<?php

namespace PhpOffice\PhpSpreadsheet\Calculation\Engineering;

use PhpOffice\PhpSpreadsheet\Calculation\Exception;
use PhpOffice\PhpSpreadsheet\Calculation\Functions;

class ConvertUOM
{
    public const CATEGORY_WEIGHT_AND_MASS = 'Weight and Mass';
    public const CATEGORY_DISTANCE = 'Distance';
    public const CATEGORY_TIME = 'Time';
    public const CATEGORY_PRESSURE = 'Pressure';
    public const CATEGORY_FORCE = 'Force';
    public const CATEGORY_ENERGY = 'Energy';
    public const CATEGORY_POWER = 'Power';
    public const CATEGORY_MAGNETISM = 'Magnetism';
    public const CATEGORY_TEMPERATURE = 'Temperature';
    public const CATEGORY_VOLUME = 'Volume and Liquid Measure';
    public const CATEGORY_AREA = 'Area';
    public const CATEGORY_INFORMATION = 'Information';
    public const CATEGORY_SPEED = 'Speed';

    /**
     * Details of the Units of measure that can be used in CONVERTUOM().
     *
     * @var mixed[]
     */
    private static $conversionUnits = [
        // Weight and Mass
        'g' => ['Group' => self::CATEGORY_WEIGHT_AND_MASS, 'Unit Name' => 'Gram', 'AllowPrefix' => true],
        'sg' => ['Group' => self::CATEGORY_WEIGHT_AND_MASS, 'Unit Name' => 'Slug', 'AllowPrefix' => false],
        'lbm' => ['Group' => self::CATEGORY_WEIGHT_AND_MASS, 'Unit Name' => 'Pound mass (avoirdupois)', 'AllowPrefix' => false],
        'u' => ['Group' => self::CATEGORY_WEIGHT_AND_MASS, 'Unit Name' => 'U (atomic mass unit)', 'AllowPrefix' => true],
        'ozm' => ['Group' => self::CATEGORY_WEIGHT_AND_MASS, 'Unit Name' => 'Ounce mass (avoirdupois)', 'AllowPrefix' => false],
        'grain' => ['Group' => self::CATEGORY_WEIGHT_AND_MASS, 'Unit Name' => 'Grain', 'AllowPrefix' => false],
        'cwt' => ['Group' => self::CATEGORY_WEIGHT_AND_MASS, 'Unit Name' => 'U.S. (short) hundredweight', 'AllowPrefix' => false],
        'shweight' => ['Group' => self::CATEGORY_WEIGHT_AND_MASS, 'Unit Name' => 'U.S. (short) hundredweight', 'AllowPrefix' => false],
        'uk_cwt' => ['Group' => self::CATEGORY_WEIGHT_AND_MASS, 'Unit Name' => 'Imperial hundredweight', 'AllowPrefix' => false],
        'lcwt' => ['Group' => self::CATEGORY_WEIGHT_AND_MASS, 'Unit Name' => 'Imperial hundredweight', 'AllowPrefix' => false],
        'hweight' => ['Group' => self::CATEGORY_WEIGHT_AND_MASS, 'Unit Name' => 'Imperial hundredweight', 'AllowPrefix' => false],
        'stone' => ['Group' => self::CATEGORY_WEIGHT_AND_MASS, 'Unit Name' => 'Stone', 'AllowPrefix' => false],
        'ton' => ['Group' => self::CATEGORY_WEIGHT_AND_MASS, 'Unit Name' => 'Ton', 'AllowPrefix' => false],
        'uk_ton' => ['Group' => self::CATEGORY_WEIGHT_AND_MASS, 'Unit Name' => 'Imperial ton', 'AllowPrefix' => false],
        'LTON' => ['Group' => self::CATEGORY_WEIGHT_AND_MASS, 'Unit Name' => 'Imperial ton', 'AllowPrefix' => false],
        'brton' => ['Group' => self::CATEGORY_WEIGHT_AND_MASS, 'Unit Name' => 'Imperial ton', 'AllowPrefix' => false],
        // Distance
        'm' => ['Group' => self::CATEGORY_DISTANCE, 'Unit Name' => 'Meter', 'AllowPrefix' => true],
        'mi' => ['Group' => self::CATEGORY_DISTANCE, 'Unit Name' => 'Statute mile', 'AllowPrefix' => false],
        'Nmi' => ['Group' => self::CATEGORY_DISTANCE, 'Unit Name' => 'Nautical mile', 'AllowPrefix' => false],
        'in' => ['Group' => self::CATEGORY_DISTANCE, 'Unit Name' => 'Inch', 'AllowPrefix' => false],
        'ft' => ['Group' => self::CATEGORY_DISTANCE, 'Unit Name' => 'Foot', 'AllowPrefix' => false],
        'yd' => ['Group' => self::CATEGORY_DISTANCE, 'Unit Name' => 'Yard', 'AllowPrefix' => false],
        'ang' => ['Group' => self::CATEGORY_DISTANCE, 'Unit Name' => 'Angstrom', 'AllowPrefix' => true],
        'ell' => ['Group' => self::CATEGORY_DISTANCE, 'Unit Name' => 'Ell', 'AllowPrefix' => false],
        'ly' => ['Group' => self::CATEGORY_DISTANCE, 'Unit Name' => 'Light Year', 'AllowPrefix' => false],
        'parsec' => ['Group' => self::CATEGORY_DISTANCE, 'Unit Name' => 'Parsec', 'AllowPrefix' => false],
        'pc' => ['Group' => self::CATEGORY_DISTANCE, 'Unit Name' => 'Parsec', 'AllowPrefix' => false],
        'Pica' => ['Group' => self::CATEGORY_DISTANCE, 'Unit Name' => 'Pica (1/72 in)', 'AllowPrefix' => false],
        'Picapt' => ['Group' => self::CATEGORY_DISTANCE, 'Unit Name' => 'Pica (1/72 in)', 'AllowPrefix' => false],
        'pica' => ['Group' => self::CATEGORY_DISTANCE, 'Unit Name' => 'Pica (1/6 in)', 'AllowPrefix' => false],
