remote-processor/RemoteCommandHandlerTemplate.h

#pragma once

#include <vector>
#include "RemoteCommandHandler.h"

template <class CCommandParser>
class TRemoteCommandHandlerTemplate : public IRemoteCommandHandler
{
public:
    // Remote command execution status
    enum CommandStatus {
        EDone,
        ESucceeded,
        EFailed,
        EShowUsage
    };

    // Remote command parsers
    typedef CommandStatus (CCommandParser::*RemoteCommandParser)(const IRemoteCommand& remoteCommand, std::string& strResult);

private:
    // Parser descriptions
    class CRemoteCommandParserItem
    {
    public:
        CRemoteCommandParserItem(const std::string& strCommandName,
                                 RemoteCommandParser pfnParser,
                                 uint32_t uiMinArgumentCount,
                                 const std::string& strHelp,
                                 const std::string& strDescription)
            : _strCommandName(strCommandName),
              _pfnParser(pfnParser),
              _uiMinArgumentCount(uiMinArgumentCount),
              _strHelp(strHelp),
              _strDescription(strDescription) {}

        const std::string& getCommandName() const
        {
            return _strCommandName;
        }

        const std::string& getDescription() const
        {
            return _strDescription;
        }

        // Usage
        std::string usage() const
        {
            return _strCommandName + " " + _strHelp;
        }

        bool parse(CCommandParser* pCommandParser, const IRemoteCommand& remoteCommand, std::string& strResult) const
        {
            // Check enough arguments supplied
            if (remoteCommand.getArgumentCount() < _uiMinArgumentCount) {

                strResult = std::string("Not enough arguments supplied\nUsage:\n") + usage();

                return false;
            }

            switch ((pCommandParser->*_pfnParser)(remoteCommand, strResult)) {
            case EDone:
                strResult = "Done";
                // Fall through intentionally
            case ESucceeded:
                return true;
            case EShowUsage:
                strResult = usage();
                // Fall through intentionally
            case EFailed:
                return false;
            }

            return false;
        }

    private:
        std::string _strCommandName;
        RemoteCommandParser _pfnParser;
        uint32_t _uiMinArgumentCount;
        std::string _strHelp;
        std::string _strDescription;
    };

public:
    TRemoteCommandHandlerTemplate(CCommandParser* pCommandParser) : _pCommandParser(pCommandParser), _uiMaxCommandUsageLength(0)
    {
        // Help Command
        addCommandParser("help", NULL, 0, "", "Show commands description and usage");
    }
    ~TRemoteCommandHandlerTemplate()
    {
        uint32_t uiIndex;

        for (uiIndex = 0; uiIndex < _remoteCommandParserVector.size(); uiIndex++) {

            delete _remoteCommandParserVector[uiIndex];
        }
    }

    // Parsers
    bool addCommandParser(const std::string& strCommandName,
        RemoteCommandParser pfnParser,
        uint32_t uiMinArgumentCount,
        const std::string& strHelp,
        const std::string& strDescription)
    {
        if (findCommandParserItem(strCommandName)) {

            // Already exists
            return false;
        }

        // Add command
        _remoteCommandParserVector.push_back(new CRemoteCommandParserItem(strCommandName, pfnParser, uiMinArgumentCount, strHelp, strDescription));

        return true;
    }

private:
    // Command processing
    bool remoteCommandProcess(const IRemoteCommand& remoteCommand, std::string& strResult)
    {
        // Dispatch
        const CRemoteCommandParserItem* pRemoteCommandParserItem = findCommandParserItem(remoteCommand.getCommand());

        if (!pRemoteCommandParserItem) {

            // Not found
            strResult = "Command not found!";

            return false;
        }

        if (remoteCommand.getCommand() == "help") {

            helpCommandProcess(strResult);

            return true;
        }

        return pRemoteCommandParserItem->parse(_pCommandParser, remoteCommand, strResult);
    }

    // Max command usage length, use for formatting
    void initMaxCommandUsageLength()
    {
        if (!_uiMaxCommandUsageLength) {
            // Show usages
            uint32_t uiIndex;

            for (uiIndex = 0; uiIndex < _remoteCommandParserVector.size(); uiIndex++) {

                const CRemoteCommandParserItem* pRemoteCommandParserItem = _remoteCommandParserVector[uiIndex];

                uint32_t uiRemoteCommandUsageLength = pRemoteCommandParserItem->usage().length();

                if (uiRemoteCommandUsageLength > _uiMaxCommandUsageLength) {

                    _uiMaxCommandUsageLength = uiRemoteCommandUsageLength;
                }
            }
        }
    }

    /////////////////// Remote command parsers
    /// Help
    void helpCommandProcess(std::string& strResult)
    {
        initMaxCommandUsageLength();

        strResult = "\n";

        // Show usages
        uint32_t uiIndex;

        for (uiIndex = 0; uiIndex < _remoteCommandParserVector.size(); uiIndex++) {

            const CRemoteCommandParserItem* pRemoteCommandParserItem = _remoteCommandParserVector[uiIndex];

            std::string strUsage = pRemoteCommandParserItem->usage();

            strResult += strUsage;

            // Align
            uint32_t uiToSpacesAdd = _uiMaxCommandUsageLength + 5 - strUsage.length();

            while (uiToSpacesAdd--) {

                strResult += " ";
            }

            strResult += std::string("=> ") + std::string(pRemoteCommandParserItem->getDescription()) + "\n";
        }
    }

    const CRemoteCommandParserItem* findCommandParserItem(const std::string& strCommandName) const
    {
        uint32_t uiIndex;

        for (uiIndex = 0; uiIndex < _remoteCommandParserVector.size(); uiIndex++) {

            const CRemoteCommandParserItem* pRemoteCommandParserItem = _remoteCommandParserVector[uiIndex];

            if (pRemoteCommandParserItem->getCommandName() == strCommandName) {

                return pRemoteCommandParserItem;
            }
        }
        return NULL;
    }

private:
    CCommandParser* _pCommandParser;
    std::vector<CRemoteCommandParserItem*> _remoteCommandParserVector;
    uint32_t _uiMaxCommandUsageLength;
};