"""
Importer for DBLP release-level (article/paper/etc) XML metadata.

Works similarly to PubMed XML importer: expects to have a large XML file
iterated over quickly, with individual elements re-parsed into smaller objects
and passed to `parse_record()`.
"""

import sys  # noqa: F401
import json
import warnings
import datetime
from typing import List, Optional, Any

import fatcat_openapi_client

from fatcat_tools.normal import (clean_doi, clean_str, parse_month,
    clean_orcid,
    clean_arxiv_id, clean_wikidata_qid, clean_isbn13)
from fatcat_tools.importers.common import EntityImporter
from fatcat_tools.transforms import entity_to_dict


class DblpReleaseImporter(EntityImporter):

    def __init__(self,
                 api,
                 dblp_container_map_file=None,
                 **kwargs):

        eg_desc = kwargs.get(
            'editgroup_description',
            "Automated import of dblp metadata via XML records"
        )
        eg_extra = kwargs.get('editgroup_extra', dict())
        eg_extra['agent'] = eg_extra.get('agent',
                                         'fatcat_tools.DblpReleaseImporter')
        # ensure default is to not do updates with this worker (override super() default)
        kwargs['do_updates'] = kwargs.get("do_updates", False)
        super().__init__(api,
                         editgroup_description=eg_desc,
                         editgroup_extra=eg_extra,
                         **kwargs)

        self.dump_json_mode = kwargs.get("dump_json_mode", False)
        self.this_year = datetime.datetime.now().year
        self.read_dblp_container_map_file(dblp_container_map_file)

    ELEMENT_TYPES = [
        "article",
        "inproceedings",
        "book",
        "incollection",
        "phdthesis",
        "mastersthesis",
        "www",
        #"data",  # no instances in 2020-11 dump
    ]

    def read_dblp_container_map_file(self, dblp_container_map_file) -> None:
        self._dblp_container_map = dict()
        if not dblp_container_map_file:
            print("Not loading a dblp prefix container map file; entities will fail to import", file=sys.stderr)
            return
        print("Loading dblp prefix container map file...", file=sys.stderr)
        for line in dblp_container_map_file:
            if line.startswith("dblp_prefix") or len(line) == 0:
                continue
            (prefix, container_id) = line.split()[0:2]
            container_id = container_id.strip()
            assert len(container_id) == 26
            self._dblp_container_map[prefix] = container_id
        print("Got {} dblp container mappings.".format(len(self._dblp_container_map)), file=sys.stderr)

    def lookup_dblp_prefix(self, prefix):
        if not prefix:
            return None
        return self._dblp_container_map.get(prefix)

    def want(self, xml_elem):
        if not xml_elem.name in self.ELEMENT_TYPES:
            self.counts['skip-type'] += 1
            return False
        if not xml_elem.get('key'):
            self.counts['skip-no-key'] += 1
            return False
        if xml_elem['key'].startswith('homepage/'):
            self.counts['skip-type-homepage'] += 1
            return False
        return True

    def parse_record(self, xml_elem):
        """
        - title
            => may contain <i>, <sub>, <sup>, <tt>
        - journal (abbrev?)
        - volume, pages, number (number -> issue)
        - publisher
        - year
            => for conferences, year of conference not of publication
        - month
        - crossref (from inproceedings to specific proceedings volume)
        - booktitle
            => for inproceedings, this is the name of conference or workshop. acronym.
        - isbn
        """

        dblp_key = xml_elem.get('key')
        if not dblp_key:
            self.counts['skip-empty-key'] += 1
            return False
        dblp_key_type = dblp_key.split('/')[0]

        # dblp_prefix may be used for container lookup
        dblp_prefix = None
        if dblp_key_type in ('journals', 'conf'):
            dblp_prefix = '/'.join(dblp_key.split('/')[:2])
        elif dblp_key_type in ('series', 'reference', 'tr', 'books'):
            dblp_prefix = '/'.join(dblp_key.split('/')[:-1])

        publtype = xml_elem.get('publtype') or None

        dblp_type = xml_elem.name
        if dblp_type not in self.ELEMENT_TYPES:
            self.counts[f'skip-dblp-type:{dblp_type}'] += 1

        if dblp_key_type in ('homepages', 'persons', 'dblpnote'):
            self.counts['skip-key-type'] += 1
            return False

        if dblp_key.startswith('journals/corr/'):
            self.counts['skip-arxiv-corr'] += 1
            return False

        title = clean_str(" ".join(xml_elem.title.stripped_strings), force_xml=True)
        if not title:
            self.counts['skip-title'] += 1
            return False
        if title.endswith('.'):
            title = title[:-1]

        release_type = None
        release_stage = 'published'
        withdrawn_status = None