        'survey_mi' => ['Group' => self::CATEGORY_DISTANCE, 'Unit Name' => 'U.S survey mile (statute mile)', 'AllowPrefix' => false],
        // Time
        'yr' => ['Group' => self::CATEGORY_TIME, 'Unit Name' => 'Year', 'AllowPrefix' => false],
        'day' => ['Group' => self::CATEGORY_TIME, 'Unit Name' => 'Day', 'AllowPrefix' => false],
        'd' => ['Group' => self::CATEGORY_TIME, 'Unit Name' => 'Day', 'AllowPrefix' => false],
        'hr' => ['Group' => self::CATEGORY_TIME, 'Unit Name' => 'Hour', 'AllowPrefix' => false],
        'mn' => ['Group' => self::CATEGORY_TIME, 'Unit Name' => 'Minute', 'AllowPrefix' => false],
        'min' => ['Group' => self::CATEGORY_TIME, 'Unit Name' => 'Minute', 'AllowPrefix' => false],
        'sec' => ['Group' => self::CATEGORY_TIME, 'Unit Name' => 'Second', 'AllowPrefix' => true],
        's' => ['Group' => self::CATEGORY_TIME, 'Unit Name' => 'Second', 'AllowPrefix' => true],
        // Pressure
        'Pa' => ['Group' => self::CATEGORY_PRESSURE, 'Unit Name' => 'Pascal', 'AllowPrefix' => true],
        'p' => ['Group' => self::CATEGORY_PRESSURE, 'Unit Name' => 'Pascal', 'AllowPrefix' => true],
        'atm' => ['Group' => self::CATEGORY_PRESSURE, 'Unit Name' => 'Atmosphere', 'AllowPrefix' => true],
        'at' => ['Group' => self::CATEGORY_PRESSURE, 'Unit Name' => 'Atmosphere', 'AllowPrefix' => true],
        'mmHg' => ['Group' => self::CATEGORY_PRESSURE, 'Unit Name' => 'mm of Mercury', 'AllowPrefix' => true],
        'psi' => ['Group' => self::CATEGORY_PRESSURE, 'Unit Name' => 'PSI', 'AllowPrefix' => true],
        'Torr' => ['Group' => self::CATEGORY_PRESSURE, 'Unit Name' => 'Torr', 'AllowPrefix' => true],
        // Force
        'N' => ['Group' => self::CATEGORY_FORCE, 'Unit Name' => 'Newton', 'AllowPrefix' => true],
        'dyn' => ['Group' => self::CATEGORY_FORCE, 'Unit Name' => 'Dyne', 'AllowPrefix' => true],
        'dy' => ['Group' => self::CATEGORY_FORCE, 'Unit Name' => 'Dyne', 'AllowPrefix' => true],
        'lbf' => ['Group' => self::CATEGORY_FORCE, 'Unit Name' => 'Pound force', 'AllowPrefix' => false],
        'pond' => ['Group' => self::CATEGORY_FORCE, 'Unit Name' => 'Pond', 'AllowPrefix' => true],
        // Energy
        'J' => ['Group' => self::CATEGORY_ENERGY, 'Unit Name' => 'Joule', 'AllowPrefix' => true],
        'e' => ['Group' => self::CATEGORY_ENERGY, 'Unit Name' => 'Erg', 'AllowPrefix' => true],
        'c' => ['Group' => self::CATEGORY_ENERGY, 'Unit Name' => 'Thermodynamic calorie', 'AllowPrefix' => true],
        'cal' => ['Group' => self::CATEGORY_ENERGY, 'Unit Name' => 'IT calorie', 'AllowPrefix' => true],
        'eV' => ['Group' => self::CATEGORY_ENERGY, 'Unit Name' => 'Electron volt', 'AllowPrefix' => true],
        'ev' => ['Group' => self::CATEGORY_ENERGY, 'Unit Name' => 'Electron volt', 'AllowPrefix' => true],
        'HPh' => ['Group' => self::CATEGORY_ENERGY, 'Unit Name' => 'Horsepower-hour', 'AllowPrefix' => false],
        'hh' => ['Group' => self::CATEGORY_ENERGY, 'Unit Name' => 'Horsepower-hour', 'AllowPrefix' => false],
        'Wh' => ['Group' => self::CATEGORY_ENERGY, 'Unit Name' => 'Watt-hour', 'AllowPrefix' => true],
        'wh' => ['Group' => self::CATEGORY_ENERGY, 'Unit Name' => 'Watt-hour', 'AllowPrefix' => true],
        'flb' => ['Group' => self::CATEGORY_ENERGY, 'Unit Name' => 'Foot-pound', 'AllowPrefix' => false],
        'BTU' => ['Group' => self::CATEGORY_ENERGY, 'Unit Name' => 'BTU', 'AllowPrefix' => false],
        'btu' => ['Group' => self::CATEGORY_ENERGY, 'Unit Name' => 'BTU', 'AllowPrefix' => false],
        // Power
        'HP' => ['Group' => self::CATEGORY_POWER, 'Unit Name' => 'Horsepower', 'AllowPrefix' => false],
        'h' => ['Group' => self::CATEGORY_POWER, 'Unit Name' => 'Horsepower', 'AllowPrefix' => false],
        'W' => ['Group' => self::CATEGORY_POWER, 'Unit Name' => 'Watt', 'AllowPrefix' => true],
        'w' => ['Group' => self::CATEGORY_POWER, 'Unit Name' => 'Watt', 'AllowPrefix' => true],
        'PS' => ['Group' => self::CATEGORY_POWER, 'Unit Name' => 'Pferdestärke', 'AllowPrefix' => false],
        'T' => ['Group' => self::CATEGORY_MAGNETISM, 'Unit Name' => 'Tesla', 'AllowPrefix' => true],
        'ga' => ['Group' => self::CATEGORY_MAGNETISM, 'Unit Name' => 'Gauss', 'AllowPrefix' => true],
        // Temperature
        'C' => ['Group' => self::CATEGORY_TEMPERATURE, 'Unit Name' => 'Degrees Celsius', 'AllowPrefix' => false],
