# Copyright 1999 by Jeffrey Chang.  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.

"""
This module provides code to work with Medline.

Classes:
Record           Holds Medline data.
Iterator         Iterates over a file containing Medline records.
RecordParser     Parses a Medline record into a Record object.

_Scanner         Scans a Medline record.
_RecordConsumer  Consumes Medline data to a Record object.

"""
from types import *

from Bio import File
from Bio.ParserSupport import *

class Record:
    """Holds information from a Medline record.

    Members:
    id                     Medline ID.
    pubmed_id              Pubmed ID.

    mesh_headings          List of MeSH headings.
    mesh_tree_numbers      List of MeSH Tree Numbers.
    mesh_subheadings       List of MeSH subheadings.

    abstract               The abstract.
    comments               List of references to comments.
    abstract_author        The author of the abstract.
    english_abstract       "A" if a foreign article has an english abstract.
    
    source                 Bibliographic information.
    publication_types      List of type of publication.
    number_of_references   Number of bibliographic references, for REVIEW pubs.

    authors                List of authors.
    no_author              "A" for anonymous.
    address                Address of the first author.

    journal_title_code     Three-character code assigned to the journal.
    title_abbreviation     Abbreviation of journal title.
    issn                   International Standard Serial Number.
    journal_subsets        List of strings that describe journal groupings.
    country                Country of publication
    languages              List of languages of the article.
    
    title                  Article title.
    transliterated_title   Title in the original language.
    call_number            The call number of the journal issue.
    issue_part_supplement  Issue, part, or supplement of journal published.
    volume_issue           Volume number of journal.
    publication_date       Date published (string).
    year                   Year published (string).
    pagination             Inclusive pages of an indexed item.
    
    special_list           Coding for the database of the citation.

    substance_name         Preferred name for a chemical or drug.
    gene_symbols           List of abbreviated gene names.
    secondary_source_ids   List of source databanks and accessions.
    identifications        List of research grant or contract numbers.
    registry_numbers       List of CAS or EC numbers.
    
    personal_name_as_subjects  List of individuals who are subjects.
    
    record_originators     List of people who worked on record.
    entry_date             Date record made machine readable (YYMMDD).
    entry_month            YYMM entered into Medline.
    class_update_date      Date touched by Class Maintenance action (string).
    last_revision_date     Date for minor revision.
    major_revision_date    Date for major revision.

    undefined              List of lines that don't match the standard.
    
    """
    def __init__(self):
        self.id = ''
        self.pubmed_id = ''
        
        self.mesh_headings = []
        self.mesh_tree_numbers = []
        self.mesh_subheadings = []
        
        self.abstract = ''
        self.comments = []
        self.abstract_author = ''
        self.english_abstract = ''
        
        self.source = ''
        self.publication_types = []
        self.number_of_references = ''
        
        self.authors = []
        self.no_author = ''
        self.address = ''
        
        self.journal_title_code = ''
        self.title_abbreviation = ''
        self.issn = ''
        self.journal_subsets = []
        self.country = ''
        self.languages = []
        
        self.title = ''
        self.transliterated_title = ''
        self.call_number = ''
        self.issue_part_supplement = ''
        self.volume_issue = ''
        self.publication_date = ''
        self.year = ''
        self.pagination = ''
        
        self.special_list = ''
        
        self.substance_name = ''
        self.gene_symbols = []
        self.secondary_source_ids = []
        self.identifications = []
        self.registry_numbers = []
        
        self.personal_name_as_subjects = []

        self.record_originators = []
        self.entry_date = ''
        self.entry_month = ''
        self.class_update_date = ''
        self.last_revision_date = ''
        self.major_revision_date = ''

        self.undefined = []
        
class Iterator:
    """Returns one record at a time from a file of Medline records.

    Methods:
    next   Return the next record from the stream, or None.

    """
    def __init__(self, handle, parser=None):
        """__init__(self, handle, parser=None)

        Create a new iterator.  handle is a file-like object.  parser
        is an optional Parser object to change the results into another form.
        If set to None, then the raw contents of the file will be returned.

        """
        if type(handle) is not FileType and type(handle) is not InstanceType:
            raise ValueError, "I expected a file handle or file-like object"
        self._uhandle = File.UndoHandle(handle)
        self._parser = parser

    def __iter__(self):
        return self

    def next(self):
        """next(self) -> object

        Return the next medline record from the file.  If no more records,
        return None.

        """
        lines = []
        while 1:
            line = self._uhandle.readline()
            if not line:
                break
            lines.append(line)
            if string.rstrip(line) == '':
                break
        while 1:  # read remaining blank lines
            line = self._uhandle.readline()
            if not line:
                break
            if string.rstrip(line) != '':
                self._uhandle.saveline(line)
                break
            lines.append(line)
            
        if not lines:
            raise StopIteration
            
        data = string.join(lines, '')
        if self._parser is not None:
            return self._parser.parse_str(data)
        return data

class RecordParser(AbstractParser):
    """Parses Medline data into a Record object.

