# -*- coding: utf-8 -*-
"""This module defines atom flags that are used in :ref:`selections`.
You can read this page in interactive sessions using ``help(flags)``.

Flag labels can be used in atom selections:

.. ipython:: python

   from prody import *
   p = parsePDB('1ubi')
   p.select('protein')

Flag labels can be combined with dot operator as follows to make selections:

.. ipython:: python

   p.protein
   p.protein.acidic  # selects acidic residues

Flag labels can be prefixed with ``'is'`` to check whether all atoms in
an :class:`.Atomic` instance are flagged the same way:

.. ipython:: python

   p.protein.ishetero
   p.water.ishetero

Flag labels can also be used to make quick atom counts:

.. ipython:: python

   p.numAtoms()
   p.numAtoms('protein')
   p.numAtoms('water')"""

from re import compile as recompile
from time import time
from collections import defaultdict

from numpy import array, ones, zeros

from prody import SETTINGS, LOGGER
from prody.utilities import joinLinks, joinTerms, wrapText

__all__ = ['flagDefinition', 'listNonstdAAProps', 'getNonstdProperties',
           'addNonstdAminoacid', 'delNonstdAminoacid']


TIMESTAMP_KEY = 'flags_timestamp'
DEFINITIONS_KEY = 'flags_definitions'
NONSTANDARD_KEY = 'flags_nonstandard'

ALIASES = {}
PLANTERS = {}
EDITORS = {}
FIELDS = defaultdict(set)  # flags that fill be nulled when a field changes
FIELDSDEFAULT = ['name', 'resname', 'resnum']
TIMESTAMP = 0

PDBLIGSUM = ('.. _{0}: '
             'http://www.pdb.org/pdb/ligand/ligandsummary.do?hetId={0}\n')

STANDARDAA = ['ALA', 'ARG', 'ASN', 'ASP', 'CYS', 'GLN', 'GLU', 'GLY', 'HIS',
              'ILE', 'LEU', 'LYS', 'MET', 'PHE', 'PRO', 'SER', 'THR', 'TRP',
              'TYR', 'VAL']

NONSTANDARD = {
    'ASX': set(['acyclic', 'surface', 'polar', 'medium']),
    'GLX': set(['acyclic', 'surface', 'large', 'polar']),
    'CSO': set(['acyclic', 'neutral', 'surface', 'medium', 'polar']),
    'CYX': set(['acyclic', 'neutral', 'buried', 'medium', 'polar']),
    'HIP': set(['cyclic', 'basic', 'surface', 'large', 'polar']),
    'HID': set(['cyclic', 'basic', 'surface', 'large', 'polar']),
    'HIE': set(['cyclic', 'basic', 'surface', 'large', 'polar']),
    'HSD': set(['cyclic', 'basic', 'surface', 'large', 'polar']),
    'HSE': set(['cyclic', 'basic', 'surface', 'large', 'polar']),
    'HSP': set(['cyclic', 'acidic', 'surface', 'large', 'polar']),
    'MSE': set(['acyclic', 'neutral', 'buried', 'large']),
    'CME': set(['acyclic', 'neutral', 'buried', 'large']),
    'SEC': set(['acyclic', 'neutral', 'buried', 'polar', 'medium']),
    'SEP': set(['acyclic', 'surface', 'acidic', 'large', 'polar']),
    'TPO': set(['acyclic', 'surface', 'acidic', 'large', 'polar']),
    'PTR': set(['cyclic', 'aromatic', 'surface', 'acidic', 'large', 'polar']),
    'PHD': set(['acyclic', 'acidic', 'surface', 'polar', 'large']),
    'XLE': set(['aliphatic', 'acyclic', 'buried', 'hydrophobic', 'large']),
    'XAA': set(),
    'MEN': set(),
    'CSB': set()
}

DEFAULTS = {

    'stdaa': set(['ALA', 'ARG', 'ASN', 'ASP', 'CYS', 'GLN', 'GLU', 'GLY',
                  'HIS', 'ILE', 'LEU', 'LYS', 'MET', 'PHE', 'PRO', 'SER',
                  'THR', 'TRP', 'TYR', 'VAL']),

    'nonstdaa': set(NONSTANDARD),

    # GLY is excluded from this list
    'aliphatic': set(['ALA', 'ILE', 'LEU', 'VAL', 'PRO', 'GLY']),
    'aromatic': set(['HIS', 'PHE', 'TRP', 'TYR']),

    'acidic': set(['ASP', 'GLU']),
    'basic': set(['LYS', 'ARG', 'HIS']),
    'neutral': set(['ALA', 'ASN', 'CYS', 'GLN', 'GLY', 'ILE', 'LEU', 'MET',
                    'PHE', 'PRO', 'SER', 'THR', 'TRP', 'TYR', 'VAL']),