        'cel' => ['Group' => self::CATEGORY_TEMPERATURE, 'Unit Name' => 'Degrees Celsius', 'AllowPrefix' => false],
        'F' => ['Group' => self::CATEGORY_TEMPERATURE, 'Unit Name' => 'Degrees Fahrenheit', 'AllowPrefix' => false],
        'fah' => ['Group' => self::CATEGORY_TEMPERATURE, 'Unit Name' => 'Degrees Fahrenheit', 'AllowPrefix' => false],
        'K' => ['Group' => self::CATEGORY_TEMPERATURE, 'Unit Name' => 'Kelvin', 'AllowPrefix' => false],
        'kel' => ['Group' => self::CATEGORY_TEMPERATURE, 'Unit Name' => 'Kelvin', 'AllowPrefix' => false],
        'Rank' => ['Group' => self::CATEGORY_TEMPERATURE, 'Unit Name' => 'Degrees Rankine', 'AllowPrefix' => false],
        'Reau' => ['Group' => self::CATEGORY_TEMPERATURE, 'Unit Name' => 'Degrees Réaumur', 'AllowPrefix' => false],
        // Volume
        'l' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Litre', 'AllowPrefix' => true],
        'L' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Litre', 'AllowPrefix' => true],
        'lt' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Litre', 'AllowPrefix' => true],
        'tsp' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Teaspoon', 'AllowPrefix' => false],
        'tspm' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Modern Teaspoon', 'AllowPrefix' => false],
        'tbs' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Tablespoon', 'AllowPrefix' => false],
        'oz' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Fluid Ounce', 'AllowPrefix' => false],
        'cup' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Cup', 'AllowPrefix' => false],
        'pt' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'U.S. Pint', 'AllowPrefix' => false],
        'us_pt' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'U.S. Pint', 'AllowPrefix' => false],
        'uk_pt' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'U.K. Pint', 'AllowPrefix' => false],
        'qt' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Quart', 'AllowPrefix' => false],
        'uk_qt' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Imperial Quart (UK)', 'AllowPrefix' => false],
        'gal' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Gallon', 'AllowPrefix' => false],
        'uk_gal' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Imperial Gallon (UK)', 'AllowPrefix' => false],
        'ang3' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Cubic Angstrom', 'AllowPrefix' => true],
        'ang^3' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Cubic Angstrom', 'AllowPrefix' => true],
        'barrel' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'US Oil Barrel', 'AllowPrefix' => false],
        'bushel' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'US Bushel', 'AllowPrefix' => false],
        'in3' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Cubic Inch', 'AllowPrefix' => false],
        'in^3' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Cubic Inch', 'AllowPrefix' => false],
        'ft3' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Cubic Foot', 'AllowPrefix' => false],
        'ft^3' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Cubic Foot', 'AllowPrefix' => false],
        'ly3' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Cubic Light Year', 'AllowPrefix' => false],
        'ly^3' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Cubic Light Year', 'AllowPrefix' => false],
        'm3' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Cubic Meter', 'AllowPrefix' => true],
        'm^3' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Cubic Meter', 'AllowPrefix' => true],
        'mi3' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Cubic Mile', 'AllowPrefix' => false],
        'mi^3' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Cubic Mile', 'AllowPrefix' => false],
        'yd3' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Cubic Yard', 'AllowPrefix' => false],
        'yd^3' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Cubic Yard', 'AllowPrefix' => false],
        'Nmi3' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Cubic Nautical Mile', 'AllowPrefix' => false],
        'Nmi^3' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Cubic Nautical Mile', 'AllowPrefix' => false],
        'Pica3' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Cubic Pica', 'AllowPrefix' => false],
