class UnitSystem {
  attribute id, String {
    definition {
      Unique identifier for the unit system.
    }
  }
  attribute name, String {
    definition {
      Name of the unit system (e.g., SI, non-SI).
    }
  }
  attribute acceptable, Boolean {
    definition {
      Whether the unit system is generally acceptable for use in scientific and
      technical documentation.
    }
  }
}

class UnitSystemRelationship {
  attribute unit_id, String {
    definition "Reference to the unit"
  }
  attribute unit_system_id, String {
    definition "Reference to the unit system"
  }
}

class Prefix {
  attribute id, String {
    definition "Unique identifier for the prefix"
  }
  attribute name, String {
    definition "Name of the prefix (e.g., kilo, milli)"
  }
  attribute symbol, PrefixSymbols {
    definition "Symbol representations in different formats"
  }
  attribute base, Integer {
    definition "The base of the exponentiation (10 for SI prefixes, 2 for binary prefixes)"
  }
  attribute power, Integer {
    definition "The power to which the base is raised"
  }
}

NISTp10_3:
  name: kilo
  symbol:
    ascii: k
    html: k
    latex: k
    unicode: k
  base: 10
  power: 3

NISTp10_-6:
  name: micro
  symbol:
    ascii: u
    html: "µ"
    latex: "$mu$"
    unicode: μ
  base: 10
  power: -6

NISTp2_10:
  name: kibi
  symbol:
    ascii: Ki
    html: Ki
    latex: Ki
    unicode: Ki
  base: 2
  power: 10

class PrefixSymbols {
  attribute ascii, String {
    definition "ASCII text representation"
  }
  attribute html, String {
    definition "HTML representation (may include HTML entities)"
  }
  attribute mathml, String {
    definition "MathML representation in XML format."
  }
  attribute latex, String {
    definition "LaTeX representation in LaTeX typeset format."
  }
  attribute unicode, String {
    definition "Unicode representation in UTF-8 encoding."
  }
}

class Quantity {
  attribute id, String {
    definition {
      "Unique identifier for the quantity.
    }
  }
  attribute dimension_url, String {
    definition {
      Reference to the dimension of the quantity.
    }
  }
  attribute quantity_type, QuantityType {
    definition {
      Type of quantity.
    }
  }
  attribute quantity_name, String {
    collection true
    definition {
      Names of the quantity.
    }
  }
  attribute unit_reference, UnitReference {
    collection true
    definition {
      References to units that can measure this quantity
    }
  }
}

NISTq1:
  dimension_url: "#NISTd1"
  quantity_type: base
  quantity_name:
  - length
  unit_reference:
  - name: meter
    url: "#NISTu1"
  - name: foot
    url: "#NISTu78"
  - name: inch
    url: "#NISTu8"
  - name: mile
    url: "#NISTu83"
  - name: yard
    url: "#NISTu84"

NISTq12:
  dimension_url: "#NISTd11"
  quantity_type: derived
  quantity_name:
  - velocity
  - speed
  unit_reference:
  - name: meter per second
    url: "#NISTu1.u3e-1/1"
  - name: kilometer per hour
    url: "#NISTu160"
  - name: mile per hour
    url: "#NISTu110"

enum QuantityType {
  base {
    definition "Base quantity"
  }
  derived {
    definition "Derived quantity"
  }
}

class UnitReference {
  attribute name, String {
    definition "Name of the unit"
  }

  attribute url, String {
    definition "Reference to the unit"
  }
}

class Dimension {
  attribute id, String {
    definition {
      Unique identifier for the dimension
    }
  }

  attribute dimensionless, Boolean {
    definition {
      Whether the dimension is dimensionless. A dimensionless dimension
      does not have any associated dimension components in `components`.
    }
  }

  attribute components, DimensionComponent {
    collection true
    definition {
      Components of the dimension, including base quantities and their powers.
      Not applicable for dimensionless quantities.
    }
  }
}

NISTd1:
  length:
    powerNumerator: 1
    symbol: L
    dim_symbols:
    - id: dim_L
      ascii: L
      html: "𝖫"
      mathml: "<mi mathvariant='sans-serif'>L</mi>"
      latex: "\\ensuremath{\\mathsf{L}}"
      unicode: "\U0001D5AB"
NISTd12:
  length:
    powerNumerator: 1
    symbol: L
  mass:
    powerNumerator: 1
    symbol: M
  time:
    powerNumerator: -2
    symbol: T
NISTd67:
  dimensionless: true

class DimensionComponent {
  attribute base_dimension, BaseDimensionEnum {
    definition {
      The base dimension represented by this component.
    }
  }

  attribute power_numerator, Integer {
    definition "The exponent (power) of the base quantity in the dimension"
  }

  attribute symbol, String {
    definition "The symbol used to represent the base quantity in dimensional formulas"
  }

  attribute dim_symbols, DimensionSymbol {
    collection true
    definition "Symbol representations in different formats"
  }
}