    'buried': set(['ALA', 'CYS', 'ILE', 'LEU', 'MET', 'PHE', 'TRP', 'VAL']),
    'surface': set(['ARG', 'ASN', 'ASP', 'GLN', 'GLU', 'GLY', 'HIS', 'LYS',
                    'PRO', 'SER', 'THR', 'TYR']),

    'cyclic': set(['HIS', 'PHE', 'PRO', 'TRP', 'TYR']),
    'acyclic': set(['ALA', 'ARG', 'ASN', 'ASP', 'CYS', 'GLN', 'GLU', 'GLY',
                    'ILE', 'LEU', 'LYS', 'MET', 'SER', 'THR', 'VAL']),

    'hydrophobic': set(['ALA', 'ILE', 'LEU', 'MET', 'PHE', 'PRO', 'TRP',
                        'VAL']),
    'polar': set(['ARG', 'ASN', 'ASP', 'CYS', 'GLN', 'GLU', 'GLY', 'HIS',
                  'LYS', 'SER', 'THR', 'TYR']),

    'small': set(['ALA', 'GLY', 'SER']),
    'medium': set(['ASN', 'ASP', 'CYS', 'PRO', 'THR', 'VAL']),
    'large': set(['ARG', 'GLN', 'GLU', 'HIS', 'ILE', 'LEU', 'LYS', 'MET',
                  'PHE', 'TRP', 'TYR']),


    'hydrogen': '[0-9]?H.*',
    'carbon': 'C.*',
    'nitrogen': 'N.*',
    'oxygen': 'O.*',
    'sulfur': 'S.*',

    'nucleobase': set(['GUN', 'ADE', 'CYT', 'THY', 'URA']),
    'nucleotide': set(['DA', 'DC', 'DG', 'DT', 'DU', 'A', 'C', 'G', 'T', 'U']),
    'nucleoside': set(['AMP', 'ADP', 'ATP', 'CDP', 'CTP', 'GMP', 'GDP', 'GTP',
                       'TMP', 'TTP', 'UMP', 'UDP', 'UTP']),

    'at': set(['ADE', 'A', 'THY', 'T']),
    'cg': set(['CYT', 'C', 'GUN', 'G']),
    'purine': set(['ADE', 'A', 'GUN', 'G']),
    'pyrimidine': set(['CYT', 'C', 'THY', 'T', 'URA', 'U']),

    'water': set(['HOH', 'DOD', 'WAT', 'TIP3', 'H2O', 'OH2', 'TIP', 'TIP2',
                  'TIP4']),

    'ion': set(['AL', 'BA', 'CA', 'CD', 'CL', 'CO', 'CS', 'CU', 'CU1', 'CUA',
                'HG', 'IN', 'IOD', 'K', 'MG', 'MN', 'MN3', 'NA', 'PB', 'PT', 'RB',
                'TB', 'TL', 'WO4', 'YB', 'ZN']),
    'ion_other': set(['CAL', 'CES', 'CLA', 'POT', 'SOD', 'ZN2']),


    'lipid': set(['GPE', 'LPP', 'OLA', 'SDS', 'STE']),
    'lipid_other': set(['DLPE', 'DMPC', 'LPPC', 'OLEO', 'PALM', 'PCGL', 'POPC',
                        'POPE', 'STEA']),

    'sugar': set(['GLC', 'GLO', 'BGC']),
    'sugar_other': set(['AGLC']),

    'heme': set(['1FH', '2FH', 'DDH', 'DHE', 'HAS', 'HDD', 'HDE', 'HDM',
                 'HEA', 'HEB', 'HEC', 'HEM', 'HEO', 'HES', 'HEV', 'NTE',
                 'SRM', 'VER']),
    'heme_other': set(['HEMO', 'HEMR'])

}

DEFAULTS['backbone'] = DEFAULTS['bb'] = set(['CA', 'C', 'O', 'N'])
DEFAULTS['backbonefull'] = DEFAULTS['bbfull'] = set(['CA', 'C', 'O', 'N', 'H',
                                                     'H1', 'H2', 'H3', 'OXT'])

CATEGORIES = {
    'aromaticity': set(['aromatic', 'aliphatic']),
    'cyclic': set(['acyclic', 'cyclic']),
    'charge': set(['acidic', 'basic', 'neutral']),
    'depth': set(['buried', 'surface']),
    'hydrophobicity': set(['hydrophobic', 'polar']),
    'size': set(['small', 'medium', 'large']),
}

CATEGORIZED = {}
for catgroup in CATEGORIES.values():
    for category in catgroup:
        CATEGORIZED[category] = list(DEFAULTS[category])
INDEPENDENT = list(CATEGORIZED)
CATEGORIZED['charged'] = list(CATEGORIZED['acidic'])
CATEGORIZED['charged'].extend(CATEGORIZED['basic'])

for resi, cats in NONSTANDARD.items():
    for cat in cats:
        CATEGORIZED[cat].append(resi)


def addPlanter(func, *labels, **kwargs):

    aliases = kwargs.get('aliases', True)
    editor = kwargs.get('editor', False)
    for label in labels:
        PLANTERS[label] = func
        if aliases:
            ALIASES[label] = labels
        else:
            ALIASES[label] = [label]
        if editor:
            EDITORS[label] = editor
    for field in kwargs.get('fields', FIELDSDEFAULT):
        FIELDS[field].update(labels)


def updateNonstandard(nonstd):

