"""
Helper functions to parse an unstructured citation string using GROBID, then
fuzzy match using the result.

- try to parse string with GROBID REST API call
- transform the GROBID XML response to a simple dict/struct

TODO: more general versions which handle multiple reference strings in a batch?
"""

import io
import sys
import xml.etree.ElementTree as ET
from typing import Optional

import requests
from fatcat_openapi_client import ReleaseContrib, ReleaseEntity, ReleaseExtIds
from grobid_tei_xml import GrobidBiblio, parse_citation_xml

from fuzzycat.config import settings
from fuzzycat.utils import clean_doi

GROBID_API_BASE = settings.get("GROBID_API_BASE", "https://grobid.qa.fatcat.wiki")


def grobid_api_process_citation(raw_citation: str,
                                grobid_api_base: str = GROBID_API_BASE,
                                timeout: float = 20.0) -> Optional[str]:
    """
    Process a single citation string using GROBID API, returning a TEI-XML response.

    Raises python TimeoutError if there was a network or request timeout.

    Raises a 'requests' error other unexpected failures (including network
    connection failures)
    """
    try:
        grobid_response = requests.post(
            grobid_api_base + "/api/processCitation",
            data={
                "citations": raw_citation,
                "consolidateCitations": 0,
            },
            timeout=timeout,
        )
    except requests.Timeout:
        raise TimeoutError("GROBID request (HTTP POST) timeout")

    if grobid_response.status_code == 204:
        return None
    elif grobid_response.status_code != 200:
        print(f"GROBID request (HTTP POST) failed: {grobid_response}", file=sys.stderr)
    grobid_response.raise_for_status()

    return grobid_response.text or None


def grobid_ref_to_release(ref: GrobidBiblio) -> ReleaseEntity:
    """
    Takes GrobidBiblio (parsed from TEI-XML) and returns a partial
    ReleaseEntity object (for use with fuzzycat)
    """
    contribs = []
    for author in ref.authors or []:
        contribs.append(
            ReleaseContrib(
                raw_name=author.full_name,
                given_name=author.given_name,
                surname=author.surname,
            ))
    release = ReleaseEntity(
        title=ref.title,
        contribs=contribs,
        volume=ref.volume,
        issue=ref.issue,
        pages=ref.pages,
        ext_ids=ReleaseExtIds(
            doi=clean_doi(ref.doi),
            pmid=ref.pmid,
            pmcid=ref.pmcid,
            arxiv=ref.arxiv_id,
        ),
    )
    if ref.journal:
        release.extra = {"container_name": ref.journal}
    if ref.date:
        if len(ref.date) >= 4 and ref.date[0:4].isdigit():
            release.release_year = int(ref.date[0:4])
        # TODO: try to parse 'date' into an ISO date format, and assign to release_date?
    return release


def grobid_parse_unstructured(raw_citation: str,
                              grobid_api_base: str = GROBID_API_BASE,
                              timeout: float = 20.0) -> Optional[ReleaseEntity]:
    """
    High-level wrapper to parse a raw citation string into a (partial) release
    entity.
    
    Returns None if it fails to parse.

    Raises various exceptions on network or remote errors.
    """
    ref_xml = grobid_api_process_citation(raw_citation,
                                          grobid_api_base=grobid_api_base,
                                          timeout=timeout)
    if not ref_xml:
        return None
    ref = parse_citation_xml(ref_xml)
    if not ref:
        return None
    return grobid_ref_to_release(ref)