// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
// vi: set et ts=4 sw=4 sts=4:
/*
  This file is part of the Open Porous Media project (OPM).

  OPM 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 2 of the License, or
  (at your option) any later version.

  OPM 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 OPM.  If not, see <http://www.gnu.org/licenses/>.

  Consult the COPYING file in the top-level source directory of this
  module for the precise wording of the license and the list of
  copyright holders.
*/
/*!
 * \file
 *
 * \brief This file provides the infrastructure to retrieve run-time parameters
 *
 * Internally, runtime parameters are implemented using
 * Dune::ParameterTree with the default value taken from the parameter
 * definition.
 */

#include <config.h>
#include <opm/models/utils/parametersystem.hpp>

#include <dune/common/parametertree.hh>

#include <opm/models/utils/terminal.hpp>

#if HAVE_QUAD
#include <opm/material/common/quad.hpp>
#endif

#include <algorithm>
#include <charconv>
#include <fstream>
#include <memory>
#include <stdexcept>
#include <sys/ioctl.h>
#include <unistd.h>

namespace {

struct ParamInfo
{
    std::string paramName;
    std::string paramTypeName;
    std::string typeTagName;
    std::string usageString;
    std::string defaultValue;
    bool isHidden;

    bool operator==(const ParamInfo& other) const
    {
        return other.paramName == paramName
            && other.paramTypeName == paramTypeName
            && other.typeTagName == typeTagName
            && other.usageString == usageString;
    }
};

struct MetaData
{
    using type = Dune::ParameterTree;

    static Dune::ParameterTree& tree()
    { return *storage_().tree; }

    static std::map<std::string, ParamInfo>& mutableRegistry()
    { return storage_().registry; }

    static const std::map<std::string, ParamInfo>& registry()
    { return storage_().registry; }

    static bool& registrationOpen()
    { return storage_().registrationOpen; }

    static void clear()
    {
        storage_().tree = std::make_unique<Dune::ParameterTree>();
        storage_().registrationOpen = true;
        storage_().registry.clear();
    }

private:
    // this is not pretty, but handling these attributes as static variables inside
    // member functions of the ParameterMetaData property class triggers a bug in clang
    // 3.5's address sanitizer which causes these variables to be initialized multiple
    // times...
    struct Storage_
    {
        Storage_()
            : tree(std::make_unique<Dune::ParameterTree>())
            , registrationOpen(true)
        {
        }

        std::unique_ptr<Dune::ParameterTree> tree;
        std::map<std::string, ParamInfo> registry;
        bool registrationOpen;
    };

    static Storage_& storage_()
    {
        static Storage_ obj;
        return obj;
    }
};


void getFlattenedKeyList(std::vector<std::string>& dest,
                         const Dune::ParameterTree& tree,
                         const std::string& prefix = "")
{
    // add the keys of the current sub-structure
    for (const auto& valueKey : tree.getValueKeys()) {
        std::string newKey(prefix + valueKey);
        dest.push_back(newKey);
    }

    // recursively add all substructure keys
    for (const auto& subKey : tree.getSubKeys()) {
        std::string newPrefix(prefix + subKey + '.');
        getFlattenedKeyList(dest, tree.sub(subKey), newPrefix);
    }
}

std::string parseKey(std::string& s)
{
    auto it = std::find_if(s.begin(), s.end(),
                           [](const char ch) { return std::isspace(ch) || ch == '='; });
    std::string ret {s.begin(), it};
    s.erase(s.begin(), it);
    return ret;
}

std::string parseQuotedValue(std::string& s, const std::string& errorPrefix)
{
    if (s.empty() || s[0] != '"') {
        throw std::runtime_error(errorPrefix + "Expected quoted string");
    }

    std::string result;
    unsigned i = 1;
    for (; i < s.size(); ++i) {
        // handle escape characters
        if (s[i] == '\\') {
            ++i;
            if (s.size() <= i) {
                throw std::runtime_error(errorPrefix + "Unexpected end of quoted string");
            }

