units.php

<?php

    declare(strict_types = 1);

    defined('INSIDE') OR exit('No direct script access allowed');

    /**
     * This class contains all information about every unit, including
     * prices, dependencies and language-bindings.
     */
    class D_Units {

        /** @var array Mapping of Unit-ID to Unit-String-ID */
        private static $units;

        /** @var array Mapping of Unit-ID to the name in the currently loaded language */
        private static $names;

        /** @var array Mapping of Unit-ID to the description, according to the current language-file */
        private static $descriptions;

        /** @var array Mapping of Unit-ID to the price for the unit */
        private static $pricelist;

        /** @var array Mapping of Unit-ID to the requirements for the unit */
        private static $requeriments;

        private static $initialized = false;

        static function destruct() {
            self::$units = null;
            self::$names = null;
            self::$descriptions = null;
            self::$pricelist = null;
            self::$requeriments = null;
            self::$initialized = false;
        }

        /**
         *
         */
        static function init() {

            // check, if already initialized
            if (self::$initialized) {
                return;
            }

            self::$initialized = true;


            require Config::$pathConfig['language'] . Config::$gameConfig['language'] . '/units.php';

            self::$units = [
                1  => 'metal_mine',
                2  => 'crystal_mine',
                3  => 'deuterium_synthesizer',
                4  => 'solar_plant',
                5  => 'fusion_reactor',
                6  => 'robotic_factory',
                7  => 'nanite_factory',
                8  => 'shipyard',
                9  => 'metal_storage',
                10 => 'crystal_storage',
                11 => 'deuterium_storage',
                12 => 'research_lab',
                13 => 'terraformer',
                14 => 'alliance_depot',
                15 => 'missile_silo',

                101 => 'espionage_tech',
                102 => 'computer_tech',
                103 => 'weapon_tech',
                104 => 'armour_tech',
                105 => 'shielding_tech',
                106 => 'energy_tech',
                107 => 'hyperspace_tech',
                108 => 'combustion_drive_tech',
                109 => 'impulse_drive_tech',
                110 => 'hyperspace_drive_tech',
                111 => 'laser_tech',
                112 => 'ion_tech',
                113 => 'plasma_tech',
                114 => 'intergalactic_research_tech',
                115 => 'graviton_tech',

                201 => 'small_cargo_ship',
                202 => 'large_cargo_ship',
                203 => 'light_fighter',
                204 => 'heavy_fighter',
                205 => 'cruiser',
                206 => 'battleship',
                207 => 'colony_ship',
                208 => 'recycler',
                209 => 'espionage_probe',
                210 => 'bomber',
                211 => 'solar_satellite',
                212 => 'destroyer',
                213 => 'battlecruiser',
                214 => 'deathstar',

                301 => 'rocket_launcher',
                302 => 'light_laser',
                303 => 'heavy_laser',
                304 => 'gauss_cannon',
                305 => 'ion_cannon',
                306 => 'plasma_turret',
                307 => 'small_shield_dome',
                308 => 'large_shield_dome',
                309 => 'anti_ballistic_missile',
                310 => 'interplanetary_missile'
            ];

            self::$names = [
                1  => $lang["metal_mine"],
                2  => $lang["crystal_mine"],
                3  => $lang["deuterium_synthesizer"],
                4  => $lang["solar_plant"],
                5  => $lang["fusion_reactor"],
                6  => $lang["robotic_factory"],
                7  => $lang["nanite_factory"],
                8  => $lang["shipyard"],
                9  => $lang["metal_storage"],
                10 => $lang["crystal_storage"],
                11 => $lang["deuterium_storage"],
                12 => $lang["research_lab"],
                13 => $lang["terraformer"],
                14 => $lang["alliance_depot"],
                15 => $lang["missile_silo"],

                101 => $lang["espionage_tech"],
                102 => $lang["computer_tech"],
                103 => $lang["weapon_tech"],
                104 => $lang["armour_tech"],
                105 => $lang["shielding_tech"],
                106 => $lang["energy_tech"],
                107 => $lang["hyperspace_tech"],
                108 => $lang["combustion_drive_tech"],
                109 => $lang["impulse_drive_tech"],
                110 => $lang["hyperspace_drive_tech"],
                111 => $lang["laser_tech"],
                112 => $lang["ion_tech"],
                113 => $lang["plasma_tech"],
                114 => $lang["intergalactic_research_tech"],
                115 => $lang["graviton_tech"],

