// Solutions to the Advent Of Code 2024.
// Copyright (C) 2025  Stefan Müller
//
// 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/>.

#include <aoc/ClawContraption.hpp>

#include <sstream>

const std::string ClawContraption::getPuzzleName() const
{
    return "Claw Contraption";
}

const int ClawContraption::getPuzzleDay() const
{
    return 13;
}

void ClawContraption::processDataLine(const std::string& line)
{
    if (!line.empty())
    {
        std::istringstream stream{ line };
        std::string token;
        char c;
        int x;
        int y;

        stream >> token;
        if (token == "Button")
        {
            stream >> c;
            std::getline(stream, token, '+');
            stream >> x;
            std::getline(stream, token, '+');
            stream >> y;
            if (c == 'A')
            {
                buttonA_ = { x, y };
            }
            else
            {
                buttonB_ = { x, y };
            }
        }
        else
        {
            std::getline(stream, token, '=');
            stream >> x;
            std::getline(stream, token, '=');
            stream >> y;
            part1 += calcTokenCost(buttonA_, buttonB_, { x, y }, 0);
            part2 += calcTokenCost(buttonA_, buttonB_, { x, y }, getConversionCorrection());
        }
    }
}

void ClawContraption::finish()
{
}

constexpr int ClawContraption::getNMaxButtonPushes()
{
    return 100;
}

constexpr int ClawContraption::getButtonACost()
{
    return 3;
}

constexpr int ClawContraption::getButtonBCost()
{
    return 1;
}

constexpr long long int ClawContraption::getConversionCorrection()
{
    return 10000000000000;
}

long long int ClawContraption::calcTokenCost(const Point2& buttonA, const Point2& buttonB, const Point2& prize,
    const long long int offset)
{
    long long int p{ (prize.y + offset) * buttonB.x - (prize.x + offset) * buttonB.y };
    long long int q{ buttonA.y * buttonB.x - buttonA.x * buttonB.y };
    long long int a{ p / q };
    if (a * q != p || (offset == 0 && a > getNMaxButtonPushes()))
    {
        return 0;
    }
    long long int r{ prize.x + offset - a * buttonA.x };
    long long int b{ r / buttonB.x };
    if (b * buttonB.x != r || (offset == 0 && b > getNMaxButtonPushes()))
    {
        return 0;
    }
    return a * getButtonACost() + b * getButtonBCost();
}