            switch (s[i]) {
            case 'n':  result += '\n'; break;
            case 'r':  result += '\r'; break;
            case 't':  result += '\t'; break;
            case '"':  result += '"';  break;
            case '\\': result += '\\'; break;
            default:   throw std::runtime_error(errorPrefix +
                                                "Unknown escape character '\\" + s[i] + "'");
            }
        }
        else if (s[i] == '"') {
            break;
        }
        else {
            result += s[i];
        }
    }

    s = s.substr(i+1);
    return result;
}

std::string parseUnquotedValue(std::string& s, const std::string&)
{
    auto it = std::find_if(s.begin(), s.end(), ::isspace);
    std::string ret{s.begin(), it};
    s.erase(s.begin(), it);
    return ret;
}

void printParamList(std::ostream& os,
                    const std::vector<std::string>& keyList,
                    bool printDefaults = false)
{
    const Dune::ParameterTree& tree = MetaData::tree();

    for (const auto& key : keyList) {
        const auto& paramInfo = MetaData::registry().at(key);
        const std::string& defaultValue = paramInfo.defaultValue;
        std::string value = defaultValue;
        if (tree.hasKey(key)) {
            value = tree.get(key, "");
        }
        os << key << "=\"" << value << "\"";
        if (printDefaults)
            os << " # default: \"" << defaultValue << "\"";
        os << "\n";
    }
}

void printParamUsage(std::ostream& os,
                     const ParamInfo& paramInfo)
{
    std::string paramMessage;

    int ttyWidth = Opm::getTtyWidth();

    // convert the CamelCase name to a command line --parameter-name.
    std::string cmdLineName = "-";
    const std::string camelCaseName = paramInfo.paramName;
    for (unsigned i = 0; i < camelCaseName.size(); ++i) {
        if (isupper(camelCaseName[i])) {
            cmdLineName += "-";
        }
        cmdLineName += static_cast<char>(std::tolower(camelCaseName[i]));
    }

    // assemble the printed output
    paramMessage = "    ";
    paramMessage += cmdLineName;

    // add the =VALUE_TYPE part
    bool isString = false;
    if (paramInfo.paramTypeName == Dune::className<std::string>()
        || paramInfo.paramTypeName == "const char *")
    {
        paramMessage += "=STRING";
        isString = true;
    }
    else if (paramInfo.paramTypeName == Dune::className<float>()
             || paramInfo.paramTypeName == Dune::className<double>()
             || paramInfo.paramTypeName == Dune::className<long double>()
#if HAVE_QUAD
             || paramInfo.paramTypeName == Dune::className<quad>()
#endif // HAVE_QUAD
            ) {
        paramMessage += "=SCALAR";
    }
    else if (paramInfo.paramTypeName == Dune::className<int>()
             || paramInfo.paramTypeName == Dune::className<unsigned int>()
             || paramInfo.paramTypeName == Dune::className<short>()
             || paramInfo.paramTypeName == Dune::className<unsigned short>()) {
        paramMessage += "=INTEGER";
    }
    else if (paramInfo.paramTypeName == Dune::className<bool>()) {
        paramMessage += "=BOOLEAN";
    }
    else if (paramInfo.paramTypeName.empty()) {
        // the parameter is a flag. Do nothing!
    }
    else {
        // unknown type
        paramMessage += "=VALUE";
    }

    // fill up the up help string to the 50th character
    paramMessage += "  ";
    while (paramMessage.size() < 50)
        paramMessage += " ";


    // append the parameter usage string.
    paramMessage += paramInfo.usageString;

    // add the default value
    if (!paramInfo.paramTypeName.empty()) {
        if (paramMessage.back() != '.') {
            paramMessage += '.';
        }
        paramMessage += " Default: ";
        if (paramInfo.paramTypeName == "bool") {
            if (paramInfo.defaultValue == "0") {
                paramMessage += "false";
            }
            else {
                paramMessage += "true";
            }
        }
        else if (isString) {
            paramMessage += "\"";
            paramMessage += paramInfo.defaultValue;
            paramMessage += "\"";
        }
        else {
            paramMessage += paramInfo.defaultValue;
        }
    }

    paramMessage = Opm::breakLines(paramMessage, /*indent=*/52, ttyWidth);
    paramMessage += "\n";