    SETTINGS[NONSTANDARD_KEY] = nonstd
    SETTINGS[TIMESTAMP_KEY] = int(time())
    SETTINGS.save()
    updateDefinitions()


def changeDefinitions(**kwargs):

    defs = SETTINGS.get(DEFINITIONS_KEY, {})
    defs.update(kwargs)
    SETTINGS[DEFINITIONS_KEY] = defs
    SETTINGS[TIMESTAMP_KEY] = int(time())
    SETTINGS.save()
    updateDefinitions()


def resetDefinitions(flag):

    if flag == 'all':
        SETTINGS.pop(DEFINITIONS_KEY, None)
        SETTINGS.pop(NONSTANDARD_KEY, None)
        SETTINGS[TIMESTAMP_KEY] = int(time())
        SETTINGS.save()
        updateDefinitions()
    elif flag == 'nonstdaa':
        SETTINGS.pop(NONSTANDARD_KEY, None)
        SETTINGS[TIMESTAMP_KEY] = int(time())
        SETTINGS.save()
        updateDefinitions()
    else:
        try:
            SETTINGS.pop(DEFINITIONS_KEY, {}).pop(flag)
        except KeyError:
            pass
        else:
            SETTINGS[TIMESTAMP_KEY] = int(time())
            SETTINGS.save()
            updateDefinitions()


def changeResnames(flag, resnames):
    """Change the list of residue names associated with a flag.  *flag* must
    be a string, and *resnames* may be a list, tuple, or set of strings.  The
    existing list of residue names will be overwritten with the given residue
    names."""

    if flag not in EDITORS:
        raise ValueError('{0} is not an editable flag'.format(repr(flag)))

    resnames = [str(rn) for rn in resnames]
    changeDefinitions(**{flag: resnames})


def changeNameRegex(flag, regex):
    """Set regular expression used for flagging elements based on atom names.
    See :ref:`element-flags` for the default list of flags."""

    if flag not in EDITORS:
        raise ValueError('{0} is not an editable flag'.format(repr(flag)))

    try:
        recompile(regex)
    except Exception as err:
        raise ValueError('{0} is not a valid regular expression, {1}'
                         .format(repr(regex), str(err)))
    else:
        changeDefinitions(**{flag: regex})


def changeBackbone(flag, names):
    """Set protein :term:`backbone` or :term:`backbonefull` atom names.
    *names* must be a list of atom names."""

    if flag not in EDITORS:
        raise ValueError('{0} is not an editable flag'.format(repr(flag)))

    names = [str(nm) for nm in names]

    if flag.endswith('full'):
        changeDefinitions(bbfull=names, backbonefull=names)
    else:
        changeDefinitions(bb=names, backbone=names)


__doc__ += """

Protein
-------------------------------------------------------------------------------

.. glossary::

   protein
   aminoacid
      indicates the twenty standard amino acids (:term:`stdaa`) and some
      non-standard amino acids (:term:`nonstdaa`) described below.  Residue
      must also have an atom named ``'CA'`` in addition to having a qualifying
      residue name.


   stdaa
      {stdaa}


   nonstdaa
      indicates one of the following residues:

      ==========  ===================================================
      `ASX`_ (B)  asparagine or aspartic acid
      `GLX`_ (Z)  glutamine or glutamic acid
      `CSO`_ (C)  S-hydroxycysteine
      `HIP`_ (H)  ND1-phosphohistidine
       HSD   (H)  prototropic tautomer of histidine, H on ND1 (CHARMM)
       HSE   (H)  prototropic tautomer of histidine, H on NE2 (CHARMM)
       HSP   (H)  protonated histidine
      `MSE`_      selenomethionine
      `SEC`_ (U)  selenocysteine
      `SEP`_ (S)  phosphoserine
      `TPO`_ (T)  phosphothreonine
      `PTR`_ (Y)  O-phosphotyrosine
       XLE   (J)  leucine or isoleucine
       XAA   (X)  unspecified or unknown
      ==========  ===================================================

      You can modify the list of non-standard amino acids using
      :func:`addNonstdAminoacid`, :func:`delNonstdAminoacid`, and
      :func:`listNonstdAAProps`.