        # primary releae_type detection: type of XML element, then prefix of key for granularity
        if dblp_type == 'article':
            release_type = 'article'
            if dblp_key_type == 'journals' and publtype != 'informal':
                release_type = 'article-journal'
            elif dblp_key_type == 'tr':
                release_type = 'report'
            elif title.startswith("Review:"):
                release_type = 'review'
        elif dblp_type == 'inproceedings':
            release_type = 'paper-conference'
        elif dblp_type == 'book':
            release_type = 'book'
        elif dblp_type == 'incollection':
            # XXX: part vs. chapter?
            release_type = 'chapter'
        elif dblp_type == 'data':
            release_type = 'dataset'
        elif dblp_type in ('mastersthesis', 'phdthesis'):
            release_type = 'thesis'

        # overrides/extensions of the above
        if publtype == 'informal':
            # for conferences, seems to indicate peer-review status
            # for journals, seems to indicate things like book reviews; split out above
            pass
        elif publtype == 'encyclopedia':
            release_type = 'entry-encyclopedia'
        elif publtype == 'edited':
            # XXX: article?
            release_type = 'editorial'
        elif publtype == 'data':
            release_type = 'dataset'
        elif publtype == 'data':
            release_type = 'dataset'
        elif publtype == 'software':
            release_type = 'software'
        elif publtype == 'widthdrawn':
            withdrawn_status = 'widthdrawn'
        elif publtype == 'survey':
            # XXX: flag as a review/survey article?
            pass

        #print((release_type, dblp_type, dblp_key_type, publtype), file=sys.stderr)

        container_name = None
        booktitle = clean_str(xml_elem.booktitle and xml_elem.booktitle.text)
        series = clean_str(xml_elem.series and xml_elem.series.text)

        if xml_elem.journal:
            container_name = clean_str(xml_elem.journal.text)

        container_id = None
        if dblp_prefix:
            container_id = self.lookup_dblp_prefix(dblp_prefix)
            # note: we will skip later if couldn't find prefix

        publisher = clean_str(xml_elem.publisher and xml_elem.publisher.text)
        volume = clean_str(xml_elem.volume and xml_elem.volume.text)
        issue = clean_str(xml_elem.number and xml_elem.number.text)
        pages = clean_str(xml_elem.pages and xml_elem.pages.text)
        release_year = clean_str(xml_elem.year and xml_elem.year.text)
        if release_year and release_year.isdigit():
            release_year = int(release_year)
        else:
            release_year = None
        release_month = parse_month(clean_str(xml_elem.month and xml_elem.month.text))
        isbn = clean_isbn13(xml_elem.isbn and xml_elem.isbn.text)
        part_of_key = clean_str(xml_elem.crossref and xml_elem.crossref.text)

        # block bogus far-future years/dates
        if release_year is not None and (release_year > (self.this_year + 5) or release_year < 1000):
            release_month = None
            release_year = None

        contribs = self.dblp_contribs(xml_elem or [])
        ext_ids = self.dblp_ext_ids(xml_elem, dblp_key)
        if isbn:
            ext_ids.isbn13 = isbn
        if ext_ids.doi:
            self.counts['has-doi'] += 1

        # dblp-specific extra
        dblp_extra = dict(type=dblp_type)
        note = clean_str(xml_elem.note and xml_elem.note.text)
        if note and not 'base-search.net' in note:
            dblp_extra['note'] = note
        if part_of_key:
            dblp_extra['part_of_key'] = part_of_key

