#!/usr/bin/python3

import html
import itertools
import json
import re
import typing

import flask
import werkzeug
from requests_oauthlib import OAuth1Session
from werkzeug.wrappers.response import Response

from add_links import api, core, mediawiki_api, wikidata_oauth
from add_links.match import NoMatch, get_diff, get_match

app = flask.Flask(__name__)
app.config.from_object("config.default")
app.debug = True

wiki_hostname = "en.wikipedia.org"
wiki_api_php = f"https://{wiki_hostname}/w/api.php"
wiki_index_php = f"https://{wiki_hostname}/w/index.php"


class Hit(typing.TypedDict):
    """Candidate articles."""

    ns: int
    title: str
    pageid: int
    size: int
    wordcount: int
    snippet: str
    timestamp: str


re_disambig = re.compile(r"^(.*) \((.*)\)$")


def load_examples() -> list[dict[str, str | int]]:
    """Load examples."""
    return [json.loads(line) for line in open("examples")]


def article_title_to_search_query(title: str) -> str:
    """Convert from article title to search query string."""
    m = re_disambig.match(title)
    return f'"{m.group(1)}" AND "{m.group(2)}"' if m else f'"{title}"'


def run_search(q: str, limit: int | str = "max") -> dict[str, typing.Any]:
    """Search Wikipedia."""
    params = {"list": "search", "srwhat": "text", "srlimit": limit, "srsearch": q}
    return typing.cast(dict[str, typing.Any], api.api_get(params)["query"])


def article_url(title: str) -> str:
    """URL for search page."""
    return flask.url_for("article_page", url_title=title.replace(" ", "_"))


def search_count(q: str) -> int:
    """How often does this article title appear in Wikipedia."""
    query = run_search(article_title_to_search_query(q), limit=0)
    return typing.cast(int, query["searchinfo"]["totalhits"]) - 1


def search_count_with_link(q: str) -> int:
    """How often does this article title appear in Wikipedia."""
    query = run_search(article_title_to_search_query(q) + f' linksto:"{q}"', limit=0)
    return typing.cast(int, query["searchinfo"]["totalhits"])


def search_no_link(q: str) -> tuple[int, list[Hit]]:
    """Search for mentions of article title with no link included."""
    query = run_search(article_title_to_search_query(q) + f' -linksto:"{q}"', "max")
    totalhits = query["searchinfo"]["totalhits"]
    results = query["search"]
    return (totalhits, results)


@app.before_request
def global_user() -> None:
    """Make username available everywhere."""
    flask.g.user = wikidata_oauth.get_username()


@app.route("/")
def index() -> str | Response:
    """Index page."""
    if "oauth_verifier" in flask.request.args and "oauth_token" in flask.request.args:
        url = flask.url_for("oauth_callback", **flask.request.args)  # type: ignore
        return flask.redirect(url)

    examples = load_examples()
    examples.sort(
        key=lambda i: float(i["with_links"]) / float(i["total"]), reverse=True
    )

    if q := flask.request.args.get("q"):
        if q_trimmed := q.strip():
            return flask.redirect(article_url(q_trimmed))

    return flask.render_template(
        "index.html", examples=examples, article_url=article_url
    )


def case_flip(s: str) -> str:
    """Switch case of character."""
    if s.islower():
        return s.upper()
    if s.isupper():
        return s.lower()
    return s


def case_flip_first(s: str) -> str:
    """Switch case of first character in string."""
    return case_flip(s[0]) + s[1:]


def tidy_snippet(snippet: str) -> str:
    """Remove HTML from snippet."""
    snippet = snippet.replace("\u2013", "-")
    snippet = snippet.replace("</span>", "")
    snippet = snippet.replace('<span class="searchmatch">', "")
    return html.unescape(snippet)


@app.route("/oauth/start")
def start_oauth() -> Response:
    """Start OAuth."""
    next_page = flask.request.args.get("next")
    if next_page:
        flask.session["after_login"] = next_page

    client_key = app.config["CLIENT_KEY"]
    client_secret = app.config["CLIENT_SECRET"]
    request_token_url = wiki_index_php + "?title=Special%3aOAuth%2finitiate"

    oauth = OAuth1Session(client_key, client_secret=client_secret, callback_uri="oob")
    fetch_response = oauth.fetch_request_token(request_token_url)

    flask.session["owner_key"] = fetch_response.get("oauth_token")
    flask.session["owner_secret"] = fetch_response.get("oauth_token_secret")

    assert flask.session["owner_key"] and flask.session["owner_secret"]

    base_authorization_url = f"https://{wiki_hostname}/wiki/Special:OAuth/authorize"
    authorization_url = oauth.authorization_url(
        base_authorization_url, oauth_consumer_key=client_key
    )
    return flask.redirect(authorization_url)


@app.route("/oauth/callback", methods=["GET"])
def oauth_callback() -> werkzeug.wrappers.response.Response:
    """Oauth callback."""
    client_key = app.config["CLIENT_KEY"]
    client_secret = app.config["CLIENT_SECRET"]

    oauth = OAuth1Session(
        client_key,
        client_secret=client_secret,
        resource_owner_key=flask.session.get("owner_key"),
        resource_owner_secret=flask.session.get("owner_secret"),
    )

    oauth_response = oauth.parse_authorization_response(flask.request.url)
    verifier = oauth_response.get("oauth_verifier")
    access_token_url = wiki_index_php + "?title=Special%3aOAuth%2ftoken"
    oauth = OAuth1Session(
        client_key,
        client_secret=client_secret,
        resource_owner_key=flask.session["owner_key"],
        resource_owner_secret=flask.session["owner_secret"],
        verifier=verifier,
    )

    oauth_tokens = oauth.fetch_access_token(access_token_url)
    flask.session["owner_key"] = oauth_tokens.get("oauth_token")
    flask.session["owner_secret"] = oauth_tokens.get("oauth_token_secret")

    print("login successful")

    next_page = flask.session.get("after_login")
    return flask.redirect(next_page if next_page else flask.url_for("index"))


@app.route("/oauth/disconnect")
def oauth_disconnect() -> werkzeug.wrappers.response.Response:
    """Disconnect OAuth."""
    for key in "owner_key", "owner_secret", "username", "after_login":
        if key in flask.session:
            del flask.session[key]
    return flask.redirect(flask.url_for("index"))


def match_type(q: str, snippet: str) -> str | None:
    """Discover match type, ''exact', 'case_mismatch' or None.