    // print everything
    os << paramMessage;
}

void removeLeadingSpace(std::string& s)
{
    s.erase(s.begin(),
            std::find_if(s.begin(), s.end(),
                         [](const char ch) { return !std::isspace(ch); }));
}

std::string transformKey(const std::string& s,
                         bool capitalizeFirstLetter,
                         const std::string& errorPrefix = "")
{
    std::string result;

    if (s.empty()) {
        throw std::runtime_error(errorPrefix + "Empty parameter names are invalid");
    }

    if (!std::isalpha(s[0])) {
        throw std::runtime_error(errorPrefix +" Parameter name '" + s +
                                 "' is invalid: First character must be a letter");
    }

    if (capitalizeFirstLetter) {
        result += static_cast<char>(std::toupper(s[0]));
    }
    else {
        result += s[0];
    }

    for (unsigned i = 1; i < s.size(); ++i) {
        if (s[i] == '-') {
            ++i;
            if (s.size() <= i || !std::isalpha(s[i])) {
                throw std::runtime_error(errorPrefix + "Invalid parameter name '" + s + "'");
            }
            result += static_cast<char>(std::toupper(s[i]));
        }
        else if (!std::isalnum(s[i])) {
            throw std::runtime_error(errorPrefix + "Invalid parameter name '" + s + "'");
        }
        else {
            result += s[i];
        }
    }

    return result;
}

} // anonymous namespace

namespace Opm::Parameters {

namespace detail {

template<class ParamType>
ParamType Get_(const std::string& paramName, ParamType defaultValue,
               bool errorIfNotRegistered)
{
    if (errorIfNotRegistered) {
        if (MetaData::registrationOpen()) {
            throw std::runtime_error("Parameters can only retrieved after _all_ of them have "
                                     "been registered.");
        }

        if (MetaData::registry().find(paramName) == MetaData::registry().end()) {
            throw std::runtime_error("Accessing parameter " + paramName +
                                     " without prior registration is not allowed.");
        }
    }

    const std::string& defVal = MetaData::mutableRegistry()[paramName].defaultValue;
    if constexpr (std::is_same_v<ParamType, std::string>) {
        defaultValue = defVal;
    }
    else if constexpr (std::is_same_v<ParamType, bool>) {
        defaultValue = defVal == "1";
    }
#if HAVE_QUAD
    else if constexpr (std::is_same_v<ParamType, quad>) {
        defaultValue = std::strtold(defVal.data(), nullptr);
    }
#endif
#if !HAVE_FLOATING_POINT_FROM_CHARS
    else if constexpr (std::is_floating_point_v<ParamType>) {
        defaultValue = std::strtod(defVal.c_str(), nullptr);
    }
#endif // !HAVE_FLOATING_POINT_FROM_CHARS
    else {
        std::from_chars(defVal.data(), defVal.data() + defVal.size(), defaultValue);
    }

    // prefix the parameter name by the model's GroupName. E.g. If
    // the model specifies its group name to be 'Stokes', in an
    // INI file this would result in something like:
    //
    // [Stokes]
    // NewtonWriteConvergence = true
    // retrieve actual parameter from the parameter tree
    return MetaData::tree().template get<ParamType>(paramName, defaultValue);
}

void Hide_(const std::string& paramName)
{
    if (!MetaData::registrationOpen()) {
        throw std::logic_error("Parameter '" + paramName + "' declared as hidden"
                               " when parameter registration was already closed.");
    }

    auto paramInfoIt = MetaData::mutableRegistry().find(paramName);
    if (paramInfoIt == MetaData::mutableRegistry().end()) {
        throw std::logic_error("Tried to declare unknown parameter '" +
                               paramName + "' hidden.");
    }

    auto& paramInfo = paramInfoIt->second;
    paramInfo.isHidden = true;
}

bool IsSet_(const std::string& paramName, bool errorIfNotRegistered)
{
    if (errorIfNotRegistered) {
        if (MetaData::registrationOpen()) {
            throw std::runtime_error("Parameters can only checked after _all_ of them have "
                                     "been registered.");
        }

        if (MetaData::registry().find(paramName) == MetaData::registry().end()) {
            throw std::runtime_error("Accessing parameter " + std::string(paramName) +
                                     " without prior registration is not allowed.");
        }
    }