        'Pica^3' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Cubic Pica', 'AllowPrefix' => false],
        'Picapt3' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Cubic Pica', 'AllowPrefix' => false],
        'Picapt^3' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Cubic Pica', 'AllowPrefix' => false],
        'GRT' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Gross Registered Ton', 'AllowPrefix' => false],
        'regton' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Gross Registered Ton', 'AllowPrefix' => false],
        'MTON' => ['Group' => self::CATEGORY_VOLUME, 'Unit Name' => 'Measurement Ton (Freight Ton)', 'AllowPrefix' => false],
        // Area
        'ha' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'Hectare', 'AllowPrefix' => true],
        'uk_acre' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'International Acre', 'AllowPrefix' => false],
        'us_acre' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'US Survey/Statute Acre', 'AllowPrefix' => false],
        'ang2' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'Square Angstrom', 'AllowPrefix' => true],
        'ang^2' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'Square Angstrom', 'AllowPrefix' => true],
        'ar' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'Are', 'AllowPrefix' => true],
        'ft2' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'Square Feet', 'AllowPrefix' => false],
        'ft^2' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'Square Feet', 'AllowPrefix' => false],
        'in2' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'Square Inches', 'AllowPrefix' => false],
        'in^2' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'Square Inches', 'AllowPrefix' => false],
        'ly2' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'Square Light Years', 'AllowPrefix' => false],
        'ly^2' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'Square Light Years', 'AllowPrefix' => false],
        'm2' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'Square Meters', 'AllowPrefix' => true],
        'm^2' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'Square Meters', 'AllowPrefix' => true],
        'Morgen' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'Morgen', 'AllowPrefix' => false],
        'mi2' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'Square Miles', 'AllowPrefix' => false],
        'mi^2' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'Square Miles', 'AllowPrefix' => false],
        'Nmi2' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'Square Nautical Miles', 'AllowPrefix' => false],
        'Nmi^2' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'Square Nautical Miles', 'AllowPrefix' => false],
        'Pica2' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'Square Pica', 'AllowPrefix' => false],
        'Pica^2' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'Square Pica', 'AllowPrefix' => false],
        'Picapt2' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'Square Pica', 'AllowPrefix' => false],
        'Picapt^2' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'Square Pica', 'AllowPrefix' => false],
        'yd2' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'Square Yards', 'AllowPrefix' => false],
        'yd^2' => ['Group' => self::CATEGORY_AREA, 'Unit Name' => 'Square Yards', 'AllowPrefix' => false],
        // Information
        'byte' => ['Group' => self::CATEGORY_INFORMATION, 'Unit Name' => 'Byte', 'AllowPrefix' => true],
        'bit' => ['Group' => self::CATEGORY_INFORMATION, 'Unit Name' => 'Bit', 'AllowPrefix' => true],
        // Speed
        'm/s' => ['Group' => self::CATEGORY_SPEED, 'Unit Name' => 'Meters per second', 'AllowPrefix' => true],
        'm/sec' => ['Group' => self::CATEGORY_SPEED, 'Unit Name' => 'Meters per second', 'AllowPrefix' => true],
        'm/h' => ['Group' => self::CATEGORY_SPEED, 'Unit Name' => 'Meters per hour', 'AllowPrefix' => true],
        'm/hr' => ['Group' => self::CATEGORY_SPEED, 'Unit Name' => 'Meters per hour', 'AllowPrefix' => true],
        'mph' => ['Group' => self::CATEGORY_SPEED, 'Unit Name' => 'Miles per hour', 'AllowPrefix' => false],
        'admkn' => ['Group' => self::CATEGORY_SPEED, 'Unit Name' => 'Admiralty Knot', 'AllowPrefix' => false],
        'kn' => ['Group' => self::CATEGORY_SPEED, 'Unit Name' => 'Knot', 'AllowPrefix' => false],
    ];

