"""
OAI-PMH protocol:
    https://sickle.readthedocs.io/en/latest/

Pubmed
    https://www.ncbi.nlm.nih.gov/pmc/tools/oai/
    https://www.ncbi.nlm.nih.gov/pmc/oai/oai.cgi?verb=GetRecord&identifier=oai:pubmedcentral.nih.gov:152494&metadataPrefix=pmc_fm
    https://github.com/titipata/pubmed_parser

arxiv
    some APIs work on a per-version basis, others do not

    http://export.arxiv.org/oai2?verb=GetRecord&identifier=oai:arXiv.org:0804.2273&metadataPrefix=arXiv
    http://export.arxiv.org/oai2?verb=GetRecord&identifier=oai:arXiv.org:0804.2273&metadataPrefix=arXivRaw

doaj
    https://github.com/miku/doajfetch

-----

actually, just going to re-use https://github.com/miku/metha for OAI-PMH stuff
    => shell script from cronjob
    => call metha-sync daily
    => metha-cat -since <whenever> | kafkacat output
    => echo "date" | kafkat state
    => some shell trick (comm?) to find missing dates; for each, do metha-cat into kafka

or, just skip kafka for this stuff for now? hrm.

crossref-like stuff is far enough along to keep

## More Miku Magic!

wowa, JSTOR KBART files!
    http://www.jstor.org/kbart/collections/all-archive-titles

https://github.com/miku/ldjtab: faster than jq for just grabbing 

sort can be told how much memory to use; eg: `sort -S50%`, and threads to use

"""

import re
import sys
import csv
import json
import time
import requests
import itertools
import datetime
from pykafka import KafkaClient
import sickle

from fatcat_tools.workers import most_recent_message
from .harvest_common import HarvestState, DATE_FMT


class HarvestOaiPmhWorker:
    """
    Base class for OAI-PMH harvesters.

    Based on Crossref importer
    """


    def __init__(self, kafka_hosts, produce_topic, state_topic,
            start_date=None, end_date=None):

        self.produce_topic = produce_topic
        self.state_topic = state_topic
        self.kafka = KafkaClient(hosts=kafka_hosts, broker_version="1.0.0")

        self.loop_sleep = 60*60 # how long to wait, in seconds, between date checks

        self.endpoint_url = None # needs override
        self.metadata_prefix = None  # needs override
        self.state = HarvestState(start_date, end_date)
        self.state.initialize_from_kafka(self.kafka.topics[self.state_topic])


    def fetch_date(self, date):

        api = sickle.Sickle(self.endpoint_url)
        date_str = date.strftime(DATE_FMT)
        produce_topic = self.kafka.topics[self.produce_topic]
        # this dict kwargs hack is to work around 'from' as a reserved python keyword
        # recommended by sickle docs
        records = api.ListRecords(**{
            'metadataPrefix': self.metadata_prefix,
            'from': date_str,
            'until': date_str,
        })

        count = 0
        with produce_topic.get_producer() as producer:
            for item in records:
                count += 1
                if count % 50 == 0:
                    print("... up to {}".format(count))
                producer.produce(item.raw.encode('utf-8'), partition_key=item.header.identifier.encode('utf-8'))

    def run(self, continuous=False):

        while True:
            current = self.state.next(continuous)
            if current:
                print("Fetching DOIs updated on {} (UTC)".format(current))
                self.fetch_date(current)
                self.state.complete(current, kafka_topic=self.kafka.topics[self.state_topic])
                continue

            if continuous:
                print("Sleeping {} seconds...".format(self.loop_sleep))
                time.sleep(self.loop_sleep())
            else:
                break
        print("{} DOI ingest caught up".format(self.name))


class HarvestArxivWorker(HarvestOaiPmhWorker):

    def __init__(self, **kwargs):
        super().__init__(**kwargs) 
        self.endpoint_url = "https://export.arxiv.org/oai2"
        self.metadata_prefix = "arXiv"


class HarvestPubmedWorker(HarvestOaiPmhWorker):

    def __init__(self, **kwargs):
        super().__init__(**kwargs) 
        self.endpoint_url = "https://www.ncbi.nlm.nih.gov/pmc/oai/oai.cgi"
        self.metadata_prefix = "pmc_fm"


class HarvestDoajJournalWorker(HarvestOaiPmhWorker):
    """
    WARNING: DOAJ OAI-PMH doesn't seem to respect 'from' and 'until' params
    """

    def __init__(self, **kwargs):
        super().__init__(**kwargs) 
        self.endpoint_url = "https://www.doaj.org/oai"
        self.metadata_prefix = "oai_dc"


class HarvestDoajArticleWorker(HarvestOaiPmhWorker):
    """
    WARNING: DOAJ OAI-PMH doesn't seem to respect 'from' and 'until' params
    """

    def __init__(self, **kwargs):
        super().__init__(**kwargs) 
        self.endpoint_url = "https://www.doaj.org/oai.article"
        self.metadata_prefix = "oai_doaj"