    // check whether the parameter is in the parameter tree
    return MetaData::tree().hasKey(paramName);
}

void Register_(const std::string& paramName,
               const std::string& paramTypeName,
               const std::string& defaultValue,
               const char* usageString)
{
    if (!MetaData::registrationOpen()) {
        throw std::logic_error("Parameter registration was already closed before "
                               "the parameter '" + paramName + "' was registered.");
    }

    ParamInfo paramInfo;
    paramInfo.paramName = paramName;
    paramInfo.paramTypeName = paramTypeName;
    paramInfo.usageString = usageString;
    paramInfo.defaultValue = defaultValue;
    paramInfo.isHidden = false;
    if (MetaData::registry().find(paramName) != MetaData::registry().end()) {
        // allow to register a parameter twice, but only if the
        // parameter name, type and usage string are exactly the same.
        if (MetaData::registry().at(paramName) == paramInfo) {
            return;
        }
        throw std::logic_error("Parameter " + paramName +
                               " registered twice with non-matching characteristics.");
    }

    MetaData::mutableRegistry()[paramName] = paramInfo;
}

void SetDefault_(const std::string& paramName,
                 const std::string& paramValue)
{
    if (MetaData::registry().find(paramName) == MetaData::registry().end()) {
        throw std::runtime_error("Accessing parameter " + paramName +
                                 " without prior registration is not allowed.");
    }
    MetaData::mutableRegistry()[paramName].defaultValue = paramValue;
}

} // namespace detail

void reset()
{
    MetaData::clear();
}

bool IsRegistrationOpen()
{
    return MetaData::registrationOpen();
}

void endRegistration()
{
    if (!MetaData::registrationOpen()) {
        throw std::logic_error("Parameter registration was already closed. It is only possible "
                               "to close it once.");
    }

    MetaData::registrationOpen() = false;
}

void getLists(std::vector<Parameter>& usedParams,
              std::vector<Parameter>& unusedParams)
{
    usedParams.clear();
    unusedParams.clear();

    if (MetaData::registrationOpen()) {
        throw std::runtime_error("Parameter lists can only retrieved after _all_ of them have "
                                 "been registered.");
    }

    // get all parameter keys
    std::vector<std::string> allKeysList;
    getFlattenedKeyList(allKeysList, MetaData::tree());

    for (const auto& key : allKeysList) {
        if (MetaData::registry().find(key) == MetaData::registry().end()) {
            // key was not registered
            unusedParams.emplace_back(key, MetaData::tree()[key]);
        }
        else {
            // key was registered
            usedParams.emplace_back(key, MetaData::tree()[key]);
        }
    }
}

void printUsage(const std::string& helpPreamble,
                std::ostream& os,
                const std::string& errorMsg,
                const bool showAll)
{
    if (!errorMsg.empty()) {
        os << errorMsg << "\n\n";
    }

    os << breakLines(helpPreamble, /*indent=*/2, /*maxWidth=*/getTtyWidth());
    os << "\n";

    os << "Recognized options:\n";

    if (!helpPreamble.empty()) {
        ParamInfo pInfo;
        pInfo.paramName = "h,--help";
        pInfo.usageString = "Print this help message and exit";
        printParamUsage(os, pInfo);
        pInfo.paramName = "-help-all";
        pInfo.usageString = "Print all parameters, including obsolete, hidden and deprecated ones.";
        printParamUsage(os, pInfo);
    }

    for (const auto& param : MetaData::registry()) {
        if (showAll || !param.second.isHidden) {
            printParamUsage(os, param.second);
        }
    }
}

bool parseParameterFile(const std::string& fileName, bool overwrite)
{
    std::set<std::string> seenKeys;
    std::ifstream ifs(fileName);
    if (!ifs.is_open()) {
        return false;
    }

    unsigned curLineNum = 0;
    while (ifs) {
        // string and file processing in c++ is quite blunt!
        std::string curLine;
        std::getline(ifs, curLine);
        curLineNum += 1;
        std::string errorPrefix = fileName + ":" + std::to_string(curLineNum) + ": ";

        // strip leading white space
        removeLeadingSpace(curLine);

        // ignore empty and comment lines
        if (curLine.empty() || curLine[0] == '#' || curLine[0] == ';') {
            continue;
        }

        // TODO (?): support for parameter groups.