   calpha
   ca
      Cα atoms of :term:`protein` residues, same as selection
      ``'name CA and protein'``


   backbone
   bb
      non-hydrogen backbone atoms of :term:`protein` residues, same as
      selection ``'name CA C O N and protein'``


   backbonefull
   bbfull
      backbone atoms of :term:`protein` residues, same as selection
      ``'name CA C O N H H1 H2 H3 OXT and protein'``


   sidechain
   sc
      side-chain atoms of :term:`protein` residues, same as selection
      ``'protein and not backbonefull'``


""".format(

stdaa = wrapText('indicates the standard amino acid residues: ' +
                 joinLinks(DEFAULTS['stdaa'], last=', and ', sort=True),
                 subsequent_indent=' '*6))


cats = list(CATEGORIZED)
cats.sort()

for cat in cats:
    res = CATEGORIZED[cat]
    res.sort()
    __doc__ += """
   {cat}
       {res}

""".format(cat=cat, res=wrapText('residues ' + ', '.join(res),
                                 subsequent_indent=' '*6))

for resi in DEFAULTS['stdaa']:
    __doc__ += PDBLIGSUM.format(resi)
for resi in DEFAULTS['nonstdaa']:
    __doc__ += PDBLIGSUM.format(resi)


__doc__ += """

Nucleic
-------------------------------------------------------------------------------

.. glossary::

   nucleic
      indicates :term:`nucleobase`, :term:`nucleotide`, and some
      :term:`nucleoside` derivatives that are described below, so it is same
      as ``'nucleobase or nucleotide or nucleoside'``.

   nucleobase
      indicates `ADE`_ (adenine), `GUN`_ (guanine), `CYT`_
      (cytosine), `THY`_ (thymine), and `URA`_ (uracil).

   nucleotide
      indicates residues with the following names:

      =======  ==================================
      `DA`_    2'-deoxyadenosine-5'-monophosphate
      `DC`_    2'-deoxycytidine-5'-monophosphate
      `DG`_    2'-deoxyguanosine-5'-monophosphate
      `DT`_    2'-deoxythymidine-5'-monophosphate
      `DU`_    2'-deoxyuridine-5'-monophosphate
      `A`_     adenosine-5'-monophosphate
      `C`_     cytidine-5'-monophosphate
      `G`_     guanosine-5'-monophosphate
      `T`_     2'-deoxythymidine-5'-monophosphate
      `U`_     uridine-5'-monophosphate
      =======  ==================================

   nucleoside
      indicates following nucleoside derivatives that are recognized by *PDB*:

      =======  ================================
      `AMP`_   adenosine monophosphate
      `ADP`_   adenosine-5'-diphosphate
      `ATP`_   adenosine-5'-triphosphate
      `CDP`_   cytidine-5'-diphosphate
      `CTP`_   cytidine-5'-triphosphate
      `GMP`_   guanosine
      `GDP`_   guanosine-5'-diphosphate
      `GTP`_   guanosine-5'-triphosphate
      `TMP`_   thymidine-5'-phosphate
      `TTP`_   thymidine-5'-triphosphate
      `UMP`_   2'-deoxyuridine 5'-monophosphate
      `UDP`_   uridine 5'-diphosphate
      `UTP`_   uridine 5'-triphosphate
      =======  ================================


   at
      same as selection ``'resname ADE A THY T'``

   cg
      same as selection ``'resname CYT C GUN G'``

   purine
      same as selection ``'resname ADE A GUN G'``

   pyrimidine
      same as selection ``'resname CYT C THY T URA U'``

"""

for resi in DEFAULTS['nucleobase']:
    __doc__ += PDBLIGSUM.format(resi)

for resi in DEFAULTS['nucleotide']:
    __doc__ += PDBLIGSUM.format(resi)

for resi in DEFAULTS['nucleoside']:
    __doc__ += PDBLIGSUM.format(resi)

__doc__ += """

Heteros
-------------------------------------------------------------------------------

.. glossary::

   hetero
      indicates anything other than a :term:`protein` or a
      :term:`nucleic` residue, i.e. ``'not (protein or nucleic)'``.


   hetatm
      is available when atomic data is parsed from a PDB or similar
      format file and indicates atoms that are marked ``'HETATM'`` in the file.


   water
      indices `HOH`_ and `DOD`_ recognized by *PDB* and also WAT, TIP3, H2O,
      OH2, TIP, TIP2, and TIP4 recognized by molecular dynamics (MD) force
      fields.

      .. _HOH: http://www.pdb.org/pdb/ligand/ligandsummary.do?hetId=HOH

      .. _DOD: http://www.pdb.org/pdb/ligand/ligandsummary.do?hetId=DOD

      Previously used water types HH0, OHH, and SOL conflict with other
      compounds in the *PDB*, so are removed from the definition of this flag.


   ion
      indicates the following ions most of which are recognized by the *PDB*
      and others by MD force fields.