    /**
     * Details of the Multiplier prefixes that can be used with Units of Measure in CONVERTUOM().
     *
     * @var mixed[]
     */
    private static $conversionMultipliers = [
        'Y' => ['multiplier' => 1E24, 'name' => 'yotta'],
        'Z' => ['multiplier' => 1E21, 'name' => 'zetta'],
        'E' => ['multiplier' => 1E18, 'name' => 'exa'],
        'P' => ['multiplier' => 1E15, 'name' => 'peta'],
        'T' => ['multiplier' => 1E12, 'name' => 'tera'],
        'G' => ['multiplier' => 1E9, 'name' => 'giga'],
        'M' => ['multiplier' => 1E6, 'name' => 'mega'],
        'k' => ['multiplier' => 1E3, 'name' => 'kilo'],
        'h' => ['multiplier' => 1E2, 'name' => 'hecto'],
        'e' => ['multiplier' => 1E1, 'name' => 'dekao'],
        'da' => ['multiplier' => 1E1, 'name' => 'dekao'],
        'd' => ['multiplier' => 1E-1, 'name' => 'deci'],
        'c' => ['multiplier' => 1E-2, 'name' => 'centi'],
        'm' => ['multiplier' => 1E-3, 'name' => 'milli'],
        'u' => ['multiplier' => 1E-6, 'name' => 'micro'],
        'n' => ['multiplier' => 1E-9, 'name' => 'nano'],
        'p' => ['multiplier' => 1E-12, 'name' => 'pico'],
        'f' => ['multiplier' => 1E-15, 'name' => 'femto'],
        'a' => ['multiplier' => 1E-18, 'name' => 'atto'],
        'z' => ['multiplier' => 1E-21, 'name' => 'zepto'],
        'y' => ['multiplier' => 1E-24, 'name' => 'yocto'],
    ];

