# SPDX-License-Identifier: AGPL-3.0-or-later
"""CORE_ (COnnecting REpositories) provides a comprehensive bibliographic
database of the world’s scholarly literature, collecting and indexing
research from repositories and journals.

.. _CORE: https://core.ac.uk/about

.. note::

   The CORE engine requires an :py:obj:`API key <api_key>`.

.. _core engine config:

Configuration
=============

The engine has the following additional settings:

- :py:obj:`api_key`

.. code:: yaml

  - name: core.ac.uk
    api_key: "..."
    inactive: false

Implementations
===============

"""

import typing as t

from datetime import datetime
from urllib.parse import urlencode

from searx.result_types import EngineResults

if t.TYPE_CHECKING:
    from searx.extended_types import SXNG_Response
    from searx.search.processors import OnlineParams


about = {
    "website": "https://core.ac.uk",
    "wikidata_id": "Q22661180",
    "official_api_documentation": "https://api.core.ac.uk/docs/v3",
    "use_official_api": True,
    "require_api_key": True,
    "results": "JSON",
}

api_key = ""
"""For an API key register at https://core.ac.uk/services/api and insert
the API key in the engine :ref:`core engine config`."""

categories = ["science", "scientific publications"]
paging = True
nb_per_page = 10
base_url = "https://api.core.ac.uk/v3/search/works/"


def setup(engine_settings: dict[str, t.Any]) -> bool:
    """Initialization of the CORE_ engine, checks whether the :py:obj:`api_key`
    is set, otherwise the engine is inactive.
    """

    key: str = engine_settings.get("api_key", "")
    if key and key not in ("unset", "unknown", "..."):
        return True
    logger.error("CORE's API key is not set or invalid.")
    return False


def request(query: str, params: "OnlineParams") -> None:

    # API v3 uses different parameters
    search_params = {
        "q": query,
        "offset": (params["pageno"] - 1) * nb_per_page,
        "limit": nb_per_page,
        "sort": "relevance",
    }

    params["url"] = base_url + "?" + urlencode(search_params)
    params["headers"] = {"Authorization": f"Bearer {api_key}"}


def response(resp: "SXNG_Response") -> EngineResults:
    # pylint: disable=too-many-branches
    res = EngineResults()
    json_data = resp.json()

    for result in json_data.get("results", []):
        # Get title
        if not result.get("title"):
            continue

        # Get URL - try different options
        url: str | None = None

        # Try DOI first
        doi: str = result.get("doi")
        if doi:
            url = f"https://doi.org/{doi}"

        if url is None and result.get("doi"):
            # use the DOI reference
            url = "https://doi.org/" + str(result["doi"])
        elif result.get("id"):
            url = "https://core.ac.uk/works/" + str(result["id"])
        elif result.get("downloadUrl"):
            url = result["downloadUrl"]
        elif result.get("sourceFulltextUrls"):
            url = result["sourceFulltextUrls"]
        else:
            continue

        # Published date
        published_date = None

        raw_date = result.get("publishedDate") or result.get("depositedDate")
        if raw_date:
            try:
                published_date = datetime.fromisoformat(result["publishedDate"].replace("Z", "+00:00"))
            except (ValueError, AttributeError):
                pass

        # Handle journals
        journals = []
        if result.get("journals"):
            journals = [j.get("title") for j in result["journals"] if j.get("title")]

        # Handle publisher
        publisher = result.get("publisher", "").strip("'")

        # Handle authors
        authors: set[str] = set()
        for i in result.get("authors", []):
            name: str | None = i.get("name")
            if name:
                authors.add(name)

        res.add(
            res.types.Paper(
                title=result.get("title"),
                url=url,
                content=result.get("fullText", "") or "",
                tags=result.get("fieldOfStudy", []),
                publishedDate=published_date,
                type=result.get("documentType", "") or "",
                authors=authors,
                editor=", ".join(result.get("contributors", [])),
                publisher=publisher,
                journal=", ".join(journals),
                doi=result.get("doi"),
                pdf_url=result.get("downloadUrl", {}) or result.get("sourceFulltextUrls", {}),
            )
        )

    return res