        // find the "key" of the key=value pair
        std::string key = parseKey(curLine);
        std::string canonicalKey = transformKey(key, /*capitalizeFirst=*/true, errorPrefix);

        if (seenKeys.count(canonicalKey) > 0) {
            throw std::runtime_error(errorPrefix + "Parameter '" + canonicalKey +
                                     "' seen multiple times in the same file");
        }
        seenKeys.insert(canonicalKey);

        // deal with the equals sign
        removeLeadingSpace(curLine);
        if (curLine.empty() || curLine[0] != '=') {
            throw std::runtime_error(errorPrefix+"Syntax error, expecting 'key=value'");
        }

        curLine = curLine.substr(1);
        removeLeadingSpace(curLine);

        if (curLine.empty() || curLine[0] == '#' || curLine[0] == ';') {
            throw std::runtime_error(errorPrefix+"Syntax error, expecting 'key=value'");
        }

        // get the value
        std::string value;
        if (curLine[0] == '"') {
            value = parseQuotedValue(curLine, errorPrefix);
        }
        else {
            value = parseUnquotedValue(curLine, errorPrefix);
        }

        // ignore trailing comments
        removeLeadingSpace(curLine);
        if (!curLine.empty() && curLine[0] != '#' && curLine[0] != ';') {
            throw std::runtime_error(errorPrefix + "Syntax error, expecting 'key=value'");
        }

        // all went well, add the parameter to the database object
        if (overwrite || !MetaData::tree().hasKey(canonicalKey)) {
            MetaData::tree()[canonicalKey] = value;
        }
    }

    return true;
}

std::string parseCommandLineOptions(int argc,
                                    const char **argv,
                                    const PositionalArgumentCallback& posArgCallback,
                                    const std::string& helpPreamble)
{
    // handle the "--help" parameter
    if (!helpPreamble.empty()) {
        for (int i = 1; i < argc; ++i) {
            if (std::string("-h") == argv[i] ||
                std::string("--help") == argv[i]) {
                printUsage(helpPreamble, std::cout, /*errorMsg=*/"");
                return "Help called";
            }
            if (std::string("--help-all") == argv[i]) {
                printUsage(helpPreamble, std::cout, /*errorMsg=*/"",  true);
                return "Help called";
            }
        }
    }

    std::set<std::string> seenKeys;
    int numPositionalParams = 0;
    for (int i = 1; i < argc; ++i) {
        // All non-positional command line options need to start with '-'
        if (strlen(argv[i]) < 4
            || argv[i][0] != '-'
            || argv[i][1] != '-')
        {
            std::string errorMsg;
            int numHandled = posArgCallback([](const std::string& k, const std::string& v)
                                            {
                                                MetaData::tree()[k] = v;
                                            }, seenKeys, errorMsg,
                                            argc, argv, i, numPositionalParams);

            if (numHandled < 1) {
                if (!helpPreamble.empty()) {
                    printUsage(helpPreamble, std::cerr, errorMsg);
                }

                return errorMsg;
            }
            else {
                ++numPositionalParams;
                i += numHandled - 1;
                continue;
            }
        }

        std::string paramName, paramValue;

        // read a --my-opt=abc option. This gets transformed
        // into the parameter "MyOpt" with the value being
        // "abc"

        // There is nothing after the '-'
        if (argv[i][2] == 0 || !std::isalpha(argv[i][2])) {
            std::ostringstream oss;
            oss << "Parameter name of argument " << i
                << " ('" << argv[i] << "') "
                << "is invalid because it does not start with a letter.";

            if (!helpPreamble.empty()) {
                printUsage(helpPreamble, std::cerr, oss.str());
            }

            return oss.str();
        }

        // copy everything after the "--" into a separate string
        std::string s(argv[i] + 2);