    /**
     * Details of the Multiplier prefixes that can be used with Units of Measure in CONVERTUOM().
     *
     * @var mixed[]
     */
    private static $binaryConversionMultipliers = [
        'Yi' => ['multiplier' => 2 ** 80, 'name' => 'yobi'],
        'Zi' => ['multiplier' => 2 ** 70, 'name' => 'zebi'],
        'Ei' => ['multiplier' => 2 ** 60, 'name' => 'exbi'],
        'Pi' => ['multiplier' => 2 ** 50, 'name' => 'pebi'],
        'Ti' => ['multiplier' => 2 ** 40, 'name' => 'tebi'],
        'Gi' => ['multiplier' => 2 ** 30, 'name' => 'gibi'],
        'Mi' => ['multiplier' => 2 ** 20, 'name' => 'mebi'],
        'ki' => ['multiplier' => 2 ** 10, 'name' => 'kibi'],
    ];

    /**
     * Details of the Units of measure conversion factors, organised by group.
     *
     * @var mixed[]
     */
    private static $unitConversions = [
        // Conversion uses gram (g) as an intermediate unit
        self::CATEGORY_WEIGHT_AND_MASS => [
            'g' => 1.0,
            'sg' => 6.85217658567918E-05,
            'lbm' => 2.20462262184878E-03,
            'u' => 6.02214179421676E+23,
            'ozm' => 3.52739619495804E-02,
            'grain' => 1.54323583529414E+01,
            'cwt' => 2.20462262184878E-05,
            'shweight' => 2.20462262184878E-05,
            'uk_cwt' => 1.96841305522212E-05,
            'lcwt' => 1.96841305522212E-05,
            'hweight' => 1.96841305522212E-05,
            'stone' => 1.57473044417770E-04,
            'ton' => 1.10231131092439E-06,
            'uk_ton' => 9.84206527611061E-07,
            'LTON' => 9.84206527611061E-07,
            'brton' => 9.84206527611061E-07,
        ],
        // Conversion uses meter (m) as an intermediate unit
        self::CATEGORY_DISTANCE => [
            'm' => 1.0,
            'mi' => 6.21371192237334E-04,
            'Nmi' => 5.39956803455724E-04,
            'in' => 3.93700787401575E+01,
            'ft' => 3.28083989501312E+00,
            'yd' => 1.09361329833771E+00,
            'ang' => 1.0E+10,
            'ell' => 8.74890638670166E-01,
            'ly' => 1.05700083402462E-16,
            'parsec' => 3.24077928966473E-17,
            'pc' => 3.24077928966473E-17,
            'Pica' => 2.83464566929134E+03,
            'Picapt' => 2.83464566929134E+03,
            'pica' => 2.36220472440945E+02,
            'survey_mi' => 6.21369949494950E-04,
        ],
        // Conversion uses second (s) as an intermediate unit
        self::CATEGORY_TIME => [
            'yr' => 3.16880878140289E-08,
            'day' => 1.15740740740741E-05,
            'd' => 1.15740740740741E-05,
            'hr' => 2.77777777777778E-04,
            'mn' => 1.66666666666667E-02,
            'min' => 1.66666666666667E-02,
            'sec' => 1.0,
            's' => 1.0,
        ],
        // Conversion uses Pascal (Pa) as an intermediate unit
        self::CATEGORY_PRESSURE => [
            'Pa' => 1.0,
            'p' => 1.0,
            'atm' => 9.86923266716013E-06,
            'at' => 9.86923266716013E-06,
            'mmHg' => 7.50063755419211E-03,
            'psi' => 1.45037737730209E-04,
            'Torr' => 7.50061682704170E-03,
        ],
        // Conversion uses Newton (N) as an intermediate unit
        self::CATEGORY_FORCE => [
            'N' => 1.0,
            'dyn' => 1.0E+5,
            'dy' => 1.0E+5,
            'lbf' => 2.24808923655339E-01,
            'pond' => 1.01971621297793E+02,
        ],
        // Conversion uses Joule (J) as an intermediate unit
        self::CATEGORY_ENERGY => [
            'J' => 1.0,
            'e' => 9.99999519343231E+06,
            'c' => 2.39006249473467E-01,
            'cal' => 2.38846190642017E-01,
            'eV' => 6.24145700000000E+18,
            'ev' => 6.24145700000000E+18,
            'HPh' => 3.72506430801000E-07,
            'hh' => 3.72506430801000E-07,
            'Wh' => 2.77777916238711E-04,
            'wh' => 2.77777916238711E-04,
            'flb' => 2.37304222192651E+01,
            'BTU' => 9.47815067349015E-04,
            'btu' => 9.47815067349015E-04,
        ],
        // Conversion uses Horsepower (HP) as an intermediate unit
        self::CATEGORY_POWER => [
            'HP' => 1.0,
            'h' => 1.0,
            'W' => 7.45699871582270E+02,
            'w' => 7.45699871582270E+02,
            'PS' => 1.01386966542400E+00,
        ],
        // Conversion uses Tesla (T) as an intermediate unit
        self::CATEGORY_MAGNETISM => [
            'T' => 1.0,
            'ga' => 10000.0,
        ],
        // Conversion uses litre (l) as an intermediate unit
        self::CATEGORY_VOLUME => [
            'l' => 1.0,
            'L' => 1.0,
            'lt' => 1.0,
            'tsp' => 2.02884136211058E+02,
            'tspm' => 2.0E+02,
            'tbs' => 6.76280454036860E+01,
            'oz' => 3.38140227018430E+01,
            'cup' => 4.22675283773038E+00,
            'pt' => 2.11337641886519E+00,
            'us_pt' => 2.11337641886519E+00,
            'uk_pt' => 1.75975398639270E+00,
            'qt' => 1.05668820943259E+00,
            'uk_qt' => 8.79876993196351E-01,
            'gal' => 2.64172052358148E-01,
            'uk_gal' => 2.19969248299088E-01,
            'ang3' => 1.0E+27,
            'ang^3' => 1.0E+27,
            'barrel' => 6.28981077043211E-03,
            'bushel' => 2.83775932584017E-02,
            'in3' => 6.10237440947323E+01,
            'in^3' => 6.10237440947323E+01,
            'ft3' => 3.53146667214886E-02,
            'ft^3' => 3.53146667214886E-02,
            'ly3' => 1.18093498844171E-51,
            'ly^3' => 1.18093498844171E-51,
            'm3' => 1.0E-03,
            'm^3' => 1.0E-03,
            'mi3' => 2.39912758578928E-13,
            'mi^3' => 2.39912758578928E-13,
            'yd3' => 1.30795061931439E-03,
            'yd^3' => 1.30795061931439E-03,
            'Nmi3' => 1.57426214685811E-13,
            'Nmi^3' => 1.57426214685811E-13,
            'Pica3' => 2.27769904358706E+07,
            'Pica^3' => 2.27769904358706E+07,
            'Picapt3' => 2.27769904358706E+07,
            'Picapt^3' => 2.27769904358706E+07,
            'GRT' => 3.53146667214886E-04,
            'regton' => 3.53146667214886E-04,
            'MTON' => 8.82866668037215E-04,
        ],
        // Conversion uses hectare (ha) as an intermediate unit
        self::CATEGORY_AREA => [
            'ha' => 1.0,
            'uk_acre' => 2.47105381467165E+00,
            'us_acre' => 2.47104393046628E+00,
            'ang2' => 1.0E+24,
            'ang^2' => 1.0E+24,
            'ar' => 1.0E+02,
            'ft2' => 1.07639104167097E+05,
            'ft^2' => 1.07639104167097E+05,
            'in2' => 1.55000310000620E+07,
            'in^2' => 1.55000310000620E+07,
            'ly2' => 1.11725076312873E-28,
            'ly^2' => 1.11725076312873E-28,
            'm2' => 1.0E+04,
            'm^2' => 1.0E+04,
            'Morgen' => 4.0E+00,
            'mi2' => 3.86102158542446E-03,
            'mi^2' => 3.86102158542446E-03,
            'Nmi2' => 2.91553349598123E-03,
            'Nmi^2' => 2.91553349598123E-03,
            'Pica2' => 8.03521607043214E+10,
            'Pica^2' => 8.03521607043214E+10,
            'Picapt2' => 8.03521607043214E+10,
            'Picapt^2' => 8.03521607043214E+10,
            'yd2' => 1.19599004630108E+04,
            'yd^2' => 1.19599004630108E+04,
        ],
        // Conversion uses bit (bit) as an intermediate unit
        self::CATEGORY_INFORMATION => [
            'bit' => 1.0,
            'byte' => 0.125,
        ],
        // Conversion uses Meters per Second (m/s) as an intermediate unit
        self::CATEGORY_SPEED => [
            'm/s' => 1.0,
            'm/sec' => 1.0,
            'm/h' => 3.60E+03,
            'm/hr' => 3.60E+03,
            'mph' => 2.23693629205440E+00,
            'admkn' => 1.94260256941567E+00,
            'kn' => 1.94384449244060E+00,
        ],
    ];