      =======  ==================  =====  ========  ==========
      \                            *PDB*  *Source*  *Conflict*
      `AL`_    aluminum            Yes
      `BA`_    barium              Yes
      `CA`_    calcium             Yes
      `CD`_    cadmium             Yes
      `CL`_    chloride            Yes
      `CO`_    cobalt (ii)         Yes
      `CS`_    cesium              Yes
      `CU`_    copper (ii)         Yes
      `CU1`_   copper (i)          Yes
      `CUA`_   dinuclear copper    Yes
      `HG`_    mercury (ii)        Yes
      `IN`_    indium (iii)        Yes
      `IOD`_   iodide              Yes
      `K`_     potassium           Yes
      `MG`_    magnesium           Yes
      `MN3`_   manganese (iii)     Yes
      `MN`_    manganese (ii)      Yes    
      `NA`_    sodium              Yes
      `PB`_    lead (ii)           Yes
      `PT`_    platinum (ii)       Yes
      `RB`_    rubidium            Yes
      `TB`_    terbium (iii)       Yes
      `TL`_    thallium (i)        Yes
      `WO4`_   thungstate (vi)     Yes
      `YB`_    ytterbium (iii)     Yes
      `ZN`_    zinc                Yes
      CAL      calcium             No     CHARMM    Yes
      CES      cesium              No     CHARMM    Yes
      CLA      chloride            No     CHARMM    Yes
      POT      potassium           No     CHARMM    Yes
      SOD      sodium              No     CHARMM    Yes
      ZN2      zinc                No     CHARMM    No
      =======  ==================  =====  ========  ==========

      Ion identifiers that are obsoleted by *PDB* (MO3, MO4, MO5, MO6, NAW,
      OC7, and ZN1) are removed from this definition.


   lipid
      {lipid}


   sugar
      {sugar}


   heme
      {heme}

   pdbter
      is available when atomic data is parsed from a PDB format file and
      indicates atoms that were followed by ``'TER'`` record.

   selpdbter
      is available when atomic data is parsed from a PDB format file and
      then a selection is made and indicates selected atoms that should
      be followed by ``'TER'`` record.

""".format(

lipid = wrapText('indicates ' +
                 joinLinks(DEFAULTS['lipid'], last=', and ', sort=True) +
                 ' from *PDB*, and also ' + ', '.join(DEFAULTS['lipid_other']) +
                 ' from *CHARMM* force field.', subsequent_indent=' '*6),

sugar = wrapText('indicates ' +
                 joinLinks(DEFAULTS['sugar'], last=', and ', sort=True) +
                 ' from *PDB*, and also AGLC from *CHARMM*.',
                 subsequent_indent=' '*6),

heme = wrapText('indicates ' +
                joinLinks(DEFAULTS['heme'], last=', and ', sort=True) +
                ' from *PDB*, and also HEMO and HEMR from CHARMM.',
                subsequent_indent=' '*6)
)


for resi in DEFAULTS['ion']:
    __doc__ += PDBLIGSUM.format(resi)

for resi in DEFAULTS['lipid']:
    __doc__ += PDBLIGSUM.format(resi)

for resi in DEFAULTS['sugar']:
    __doc__ += PDBLIGSUM.format(resi)

for resi in DEFAULTS['heme']:
    __doc__ += PDBLIGSUM.format(resi)


__doc__ += """

Elements
-------------------------------------------------------------------------------

Following elements found in proteins are recognized by applying regular
expressions to atom names:

.. glossary::

   carbon
      carbon atoms, same as ``'name "C.*" and not ion'``

   nitrogen
      nitrogen atoms, same as ``'name "N.*" and not ion'``

   oxygen
      oxygen atoms, same as ``'name "O.*" and not ion'``

   sulfur
      sulfur atoms, same as ``'name "S.*" and not ion'``

   hydrogen
      hydrogen atoms, same as ``'name "[1-9]?H.*" and not ion'``

   noh
   heavy
      non hydrogen atoms, same as ``'not hydrogen``


``'not ion'`` is appended to above definitions to avoid conflicts with
:term:`ion` atoms.

Structure
-------------------------------------------------------------------------------

Following secondary structure flags are defined but before they can be used,
secondary structure assignments must be made.

.. glossary::

   extended
      extended conformation, same as ``'secondary E'``

   helix
      α-helix conformation, same as ``'secondary H'``

   helix310
      3_10-helix conformation, same as ``'secondary G'``

   helixpi
      π-helix conformation, same as ``'secondary I'``

   turn
      hydrogen bonded turn conformation, same as ``'secondary T'``

   bridge
      isolated beta-bridge conformation, same as ``'secondary B'``

   bend
      bend conformation, same as ``'secondary S'``

   coil
      not in one of above conformations, same as ``'secondary C'``

Others
-------------------------------------------------------------------------------

.. glossary::

   all
      indicates all atoms, returns a new view of the instance

   none
      indicates no atoms, returns **None**

   dummy
      indicates dummy atoms in an :class:`.AtomMap`

   mapped
      indicates mapped atoms in an :class:`.AtomMap`

Functions
===============================================================================

