from flask import Blueprint, request, session, render_template, redirect, url_for, abort
from user_agents import parse as user_agent
from datetime import datetime
from dateutil.parser import isoparse
from .umbrellas import Umbrellas
from .admin_log import AdminLog
from .users import Users
from .exceptions import *
from .config import *
from .utils import human_timedelta, CST

bp = Blueprint("admin", __name__, url_prefix="/admin")
db = Umbrellas(DATABASE_PATH)
users = Users(DATABASE_PATH)
admin_log = AdminLog(ADMIN_LOG_PATH)


@bp.before_request
def check_privilege():
    # only clients who have obtained a session and sent it in the Cookie header
    # will have a decryptable username here
    if "username" not in session:
        return redirect(url_for("auth.auth", action="login"))

    username = session["username"]
    user = users.find(username)  # under normal circumstances it must exist
    if user["role"] != "admin":
        abort(403)


@bp.route("/")
def index():
    umbrellas = db.read()
    # count # of umbrellas in each status
    status_count = {
        status: len([u for u in umbrellas if u["status"] == status])
        for status in ("available", "lent", "overdue")
    }
    return render_template(
        "admin/index.html",
        umbrellas=len(umbrellas),
        available=status_count["available"],
        lent=status_count["lent"],
        overdue=status_count["overdue"],
        mobile=user_agent(request.user_agent.string).is_mobile,
    )


@bp.route("/umbrellas")
def umbrellas():
    # sqlite3.Row does not support item assignment, but dict does
    umbrellas = [dict(umb) for umb in db.read()]
    edit = request.args.get("edit")
    if edit is not None:
        if not edit.isnumeric():
            abort(400)
        edit = int(edit)

    for umb in umbrellas:
        if umb["id"] == edit and not umb["lent_at"]:
            # autofill current time when admin is editing and lent_at is empty
            umb["lent_at"] = datetime.now().isoformat(timespec="seconds")
        elif umb["lent_at"]:
            try:
                # web interface provides no timezone so UTC+8 is assumed
                lent_at = isoparse(umb["lent_at"]).replace(tzinfo=CST)
                umb["lent_at"] = lent_at.isoformat(timespec="seconds")
                umb["lent_time_ago"] = (
                    human_timedelta(datetime.now().astimezone(CST) - lent_at) + " ago"
                )
            except ValueError:
                umb["lent_at"] = "Invalid date"
                umb["lent_time_ago"] = ""

    error = request.args.get("error")
    template = (
        "admin/umbrellas_mobile.html"
        if user_agent(request.user_agent.string).is_mobile
        else "admin/umbrellas_desktop.html"
    )
    return render_template(
        template,
        umbrellas=umbrellas,
        edit=edit,
        error=error,
    )


@bp.route("/umbrellas/edit", methods=["POST"])
def umbrellas_edit():
    data = {}
    for key in [
        "id",
        "status",
        "tenant_name",
        "tenant_id",
        "tenant_phone",
        "lent_at",
    ]:
        data[key] = request.form.get(key)

    try:
        diff = db.update(data)
    except UmbrellaValueError as e:
        # invalid field is in `e.message`.
        return redirect(
            "{0}?edit={1}&error={2}".format(
                url_for("admin.umbrellas"), request.form.get("id"), e.message
            )
        )
    except UmbrellaNotFoundError:
        abort(400)

    for column, value_pair in diff.items():
        past, new = value_pair
        admin_log.log(
            "ADMIN_MODIFY_DB",
            {
                "admin_name": session["username"],
                "id": data["id"],
                "column": column,
                "past_value": past,
                "new_value": new,
            },
        )

    return redirect(url_for("admin.umbrellas"))


@bp.route("/logs")
def logs():
    logs = admin_log.read()
    return render_template("admin/logs.html", logs=logs)