        # generic extra
        extra = dict()
        if not container_id and container_name:
            extra['container_name'] = container_name

        if series and (dblp_key_type == 'series' or dblp_type == 'book'):
            extra['series-title'] = series
        elif series:
            dblp_extra['series'] = series

        if booktitle and dblp_key_type == 'series':
            extra['container-title'] = booktitle
        elif booktitle and dblp_key_type == 'conf':
            extra['event'] = booktitle
        elif booktitle:
            dblp_extra['booktitle'] = booktitle

        if release_year and release_month:
            # TODO: release_month schema migration
            extra['release_month'] = release_month

        if dblp_extra:
            extra['dblp'] = dblp_extra
        if not extra:
            extra = None

        re = fatcat_openapi_client.ReleaseEntity(
            work_id=None,
            container_id=container_id,
            release_type=release_type,
            release_stage=release_stage,
            withdrawn_status=withdrawn_status,
            title=title,
            release_year=release_year,
            #release_date,
            publisher=publisher,
            ext_ids=ext_ids,
            contribs=contribs,
            volume=volume,
            issue=issue,
            pages=pages,
            extra=extra,
        )
        re = self.biblio_hacks(re)

        if self.dump_json_mode:
            re_dict = entity_to_dict(re, api_client=self.api.api_client)
            re_dict['_dblp_ee_urls'] = self.dblp_ext_urls(xml_elem)
            re_dict['_dblp_prefix'] = dblp_prefix
            print(json.dumps(re_dict, sort_keys=True))
            return False

        if not re.container_id:
            self.counts["skip-dblp-container-missing"] += 1
            return False
        return re

    @staticmethod
    def biblio_hacks(re):
        """
        This function handles known special cases. For example,
        publisher-specific or platform-specific workarounds.
        """
        return re

    def try_update(self, re):

        # lookup existing release by dblp article id
        existing = None
        try:
            existing = self.api.lookup_release(dblp=re.ext_ids.dblp)
        except fatcat_openapi_client.rest.ApiException as err:
            if err.status != 404:
                raise err

        # then try other ext_id lookups
        if not existing:
            for extid_type in ('doi', 'wikidata_qid', 'isbn13', 'arxiv'):
                extid_val = getattr(re.ext_ids, extid_type)
                if not extid_val:
                    continue
                #print(f"  lookup release type: {extid_type} val: {extid_val}")
                try:
                    existing = self.api.lookup_release(**{extid_type: extid_val})
                except fatcat_openapi_client.rest.ApiException as err:
                    if err.status != 404:
                        raise err
                if existing:
                    if existing.ext_ids.dblp:
                        warn_str = f"unexpected dblp ext_id match after lookup failed dblp={re.ext_ids.dblp} ident={existing.ident}"
                        warnings.warn(warn_str)
                        self.counts["skip-dblp-id-mismatch"] += 1
                        return False
                    break

        # TODO: in the future could do fuzzy match here, eg using elasticsearch

        # create entity
        if not existing:
            return True

        # other logic could go here about skipping updates
        if not self.do_updates or existing.ext_ids.dblp:
            self.counts['exists'] += 1
            return False

        # fields to copy over for update
        # TODO: granular contrib metadata
        existing.contribs = existing.contribs or re.contribs
        existing.ext_ids.dblp = existing.ext_ids.dblp or re.ext_ids.dblp
        existing.ext_ids.wikidata_qid = existing.ext_ids.wikidata_qid or re.ext_ids.wikidata_qid
        existing.release_type = existing.release_type or re.release_type
        existing.release_stage = existing.release_stage or re.release_stage
        existing.withdrawn_status = existing.withdrawn_status or re.withdrawn_status
        existing.container_id = existing.container_id or re.container_id
        existing.extra['dblp'] = re.extra['dblp']
        existing.volume = existing.volume or re.volume
        existing.issue = existing.issue or re.issue
        existing.pages = existing.pages or re.pages

        try:
            self.api.update_release(self.get_editgroup_id(), existing.ident, existing)
            self.counts['update'] += 1
        except fatcat_openapi_client.rest.ApiException as err:
            # there is a code path where we try to update the same release
            # twice in a row; if that happens, just skip
            # NOTE: API behavior might change in the future?
            if "release_edit_editgroup_id_ident_id_key" in err.body:
                self.counts['skip-update-conflict'] += 1
                return False
            else:
                raise err

        return False

    def insert_batch(self, batch):
        self.api.create_release_auto_batch(fatcat_openapi_client.ReleaseAutoBatch(
            editgroup=fatcat_openapi_client.Editgroup(
                description=self.editgroup_description,
                extra=self.editgroup_extra),
            entity_list=batch))

