//
// <copyright file="ConfigFile.cpp" company="Microsoft">
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright>
//
// ConfigFile.cpp : Defines the configuration file loader.
//
#ifndef _CRT_SECURE_NO_WARNINGS
#define _CRT_SECURE_NO_WARNINGS // "secure" CRT not available on all platforms  --add this at the top of all CPP files that give "function or variable may be unsafe" warnings
#endif

#include "File.h"
#include "commandArgUtil.h"

namespace Microsoft { namespace MSR { namespace CNTK {


    // ParseCommandLine - parse the command line parameters
    // argc - count of arguments
    // argv - array of argument parameters
    // config - config to return
    std::string ConfigParameters::ParseCommandLine(int argc, wchar_t* argv[], ConfigParameters& config)
    {
        config.SetName(std::string("global"));
        
        // This vector keeps track of the config files we have already read
        std::vector<std::string> resolvedConfigFiles;
        std::string configString;
        
        // start at 1, because 0 is the name of the EXE
        for (int i=1; i < argc; ++i)
        {
            wstring str = argv[i];

            // see if they are loading a config file
            wstring configDescriptor = L"configFile=";
            int compare = _wcsnicmp(configDescriptor.c_str(), str.c_str(), configDescriptor.length());

            // no config file, parse as regular argument
            if (compare)
            {
                configString += (msra::strfun::utf8(str) + "\n");
            }
            else // One or more config file paths specified in a "+"-separated list.
            {
                const std::string filePaths = msra::strfun::utf8(str.substr(configDescriptor.length()));
                std::vector<std::string> filePathsVec = msra::strfun::split(filePaths, "+");
                for (auto filePath : filePathsVec)
                {
                    if (std::find(resolvedConfigFiles.begin(), resolvedConfigFiles.end(), filePath) == resolvedConfigFiles.end())
                    {
                        // if haven't already read this file, read it
                        resolvedConfigFiles.push_back(filePath);
                        configString += config.ReadConfigFile(filePath);
                    }
                    else
                       RuntimeError("Cannot specify same config file multiple times at the command line.");
                }
            }
        }
        // now, configString is a concatenation of lines, including parameters from the command line, with comments stripped

        // expand any lines of the form include=
        configString = config.ResolveIncludeStatements(configString, resolvedConfigFiles);

        // convert into a ConfigDictionary--top-level expressions of the form var=val; if val is a block in braces, it is kept verbatim (not parsed inside)
        config.FileParse(configString);
        return configString;
    }

    // ResolveIncludeStatements - this function takes a config string, and looks for all lines of the
    //     form "include=configPaths", where 'configPaths' is a "+" separated list of paths to config files.
    //     If it encounters one of these lines, it reads the config files listed in 'configPaths' (in the specified order),
    //     and includes the body of each file in the string which is eventually returned by this function.  If the included
    //     config file includes other config files, this function will recursively include those files as well.
    // configString - the config string within which to look for "include" statements
    // resolvedConfigFiles - the paths to all the config files that have already been resolved.  This vector is used to prevent include loops,
    //     and to prevent files from being included multiple times.
    // returns: The config string, with all the "include" statements replaced with the bodies of the specified config files.
    std::string ConfigParser::ResolveIncludeStatements(const std::string &configString, std::vector<std::string> &resolvedConfigFiles)
    {
        std::vector<std::string> lines = msra::strfun::split(configString, "\n");
        std::string includeKeyword = "include=";
        std::size_t includeKeywordSize = includeKeyword.size();
        std::string newConfigString;
        for (std::string line : lines)
        {
            if (line.compare(0, includeKeywordSize, includeKeyword) == 0)
            {
                std::string filePaths = line.substr(includeKeywordSize, line.size() - includeKeywordSize);
                if (filePaths.find(openBraceVar) != std::string::npos)
                {
                    RuntimeError("Variable usage (eg, \"$varName$\") not supported in \"include\" statements. Explicit path to config file must be provided");
                }

                std::vector<std::string> filePathVec = msra::strfun::split (filePaths, "+");
                for (auto filePath : filePathVec)
                {
                    // if file hasn't already been resolved (the resolvedPaths vector doesn't contain it), resolve it.
                    if (std::find(resolvedConfigFiles.begin(), resolvedConfigFiles.end(), filePath) == resolvedConfigFiles.end())
                    {
                        // Recursively resolve the include statements in the included config files.
                        // Ensure that the same config file isn't included twice, by keeping track of the config
                        // files that have already been resolved in the resolvedPaths vector.
                        resolvedConfigFiles.push_back(filePath);
                        newConfigString += ResolveIncludeStatements(
                                               ReadConfigFile(filePath), 
                                               resolvedConfigFiles
                                           );
                    }
                    else
                    {
                        // We already resolved this path.  Write a warning so that user is aware of this.
                        // TODO: This message is written to stderr before stderr gets redirected to the specified file.  Fix this.
                        fprintf(stderr, "Warning: Config file included multiple times.  Not including config file again: %s", filePath.c_str());
                    }
                }
            }
            else
            {
                newConfigString += (line + "\n");
            }
        }
        return newConfigString;
    }

    // LoadConfigFiles - load multiple configuration file, and adds to config parameters
    // filePaths - A "+" delimited list of file paths, corresponding to config files to load
    // configStringToAppend - A config string which should be processed together with the config files
    void ConfigParser::LoadConfigFiles(const std::wstring &filePaths, const std::string *configStringToAppend)
    {
        std::string configString = ReadConfigFiles(filePaths);
        if(configStringToAppend != nullptr)
        {
            configString += *configStringToAppend;
        }

