// Copyright 2022, FOSS-VG Developers and Contributers
//
// This program is free software: you can redistribute it and/or modify it
// under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, version 3.
//
// 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// version 3 along with this program.
// If not, see https://www.gnu.org/licenses/agpl-3.0.en.html

#include "cli.h++"

#include <string>
#include <vector>
#include <map>

#include "error.h++"

namespace CLI {
    Flag::Flag() {
        this->present = false;
    }
    Flag::Flag(char shortName, std::string longName, std::string description) {
        this->shortName = shortName;
        this->longName = longName;
        this->description = description;
        this->present = false;
    }

    UnpositionalArgument::UnpositionalArgument() {
        this->present = false;
    }
    UnpositionalArgument::UnpositionalArgument(char shortName, std::string longName, std::string placeholder, std::string description) {
        this->shortName = shortName;
        this->longName = longName;
        this->description = description;
        this->placeholder = placeholder;
        this->present = false;
    }

    PositionalArgument::PositionalArgument() {
        this->present = false;
    }
    PositionalArgument::PositionalArgument(std::string placeholder, std::string description) {
        this->description = description;
        this->placeholder = placeholder;
        this->present = false;
    }

    // using int here bc that's how main() is defined
    ArgumentsParser::ArgumentsParser(int argc, char* argv[], std::vector<Flag> flags, std::vector<UnpositionalArgument> unpositionalArguments, std::vector<PositionalArgument> positionalArguments) {
        this->wrongUsage = false;
        this->wrongUsageMessages = std::vector<std::string>();
        this->programName = std::string(argv[0]);
        this->positionalArguments = positionalArguments;
        // create lookup tables for all flags and unpositional arguments
        // by their names
        this->flagsByShortName = std::map<char, Flag*>();
        this->flagsByLongName  = std::map<std::string, Flag*>();
        for (Flag flag: flags) {
            Flag* flagPointer = new Flag();
            *flagPointer = flag;
            this->flagsByShortName[flag.shortName] = flagPointer;
            this->flagsByLongName[flag.longName]   = flagPointer;
        }
        this->argumentsByShortName = std::map<char, UnpositionalArgument*>();
        this->argumentsByLongName = std::map<std::string, UnpositionalArgument*>();
        for (UnpositionalArgument unpositionalArgument: unpositionalArguments) {
            UnpositionalArgument* argumentPointer = new UnpositionalArgument();
            *argumentPointer = unpositionalArgument;
            this->argumentsByShortName[unpositionalArgument.shortName] = argumentPointer;
            this->argumentsByLongName[unpositionalArgument.longName]   = argumentPointer;
        }

        UnpositionalArgument* argumentWaitingForValue = nullptr;
        std::vector<CLI::PositionalArgument>::size_type positionalArgumentCounter = 0;
        for (int i=1; i<argc; i++) {
            std::string argument(argv[i]);
            if (argument[0]=='-') {
                // do we have unfinished business?
                if (argumentWaitingForValue!=nullptr) {
                    this->wrongUsage = true;
                    this->wrongUsageMessages.push_back(std::string("Argument expects value but has none: ")+argumentWaitingForValue->longName);
                    argumentWaitingForValue = nullptr;
                }
                // long name or short name?
                if (argument[1]=='-') {
                    // long name
                    //FIXME: instead of auto, this should be what string
                    // length is defined as
                    // (std::__cxx11::basic_string<char>::size_type ?)
                    // argument with =value specified?
                    auto position = argument.find("=");
                    if (position==std::string::npos) {
                        // no =value
                        //is argument or flag?
                        std::string argumentName = argument.substr(2,argument.length());
                        if (flagsByLongName.contains(argumentName)) {
                            // flag
                            flagsByLongName[argumentName]->present = true;
                        } else if (argumentsByLongName.contains(argumentName)) {
                            // unpositional argument
                            argumentsByLongName[argumentName]->present = true;
                            argumentWaitingForValue = argumentsByLongName[argumentName];
                        } else {
                            this->wrongUsage = true;
                            this->wrongUsageMessages.push_back(std::string("Unknown argument or flag: ")+argument);
                        }
                    } else {
                        // has =value
                        std::string value = argument.substr(position, argument.length());
                        std::string argumentName = argument.substr(2, position);
                        if (argumentsByLongName.contains(argumentName)) {
                            argumentsByLongName[argumentName]->present = true;
                            argumentsByLongName[argumentName]->value = value;
                        } else {
                            this->wrongUsage = true;
                            this->wrongUsageMessages.push_back(std::string("Unknown argument (or it's a flag that doesn't take a value): ")+argument);
                        }
                    }
                } else {
                    // short name
                    //FIXME: instead of int, this should use what string
                    // length is defined as
                    // (std::__cxx11::basic_string<char>::size_type ?)
                    // starting at 1 because 0 is '-'
                    for (int i=1; i<(int) argument.length(); i++) {
                        //is argument or flag?
                        if (flagsByShortName.contains(argument[i])) {
                            flagsByShortName[argument[i]]->present = true;
                        } else if (argumentsByShortName.contains(argument[i])) {
                            argumentsByShortName[argument[i]]->present = true;
                            //FIXME: see above
                            if (i+1==(int) argument.length()) {
                                argumentWaitingForValue = argumentsByShortName[argument[i]];
                            } else {
                                //assume the rest of the argv is a concatenated argument value
                                argumentsByShortName[argument[i]]->value = argument.substr(i+1, argument.length());
                                break;
                            }
                        } else {
                            this->wrongUsage = true;
                            this->wrongUsageMessages.push_back(std::string("Unknown argument or flag(s): ")+argument.substr(i, argument.length()));
                            // err on the side of caution to ensure that
                            // no unwanted options get activated on programs
                            // that deal gracefully with unrecognized command
                            // line parameters
                            break;
                        }
                    }
                }
            } else {
                // positional argument or value for unpositional arg?
                if (argumentWaitingForValue==nullptr) {
                    // positional argument
                    if (positionalArgumentCounter < this->positionalArguments.size()) {
                        this->positionalArguments.at(positionalArgumentCounter).present = true;
                        this->positionalArguments.at(positionalArgumentCounter).value = argument;
                    } else {
                        this->wrongUsage = true;
                        this->wrongUsageMessages.push_back(std::string("Too many positional arguments. Unexpected encounter of: ")+argument);
                    }
                    positionalArgumentCounter++;
                } else {
                    // value for unpositional argument
                    argumentWaitingForValue->value = argument;
                }
            }
        }
        for (PositionalArgument const& positionalArgument: this->positionalArguments) {
            if (!positionalArgument.present) {
                this->wrongUsage = true;
                this->wrongUsageMessages.push_back(std::string("Too few positional arguments! Missing: ")+positionalArgument.placeholder);
            }
        }
    }