The following functions can be used to customize flag definitions:

    * :func:`.flagDefinition`
    * :func:`.addNonstdAminoacid`
    * :func:`.delNonstdAminoacid`
    * :func:`.listNonstdAAProps`

"""

# join split lists
for key in ['ion', 'lipid', 'sugar', 'heme']:
    DEFAULTS[key].update(DEFAULTS.pop(key + '_other'))

DEFINITIONS = None
AMINOACIDS = None
BACKBONE = None


def updateDefinitions():
    """Update definitions and set some global variables.  This function must be
    called at the end of the module."""

    global DEFINITIONS, AMINOACIDS, BACKBONE, TIMESTAMP
    DEFINITIONS = {}
    user = SETTINGS.get('flags_definitions', {})

    # nucleics
    nucleic = set()
    for key in ['nucleobase', 'nucleoside', 'nucleotide']:
        aset = set(user.get(key, DEFAULTS[key]))
        nucleic.update(aset)
        DEFINITIONS[key] = aset
    DEFINITIONS['nucleic'] = nucleic

    # heteros
    for key in ['water', 'lipid', 'ion', 'sugar', 'heme',
                'at', 'cg', 'purine', 'pyrimidine']:
        DEFINITIONS[key] = set(user.get(key, DEFAULTS[key]))

    DEFINITIONS['backbone'] = DEFINITIONS['bb'] = set(user.get(key,
                                                      DEFAULTS['bb']))
    DEFINITIONS['backbonefull'] = DEFINITIONS['bbfull'] = set(user.get(key,
                                                           DEFAULTS['bbfull']))

    # element regex
    for key in ['hydrogen', 'carbon', 'nitrogen', 'oxygen', 'sulfur']:
        DEFINITIONS[key] = recompile(user.get(key, DEFAULTS[key]))

    try:
        nonstd = SETTINGS[NONSTANDARD_KEY]

    except KeyError:
        nonstd = NONSTANDARD
        DEFINITIONS.update(CATEGORIZED)
    else:

        for cat in CATEGORIES:
            for key in CATEGORIES[cat]:
                DEFINITIONS[key] = set(DEFAULTS[key])

        DEFINITIONS['charged'] = set(DEFINITIONS['acidic'])
        DEFINITIONS['charged'].update(DEFINITIONS['basic'])

        for resi, props in nonstd.items():
            for prop in props:
                DEFINITIONS[prop].add(resi)

    DEFINITIONS['stdaa'] = DEFAULTS['stdaa']
    DEFINITIONS['nonstdaa'] = set(nonstd)
    AMINOACIDS = set(DEFINITIONS['stdaa'])
    AMINOACIDS.update(DEFINITIONS['nonstdaa'])
    DEFINITIONS['protein'] = DEFINITIONS['aminoacid'] = AMINOACIDS

    BACKBONE = DEFINITIONS['bb']

    global TIMESTAMP
    TIMESTAMP = SETTINGS.get(TIMESTAMP_KEY, 0)


#==============================================================================
# PLANTERS
#==============================================================================

# flag planters are functions that take an AtomGroup instance
# and set flags for a given label using the atomic data stored in the AtomGroup
# a planter can also set the indices of subset atoms for calculated flag
# planters return the flags after calculation is over

# protein
#==============================================================================

def setCalpha(ag, label):

    flags = ag._getNames() == 'CA'
    indices = flags.nonzero()[0]
    if len(indices):
        torf = array([rn in AMINOACIDS for rn in ag._getResnames()[indices]])
        flags[indices] = torf
        ag._setFlags(label, flags)
        ag._setSubset(label, indices[torf])
    else:
        ag._setFlags(label, flags)
        ag._setSubset(label, array([]))
    return flags

addPlanter(setCalpha, 'ca', 'calpha')


def setProtein(ag, label):

    calpha = ag._getSubset('calpha')
    if len(calpha):
        torf = zeros(ag.numResidues(), bool)
        resindices = ag._getResindices()
        torf[resindices[calpha]] = True
        flags = torf[resindices]
    else:
        flags = zeros(ag.numAtoms(), bool)
        
    water = ag._getSubset("water")
    if len(water):
        flags[water] = False
        
    ions = ag._getSubset("ion")
    if len(ions):
        flags[ions] = False
    
    ag._setFlags('protein', flags)
    return flags

addPlanter(setProtein, 'protein', 'aminoacid')

