__all__ = ['mni2tal']

def mni2tal(xin):

    """

    mni2tal for converting from ch2/mni space to tal - very approximate.

    This is a standard approach but it's not very accurate.

    ANTsR function: `mni2tal`

    Arguments

    ---------

    xin : tuple

        point in mni152 space.

    Returns

    -------

    tuple

    Example

    -------

    >>> import ants

    >>> ants.mni2tal( (10,12,14) )

    References

    ----------

    http://bioimagesuite.yale.edu/mni2tal/501_95733_More\\%20Accurate\\%20Talairach\\%20Coordinates\\%20SLIDES.pdf

    http://imaging.mrc-cbu.cam.ac.uk/imaging/MniTalairach

    """

    if (not isinstance(xin, (tuple,list))) or (len(xin) != 3):

        raise ValueError('xin must be tuple/list with 3 coordinates')

    x = list(xin)

    # The input image is in RAS coordinates but we use ITK which returns LPS

    # coordinates.  So we need to flip the coordinates such that L => R and P => A to

    # get RAS (MNI) coordinates

    x[0] = x[0] * (-1)  # flip X

    x[1] = x[1] * (-1)  # flip Y

    xout = x

    if (x[2] >= 0):

        xout[0] = x[0] * 0.99

        xout[1] = x[1] * 0.9688 + 0.046 * x[2]

        xout[2] = x[1] * (-0.0485) + 0.9189 * x[2]

    if (x[2] < 0):

        xout[0] = x[0] * 0.99

        xout[1] = x[1] * 0.9688 + 0.042 * x[2]

        xout[2] = x[1] * (-0.0485) + 0.839 * x[2]

    return(xout)