    """
    def __init__(self):
        self._scanner = _Scanner()
        self._consumer = _RecordConsumer()

    def parse(self, handle):
        self._scanner.feed(handle, self._consumer)
        return self._consumer.data

class _Scanner:
    """Scans a Medline record.
    
    """
    # map the category qualifier to an event
    _categories = {
        "AA" : "abstract_author",
        "AB" : "abstract",
        "AD" : "address",
        "AU" : "author",
        "CA" : "call_number",
        "CM" : "comments",
        "CU" : "class_update_date",
        "CY" : "country",
        "DA" : "entry_date",
        "DP" : "publication_date",
        "EA" : "english_abstract",
        "EM" : "entry_month",
        "GS" : "gene_symbol",
        "ID" : "identification",
        "IP" : "issue_part_supplement",
        "IS" : "issn",
        "JC" : "journal_title_code",
        "LA" : "language",
        "LI" : "special_list",
        "LR" : "last_revision_date",
        "MH" : "mesh_heading",
        "MN" : "mesh_tree_number",
        "MR" : "major_revision_date",
        "NI" : "no_author",
        "NM" : "substance_name",
        "PG" : "pagination",
        "PS" : "personal_name_as_subject",
        "PT" : "publication_type",
        "RF" : "number_of_references",
        "RN" : "cas_registry_number",
        "RO" : "record_originator",
        "SB" : "journal_subset",
        "SH" : "subheadings",
        "SI" : "secondary_source_id",
        "SO" : "source",
        "TA" : "title_abbreviation",
        "TI" : "title",
        "TT" : "transliterated_title",
        "UI" : "unique_identifier",
        "VI" : "volume_issue",
        "YR" : "year",

        # Not documented.
        "PMID" : "pubmed_id",
        }

    def feed(self, handle, consumer):
        """feed(self, handle, consumer)

        Feed in a Medline unit record for scanning.  handle is a file-like
        object that contains a Medline record.  consumer is a
        Consumer object that will receive events as the report is scanned.

        """
        if isinstance(handle, File.UndoHandle):
            uhandle = handle
        else:
            uhandle = File.UndoHandle(handle)

        # Read the Entrez header information, if it exists
        if attempt_read_and_call(uhandle, consumer.noevent, start='Entrez'):
            read_and_call(uhandle, consumer.noevent, start='----------------')
        self._scan_record(uhandle, consumer)

    def _scan_record(self, uhandle, consumer):
        consumer.start_record()

        prev_qualifier = None
        while 1:
            line = uhandle.readline()
            if is_blank_line(line):
                break

            # There are 2 possible formats for a line:
            # TI  - Epidemiology of mycobacterial resistance (especially Mycoba
            #       tuberculosis).
            # 1) qualifier + '-' + data
            # 2) continuation, with just data

            # Check to see if it's a continuation line.
            qualifier = string.rstrip(line[:4])
            # There's a bug in some MH lines where the "isolation &
            # purification" subheading gets split across lines and
            # purification at the beginning of the line, with only 1
            # space.
            if line[0] == '\t' or qualifier == '' or \
               line[:13] == ' purification':
                if prev_qualifier is None:
                    raise ValueError, "Continuation on first line\n%s" % line
                qualifier = prev_qualifier
            else:
                # Make sure it contains a '-'
                if len(line) < 5 or line[4] != '-':
                    raise ValueError, \
                          "I don't understand the format of line %s" % line
            prev_qualifier = qualifier
            
            try:
                fn = getattr(consumer, self._categories[qualifier])
            except KeyError:
                # call an 'undefined' function for 
                consumer.undefined(line)
            else:
                fn(line)
        
        consumer.end_record()

class _RecordConsumer(AbstractConsumer):
    """Consumer that converts a Medline record to a Record object.

    Members:
    data    Record with Medline data.

    """
    def __init__(self):
        self.data = None

    def start_record(self):
        self.data = Record()

    def end_record(self):
        self._clean_record(self.data)

    def abstract_author(self, line):
        self.data.abstract_author = self._clean(line)
    
    def abstract(self, line):
        self.data.abstract = self.data.abstract + self._clean(line, rstrip=0)
    
    def address(self, line):
        self.data.address = self.data.address + self._clean(line, rstrip=0)
    
    def author(self, line):
        self.data.authors.append(self._clean(line))
    
    def call_number(self, line):
        assert not self.data.call_number, "call numbers already defined"
        self.data.call_number = self._clean(line)
    
    def comments(self, line):
        self.data.comments.append(self._clean(line))
    
    def class_update_date(self, line):
        assert not self.data.class_update_date, \
               "class update date already defined"
        self.data.class_update_date = self._clean(line)
    
    def country(self, line):
        assert not self.data.country, "country already defined"
        self.data.country = self._clean(line)
    
    def entry_date(self, line):
        assert not self.data.entry_date, "entry date already defined"
        self.data.entry_date = self._clean(line)
    
    def publication_date(self, line):
        assert not self.data.publication_date, \
               "publication date already defined"
        self.data.publication_date = self._clean(line)
    
    def english_abstract(self, line):
        assert not self.data.english_abstract, \
               "english abstract already defined"
        self.data.english_abstract = self._clean(line)
    