# subsets
#==============================================================================


def setBackbone(ag, label):

    protein = ag._getSubset('protein')
    if len(protein):
        bb = DEFINITIONS[label]
        names = ag._getNames()[protein]
        flags = zeros(ag.numAtoms(), bool)
        flags[protein] = [nm in bb for nm in names]
    else:
        flags = zeros(ag.numAtoms(), bool)
    ag._setFlags(label, flags)
    return flags

addPlanter(setBackbone, 'bb', 'backbone', editor=changeBackbone)
addPlanter(setBackbone, 'bbfull', 'backbonefull', editor=changeBackbone)


def setSidechain(ag, label):

    protein = ag._getSubset('protein')
    if len(protein):
        flags = zeros(ag.numAtoms(), bool)
        flags[protein] = True
        flags[ag._getSubset('bbfull')] = False
    else:
        flags = zeros(ag.numAtoms(), bool)
    ag._setFlags(label, flags)
    return flags

addPlanter(setSidechain, 'sc', 'sidechain')


def setCategories(ag, label):

    calpha = ag._getSubset('ca')
    if len(calpha):
        resnames = DEFINITIONS[label]
        residx = ag._getResindices()
        torf = zeros(ag.numResidues(), bool)
        torf[residx[calpha]] = [rn in resnames
                                for rn in ag._getResnames()[calpha]]
        flags = torf[residx]
    else:
        flags = zeros(ag.numAtoms(), bool)
    ag._setFlags(label, flags)
    return flags

addPlanter(setCategories, 'stdaa', 'nonstdaa', *list(CATEGORIZED.keys()),
           aliases=False)


def setAll(ag, label):

    flags = ones(ag.numAtoms(), bool)
    ag._setFlags('all', flags)
    return flags

addPlanter(setAll, 'all')


def setNone(ag, label):

    flags = zeros(ag.numAtoms(), bool)
    ag._setFlags('none', flags)
    return flags

addPlanter(setNone, 'none')

# hetero, nucleic, water, etc.
#==============================================================================


def setResiflag(ag, label):

    resnames = DEFINITIONS[label]
    flags = array([rn in resnames for rn in ag._getResnames()], bool)
    ag._setFlags(label, flags)
    return flags

addPlanter(setResiflag, 'nucleobase', 'nucleoside', 'nucleotide',
           'water', 'ion', 'lipid', 'sugar', 'heme', 'at', 'cg', 'purine',
           'pyrimidine', aliases=False, editor=changeResnames)
addPlanter(setResiflag, 'nucleic')


def setHetero(ag, label):

    flags = ones(ag.numAtoms(), bool)
    flags[ag._getSubset('protein')] = False
    flags[ag._getSubset('nucleic')] = False
    ag._setFlags('hetero', flags)
    return flags

addPlanter(setHetero, 'hetero',)


# element
#==============================================================================

def setElement(ag, label):

    match = DEFINITIONS[label].match
    flags = array([match(nm) is not None for nm in ag._getNames()])
    flags[ag._getSubset('ion')] = False
    ag._setFlags(label, flags)
    return flags

addPlanter(setElement, 'hydrogen', 'carbon', 'nitrogen', 'oxygen', 'sulfur',
           aliases=False, editor=changeNameRegex)


def setNoh(ag, label):

    flags = ones(ag.numAtoms(), bool)
    flags[ag._getSubset('hydrogen')] = False
    ag._setFlags(label, flags)
    return flags

addPlanter(setNoh, 'noh', 'heavy')


# secondary
#==============================================================================

SECONDARY = {'extended': 'E', 'helix': 'H', 'helix310': 'G', 'helixpi': 'I',
             'turn': 'T', 'bridge': 'B', 'bend': 'S', 'coil': 'C'}


def setSecondary(ag, label):

    secstrs = ag._getSecstrs()
    if secstrs is None:
        raise ValueError('no secondary structure assignments')
    flags = secstrs == SECONDARY[label]
    ag._setFlags(label, flags)
    return flags

addPlanter(setSecondary, *list(SECONDARY.keys()), aliases=False,
           fields=['secondary'])


# secondary
#==============================================================================

def setDummy(ag, label):

    if label == 'dummy':
        flags = zeros(len(ag), bool)
    else:
        flags = ones(len(ag), bool)
    ag._setFlags(label, flags)
    return flags

addPlanter(setDummy, 'dummy', 'mapped', aliases=False, fields=[])


#==============================================================================
# User functions
#==============================================================================

def flagDefinition(*arg, **kwarg):
    """Learn, change, or reset :ref:`flags` definitions.

    **Learn a definition**

    Calling this function with no arguments will return list of flag names
    whose definitions you can learn:

    .. ipython:: python

       flagDefinition()

    Passing a flag name will return its definition:

    .. ipython:: python

       flagDefinition('backbone')
       flagDefinition('hydrogen')

    **Change a definition**

    Calling the function with ``editable=True`` argument will return flag
    names those definitions that can be edited:

    .. ipython:: python

       flagDefinition(editable=True)

    Pass an editable flag name with its new definition:

    .. ipython:: python

       flagDefinition(nitrogen='N.*')
       flagDefinition(backbone=['CA', 'C', 'O', 'N'])
       flagDefinition(nucleobase=['ADE', 'CYT', 'GUN', 'THY', 'URA'])

    Note that the type of the new definition must be the same as the type
    of the old definition.  Flags with editable definitions are:
    {editable}

    **Reset definitions**

    Pass *reset* keyword as follows to restore all default definitions of
    editable flags and also non-standard amino acids.