    /**
     *    getConversionGroups
     * Returns a list of the different conversion groups for UOM conversions.
     *
     * @return array
     */
    public static function getConversionCategories()
    {
        $conversionGroups = [];
        foreach (self::$conversionUnits as $conversionUnit) {
            $conversionGroups[] = $conversionUnit['Group'];
        }

        return array_merge(array_unique($conversionGroups));
    }

    /**
     *    getConversionGroupUnits
     * Returns an array of units of measure, for a specified conversion group, or for all groups.
     *
     * @param string $category The group whose units of measure you want to retrieve
     *
     * @return array
     */
    public static function getConversionCategoryUnits($category = null)
    {
        $conversionGroups = [];
        foreach (self::$conversionUnits as $conversionUnit => $conversionGroup) {
            if (($category === null) || ($conversionGroup['Group'] == $category)) {
                $conversionGroups[$conversionGroup['Group']][] = $conversionUnit;
            }
        }

        return $conversionGroups;
    }

    /**
     * getConversionGroupUnitDetails.
     *
     * @param string $category The group whose units of measure you want to retrieve
     *
     * @return array
     */
    public static function getConversionCategoryUnitDetails($category = null)
    {
        $conversionGroups = [];
        foreach (self::$conversionUnits as $conversionUnit => $conversionGroup) {
            if (($category === null) || ($conversionGroup['Group'] == $category)) {
                $conversionGroups[$conversionGroup['Group']][] = [
                    'unit' => $conversionUnit,
                    'description' => $conversionGroup['Unit Name'],
                ];
            }
        }

        return $conversionGroups;
    }

    /**
     *    getConversionMultipliers
     * Returns an array of the Multiplier prefixes that can be used with Units of Measure in CONVERTUOM().
     *
     * @return array of mixed
     */
    public static function getConversionMultipliers()
    {
        return self::$conversionMultipliers;
    }

    /**
     *    getBinaryConversionMultipliers
     * Returns an array of the additional Multiplier prefixes that can be used with Information Units of Measure in CONVERTUOM().
     *
     * @return array of mixed
     */
    public static function getBinaryConversionMultipliers()
    {
        return self::$binaryConversionMultipliers;
    }