                201 => $lang["small_cargo_ship"],
                202 => $lang["large_cargo_ship"],
                203 => $lang["light_fighter"],
                204 => $lang["heavy_fighter"],
                205 => $lang["cruiser"],
                206 => $lang["battleship"],
                207 => $lang["colony_ship"],
                208 => $lang["recycler"],
                209 => $lang["espionage_probe"],
                210 => $lang["bomber"],
                211 => $lang["solar_satellite"],
                212 => $lang["destroyer"],
                213 => $lang["battlecruiser"],
                214 => $lang["deathstar"],

                301 => $lang["rocket_launcher"],
                302 => $lang["light_laser"],
                303 => $lang["heavy_laser"],
                304 => $lang["gauss_cannon"],
                305 => $lang["ion_cannon"],
                306 => $lang["plasma_turret"],
                307 => $lang["small_shield_dome"],
                308 => $lang["large_shield_dome"],
                309 => $lang["anti_ballistic_missile"],
                310 => $lang["interplanetary_missile"]
            ];

            self::$descriptions = [
                1  => $lang["metal_mine_descr"],
                2  => $lang["crystal_mine_descr"],
                3  => $lang["deuterium_synthesizer_descr"],
                4  => $lang["solar_plant_descr"],
                5  => $lang["fusion_reactor_descr"],
                6  => $lang["robotic_factory_descr"],
                7  => $lang["nanite_factory_descr"],
                8  => $lang["shipyard_descr"],
                9  => $lang["metal_storage_descr"],
                10 => $lang["crystal_storage_descr"],
                11 => $lang["deuterium_storage_descr"],
                12 => $lang["research_lab_descr"],
                13 => $lang["terraformer_descr"],
                14 => $lang["alliance_depot_descr"],
                15 => $lang["missile_silo_descr"],


                101 => $lang["espionage_tech_descr"],
                102 => $lang["computer_tech_descr"],
                103 => $lang["weapon_tech_descr"],
                104 => $lang["armour_tech_descr"],
                105 => $lang["shielding_tech_descr"],
                106 => $lang["energy_tech_descr"],
                107 => $lang["hyperspace_tech_descr"],
                108 => $lang["combustion_drive_tech_descr"],
                109 => $lang["impulse_drive_tech_descr"],
                110 => $lang["hyperspace_drive_tech_descr"],
                111 => $lang["laser_tech_descr"],
                112 => $lang["ion_tech_descr"],
                113 => $lang["plasma_tech_descr"],
                114 => $lang["intergalactic_research_tech_descr"],
                115 => $lang["graviton_tech_descr"],

                201 => $lang["small_cargo_ship_descr"],
                202 => $lang["large_cargo_ship_descr"],
                203 => $lang["light_fighter_descr"],
                204 => $lang["heavy_fighter_descr"],
                205 => $lang["cruiser_descr"],
                206 => $lang["battleship_descr"],
                207 => $lang["colony_ship_descr"],
                208 => $lang["recycler_descr"],
                209 => $lang["espionage_probe_descr"],
                210 => $lang["bomber_descr"],
                211 => $lang["solar_satellite_descr"],
                212 => $lang["destroyer_descr"],
                213 => $lang["battlecruiser_descr"],
                214 => $lang["deathstar_descr"],

                301 => $lang["rocket_launcher_desc"],
                302 => $lang["light_laser_desc"],
                303 => $lang["heavy_laser_desc"],
                304 => $lang["gauss_cannon_desc"],
                305 => $lang["ion_cannon_desc"],
                306 => $lang["plasma_turret_desc"],
                307 => $lang["small_shield_dome_desc"],
                308 => $lang["large_shield_dome_desc"],
                309 => $lang["anti_ballistic_missile_desc"],
                310 => $lang["interplanetary_missile_desc"]
            ];

