import email.utils
import mimetypes
from email.message import EmailMessage
from io import BytesIO
from smtplib import (
    SMTP_SSL,
    SMTPAuthenticationError,
    SMTPException,
    SMTPHeloError,
    SMTPNotSupportedError,
)
from urllib.parse import urlparse

from flask import abort, current_app, flash, redirect, render_template, request, url_for
from flask_babel import gettext, lazy_gettext
from flask_login import current_user, logout_user
from flask_paginate import Pagination, get_page_parameter, get_per_page_parameter
from flask_wtf import FlaskForm
from werkzeug.utils import secure_filename
from wtforms import (
    EmailField,
    MultipleFileField,
    PasswordField,
    StringField,
    SubmitField,
    TextAreaField,
    validators,
)

from .model.read_mails import QMAuthError
from .read_mails import get_read_mails_logged_in
from .read_mails import login as rm_login
from .render_mail import to_mime_type


class LoginForm(FlaskForm):
    username = StringField(lazy_gettext("Username"), [validators.Email()])
    password = PasswordField(
        lazy_gettext("Password"), [validators.Length(min=5, max=35)]
    )


class WriteForm(FlaskForm):
    send_to = EmailField("Send to", [validators.InputRequired()])
    subject = StringField("Subject", [validators.InputRequired()])
    cc = StringField("CC")
    bcc = StringField("BCC")
    answer_to = EmailField("Answer to")
    content = TextAreaField("Content")
    attachments = MultipleFileField("Attachments")
    submit = SubmitField("Send")


def login():
    if current_user.is_authenticated:
        return redirect(url_for("displayheaders"), 307)

    form = LoginForm()
    warn = ""
    rc = 200

    if form.validate_on_submit():
        if rm_login(form.username.data, form.password.data):
            nxt = request.args.get("next")

            if urlparse(nxt).netloc:
                abort(401)
            return redirect(nxt or url_for("displayheaders"), 303)
        else:
            warn = gettext("login failed!")
    elif request.method == "POST":
        rc = 401

    return render_template("login.html", login_form=form, warn=warn), rc


def logout():
    logout_user()
    return redirect(url_for("login"), 303)


def about():
    view_model = {
        "scriptadmin": current_app.config["JWEBMAIL"]["ADMIN_MAIL"],
        "http_host": request.host,
        "request_uri": request.full_path,
        "remote_addr": request.remote_addr,
        "languages": current_app.extensions["babel"].instance.list_translations(),
    }
    return render_template("about.html", **view_model)


def displayheaders(folder=""):
    folders = get_read_mails_logged_in().folders()

    if folder and folder not in folders:
        return render_template("error", error="no_folder", links=folders), 404

    sort = request.args.get("sort", "!date")
    search = request.args.get("search")

    s = sort[1:] if sort[0] == "!" else sort
    if s not in ["date", "size", "sender"]:
        abort(400)

    count = get_read_mails_logged_in().count(folder)

    page = request.args.get(get_page_parameter(), type=int, default=1)
    per_page = request.args.get(get_per_page_parameter(), type=int, default=25)

    pgn = Pagination(
        page=page,
        per_page=per_page,
        total=count["total_mails"],
        record_name="mails",
        css_framework="bulma",
        display_msg=gettext(
            "displaying <b>{start} - {end}</b> of <b>{total}</b> {record_name}"
        ),
        inner_window=1,
        outer_window=0,
    )

    if search:
        headers = get_read_mails_logged_in().search(search, folder)
    else:
        headers = get_read_mails_logged_in().read_headers_for(
            folder=folder,
            start=(pgn.page - 1) * pgn.per_page,
            end=(pgn.page - 1) * pgn.per_page + pgn.per_page,
            sort=sort,
        )

    vals = {
        "folder": folder,
        "pgn": pgn,
        "msgs": headers,
        "mail_folders": folders,
        "total_size": count["byte_size"],
        "total_new_mails": count["unread_mails"],
    }
    return render_template("displayheaders.html", **vals)