    def dblp_contribs(self, authors: List[dict]) -> List[fatcat_openapi_client.ReleaseContrib]:
        """
        - author (multiple; each a single string)
            => may have HTML entities
            => may have a number at the end, to aid with identifier creation
            => orcid
        - editor (same as author)
            => orcid
        """
        contribs = []
        index = 0
        for elem in authors.find_all('author'):
            contrib = self.dblp_contrib_single(elem)
            contrib.role = "author"
            contrib.index = index
            contribs.append(contrib)
            index += 1

        for elem in authors.find_all('editor'):
            contrib = self.dblp_contrib_single(elem)
            contrib.role = "editor"
            contribs.append(contrib)

        return contribs

    def dblp_contrib_single(self, elem: Any) -> fatcat_openapi_client.ReleaseContrib:
        """
        In the future, might try to implement creator key-ificiation and lookup here.

        Example rows:

            <author>Michael H. B&ouml;hlen</author>
            <author orcid="0000-0002-4354-9138">Nicolas Heist</author>
            <author orcid="0000-0001-9108-4278">Jens Lehmann 0001</author>
        """

        creator_id = None
        extra = None
        raw_name = clean_str(elem.text)

        # remove number in author name, if present
        if raw_name.split()[-1].isdigit():
            raw_name = ' '.join(raw_name.split()[:-1])

        if elem.get('orcid'):
            orcid = clean_orcid(elem['orcid'])
            if orcid:
                creator_id = self.lookup_orcid(orcid)
                if not creator_id:
                    extra = dict(orcid=orcid)
        return fatcat_openapi_client.ReleaseContrib(
            raw_name=raw_name,
            creator_id=creator_id,
            extra=extra,
        )

    def dblp_ext_ids(self, xml_elem: Any, dblp_key: str) -> fatcat_openapi_client.ReleaseExtIds:
        """
        Takes a full XML object and returns external identifiers.

        Currently these can be arixv identifiers, DOI, or wikidata QID

        - ee (electronic edition; often DOI?)
            => in some cases a "local" URL
            => publisher URL; often DOI
            => type attr
        - url
            => dblp internal link to table-of-contents
        """

        doi: Optional[str] = None
        wikidata_qid: Optional[str] = None
        arxiv_id: Optional[str] = None
        for ee in xml_elem.find_all('ee'):
            url = ee.text
            # convert DOI-like domains, which mostly have DOIs anyways
            if '://doi.acm.org/' in url:
                url = url.replace('://doi.acm.org/', '://doi.org/')
            elif '://doi.ieeecomputersociety.org/' in url:
                url = url.replace('://doi.ieeecomputersociety.org/', '://doi.org/')

            if 'doi.org/10.' in url and not doi:
                doi = clean_doi(url)
            elif 'wikidata.org/entity/Q' in url and not wikidata_qid:
                wikidata_qid = clean_wikidata_qid(url)
            elif '://arxiv.org/abs/' in url and not wikidata_qid:
                arxiv_id = url.replace('http://', '').replace('https://', '').replace('arxiv.org/abs/', '')
                arxiv_id = clean_arxiv_id(arxiv_id)
                wikidata_qid = clean_wikidata_qid(url)

        return fatcat_openapi_client.ReleaseExtIds(
            dblp=dblp_key,
            doi=doi,
            wikidata_qid=wikidata_qid,
            arxiv=arxiv_id,
        )

    def dblp_ext_urls(self, xml_elem: Any) -> List[str]:
        """
        Takes a full XML object and returns a list of possible-fulltext URLs.

        Used only in JSON dump mode, with the intent of transforming into
        sandcrawler ingest requests.
        """
        EXTID_PATTERNS = [
            '://doi.acm.org/',
            '://doi.ieeecomputersociety.org/',
            'doi.org/10.',
            'wikidata.org/entity/Q',
            '://arxiv.org/abs/',
        ]
        urls = []
        for ee in xml_elem.find_all('ee'):
            url = ee.text
            skip = False
            for pattern in EXTID_PATTERNS:
                if pattern in url:
                    skip = True
                    break
            if skip:
                break
            urls.append(url)
        return urls