            self::$pricelist = [
                // Buildings
                1   => ['metal' => 60, 'crystal' => 15, 'deuterium' => 0, 'energy' => 0, 'factor' => 1.5],
                2   => ['metal' => 48, 'crystal' => 24, 'deuterium' => 0, 'energy' => 0, 'factor' => 1.6],
                3   => ['metal' => 225, 'crystal' => 75, 'deuterium' => 0, 'energy' => 0, 'factor' => 1.5],
                4   => ['metal' => 75, 'crystal' => 30, 'deuterium' => 0, 'energy' => 0, 'factor' => 1.5],
                5   => ['metal' => 900, 'crystal' => 360, 'deuterium' => 180, 'energy' => 0, 'factor' => 1.8],
                6   => ['metal' => 400, 'crystal' => 120, 'deuterium' => 200, 'energy' => 0, 'factor' => 2],
                7   => ['metal' => 1000000, 'crystal' => 500000, 'deuterium' => 100000, 'energy' => 0, 'factor' => 2],
                8   => ['metal' => 400, 'crystal' => 200, 'deuterium' => 100, 'energy' => 0, 'factor' => 2],
                9   => ['metal' => 1000, 'crystal' => 0, 'deuterium' => 0, 'energy' => 0, 'factor' => 2],
                10  => ['metal' => 1000, 'crystal' => 500, 'deuterium' => 0, 'energy' => 0, 'factor' => 2],
                11  => ['metal' => 1000, 'crystal' => 1000, 'deuterium' => 0, 'energy' => 0, 'factor' => 2],
                12  => ['metal' => 200, 'crystal' => 400, 'deuterium' => 200, 'energy' => 0, 'factor' => 2],
                13  => ['metal' => 0, 'crystal' => 50000, 'deuterium' => 100000, 'energy' => 1000, 'factor' => 2],
                14  => ['metal' => 20000, 'crystal' => 40000, 'deuterium' => 0, 'energy' => 0, 'factor' => 2],
                15  => ['metal' => 20000, 'crystal' => 20000, 'deuterium' => 1000, 'energy' => 0, 'factor' => 2],

                // Techs
                101 => ['metal' => 200, 'crystal' => 1000, 'deuterium' => 200, 'energy' => 0, 'factor' => 2],
                102 => ['metal' => 0, 'crystal' => 400, 'deuterium' => 600, 'energy' => 0, 'factor' => 2],
                103 => ['metal' => 800, 'crystal' => 200, 'deuterium' => 0, 'energy' => 0, 'factor' => 2],
                104 => ['metal' => 200, 'crystal' => 600, 'deuterium' => 0, 'energy' => 0, 'factor' => 2],
                105 => ['metal' => 1000, 'crystal' => 0, 'deuterium' => 0, 'energy' => 0, 'factor' => 2],
                106 => ['metal' => 0, 'crystal' => 800, 'deuterium' => 400, 'energy' => 0, 'factor' => 2],
                107 => ['metal' => 0, 'crystal' => 4000, 'deuterium' => 2000, 'energy' => 0, 'factor' => 2],
                108 => ['metal' => 400, 'crystal' => 0, 'deuterium' => 600, 'energy' => 0, 'factor' => 2],
                109 => ['metal' => 2000, 'crystal' => 4000, 'deuterium' => 600, 'energy' => 0, 'factor' => 2],
                110 => ['metal' => 10000, 'crystal' => 20000, 'deuterium' => 6000, 'energy' => 0, 'factor' => 2],
                111 => ['metal' => 200, 'crystal' => 100, 'deuterium' => 0, 'energy' => 0, 'factor' => 2],
                112 => ['metal' => 1000, 'crystal' => 300, 'deuterium' => 100, 'energy' => 0, 'factor' => 2],
                113 => ['metal' => 2000, 'crystal' => 4000, 'deuterium' => 1000, 'energy' => 0, 'factor' => 2],
                114 => ['metal' => 240000, 'crystal' => 400000, 'deuterium' => 160000, 'energy' => 0, 'factor' => 2],
                115 => ['metal' => 0, 'crystal' => 0, 'deuterium' => 0, 'energy' => 300000, 'factor' => 3],