    /**
     * CONVERT.
     *
     * Converts a number from one measurement system to another.
     *    For example, CONVERT can translate a table of distances in miles to a table of distances
     * in kilometers.
     *
     *    Excel Function:
     *        CONVERT(value,fromUOM,toUOM)
     *
     * @param float|int $value the value in fromUOM to convert
     * @param string $fromUOM the units for value
     * @param string $toUOM the units for the result
     *
     * @return float|string
     */
    public static function CONVERT($value, $fromUOM, $toUOM)
    {
        $value = Functions::flattenSingleValue($value);
        $fromUOM = Functions::flattenSingleValue($fromUOM);
        $toUOM = Functions::flattenSingleValue($toUOM);

        if (!is_numeric($value)) {
            return Functions::VALUE();
        }

        try {
            [$fromUOM, $fromCategory, $fromMultiplier] = self::getUOMDetails($fromUOM);
            [$toUOM, $toCategory, $toMultiplier] = self::getUOMDetails($toUOM);
        } catch (Exception $e) {
            return Functions::NA();
        }

        if ($fromCategory !== $toCategory) {
            return Functions::NA();
        }

        $value *= $fromMultiplier;

        if (($fromUOM === $toUOM) && ($fromMultiplier === $toMultiplier)) {
            //    We've already factored $fromMultiplier into the value, so we need
            //        to reverse it again
            return $value / $fromMultiplier;
        } elseif ($fromUOM === $toUOM) {
            return $value / $toMultiplier;
        } elseif ($fromCategory === self::CATEGORY_TEMPERATURE) {
            return self::convertTemperature($fromUOM, $toUOM, $value);
        }

        $baseValue = $value * (1.0 / self::$unitConversions[$fromCategory][$fromUOM]);

        return ($baseValue * self::$unitConversions[$fromCategory][$toUOM]) / $toMultiplier;
    }

    private static function getUOMDetails(string $uom)
    {
        if (isset(self::$conversionUnits[$uom])) {
            $unitCategory = self::$conversionUnits[$uom]['Group'];

            return [$uom, $unitCategory, 1.0];
        }

        // Check 1-character standard metric multiplier prefixes
        $multiplierType = substr($uom, 0, 1);
        $uom = substr($uom, 1);
        if (isset(self::$conversionUnits[$uom], self::$conversionMultipliers[$multiplierType])) {
            if (self::$conversionUnits[$uom]['AllowPrefix'] === false) {
                throw new Exception('Prefix not allowed for UoM');
            }
            $unitCategory = self::$conversionUnits[$uom]['Group'];

            return [$uom, $unitCategory, self::$conversionMultipliers[$multiplierType]['multiplier']];
        }

        $multiplierType .= substr($uom, 0, 1);
        $uom = substr($uom, 1);

        // Check 2-character standard metric multiplier prefixes
        if (isset(self::$conversionUnits[$uom], self::$conversionMultipliers[$multiplierType])) {
            if (self::$conversionUnits[$uom]['AllowPrefix'] === false) {
                throw new Exception('Prefix not allowed for UoM');
            }
            $unitCategory = self::$conversionUnits[$uom]['Group'];

            return [$uom, $unitCategory, self::$conversionMultipliers[$multiplierType]['multiplier']];
        }

        // Check 2-character binary multiplier prefixes
        if (isset(self::$conversionUnits[$uom], self::$binaryConversionMultipliers[$multiplierType])) {
            if (self::$conversionUnits[$uom]['AllowPrefix'] === false) {
                throw new Exception('Prefix not allowed for UoM');
            }
            $unitCategory = self::$conversionUnits[$uom]['Group'];
            if ($unitCategory !== 'Information') {
                throw new Exception('Binary Prefix is only allowed for Information UoM');
            }

            return [$uom, $unitCategory, self::$binaryConversionMultipliers[$multiplierType]['multiplier']];
        }

        throw new Exception('UoM Not Found');
    }

    /**
     * @param float|int $value
     *
     * @return float|int
     */
    protected static function convertTemperature(string $fromUOM, string $toUOM, $value)
    {
        $fromUOM = self::resolveTemperatureSynonyms($fromUOM);
        $toUOM = self::resolveTemperatureSynonyms($toUOM);

        if ($fromUOM === $toUOM) {
            return $value;
        }

        // Convert to Kelvin
        switch ($fromUOM) {
            case 'F':
                $value = ($value - 32) / 1.8 + 273.15;

                break;
            case 'C':
                $value += 273.15;

                break;
            case 'Rank':
                $value /= 1.8;

                break;
            case 'Reau':
                $value = $value * 1.25 + 273.15;

                break;
        }

        // Convert from Kelvin
        switch ($toUOM) {
            case 'F':
                $value = ($value - 273.15) * 1.8 + 32.00;

                break;
            case 'C':
                $value -= 273.15;

                break;
            case 'Rank':
                $value *= 1.8;

                break;
            case 'Reau':
                $value = ($value - 273.15) * 0.80000;

                break;
        }

        return $value;
    }

    private static function resolveTemperatureSynonyms(string $uom)
    {
        switch ($uom) {
            case 'fah':
                return 'F';
            case 'cel':
                return 'C';
            case 'kel':
                return 'K';
        }

        return $uom;
    }
}