    ArgumentsParser::~ArgumentsParser() {
        //TODO: check that this actually runs
        for (auto const& [shortName, flag]: this->flagsByShortName) {
            delete flag;
        }
        for (auto const& [shortName, unpositionalArgument]: this->argumentsByShortName) {
            delete unpositionalArgument;
        }
    }

    ErrorOr<std::string> ArgumentsParser::getProgramName() {
        if (this->wrongUsage) {
            return ErrorOr<std::string>(true, ErrorCodes::WRONG_USAGE, this->programName);
        }
        return ErrorOr<std::string>(this->programName);
    }

    ErrorOr<bool> ArgumentsParser::getFlag(int argc, char* argv[], char shortName) {
        if (!this->flagsByShortName.contains(shortName)) return ErrorOr<bool>(true, ErrorCodes::UNKNOWN_KEY, false);
        if (this->wrongUsage) {
            return ErrorOr<bool>(true, ErrorCodes::WRONG_USAGE, this->flagsByShortName[shortName]->present);
        }
        return ErrorOr<bool>(this->flagsByShortName[shortName]->present);
    }

    ErrorOr<bool> ArgumentsParser::getFlag(int argc, char* argv[], std::string longName) {
        if (!this->flagsByLongName.contains(longName)) return ErrorOr<bool>(true, ErrorCodes::UNKNOWN_KEY, false);
        if (this->wrongUsage) {
            return ErrorOr<bool>(true, ErrorCodes::WRONG_USAGE, this->flagsByLongName[longName]->present);
        }
        return ErrorOr<bool>(this->flagsByLongName[longName]->present);
    }

    ErrorOr<std::string> ArgumentsParser::getPositionalArgument(int argc, char* argv[], std::vector<CLI::PositionalArgument>::size_type position){
        if (position >= this->positionalArguments.size()) return ErrorOr<std::string>(true, ErrorCodes::OUT_OF_RANGE, std::string(""));
        if (this->wrongUsage) {
            if (this->positionalArguments.at(position).present) return ErrorOr<std::string>(true, ErrorCodes::WRONG_USAGE, this->positionalArguments.at(position).value);
            else return ErrorOr<std::string>(true, ErrorCodes::NOT_PRESENT, std::string(""));
        }
        return ErrorOr<std::string>(this->positionalArguments.at(position).value);
    }

    ErrorOr<std::string> ArgumentsParser::getUnpositionalArgument(int argc, char* argv[], char shortName) {
        if (!this->argumentsByShortName.contains(shortName)) return ErrorOr<std::string>(true, ErrorCodes::UNKNOWN_KEY, std::string(""));
        if (this-wrongUsage) {
            if (this->argumentsByShortName[shortName]->present) return ErrorOr<std::string>(true, ErrorCodes::WRONG_USAGE, this->argumentsByShortName[shortName]->value);
            else return ErrorOr<std::string>(true, ErrorCodes::NOT_PRESENT, std::string(""));
        }
        if (this->argumentsByShortName[shortName]->present) return ErrorOr<std::string>(this->argumentsByShortName[shortName]->value);
        // argument is not present, but this is not an error -> false, NOT_PRESENT, ""
        else return ErrorOr<std::string>(false, ErrorCodes::NOT_PRESENT, std::string(""));
    }

    ErrorOr<std::string> ArgumentsParser::getUnpositionalArgument(int argc, char* argv[], std::string longName) {
        if (!this->argumentsByLongName.contains(longName)) return ErrorOr<std::string>(true, ErrorCodes::UNKNOWN_KEY, std::string(""));
        if (this-wrongUsage) {
            if (this->argumentsByLongName[longName]->present) return ErrorOr<std::string>(true, ErrorCodes::WRONG_USAGE, this->argumentsByLongName[longName]->value);
            else return ErrorOr<std::string>(true, ErrorCodes::NOT_PRESENT, std::string(""));
        }
        if (this->argumentsByLongName[longName]->present) return ErrorOr<std::string>(this->argumentsByLongName[longName]->value);
        // argument is not present, but this is not an error -> false, NOT_PRESENT, ""
        else return ErrorOr<std::string>(false, ErrorCodes::NOT_PRESENT, std::string(""));
    }
    //std::string ArgumentsParser::getUsage();
}