class BaseDimensionEnum {
  definition {
    Enumeration of base dimensions.
  }

  value length {
    definition {
      The base dimension of length
    }
  }
  value mass {
    definition {
      The base dimension of mass
    }
  }
  value time {
    definition {
      The base dimension of time
    }
  }
  value electric_current {
    definition {
      The base dimension of electric current
    }
  }
  value thermodynamic_temperature {
    definition {
      The base dimension of thermodynamic temperature
    }
  }
  value amount_of_substance {
    definition {
      The base dimension of amount of substance
    }
  }
  value luminous_intensity {
    definition {
      The base dimension of luminous intensity
    }
  }

  value plane_angle {
    definition {
      The base dimension of the dimensionless plane angle. This is a special
      case that is not a base dimension in the SI system but is often treated as
      such in dimensional analysis.
    }
  }
}

class DimensionSymbol {
  attribute id, String {
    definition "Unique identifier for the symbol representation"
  }

  attribute ascii, String {
    definition "ASCII text representation"
  }

  attribute html, String {
    definition "HTML representation (may include HTML entities)"
  }

  attribute mathml, String {
    definition "MathML representation in XML format."
  }

  attribute latex, String {
    definition "LaTeX representation in LaTeX typeset format."
  }

  attribute unicode, String {
    definition "Unicode representation in UTF-8 encoding."
  }
}

class Unit {
  attribute id, String {
    definition {
      Unique identifier for the unit.

      NOTE: Currently this is in the pattern `NISTuX` where X is a number.
    }
  }
  attribute short_name, String {
    definition {
      Short name for the unit. This is a unique identifier for the unit.
    }
  }
  attribute root, Boolean {
    definition {
      Whether the unit can be used as a root unit to create derived units.
    }
  }
  attribute prefixed, Boolean {
    definition {
      Whether the unit is prefixed itself.
    }
  }
  attribute unit_name, String {
    collection true
    definition {
      One or more names of the unit.
    }
  }
  attribute unit_symbol, UnitSymbol {
    collection true
    definition {
      One or more symbol representations in different formats.
    }
  }
  attribute unit_system, UnitSystemReference {
    definition {
      Reference to the unit system to which the unit belongs.
    }
  }
  attribute dimension_ref, DimensionReference {
    definition {
      Reference to the dimension of the unit.
    }
  }
  attribute quantity_ref, QuantityReference {
    collection true
    definition {
      Reference to the quantity measured by the unit.
    }
  }
  attribute root_units, RootUnitReference {
    collection true
    definition {
      For derived units, the component root units with exponents.
    }
  }
  attribute si_derived_bases, SiBaseUnitReference {
    collection true
    definition {
      For SI-derived units, the SI base units with exponents.
    }
  }
}

class UnitSymbol {
  attribute id, String {
    definition "Unique identifier for the symbol representation"
  }
  attribute ascii, String {
    definition "ASCII text representation"
  }
  attribute html, String {
    definition "HTML representation (may include HTML entities)"
  }
  attribute mathml, String {
    definition "MathML representation in XML format."
  }
  attribute latex, String {
    definition "LaTeX representation in LaTeX typeset format."
  }
  attribute unicode, String {
    definition "Unicode representation in UTF-8 encoding."
  }
}

class DimensionReference {
  attribute dimension_url, String {
    definition "URL associated with the dimension"
  }
}

class UnitSystemReference {
  attribute type, String {
    definition "Type of the unit system"
  }
  attribute name, String {
    definition "Name of the unit system"
  }
}

class SiBaseUnitReference {
  attribute id, String {
    definition {
      Unique identifier for the SI base unit. e.g. `NISTu1`.
    }
  }
  attribute prefix, String {
    definition {
      Prefix for the SI base unit, if applicable. Defaults to empty string.
    }
  }
  attribute power, Integer {
    definition {
      Power of the SI base unit in the derived unit. Defaults to 1.
    }
  }
}

class RootUnitReference {
  attribute unit, String {
    definition "Unit `short` name of the root unit which is a Unit object."
  }
  attribute power_numerator, Integer {
    definition "Power of the numerator."
  }
  attribute power_denominator, Integer {
    definition "Power of the denominator."
  }
  attribute prefix, String {
    definition "Prefix for the unit, if applicable."
  }
}

class QuantityReference {
  attribute name, String {
    definition "Name of the quantity"
  }
  attribute url, String {
    definition "URL reference to the quantity"
  }
}

class DataIntegrityCheck {
  attribute check_type, String {
    definition "Type of integrity check"
  }
  attribute description, String {
    definition "Description of the check"
  }
  attribute severity, String {
    definition "Severity level if check fails (error, warning, info)"
  }
}

class ChangeManagement {
  attribute change_type, String {
    definition "Type of change"
  }
  attribute rules, Array {
    definition "Rules governing this type of change"
  }
  attribute impact, String {
    definition "Potential impact of this type of change"
  }
}

class SymbolRepresentation {
  attribute id, String {
    definition "Unique identifier for the symbol representation"
  }

  attribute ascii, String {
    definition "ASCII text representation"
  }

  attribute html, String {
    definition "HTML representation (may include HTML entities)"
  }

  attribute mathml, String {
    definition "MathML representation in XML format."
  }

  attribute latex, String {
    definition "LaTeX representation in LaTeX typeset format."
  }

  attribute unicode, String {
    definition "Unicode representation in UTF-8 encoding."
  }
}

class CrossReference {
  attribute identifier, String {
    definition "Identifier of the referenced entity"
  }
}