                // Fleet
                201 => ['metal'       => 2000,
                        'crystal'     => 2000,
                        'deuterium'   => 0,
                        'energy'      => 0,
                        'factor'      => 1,
                        'consumption' => 20,
                        'speed'       => 28000,
                        'capacity'    => 5000
                ],
                202 => ['metal'       => 6000,
                        'crystal'     => 6000,
                        'deuterium'   => 0,
                        'energy'      => 0,
                        'factor'      => 1,
                        'consumption' => 50,
                        'speed'       => 17250,
                        'capacity'    => 25000
                ],
                203 => ['metal'       => 3000,
                        'crystal'     => 1000,
                        'deuterium'   => 0,
                        'energy'      => 0,
                        'factor'      => 1,
                        'consumption' => 20,
                        'speed'       => 28750,
                        'capacity'    => 50
                ],
                204 => ['metal'       => 6000,
                        'crystal'     => 4000,
                        'deuterium'   => 0,
                        'energy'      => 0,
                        'factor'      => 1,
                        'consumption' => 75,
                        'speed'       => 28000,
                        'capacity'    => 100
                ],
                205 => ['metal'       => 20000,
                        'crystal'     => 7000,
                        'deuterium'   => 2000,
                        'energy'      => 0,
                        'factor'      => 1,
                        'consumption' => 300,
                        'speed'       => 42000,
                        'capacity'    => 800
                ],
                206 => ['metal'       => 45000,
                        'crystal'     => 15000,
                        'deuterium'   => 0,
                        'energy'      => 0,
                        'factor'      => 1,
                        'consumption' => 500,
                        'speed'       => 31000,
                        'capacity'    => 1500
                ],
                207 => ['metal' => 10000, 'crystal' => 20000, 'deuterium' => 10000, 'energy' => 0, 'factor' => 1],
                208 => ['metal'       => 10000,
                        'crystal'     => 6000,
                        'deuterium'   => 2000,
                        'energy'      => 0,
                        'factor'      => 1,
                        'consumption' => 300,
                        'speed'       => 4600,
                        'capacity'    => 20000
                ],
                209 => ['metal'       => 0,
                        'crystal'     => 1000,
                        'deuterium'   => 0,
                        'energy'      => 0,
                        'factor'      => 1,
                        'consumption' => 1,
                        'speed'       => 230000000,
                        'capacity'    => 5
                ],
                210 => ['metal'       => 50000,
                        'crystal'     => 25000,
                        'deuterium'   => 15000,
                        'energy'      => 0,
                        'factor'      => 1,
                        'consumption' => 1000,
                        'speed'       => 11200,
                        'capacity'    => 500
                ],
                211 => ['metal' => 0, 'crystal' => 2000, 'deuterium' => 500, 'energy' => 0, 'factor' => 1],
                212 => ['metal'       => 60000,
                        'crystal'     => 50000,
                        'deuterium'   => 15000,
                        'energy'      => 0,
                        'factor'      => 1,
                        'consumption' => 1000,
                        'speed'       => 15500,
                        'capacity'    => 2000
                ],
                213 => ['metal' => 30000, 'crystal' => 40000, 'deuterium' => 15000, 'energy' => 0, 'factor' => 1],
                214 => ['metal' => 5000000, 'crystal' => 4000000, 'deuterium' => 1000000, 'energy' => 0, 'factor' => 1],

                // Defense
                301 => ['metal' => 2000, 'crystal' => 0, 'deuterium' => 0, 'energy' => 0, 'factor' => 1],
                302 => ['metal' => 1500, 'crystal' => 500, 'deuterium' => 0, 'energy' => 0, 'factor' => 1],
                303 => ['metal' => 6000, 'crystal' => 2000, 'deuterium' => 0, 'energy' => 0, 'factor' => 1],
                304 => ['metal' => 20000, 'crystal' => 15000, 'deuterium' => 2000, 'energy' => 0, 'factor' => 1],
                305 => ['metal' => 2000, 'crystal' => 6000, 'deuterium' => 0, 'energy' => 0, 'factor' => 1],
                306 => ['metal' => 50000, 'crystal' => 50000, 'deuterium' => 30000, 'energy' => 0, 'factor' => 1],
                307 => ['metal' => 10000, 'crystal' => 10000, 'deuterium' => 0, 'energy' => 0, 'factor' => 1],
                308 => ['metal' => 50000, 'crystal' => 50000, 'deuterium' => 0, 'energy' => 0, 'factor' => 1],
                309 => ['metal' => 8000, 'crystal' => 2000, 'deuterium' => 0, 'energy' => 0, 'factor' => 1],
                310 => ['metal' => 12500, 'crystal' => 2500, 'deuterium' => 10000, 'energy' => 0, 'factor' => 1]
            ];

            self::$requeriments = [
                // buildings
                5   => [3 => 5, 106 => 3],
                7   => [6 => 10, 102 => 10],
                8   => [6 => 2],
                13  => [7 => 1, 106 => 12],

