; }

  /**
   * Get the number of stored @a Message instances with a poll priority.
   * @return the the number of stored @a Message instances with a poll priority.
   */
  size_t sizePoll() { return m_pollMessages.size(); }

  /**
   * Get the next @a Message to poll.
   * @return the next @a Message to poll, or NULL.
   * Note: the caller may not free the returned instance.
   */
  Message* getNextPoll();

  /**
   * Get the number of stored @a Condition instances.
   * @return the number of stored @a Condition instances.
   */
  size_t sizeConditions() { return m_conditions.size(); }

  /**
   * Get the stored @a Condition instances.
   * @return the @a Condition instances by filename and condition name.
   */
  map<string, Condition*>& getConditions() { return m_conditions; }

  /**
   * Write the message definitions to the @a ostream.
   * @param output the @a ostream to append the formatted messages to.
   * @param withConditions whether to include the optional conditions prefix.
   */
  void dump(ostream& output, bool withConditions = false);


 private:
  /** whether to add all messages, even if duplicate. */
  const bool m_addAll;

  /** the @a Message instance used for scanning. */
  Message* m_scanMessage;

  /** the loaded configuration files by slave address. */
  map<unsigned char, string> m_loadedFiles;

  /** the maximum ID length used by any of the known @a Message instances. */
  unsigned char m_maxIdLength;

  /** the number of distinct @a Message instances stored in @a m_messagesByName. */
  size_t m_messageCount;

  /** the number of conditional @a Message instances part of @a m_messageCount. */
  size_t m_conditionalMessageCount;

  /** the number of distinct passive @a Message instances stored in @a m_messagesByKey. */
  size_t m_passiveMessageCount;

  /** the known @a Message instances by lowercase circuit and name. */
  map<string, vector<Message*> > m_messagesByName;

  /** the known @a Message instances by key. */
  map<uint64_t, vector<Message*> > m_messagesByKey;

  /** the known @a Message instances to poll, by priority. */
  MessagePriorityQueue m_pollMessages;

  /** the @a Condition instances by filename and condition name. */
  map<string, Condition*> m_conditions;

  /** the list of @a Instruction instances by filename. */
  map<string, vector<Instruction*> > m_instructions;
};

}  // namespace ebusd

#endif  // LIB_EBUS_MESSAGE_H_