<?php

declare(strict_types=1);

/*
 * This file is a part of the Dragon-Knight project.
 *
 * Copyright (c) 2024-present Sharkk
 *
 * This file is subject to the MIT license that is bundled
 * with this source code in the LICENSE.md file.
 */

namespace DragonKnight;

class Math
{
    /*
        Internal math public static functions, such as to calculate EXP, HP, stats, etc.
    */

    /**
     * Calculates the ***total*** EXP required at a particular level in order to level up.
     */
    public static function calculate_exp(int $level, int $growth_rate): int
    {
        if ($level < 1) {
            throw new \InvalidArgumentException('Level must be 1 or greater');
        }

        // Growth rates:
        // 0 = Erratic
        // 1 = Fast
        // 2 = Medium Fast
        // 3 = Medium Slow
        // 4 = Slow
        // 5 = Fluctuating

        if ($growth_rate < 0 || $growth_rate > 5) {
            throw new \InvalidArgumentException('Growth rate must be between 0 and 5');
        }

        return match ($growth_rate) {
            0 => Math::calculate_erratic_exp($level),
            1 => (4 * pow($level, 3)) / 5,
            2 => pow($level, 3),
            3 => ((6 * pow($level, 3)) / 5) - (15 * pow($level, 2)) + (100 * $level) - 140,
            4 => (5 * pow($level, 3)) / 4,
            5 => Math::calculate_fluctuating_exp($level),
        };
    }

    /**
     * Calculate the ***total*** EXP for a given level in the Erratic formula.
     */
    public static function calculate_erratic_exp(int $level): int
    {
        if ($level <= 50) {
            return (pow($level, 3) * (100 - $level)) / 50;
        } elseif ($level <= 68) {
            return (pow($level, 3) * (150 - $level)) / 100;
        } elseif ($level <= 98) {
            return (pow($level, 3) * ((1911 - (10 * $level)) / 3)) / 500;
        }

        return (pow($level, 3) * (160 - $level)) / 100;
    }

    /**
     * Calculate the ***total*** EXP for a given level in the Fluctuating formula.
     */
    public static function calculate_fluctuating_exp(int $level): int
    {
        if ($level <= 15) {
            return pow($level, 3) * ((((($level + 1) / 3) + 24) / 50));
        } elseif ($level <= 36) {
            return pow($level, 3) * (($level + 14) / 50);
        }

        return pow($level, 3) * ((($level / 2) + 32) / 50);
    }

    /**
     * Calculate a points total from a base. Modes: 1 (weak), 2 (normal), 3 (strong).
     */
    public static function calculate_points(int $base_points, int $level, int $mode = 2): int
    {
        if ($level < 1) {
            throw new \InvalidArgumentException('Level must be 1 or greater');
        }

        $growth_multiplier = match ($mode) {
            1 => 0.15,
            2 => 0.3,
            3 => 0.6,
            default => throw new \InvalidArgumentException('Invalid mode. Use 1 (weak), 2 (normal), or 3 (strong)')
        };

        return (int) floor((2 * $base_points * $level * $growth_multiplier) / 100) + $level + 10;
    }

    /**
     * Calculate a stat total from a base. Modes: 1 (weak), 2 (normal), 3 (strong).
     */
    public static function calculate_stat(int $base_stat, int $level, int $mode = 2): int
    {
        if ($level < 1) {
            throw new \InvalidArgumentException('Level must be 1 or greater');
        }

        $growth_multiplier = match ($mode) {
            1 => 0.15,
            2 => 0.3,
            3 => 0.6,
            default => throw new \InvalidArgumentException('Invalid mode. Use 1 (weak), 2 (normal), or 3 (strong)')
        };

        return (int) floor((2 * $base_stat * $level * $growth_multiplier) / 100) + 5;
    }
}