        FileParse(configString);
    }

    // LoadConfigFileAndResolveVariables - load a configuration file, and add to config parameters.
    //     If the config file contains references to variables, which are defined in the 'config' ConfigParameters,
    //     then this method will resolve those variables.  This method is meant for the processing of NDL/MEL config files,
    //     in order to allow them to access variables defined in the primary config file via $varName$ syntax.
    // filePath - filePath to the file to load
    // config - These ConfigParameters are used in order to resolve the $varName$ instances in the config file.
    void ConfigParser::LoadConfigFileAndResolveVariables(const std::wstring &filePath, const ConfigParameters& config)
    {
        // read file, resolve variables, and then parse.
        std::string fileContents = ReadConfigFile(filePath);
        fileContents = config.ResolveVariables(fileContents);
        FileParse(fileContents);
    }

    // LoadConfigFile - load a configuration file, and add to config parameters
    // filePath - filePath to the file to read
    void ConfigParser::LoadConfigFile(const std::wstring &filePath)
    {
        // read and then parse
        FileParse(ReadConfigFile(filePath));
    }
    
    // Same as "ReadConfigFiles" function below, but takes as input string instead of wstring
    std::string ConfigParser::ReadConfigFiles(const std::string &filePaths)
    {
        return ReadConfigFiles(msra::strfun::utf16(filePaths));
    }

    // ReadConfigFiles - reads multiple config files, concatenates the content from each file, and returns a string
    // filePaths - A "+" delimited list of file paths, corresponding to config files to read
    // returns: a string with the concatentated file contents
    std::string ConfigParser::ReadConfigFiles(const std::wstring &filePaths)
    {
        std::string configString;
        std::vector<std::wstring> filePathVec = msra::strfun::split (filePaths, L"+");
        for (auto filePath : filePathVec)
        {
            configString += ReadConfigFile(filePath);
        }
        return configString;
    }

    // Same as "ReadConfigFile" function below, but takes as input string instead of wstring
    std::string ConfigParser::ReadConfigFile(const std::string &filePath)
    {
        return ReadConfigFile(msra::strfun::utf16(filePath));
    }

    // ReadConfigFile - read a configuration file, and return all lines, stripped of comments, concatenated by newlines, as one long string (no other processing, expansion etc.)
    // filePath - the path to the config file to read
    // returns: a string with the concatentated file contents
    std::string ConfigParser::ReadConfigFile(const std::wstring &filePath)
    {
        File file(filePath, fileOptionsRead);

        // initialize configName with file name
        std::string configName = msra::strfun::utf8(filePath);
        auto location = configName.find_last_of("/\\");
        if (location != npos)
            configName = configName.substr(location+1);
        m_configName = move(configName);

        // read the entire file into a string
        // CONSIDER: should the File API support this, instead of us having to call it line by line?
        size_t fileLength = file.CanSeek() ? file.Size() : 0;
        string str;
        string configFile;
        configFile.reserve(fileLength);
        while (!file.IsEOF())
        {
            file.GetLine(str);
            str = StripComments(str);
            if (str != "")
            {
                configFile.append(str);
                configFile.append("\n");
            }
        }
        return configFile;
    }

    // GetFileConfigNames - determine the names of the features and labels sections in the config file
    // features - [in,out] a vector of feature name strings
    // labels - [in,out] a vector of label name strings
    void GetFileConfigNames(const ConfigParameters& readerConfig, std::vector<std::wstring>& features, std::vector<std::wstring>& labels)
    {
        for (auto iter = readerConfig.begin(); iter != readerConfig.end(); ++iter)
        {
            auto pair = *iter;
            ConfigParameters temp (iter->second);
            // see if we have a config parameters that contains a "dim" element, it's a sub key, use it
            if (temp.ExistsCurrent("dim"))
            {
                if (temp.ExistsCurrent("labelMappingFile") 
                    || temp.ExistsCurrent("labelDim")
                    || temp.ExistsCurrent("labelType")
                    || (temp.ExistsCurrent("sectionType") && temp("sectionType") == "labels"))
                {
                    labels.push_back(msra::strfun::utf16(iter->first));
                }
                else
                {
                    features.push_back(msra::strfun::utf16(iter->first));
                }
            }
        }
    }

    // FindConfigNames - determine the names of the heirarchy of sections in the config file that contain a particular key
    // config - configuration to search
    // key - string we ar searching for in each config section
    // names - [in,out] a vector of section names in "path" format (i.e. base\subsection)
    void FindConfigNames(const ConfigParameters& config, std::string key, std::vector<std::wstring>& names)
    {
        for (auto iter = config.begin(); iter != config.end(); ++iter)
        {
            auto pair = *iter;
            ConfigParameters temp (iter->second);
            // see if we have a config parameters that contains a "key" element, if so use it
            if (temp.ExistsCurrent(key))
            {
                names.push_back(msra::strfun::utf16(iter->first));
            }
        }
    }

    // Trim - trim white space off the start and end of the string
    // str - string to trim
    // NOTE: if the entire string is empty, then the string will be set to an empty string
    void Trim(std::string& str)
    {
        auto found = str.find_first_not_of(" \t");
        if (found == npos)
        {
            str.erase(0);
            return;
        }
        str.erase(0, found);
        found = str.find_last_not_of(" \t");
        if (found != npos)
            str.erase(found+1);
    }

}}}