"""
    doilinks
    ~~~~~~~~
    Extension to add links to DOIs. With this extension you can use e.g.
    :doi:`10.1016/S0022-2836(05)80360-2` in your documents. This will
    create a link to a DOI resolver
    (``https://doi.org/10.1016/S0022-2836(05)80360-2``).
    The link caption will be the raw DOI.
    You can also give an explicit caption, e.g.
    :doi:`Basic local alignment search tool <10.1016/S0022-2836(05)80360-2>`.

    :copyright: Copyright 2015  Jon Lund Steffensen. Based on extlinks by
        the Sphinx team.
    :license: BSD.
"""

from docutils import nodes, utils
from sphinx.util.nodes import split_explicit_title


def reference_role(typ, rawtext, text, lineno, inliner, options={}, content=[]):
    text = utils.unescape(text)
    has_explicit_title, title, part = split_explicit_title(text)
    if typ in ["arXiv", "arxiv"]:
        full_url = "https://arxiv.org/abs/" + part
        if not has_explicit_title:
            title = "arXiv:" + part
        pnode = nodes.reference(title, title, internal=False, refuri=full_url)
        return [pnode], []
    if typ in ["doi", "DOI"]:
        full_url = "https://doi.org/" + part
        if not has_explicit_title:
            title = "DOI:" + part
        pnode = nodes.reference(title, title, internal=False, refuri=full_url)
        return [pnode], []


def setup_link_role(app):
    app.add_role("arxiv", reference_role, override=True)
    app.add_role("arXiv", reference_role, override=True)
    app.add_role("doi", reference_role, override=True)
    app.add_role("DOI", reference_role, override=True)


def setup(app):
    app.connect("builder-inited", setup_link_role)
    return {"version": "0.1", "parallel_read_safe": True}
