import sys
from datetime import datetime
from os import environ
from shutil import which

from babel import parse_locale
from flask import Flask, abort, g, redirect, request_finished, url_for
from flask_babel import Babel, get_locale
from flask_login import LoginManager, login_required
from flask_wtf.csrf import CSRFProtect
from jinja2 import ChainableUndefined
from markupsafe import Markup
from werkzeug.middleware.proxy_fix import ProxyFix

from .css import compile_css_command
from .read_mails import load_user
from .render_mail import format_mail
from .webmail import (
    about,
    displayheaders,
    login,
    logout,
    move,
    readmail,
    remove,
    sendmail,
    writemail,
)

if sys.version_info >= (3, 11):
    from tomllib import load as toml_load

    toml_read_file = dict(load=toml_load, text=False)
else:
    from toml import load as toml_load

    toml_read_file = dict(load=toml_load, text=True)

__version__ = "2.8.1.dev3"

csrf = CSRFProtect()


def validate_config(app):
    conf = app.config

    assert "@" in conf["JWEBMAIL"]["ADMIN_MAIL"]

    assert which(conf["JWEBMAIL"]["READ_MAILS"]["BACKEND"])

    assert which(
        conf["JWEBMAIL"]["READ_MAILS"].setdefault("AUTHENTICATOR", "qmail-authuser")
    )


def create_app():
    app = Flask(__name__)
    app.jinja_options = dict(undefined=ChainableUndefined)

    if app.config["DEBUG"]:
        app.config.from_file("../../jwebmail.toml", **toml_read_file)
    else:
        app.config.from_file(environ["JWEBMAIL_CONFIG"], **toml_read_file)

    if app.config["JWEBMAIL"].get("PROXY"):
        app.wsgi_app = ProxyFix(
            app.wsgi_app, x_for=True, x_proto=True, x_host=True, x_prefix=True
        )

    validate_config(app)

    csrf.init_app(app)

    babel = Babel(app, locale_selector=lambda: g.get("lang_code"))

    app.cli.add_command(compile_css_command)

    login_manager = LoginManager()
    login_manager.login_view = "login"
    login_manager.user_loader(load_user)
    login_manager.init_app(app)

    route(app)

    tr_dict = {
        "en": str.maketrans({" ": " "}),
        "de": str.maketrans({".": ",", " ": " "}),
    }

    @app.template_filter("num_localize")
    def num_localize(txt):
        if str(get_locale()).startswith("de"):
            return Markup(txt.translate(tr_dict["de"]))
        else:
            return Markup(txt.translate(tr_dict["en"]))

    @app.context_processor
    def inject_version():
        return {
            "version": __version__,
            "get_locale": get_locale,
            "format_mail": format_mail,
            "parse_iso_date": datetime.fromisoformat,
        }

    @app.url_defaults
    def add_language_code(endpoint, values):
        if "lang_code" in values:
            return
        if app.url_map.is_endpoint_expecting(endpoint, "lang_code"):
            values["lang_code"] = g.get("lang_code", babel.default_locale.language)

    @app.url_value_preprocessor
    def pull_lang_code(endpoint, values):
        if values and values.get("lang_code"):
            try:
                pl = parse_locale(values["lang_code"])
                if pl[0] in ["en", "de"]:
                    g.lang_code = values.pop("lang_code")
                else:
                    abort(404)
            except ValueError:
                abort(404)

    @request_finished.connect_via(app)
    def close_qma(_app, **_):
        if "read_mails" in g:
            g.read_mails.close()
            g.read_mails = None

    return app


def route(app):
    app.add_url_rule(
        "/",
        endpoint="root",
        view_func=lambda: redirect(url_for("login", lang_code=get_locale().language)),
    )

    app.add_url_rule("/<lang_code>/", view_func=login, methods=["GET", "POST"])

    app.add_url_rule("/<lang_code>/about", view_func=about)

    app.add_url_rule("/<lang_code>/logout", view_func=logout)

    dh = login_required(displayheaders)
    app.add_url_rule("/<lang_code>/home/", view_func=dh)
    app.add_url_rule("/<lang_code>/home/<folder>", view_func=dh)

    lr_readmail = login_required(readmail)
    app.add_url_rule(
        "/<lang_code>/read/<msgid>", endpoint="read", view_func=lr_readmail
    )
    app.add_url_rule(
        "/<lang_code>/read/<folder>/<msgid>", endpoint="read", view_func=lr_readmail
    )

    lr_writemail = login_required(writemail)
    app.add_url_rule("/<lang_code>/write", endpoint="write", view_func=lr_writemail)
    app.add_url_rule(
        "/<lang_code>/write",
        endpoint="send",
        view_func=login_required(sendmail),
        methods=["POST"],
    )

    lr_move = login_required(move)
    app.add_url_rule("/<lang_code>/move/", view_func=lr_move, methods=["POST"])
    app.add_url_rule("/<lang_code>/move/<folder>", view_func=lr_move, methods=["POST"])

    lr_remove = login_required(remove)
    app.add_url_rule(
        "/<lang_code>/remove/",
        view_func=lr_remove,
        methods=["POST"],
    )
    app.add_url_rule(
        "/<lang_code>/remove/<folder>",
        view_func=lr_remove,
        methods=["POST"],
    )