        // parse argument
        paramName = transformKey(parseKey(s), /*capitalizeFirst=*/true);
        if (seenKeys.count(paramName) > 0) {
            const std::string msg = "Parameter '" + paramName +
                                    "' specified multiple times as a "
                                    "command line parameter";

            if (!helpPreamble.empty()) {
                printUsage(helpPreamble, std::cerr, msg);
            }
            return msg;
        }
        seenKeys.insert(paramName);

        if (s.empty() || s[0] != '=') {
            const std::string msg = "Parameter '" + paramName +
                                    "' is missing a value. "
                                    " Please use " + argv[i] + "=value.";

            if (!helpPreamble.empty()) {
                printUsage(helpPreamble, std::cerr, msg);
            }
            return msg;
        }

        paramValue = s.substr(1);

        // Put the key=value pair into the parameter tree
        MetaData::tree()[paramName] = paramValue;
    }
    return "";
}

void printValues(std::ostream& os)
{
    std::vector<std::string> runTimeAllKeyList;
    std::vector<std::string> runTimeKeyList;
    std::vector<std::string> unknownKeyList;

    getFlattenedKeyList(runTimeAllKeyList, MetaData::tree());
    for (const auto& key : runTimeAllKeyList) {
        if (MetaData::registry().find(key) == MetaData::registry().end()) {
            // key was not registered by the program!
            unknownKeyList.push_back(key);
        }
        else {
            // the key was specified at run-time
            runTimeKeyList.push_back(key);
        }
    }

    // loop over all registered parameters
    std::vector<std::string> compileTimeKeyList;
    for (const auto& reg : MetaData::registry()) {
        // check whether the key was specified at run-time
        if (MetaData::tree().hasKey(reg.first)) {
            continue;
        } else {
            compileTimeKeyList.push_back(reg.first);
        }
    }

    // report the values of all registered (and unregistered)
    // parameters
    if (runTimeKeyList.size() > 0) {
        os << "# [known parameters which were specified at run-time]\n";
        printParamList(os, runTimeKeyList, /*printDefaults=*/true);
    }

    if (compileTimeKeyList.size() > 0) {
        os << "# [parameters which were specified at compile-time]\n";
        printParamList(os, compileTimeKeyList, /*printDefaults=*/false);
    }

    if (unknownKeyList.size() > 0) {
        os << "# [unused run-time specified parameters]\n";
        for (const auto& unused : unknownKeyList) {
            os << unused << "=\"" << MetaData::tree().get(unused, "") << "\"\n" << std::flush;
        }
    }
}

bool printUnused(std::ostream& os)
{
    std::vector<std::string> runTimeAllKeyList;
    std::vector<std::string> unknownKeyList;

    getFlattenedKeyList(runTimeAllKeyList, MetaData::tree());
    std::copy_if(runTimeAllKeyList.begin(), runTimeAllKeyList.end(),
                 std::back_inserter(unknownKeyList),
                 [](const auto& key)
                 {
                    return MetaData::registry().find(key) == MetaData::registry().end();
                 });

    if (!unknownKeyList.empty()) {
        os << "# [unused run-time specified parameters]\n";
        for (const auto& unused : unknownKeyList) {
            os << unused << "=\""
               << MetaData::tree().get(unused, "") << "\"\n" << std::flush;
        }
        return true;
    }
    return false;
}

namespace detail {

template bool Get_(const std::string&, bool, bool);
template double Get_(const std::string&, double, bool);
template float Get_(const std::string&, float, bool);
template int Get_(const std::string&, int, bool);
template long Get_(const std::string&, long, bool);
template std::string Get_(const std::string&, std::string, bool);
template unsigned Get_(const std::string&, unsigned, bool);

#if HAVE_QUAD
template quad Get_(const std::string&, quad, bool);
#endif

} // namespace detail

} // namespace Opm::Parameters