    .. ipython:: python

       flagDefinition(reset='all')

    Or, pass a specific editable flag label to restore its definition:

    .. ipython:: python

       flagDefinition(reset='nitrogen')"""

    if arg and kwarg:
        raise ValueError('only a single argument or a single keyword '
                         'argument is accepted at a time')

    elif arg:
        if len(arg) > 1:
            raise ValueError('specify only one flag label')
        arg = arg[0]
        try:
            definition = DEFINITIONS[arg]
        except KeyError:
            raise ValueError('{0} is not a valid flag label'
                             .format(repr(arg)))
        else:
            try:
                return definition.pattern
            except AttributeError:
                definition = list(definition)
                definition.sort()
                return definition

    elif kwarg:
        if len(kwarg) > 1:
            raise ValueError('specify only one keyword argument')
        key, val = list(kwarg.items())[0]
        if key == 'editable' and val:
            alist = list(EDITORS)
            alist.sort()
            return alist
        if key == 'reset' and val:
            resetDefinitions(val)
            return
        try:
            editor = EDITORS[key]
        except KeyError:
            raise ValueError('{0} is not an editable flag or a valid '
                             'keyword'.format(repr(key)))
        else:
            type_ = type(flagDefinition(key))
            if type(val) != type_:
                raise TypeError('expected {0} as type of new definition, '
                                'found {1}'.format(repr(type_.__name__),
                                repr(type(val).__name__)))
            editor(key, val)
    else:
        alist = list(DEFINITIONS)
        alist.sort()
        return alist

flagDefinition.__doc__ = flagDefinition.__doc__.format(
    editable=wrapText(joinTerms(flagDefinition(editable=True), last=', and '),
                      subsequent_indent=' '*4))


def addNonstdAminoacid(resname, *properties):
    """Add non-standard amino acid *resname* with *properties* selected from:

      * {props}

    .. ipython:: python

       addNonstdAminoacid('PTR', 'acidic', 'aromatic', 'cyclic', 'large',
       'polar', 'surface')

    Default set of non-standard amino acids can be restored as follows:

    .. ipython:: python

       flagDefinition(reset='nonstdaa')"""

    resname = str(resname)
    if len(resname) > 4:
        LOGGER.warn('Residue name {0} is unusually long.'
                    .format(repr(resname)))
    propset = set(properties)
    for cat, val in CATEGORIES.items():
        intersection = val.intersection(propset)
        if intersection:
            if len(intersection) > 1:
                raise ValueError('amino acid properties {0} cannot be '
                                 'present together'
                                 .format(', '.join([repr(prp)
                                                    for prp in intersection])))
            for prop in intersection:
                propset.remove(prop)
    if propset:
        raise ValueError('amino acid property {0} is not valid'
                         .format(repr(propset.pop())))

    nonstd = SETTINGS.get(NONSTANDARD_KEY, NONSTANDARD)
    nonstd[resname] = set(properties)
    updateNonstandard(nonstd)

INDEPENDENT.sort()
addNonstdAminoacid.__doc__ = addNonstdAminoacid.__doc__.format(
    props='\n      * '.join([
        '*{0}*: {1}'.format(cat, joinTerms(terms, last=', or ', sort=True))
        for cat, terms in CATEGORIES.items()
    ])
)


def delNonstdAminoacid(resname):
    """Delete non-standard amino acid *resname*.

    .. ipython:: python

       delNonstdAminoacid('PTR')
       flagDefinition('nonstdaa')

    Default set of non-standard amino acids can be restored as follows:

    .. ipython:: python

       flagDefinition(reset='nonstdaa')"""

    nonstd = SETTINGS.get(NONSTANDARD_KEY, NONSTANDARD)
    try:
        nonstd.pop(resname)
    except KeyError:
        raise ValueError('{0} is not a non-standard residue name'
                         .format(repr(resname)))
    else:
        updateNonstandard(nonstd)


def getNonstdProperties(resname):
    """Deprecated for removal in v1.4, use :func:`listNonstdAAProps` instead.
    """

    from prody import deprecate
    deprecate('getNonstdProperties', 'listNonstdAAProps')

    return listNonstdAAProps(resname)


def listNonstdAAProps(resname):
    """Returns properties of non-standard amino acid *resname*.

    .. ipython:: python

       listNonstdAAProps('PTR')"""

    try:
        alist = list(SETTINGS.get(NONSTANDARD_KEY, NONSTANDARD)[resname])
    except KeyError:
        raise ValueError('{0} is not a non-standard residue name'
                         .format(repr(resname)))
    else:
        alist.sort()
        return alist


updateDefinitions()