    >>> match_type('foo', 'foo')
    'exact'
    >>> match_type('foo', 'bar') is None
    True
    >>> match_type('bar', 'foo bar baz')
    'exact'
    >>> match_type('clean coal technology', 'foo clean coal technologies baz')
    'exact'
    >>> match_type('bar', 'foo Bar baz')
    'exact'
    >>> match_type('bar', 'foo BAR baz')
    'case_mismatch'
    >>> match_type('foo-bar', 'aa foo-bar cc')
    'exact'
    >>> match_type(u'foo\u2013bar', 'aa foo-bar cc')
    'exact'
    """
    q = q.replace("\u2013", "-")
    snippet = tidy_snippet(snippet)

    if q in snippet or case_flip_first(q) in snippet:
        return "exact"
    match = None
    if q.lower() in snippet.lower():
        match = "case_mismatch"
    if match != "exact" and q.endswith("y"):
        if q[:-1] in snippet or case_flip_first(q[:-1]) in snippet:
            return "exact"
    elif match is None:
        if q[:-1].lower() in snippet.lower():
            match = "case_mismatch"
    return match


class NoGoodHit(Exception):
    """No good hit."""


def get_best_hit(title: str, hits: list[Hit]) -> tuple[Hit, dict[str, typing.Any]]:
    """Find the best hit within the search results."""
    for hit in hits:
        if hit["title"].lower() == title.lower():
            continue
        if match_type(title, hit["snippet"]) != "exact":
            continue

        try:
            print(f'get diff: {hit["title"]}, {title}')
            found = get_diff(title, hit["title"], None)
        except NoMatch:
            print("no match")
            continue

        return (hit, found)

    raise NoGoodHit


@app.route("/link/<path:url_title>", methods=["GET", "POST"])
def article_page(url_title: str) -> str | Response:
    """Article page."""
    from_title = url_title.replace("_", " ").strip()

    if flask.request.method == "POST":
        hit_title = flask.request.form["hit"]
        try:
            do_save(from_title, hit_title)
        except wikidata_oauth.LoginNeeded:
            return flask.redirect(flask.url_for("start_oauth"))
        return flask.redirect(
            flask.url_for("article_page", url_title=url_title, after=hit_title)
        )

    article_title = flask.request.args.get("title")

    total = search_count(from_title)
    with_link = search_count_with_link(from_title)

    no_link_count, hits = search_no_link(from_title)

    by_title = {hit["title"]: hit for hit in hits}

    if article_title in by_title:
        hit = by_title[article_title]
        found = get_diff(from_title, hit["title"], None)
    else:
        after = flask.request.args.get("after")
        if after:
            print(after)
            hits_iter = itertools.dropwhile(lambda hit: hit["title"] != after, hits)
            skip = next(hits_iter, None)
            if skip:
                hits = list(hits_iter)

        try:
            hit, found = get_best_hit(from_title, hits)
        except NoGoodHit:
            return flask.render_template("all_done.html")

    return flask.render_template(
        "article.html",
        title=from_title,
        total=total,
        with_link=with_link,
        hit_title=hit["title"],
        hits=hits,
        replacement=found["replacement"],
        diff=found["diff"],
        found=found,
        url_title=url_title,
    )


def do_save(title: str, hit_title: str) -> str:
    """Update page on Wikipedia."""
    token = wikidata_oauth.get_token()

    found = get_match(title, hit_title, None)

    summary = (
        f"link [[{found['replacement']}]] using [[:en:User:Edward/Find link|Find link]]"
    )

    edit = mediawiki_api.edit_page(
        pageid=found["pageid"],
        section=found["section_num"],
        text=found["section_text"],
        summary=summary,
        baserevid=found["revid"],
        token=token,
    )

    return edit


@app.route("/saved")
def save_done() -> str:
    """Save complete."""
    return flask.render_template("save_done.html")


@app.route("/api/1/hits")
def api_hits() -> werkzeug.wrappers.response.Response:
    """Return canidates for the given article title."""
    title = flask.request.args.get("title")
    assert title
    ret = core.do_search(title)
    return flask.jsonify(title=title, hits=ret["results"])

    # mock_hits: list[Hit] = json.load(open("sample.json"))
    # return flask.jsonify(title=title, hits=mock_hits)


@app.route("/api/1/valid_hit")
def api_valid_hit() -> werkzeug.wrappers.response.Response:
    """Return canidates for the given article title."""
    link_from = flask.request.args["link_from"]
    link_to = flask.request.args["link_to"]

    try:
        diff, replacement = get_diff(link_to, link_from, None)
    except NoMatch:
        return flask.jsonify(valid=False)

    return flask.jsonify(valid=True, diff=diff, replacement=replacement)


@app.route("/favicon.ico")
def favicon() -> Response:
    """No favicon."""
    return flask.Response(status=404)


if __name__ == "__main__":
    app.run(host="0.0.0.0", port=8000)