from datetime import datetime, timezone
from typing import List, Optional

from flask import Blueprint, Response, flash, redirect, render_template, url_for
from flask.typing import ResponseReturnValue
from flask_wtf import FlaskForm
from sqlalchemy import exc
from wtforms import IntegerField, SelectField, StringField, SubmitField
from wtforms.validators import DataRequired, NumberRange

from app.extensions import db
from app.models.base import Pool
from app.models.bridges import BridgeConf, ProviderAllocation
from app.portal.util import response_404, view_lifecycle

bp = Blueprint("bridgeconf", __name__)


_SECTION_TEMPLATE_VARS = {
    "section": "bridgeconf",
    "help_url": "https://bypass.censorship.guide/user/bridges.html",
}


class NewBridgeConfForm(FlaskForm):  # type: ignore
    method = SelectField("Distribution Method", validators=[DataRequired()])
    description = StringField("Description")
    pool = SelectField("Pool", validators=[DataRequired()])
    target_number = IntegerField(
        "Target Number",
        description="The number of active bridges to deploy (excluding deprecated bridges).",
        validators=[NumberRange(1, message="One or more bridges must be created.")],
    )
    max_number = IntegerField(
        "Maximum Number",
        description="The maximum number of bridges to deploy (including deprecated bridges).",
        validators=[
            NumberRange(
                1, message="Must be at least 1, ideally greater than target number."
            )
        ],
    )
    expiry_hours = IntegerField(
        "Expiry Timer (hours)",
        description=(
            "The number of hours to wait after a bridge is deprecated before its "
            "destruction."
        ),
    )
    provider_allocation = SelectField(
        "Provider Allocation Method",
        description="How to allocate new bridges to providers.",
        choices=[
            ("COST", "Use cheapest provider first"),
            ("RANDOM", "Use providers randomly"),
        ],
    )
    submit = SubmitField("Save Changes")


class EditBridgeConfForm(FlaskForm):  # type: ignore
    description = StringField("Description")
    target_number = IntegerField(
        "Target Number",
        description="The number of active bridges to deploy (excluding deprecated bridges).",
        validators=[NumberRange(1, message="One or more bridges must be created.")],
    )
    max_number = IntegerField(
        "Maximum Number",
        description="The maximum number of bridges to deploy (including deprecated bridges).",
        validators=[
            NumberRange(
                1, message="Must be at least 1, ideally greater than target number."
            )
        ],
    )
    expiry_hours = IntegerField(
        "Expiry Timer (hours)",
        description=(
            "The number of hours to wait after a bridge is deprecated before its "
            "destruction."
        ),
    )
    provider_allocation = SelectField(
        "Provider Allocation Method",
        description="How to allocate new bridges to providers.",
        choices=[
            ("COST", "Use cheapest provider first"),
            ("RANDOM", "Use providers randomly"),
        ],
    )
    submit = SubmitField("Save Changes")


@bp.route("/list")
def bridgeconf_list() -> ResponseReturnValue:
    bridgeconfs: List[BridgeConf] = BridgeConf.query.filter(
        BridgeConf.destroyed.is_(None)
    ).all()
    return render_template(
        "list.html.j2",
        title="Tor Bridge Configurations",
        item="bridge configuration",
        items=bridgeconfs,
        new_link=url_for("portal.bridgeconf.bridgeconf_new"),
        **_SECTION_TEMPLATE_VARS,
    )


@bp.route("/new", methods=["GET", "POST"])
@bp.route("/new/<group_id>", methods=["GET", "POST"])
def bridgeconf_new(group_id: Optional[int] = None) -> ResponseReturnValue:
    form = NewBridgeConfForm()
    form.pool.choices = [
        (x.id, x.pool_name) for x in Pool.query.filter(Pool.destroyed.is_(None)).all()
    ]
    form.method.choices = [
        ("any", "Any (BridgeDB)"),
        ("email", "E-Mail (BridgeDB)"),
        ("moat", "Moat (BridgeDB)"),
        ("settings", "Settings (BridgeDB)"),
        ("https", "HTTPS (BridgeDB)"),
        ("none", "None (Private)"),
    ]
    if form.validate_on_submit():
        bridgeconf = BridgeConf()
        bridgeconf.pool_id = form.pool.data
        bridgeconf.method = form.method.data
        bridgeconf.description = form.description.data
        bridgeconf.target_number = form.target_number.data
        bridgeconf.max_number = form.max_number.data
        bridgeconf.expiry_hours = form.expiry_hours.data
        bridgeconf.provider_allocation = ProviderAllocation[
            form.provider_allocation.data
        ]
        bridgeconf.added = datetime.now(tz=timezone.utc)
        bridgeconf.updated = datetime.now(tz=timezone.utc)
        try:
            db.session.add(bridgeconf)
            db.session.commit()
            flash(f"Created new bridge configuration {bridgeconf.id}.", "success")
            return redirect(url_for("portal.bridgeconf.bridgeconf_list"))
        except exc.SQLAlchemyError:
            flash("Failed to create new bridge configuration.", "danger")
            return redirect(url_for("portal.bridgeconf.bridgeconf_list"))
    if group_id:
        form.group.data = group_id
    return render_template("new.html.j2", form=form, **_SECTION_TEMPLATE_VARS)


@bp.route("/edit/<bridgeconf_id>", methods=["GET", "POST"])
def bridgeconf_edit(bridgeconf_id: int) -> ResponseReturnValue:
    bridgeconf = BridgeConf.query.filter(BridgeConf.id == bridgeconf_id).first()
    if bridgeconf is None:
        return Response(
            render_template(
                "error.html.j2",
                header="404 Bridge Configuration Not Found",
                message="The requested bridge configuration could not be found.",
                **_SECTION_TEMPLATE_VARS,
            ),
            status=404,
        )
    form = EditBridgeConfForm(
        description=bridgeconf.description,
        target_number=bridgeconf.target_number,
        max_number=bridgeconf.max_number,
        expiry_hours=bridgeconf.expiry_hours,
        provider_allocation=bridgeconf.provider_allocation.name,
    )
    if form.validate_on_submit():
        bridgeconf.description = form.description.data
        bridgeconf.target_number = form.target_number.data
        bridgeconf.max_number = form.max_number.data
        bridgeconf.expiry_hours = form.expiry_hours.data
        bridgeconf.provider_allocation = ProviderAllocation[
            form.provider_allocation.data
        ]
        bridgeconf.updated = datetime.now(tz=timezone.utc)
        try:
            db.session.commit()
            flash("Saved changes to bridge configuration.", "success")
        except exc.SQLAlchemyError:
            flash(
                "An error occurred saving the changes to the bridge configuration.",
                "danger",
            )
    return render_template(
        "bridgeconf.html.j2", bridgeconf=bridgeconf, form=form, **_SECTION_TEMPLATE_VARS
    )


@bp.route("/destroy/<bridgeconf_id>", methods=["GET", "POST"])
def bridgeconf_destroy(bridgeconf_id: int) -> ResponseReturnValue:
    bridgeconf = BridgeConf.query.filter(
        BridgeConf.id == bridgeconf_id, BridgeConf.destroyed.is_(None)
    ).first()
    if bridgeconf is None:
        return response_404("The requested bridge configuration could not be found.")
    return view_lifecycle(
        header="Destroy bridge configuration?",
        message=bridgeconf.description,
        success_view="portal.bridgeconf.bridgeconf_list",
        success_message="All bridges from the destroyed configuration will shortly be destroyed at their providers.",
        section="bridgeconf",
        resource=bridgeconf,
        action="destroy",
    )