                // techs
                101 => [12 => 3],
                102 => [12 => 1],
                103 => [12 => 4],
                104 => [12 => 2],
                105 => [12 => 6, 106 => 3],
                106 => [12 => 1],
                107 => [12 => 7, 106 => 5, 105 => 5],
                108 => [12 => 1, 106 => 1],
                109 => [12 => 2, 106 => 1],
                110 => [12 => 7, 107 => 3],
                111 => [12 => 1, 106 => 2],
                112 => [12 => 4, 106 => 4, 111 => 5],
                113 => [12 => 4, 106 => 8, 111 => 10, 112 => 5],
                114 => [12 => 10, 102 => 8, 107 => 8],
                115 => [12 => 12],

                // fleet
                201 => [8 => 2, 108 => 2],
                202 => [8 => 4, 108 => 6],
                203 => [8 => 1, 108 => 1],
                204 => [8 => 3, 104 => 2, 109 => 2],
                205 => [8 => 5, 109 => 4, 112 => 2],
                206 => [8 => 7, 110 => 4],
                207 => [8 => 4, 109 => 3],
                208 => [8 => 4, 108 => 6, 105 => 2],
                209 => [8 => 3, 108 => 3, 101 => 2],
                210 => [8 => 8, 109 => 6, 113 => 5],
                211 => [8 => 1],
                212 => [8 => 9, 107 => 5, 110 => 6],
                213 => [8 => 8, 111 => 12, 107 => 5, 110 => 5],
                214 => [8 => 12, 115 => 1, 107 => 6, 110 => 7]
            ];

        }

        /**
         * Returns the unitID given the unit-string-ID
         * @param string $unitName the unit-string-ID
         * @return int the unitID
         */
        static function getUnitID(string $unitName) : int {
            return array_keys(self::$units, $unitName)[0];
        }

        /**
         * Returns the name of the unit-string-ID given the unitID
         * @param int $id the unitID
         * @return string the unit-string-ID
         */
        static function getUnitName(int $id) : string {
            if (isset(self::$units[$id])) {
                return self::$units[$id];
            }

            return "";
        }

        /**
         * Returns an array, containing all buildings with the unitID as the key and the unit-string-ID as the value
         * @return array all buildings with the unitID as the key and the unit-string-ID as the value
         */
        static function getBuildings() : array {
            return array_slice(self::$units, 0, 15, true);
        }

        /**
         * Returns an array, containing all technologies with the unitID as the key and the unit-string-ID as the value
         * @return array all technologies with the unitID as the key and the unit-string-ID as the value
         */
        static function getTechnologies() : array {
            return array_slice(self::$units, 15, 15, true);
        }

        /**
         * Returns an array, containing all fleets with the unitID as the key and the unit-string-ID as the value
         * @return array all fleets with the unitID as the key and the unit-string-ID as the value
         */
        static function getFleet() : array {
            return array_slice(self::$units, 30, 14, true);
        }

        /**
         * Returns an array, containing all defenses with the unitID as the key and the unit-string-ID as the value
         * @return array all defenses with the unitID as the key and the unit-string-ID as the value
         */
        static function getDefense() : array {
            return array_slice(self::$units, 44, 10, true);
        }

        /**
         * Returns the name of the unit, according to the current language-file
         * @param int $id the unitID
         * @return string the name of the unit, according to the current language-file
         */
        static function getName(int $id) : string {
            if (isset(self::$names[$id])) {
                return self::$names[$id];
            }

            return "";
        }

        /**
         * Returns the description of the unit, according to the current language-file
         * @param int $id the unitID
         * @return string the description of the unit, according to the current language-file
         */
        static function getDescription(int $id) : string {

            if (isset(self::$descriptions[$id])) {
                return self::$descriptions[$id];
            }

            return "";
        }

        /**
         * Returns the pricelist fot the unit
         * @param int $id the unitID
         * @return array the pricelist for the unit
         */
        static function getPriceList(int $id) : array {

            if (isset(self::$pricelist[$id])) {
                return self::$pricelist[$id];
            } else {
                return [];
            }
        }

        /**
         * Returns the requirements for the unit, which are represented as key-value-pairs with the key being the id of
         * the required unit and the value being the required level of this unit
         * @param int $id the unitID
         * @return array the requirements for the unit
         */
        static function getRequirements(int $id) : array {

            if (isset(self::$requeriments[$id])) {
                return self::$requeriments[$id];
            } else {
                return [];
            }
        }

