# Copyright 2001 by Tarjei Mikkelsen.  All rights reserved.
# Copyright 2007 by Michiel de Hoon.  All rights reserved.
# This code is part of the Biopython distribution and governed by its
# license.  Please see the LICENSE file that should have been included
# as part of this package.

"""Code to work with the KEGG Ligand/Compound database.

Functions:
 - parse - Returns an iterator giving Record objects.

Classes:
 - Record - A representation of a KEGG Ligand/Compound.
"""

# other Biopython stuff
from __future__ import print_function

from Bio.KEGG import _write_kegg
from Bio.KEGG import _wrap_kegg


# Set up line wrapping rules (see Bio.KEGG._wrap_kegg)
name_wrap = [0, "",
             (" ", "$", 1, 1),
             ("-", "$", 1, 1)]
id_wrap = lambda indent: [indent, "", (" ", "", 1, 0)]
struct_wrap = lambda indent: [indent, "", ("  ", "", 1, 1)]


class Record(object):
    """Holds info from a KEGG Ligand/Compound record.

    Attributes:
     - entry       The entry identifier.
     - name        A list of the compund names.
     - formula     The chemical formula for the compound
     - mass        The molecular weight for the compound
     - pathway     A list of 3-tuples: ('PATH', pathway id, pathway)
     - enzyme      A list of the EC numbers.
     - structures  A list of 2-tuples: (database, list of struct ids)
     - dblinks     A list of 2-tuples: (database, list of link ids)

    """

    def __init__(self):
        """Initialize as new record."""
        self.entry = ""
        self.name = []
        self.formula = ""
        self.mass = ""
        self.pathway = []
        self.enzyme = []
        self.structures = []
        self.dblinks = []

    def __str__(self):
        """Return a string representation of this Record."""
        return (self._entry() +
                self._name() +
                self._formula() +
                self._mass() +
                self._pathway() +
                self._enzyme() +
                self._structures() +
                self._dblinks() +
                "///")

    def _entry(self):
        return _write_kegg("ENTRY",
                           [self.entry])

    def _name(self):
        return _write_kegg("NAME",
                           [_wrap_kegg(l, wrap_rule=name_wrap)
                            for l in self.name])

    def _formula(self):
        return _write_kegg("FORMULA",
                           [self.formula])

    def _mass(self):
        return _write_kegg("MASS",
                           [self.mass])

    def _pathway(self):
        s = []
        for entry in self.pathway:
            s.append(entry[0] + "  " + entry[1])
        return _write_kegg("PATHWAY",
                           [_wrap_kegg(l, wrap_rule=id_wrap(16))
                            for l in s])

    def _enzyme(self):
        return _write_kegg("ENZYME",
                           [_wrap_kegg(l, wrap_rule=name_wrap)
                            for l in self.enzyme])

    def _structures(self):
        s = []
        for entry in self.structures:
            s.append(entry[0] + ": " + "  ".join(entry[1]) + "  ")
        return _write_kegg("STRUCTURES",
                           [_wrap_kegg(l, wrap_rule=struct_wrap(5))
                            for l in s])

    def _dblinks(self):
        s = []
        for entry in self.dblinks:
            s.append(entry[0] + ": " + " ".join(entry[1]))
        return _write_kegg("DBLINKS",
                           [_wrap_kegg(l, wrap_rule=id_wrap(9))
                            for l in s])


def parse(handle):
    """Parse a KEGG Ligan/Compound file, returning Record objects.

    This is an iterator function, typically used in a for loop.  For
    example, using one of the example KEGG files in the Biopython
    test suite,

    >>> with open("KEGG/compound.sample") as handle:
    ...     for record in parse(handle):
    ...         print("%s %s" % (record.entry, record.name[0]))
    ...
    C00023 Iron
    C00017 Protein
    C00099 beta-Alanine
    C00294 Inosine
    C00298 Trypsin
    C00348 all-trans-Undecaprenyl phosphate
    C00349 2-Methyl-3-oxopropanoate
    C01386 NH2Mec

    """
    record = Record()
    for line in handle:
        if line[:3] == "///":
            yield record
            record = Record()
            continue
        if line[:12] != "            ":
            keyword = line[:12]
        data = line[12:].strip()
        if keyword == "ENTRY       ":
            words = data.split()
            record.entry = words[0]
        elif keyword == "NAME        ":
            data = data.strip(";")
            record.name.append(data)
        elif keyword == "ENZYME      ":
            while data:
                column = data[:16]
                data = data[16:]
                enzyme = column.strip()
                record.enzyme.append(enzyme)
        elif keyword == "PATHWAY     ":
            map, name = data.split("  ")
            pathway = ('PATH', map, name)
            record.pathway.append(pathway)
        elif keyword == "FORMULA     ":
            record.formula = data
        elif keyword == "MASS        ":
            record.mass = data
        elif keyword == "DBLINKS     ":
            if ":" in data:
                key, values = data.split(":")
                values = values.split()
                row = (key, values)
                record.dblinks.append(row)
            else:
                row = record.dblinks[-1]
                key, values = row
                values.extend(data.split())
                row = key, values
                record.dblinks[-1] = row


if __name__ == "__main__":
    from Bio._utils import run_doctest
    run_doctest()