def readmail(msgid, folder=""):
    format = request.args.get("format", "html").lower()

    if format == "html":
        try:
            mail = get_read_mails_logged_in().show(folder, msgid)
        except QMAuthError:
            return render_template("not_found.html"), 404

        return render_template("readmail.html", msg=mail, folder=folder)

    elif format == "raw":
        path = request.args.get("path", "")

        content = get_read_mails_logged_in().raw(folder, msgid, path)

        headers = []

        cd = content["head"].get("content_disposition")
        if cd and cd.lower() == "attachment":
            headers.append(
                (
                    "Content-Disposition",
                    f"attachment; filename={content['head']['filename']}",
                )
            )
        ct = to_mime_type(content["head"])
        if ct.startswith("text/"):
            ct += "; charset=UTF-8"
        headers.append(("Content-Type", ct))

        return content["body"], headers

    elif format == "json":
        mail = get_read_mails_logged_in().show(folder, msgid)
        return mail
    else:
        abort(404)


def writemail():
    return render_template("writemail.html", form=WriteForm())


def move(folder=""):
    folders = get_read_mails_logged_in().folders()

    mm = request.form.getlist("mail")
    to_folder = request.form["select-folder"]

    if folder not in folders or to_folder not in folders:
        raise ValueError("folder not valid")

    for m in mm:
        get_read_mails_logged_in().move(m, folder, to_folder)

    flash(gettext("succ_move"))
    return redirect(url_for("displayheaders", folder=folder), 303)


def remove(folder=""):
    folders = get_read_mails_logged_in().add_folder("Trash")

    mm = request.form.getlist("mail")

    folders = get_read_mails_logged_in().folders()

    if folder not in folders:
        raise ValueError("folder not valid")

    if folder == "Trash":
        for m in mm:
            get_read_mails_logged_in().remove(m, folder)
    else:
        for m in mm:
            get_read_mails_logged_in().move(m, folder, "Trash")

    flash(gettext("succ_remove"))
    return redirect(url_for("displayheaders", folder=folder), 303)


def sendmail():
    form = WriteForm()

    if not form.validate():
        abort(400)

    mail = EmailMessage()
    mail["From"] = current_user.id
    mail["To"] = form.send_to.data
    mail["Subject"] = form.subject.data
    mail["Date"] = email.utils.localtime()
    mail["Message-ID"] = email.utils.make_msgid()

    if form.cc.data:
        mail["Cc"] = form.cc.data
    if form.bcc.data:
        mail["Bcc"] = form.bcc.data
    if form.answer_to.data:
        mail["Reply"] = form.answer_to.data

    mail.set_content(form.content.data)

    for f in form.attachments.data:
        if not f.filename:
            continue
        bio = BytesIO()
        f.save(bio)
        fname = secure_filename(f.filename)
        mt, _ce = mimetypes.guess_type(fname)
        if mt is None:
            abort(400, gettext("invalid mimetype"))
        maintype, subtype = mt.split("/")
        mail.add_attachment(
            bio.getvalue(), maintype, subtype, cte="base64", filename=fname
        )

    if current_app.config["JWEBMAIL"]["WRITE_MAILS"].get("DEBUG"):
        print(mail.as_string())
        flash(gettext("succ_send"))
        return redirect(url_for("displayheaders"), 303)

    _, send_server = current_user.id.split("@")
    send_server = "mail." + send_server

    try:
        with SMTP_SSL(send_server) as smtp:
            smtp.login(current_user.id, current_user.password)
            smtp.send_message(mail)
    except (
        SMTPHeloError,
        SMTPAuthenticationError,
        SMTPNotSupportedError,
        SMTPException,
    ):
        return (
            render_template("writemail.html", form=form, warning=gettext("error_send")),
            400,
        )

    flash(gettext("succ_send"))
    return redirect(url_for("displayheaders"), 303)