        /**
         * Calculates and returns the build-time for the next level (or one unit for fleet/defense) of the Unit
         * @param U_Unit $unit        the unit-object of the given unit
         * @param int    $robotLvl    the level of the robotic factory
         * @param int    $shipYardLvl the level of the shipyard factory
         * @param int    $naniteLvl   the level of the nanite factory
         * @return float the needed time to build in seconds
         */
        static function getBuildTime(U_Unit $unit, int $robotLvl, int $shipYardLvl, int $naniteLvl) : float {

            if($robotLvl < 0 || $shipYardLvl < 0 || $naniteLvl < 0) {
                return -1.0;
            }

            $metal = $unit->getCostMetal();
            $crystal = $unit->getCostCrystal();
            $factor = $unit->getFactor();

            // building
            if ($unit->getUnitId() < 100) {
                //(39410 + 9852)/(2500 * (1+10) * 2^3)
                return ($metal + $crystal) / (2500 * (1 + $robotLvl) * (2 ** $naniteLvl));
            }

            // TODO: research-lab-level and research-network level

            // tech
            if ($unit->getUnitId() > 100 && $unit->getUnitId() < 200) {
                return ($metal * $factor + $crystal * $factor) / (2500 * (1 + $robotLvl) * pow(2, $naniteLvl));
            }

            // fleet and defense
            if ($unit->getUnitId() > 200 && $unit->getUnitId() < 400) {
                return ($metal + $crystal) / (2500 * (1 + $shipYardLvl) * pow(2, $naniteLvl));
            }

            return -1.0;

        }

        /**
         * Returns the storage-capacity for a resource, given the storage level
         * @param int $storage_level the storage level
         * @return float the storage capacity
         */
        static function getStorageCapacity(int $storage_level) : float {

            if ($storage_level >= 0) {
                // Source: http://ogame.wikia.com/wiki/Metal_Storage
                return 100000 + 50000 * (ceil(pow(1.5, $storage_level)) - 1);
            }

            return -1.0;

        }

        /**
         * Returns the metal-production per hour
         * @param int $level the level of the metal-mine
         * @return float the metal-production per hour
         */
        static function getMetalProductionPerHour(int $level, int $plasmaLevel) : float {
            if ($level >= 0) {
                return floor(30 * $level * pow(1.1, $level)) * ((100 + 1 * $plasmaLevel)/100);
            }

            return -1.0;
        }

        /**
         * Returns the crystal-production per hour
         * @param int $level the level of the metal-mine
         * @return float the metal-production per hour
         */
        static function getCrystalProductionPerHour(int $level, int $plasmaLevel) : float {
            if ($level >= 0) {
                return floor(20 * $level * pow(1.1, $level)) * ((100 + 0.66 * $plasmaLevel)/100);
            }

            return -1.0;
        }

        /**
         * Returns the deuterium-production per hour
         * @param int $level the level of the metal-mine
         * @return float the metal-production per hour
         */
        static function getDeuteriumProductionPerHour(int $level, float $maxTemp) : float {
            if ($level >= 0) {
                return floor(10 * $level * pow(1.1, $level) * (1.28 - 0.002 * $maxTemp));
            }

            return -1.0;
        }

        /**
         * Returns the energy-production for each energy-producing unit
         * @param int $solarLevel    the level of the Solar Plant
         * @param int $fusionLevel   the level of the Fusion Reactor
         * @param int $energytech    the level of the Energy Technology
         * @param int $numSolarSats  the amount of the Solar Satellites
         * @param int $planetMaxTemp the maximum temperature of the current planet
         * @return array the energy-production of each energy-producing unit
         */
        static function getEnergyProduction(int $solarLevel, int $fusionLevel, int $energytech, int $numSolarSats,
            int $planetMaxTemp) : array {

            if ($solarLevel >= 0 && $fusionLevel >= 0 && $energytech >= 0 && $numSolarSats >= 0) {
                return [
                    self::$units[4]   => 20 * $solarLevel * pow(1.1, $solarLevel),
                    self::$units[5]   => 30 * $fusionLevel * pow((1.05 + $energytech + 0.01), $fusionLevel),
                    self::$units[211] => (($planetMaxTemp / 4) + 20) * $numSolarSats
                ];
            }

            return [];

        }

        /**
         * Returns the energy consumption of a given unit
         * @param int $level the level of the unit
         * @return float the energy consumption
         */
        static function getEnergyConsumption(int $level) : float {
            //TODO: check if a energy-consuming unit or not
            if ($level >= 0) {
                return 10 * $level * pow(1.1, $level);
            }

            return -1.0;
        }
    }