    def entry_month(self, line):
        assert not self.data.entry_month, \
               "entry month already defined"
        self.data.entry_month = self._clean(line)
    
    def gene_symbol(self, line):
        self.data.gene_symbols.append(self._clean(line))
    
    def identification(self, line):
        self.data.identifications.append(self._clean(line))
    
    def issue_part_supplement(self, line):
        assert not self.data.issue_part_supplement, \
               "issue/part/supplement already defined"
        self.data.issue_part_supplement = self._clean(line)
    
    def issn(self, line):
        assert not self.data.issn, "ISSN already defined"
        self.data.issn = self._clean(line)
    
    def journal_title_code(self, line):
        assert not self.data.journal_title_code, \
               "journal title code already defined"
        self.data.journal_title_code = self._clean(line)
    
    def language(self, line):
        self.data.languages.append(self._clean(line))
    
    def special_list(self, line):
        assert not self.data.special_list, "special list already defined"
        self.data.special_list = self._clean(line)
    
    def last_revision_date(self, line):
        assert not self.data.last_revision_date, \
               "last revision date already defined"
        self.data.last_revision_date = self._clean(line)
    
    def mesh_heading(self, line):
        # Check to see whether this is a new MH line, or a
        # continuation of an old one.  If it's a continuation of an
        # old one, append it to the previous line.
        # See PMID 12107064 for an example, found by Dan Rubin.
        if line[:2] == 'MH':
            self.data.mesh_headings.append(self._clean(line))
        else:
            prev_mh = self.data.mesh_headings.pop()
            continued_mh = self._clean(line)
            self.data.mesh_headings.append("%s %s" % (prev_mh, continued_mh))
    
    def mesh_tree_number(self, line):
        self.data.mesh_tree_numbers.append(self._clean(line))
    
    def major_revision_date(self, line):
        assert not self.data.major_revision_date, \
               "major revision date already defined"
        self.data.major_revision_date = self._clean(line)
    
    def no_author(self, line):
        assert not self.data.no_author, "no author already defined"
        self.data.no_author = self._clean(line)
    
    def substance_name(self, line):
        assert not self.data.substance_name, "substance name already defined"
        self.data.substance_name = self._clean(line)
    
    def pagination(self, line):
        assert not self.data.pagination, "pagination already defined"
        self.data.pagination = self._clean(line)
    
    def personal_name_as_subject(self, line):
        self.data.personal_name_as_subjects.append(self._clean(line))
    
    def publication_type(self, line):
        self.data.publication_types.append(self._clean(line))
    
    def number_of_references(self, line):
        assert not self.data.number_of_references, \
               "num of references already defined"
        self.data.number_of_references = self._clean(line)
    
    def cas_registry_number(self, line):
        self.data.registry_numbers.append(self._clean(line))
    
    def record_originator(self, line):
        self.data.record_originators.append(self._clean(line))
    
    def journal_subset(self, line):
        self.data.journal_subsets.append(self._clean(line))
    
    def subheadings(self, line):
        self.data.mesh_subheadings.append(self._clean(line))
    
    def secondary_source_id(self, line):
        self.data.secondary_source_ids.append(self._clean(line))
    
    def source(self, line):
        self.data.source = self.data.source + self._clean(line, rstrip=0)
    
    def title_abbreviation(self, line):
        self.data.title_abbreviation = self.data.title_abbreviation + \
                                       self._clean(line, rstrip=0)
    
    def title(self, line):
        self.data.title = self.data.title + self._clean(line, rstrip=0)
    
    def transliterated_title(self, line):
        self.data.transliterated_title = self.data.transliterated_title + \
                                         self._clean(line, rstrip=0)
    
    def unique_identifier(self, line):
        assert not self.data.id, "id already defined"
        self.data.id = self._clean(line)
    
    def volume_issue(self, line):
        assert not self.data.volume_issue, "volume issue already defined"
        self.data.volume_issue = self._clean(line)
    
    def year(self, line):
        assert not self.data.year, "year already defined"
        self.data.year = self._clean(line)
    
    def pubmed_id(self, line):
        assert not self.data.pubmed_id, "PMID already defined"
        self.data.pubmed_id = self._clean(line)

    def undefined(self, line):
        # Records sometimes contain lines with qualifiers that don't match
        # any in the standard.  All these lines go into another variable.
        # Some undefined qualifiers:
        # 4098, 4099, 4100, 4101
        # 634
        # NP, PID, EDAT, MHDA
        
        self.data.undefined.append(line)

    def _clean(self, line, rstrip=1):
        tab = string.find(line, '\t')
        if tab >= 0:
            nospace = line[tab+1:]
        elif line[:13] == ' purification':
            nospace = line[1:]
        else:
            nospace = line[6:]
        if rstrip:
            return string.rstrip(nospace)
        return nospace

    _needs_stripping = [
        'abstract', 'source', 'address', 'title_abbreviation',
        'title', 'transliterated_title'
        ]
    def _clean_record(self, rec):
        # Remove trailing newlines
        for m in self._needs_stripping:
            value = getattr(rec, m)
            setattr(rec, m, string.rstrip(value))

