# Source code for pint.facets.measurement.objects

    """
        pint.facets.measurement.objects
        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

        :copyright: 2022 by Pint Authors, see AUTHORS for more details.
        :license: BSD, see LICENSE for more details.
    """

    from __future__ import annotations

    import copy
    import re
    from typing import Generic

    from ...compat import ufloat
    from ..plain import MagnitudeT, PlainQuantity, PlainUnit

    MISSING = object()

    class MeasurementQuantity(Generic[MagnitudeT], PlainQuantity[MagnitudeT]):
        # Measurement support
        def plus_minus(self, error, relative=False):
            if isinstance(error, self.__class__):
                if relative:
                    raise ValueError(f"{error} is not a valid relative error.")
                error = error.to(self._units).magnitude
            else:
                if relative:
                    error = error * abs(self.magnitude)

            return self._REGISTRY.Measurement(copy.copy(self.magnitude), error, self._units)

    class MeasurementUnit(PlainUnit):
        pass

    class Measurement(PlainQuantity):
        """Implements a class to describe a quantity with uncertainty.

        Parameters
        ----------
        value : pint.Quantity or any numeric type
            The expected value of the measurement
        error : pint.Quantity or any numeric type
            The error or uncertainty of the measurement

        Returns
        -------

        """

        def __new__(cls, value, error=MISSING, units=MISSING):
            if units is MISSING:
                try:
                    value, units = value.magnitude, value.units
                except AttributeError:
                    # if called with two arguments and the first looks like a ufloat
                    # then assume the second argument is the units, keep value intact
                    if hasattr(value, "nominal_value"):
                        units = error
                        error = MISSING  # used for check below
                    else:
                        units = ""
            if error is MISSING:
                # We've already extracted the units from the Quantity above
                mag = value
            else:
                try:
                    error = error.to(units).magnitude
                except AttributeError:
                    pass
                if error < 0:
                    raise ValueError("The magnitude of the error cannot be negative")
                else:
                    mag = ufloat(value, error)

            inst = super().__new__(cls, mag, units)
            return inst

        @property
        def value(self):
            return self._REGISTRY.Quantity(self.magnitude.nominal_value, self.units)

        @property
        def error(self):
            return self._REGISTRY.Quantity(self.magnitude.std_dev, self.units)

        @property
        def rel(self):
            return abs(self.magnitude.std_dev / self.magnitude.nominal_value)

        def __reduce__(self):
            # See notes in Quantity.__reduce__
            from pint import _unpickle_measurement

            return _unpickle_measurement, (Measurement, self.magnitude, self._units)

        def __repr__(self):
            return "<Measurement({}, {}, {})>".format(
                self.magnitude.nominal_value, self.magnitude.std_dev, self.units
            )

        def __str__(self):
            return f"{self}"

        def __format__(self, spec):
            spec = spec or self._REGISTRY.default_format
            return self._REGISTRY.formatter.format_measurement(self, spec)

        def old_format(self, spec):
            # TODO: provisional
            from ...formatting import _FORMATS, extract_custom_flags, siunitx_format_unit

            # special cases
            if "Lx" in spec:  # the LaTeX siunitx code
                # the uncertainties module supports formatting
                # numbers in value(unc) notation (i.e. 1.23(45) instead of 1.23 +/- 0.45),
                # using type code 'S', which siunitx actually accepts as input.
                # However, the implementation is incompatible with siunitx.
                # Uncertainties will do 9.1(1.1), which is invalid, should be 9.1(11).
                # TODO: add support for extracting options
                #
                # Get rid of this code, we'll deal with it here
                spec = spec.replace("Lx", "")
                # The most compatible format from uncertainties is the default format,
                # but even this requires fixups.
                # For one, SIUnitx does not except some formats that unc does, like 'P',
                # and 'S' is broken as stated, so...
                spec = spec.replace("S", "").replace("P", "")
                # get SIunitx options
                # TODO: allow user to set this value, somehow
                opts = _FORMATS["Lx"]["siopts"]
                if opts != "":
                    opts = r"[" + opts + r"]"
                # SI requires space between "+-" (or "\pm") and the nominal value
                # and uncertainty, and doesn't accept "+/-", so this setting
                # selects the desired replacement.
                pm_fmt = _FORMATS["Lx"]["pm_fmt"]
                mstr = format(self.magnitude, spec).replace(r"+/-", pm_fmt)
                # Also, SIunitx doesn't accept parentheses, which uncs uses with
                # scientific notation ('e' or 'E' and sometimes 'g' or 'G').
                mstr = mstr.replace("(", "").replace(")", " ")
                ustr = siunitx_format_unit(self.units._units.items(), self._REGISTRY)
                return rf"\SI{opts}{{{mstr}}}{{{ustr}}}"

            # standard cases
            if "L" in spec:
                newpm = pm = r"  \pm  "
                pars = _FORMATS["L"]["parentheses_fmt"]
            elif "P" in spec:
                newpm = pm = "±"
                pars = _FORMATS["P"]["parentheses_fmt"]
            else:
                newpm = pm = "+/-"
                pars = _FORMATS[""]["parentheses_fmt"]

            if "C" in spec:
                sp = ""
                newspec = spec.replace("C", "")
                pars = _FORMATS["C"]["parentheses_fmt"]
            else:
                sp = " "
                newspec = spec

            if "H" in spec:
                newpm = "&plusmn;"
                newspec = spec.replace("H", "")
                pars = _FORMATS["H"]["parentheses_fmt"]

            mag = format(self.magnitude, newspec).replace(pm, sp + newpm + sp)
            if "(" in mag:
                # Exponential format has its own parentheses
                pars = "{}"

            if "L" in newspec and "S" in newspec:
                mag = mag.replace("(", r"\left(").replace(")", r"\right)")

            if "L" in newspec:
                space = r"\ "
            else:
                space = " "

            uspec = extract_custom_flags(spec)
            ustr = format(self.units, uspec)
            if not ("uS" in newspec or "ue" in newspec or "u%" in newspec):
                mag = pars.format(mag)

            if "H" in spec:
                # Fix exponential format
                mag = re.sub(r"\)e\+0?(\d+)", r")×10<sup>\1</sup>", mag)
                mag = re.sub(r"\)e-0?(\d+)", r")×10<sup>-\1</sup>", mag)

            return mag + space + ustr