from flask import Blueprint
from flask import request, jsonify

from peewee import SQL, fn
from database import Message, Member

from datetime import datetime

statistics_api = Blueprint('statistics_api', __name__)


@statistics_api.route("/top-users", methods=["GET"])
def top_users():
    """
    /top_users - top users for activity
    :param number - number top users
    """
    
    data = []

    number = int(request.args.get("number"))
    
    if not number:
        number = 3
    
    query = (Member
        .select(fn.count(Message.id).alias("count"), Member)
        .join(Message)
        .group_by(Member)
        .order_by(SQL("count").desc())
    )
    
    for group in query:
        data.append({
            "user": group.first_name,
            "count": group.count,
        })
   
    data.insert(0, {
        "user": "Others",
        "count": sum(item["count"] for i, item in enumerate(data) if i >= number),
    })
    
    return jsonify(data[:number + 1])


@statistics_api.route("/last-chat-activity", methods=["GET"])
def last_chat_activity():
    """
    /last-chat-activity - last chat activity selected range
    :param startDate: datetime at which start(optional)
    :param endDate: datetime at which end
    :param groupBy: year, month, day, hour
    :param formatDatetime: format string datetime object(default: %Y-%m-%d)
    """
    
    data = []
    
    start_date = request.args.get("startDate")
    end_date = request.args.get("endDate")
    
    if not start_date or not end_date:
        return jsonify({
            "err": "startDate/endDate must be defined"
        }), 422
    
    date_format = request.args.get("formatDatetime")
    if not date_format:
        date_format = "%Y-%m-%d"
    
    groupby_keys = ["year", "month", "week", "day"]
    group_by = request.args.get("groupBy")
    if not group_by or not (group_by in groupby_keys):
        return jsonify({
            "err": "invalid groupBy parametr(year, month, day, hour)"
        }), 422
    
    try:
        start_date = datetime.strptime(start_date, date_format)
        end_date = datetime.strptime(end_date, date_format)
    except ValueError:
        return jsonify({
            "err": "Can't unparse startDate/endDate"
        }), 422
     
    query = (Message
        .select(fn.date_trunc(group_by, Message.timestamp).alias('range'), fn.count(Message.id).alias('count'))
        .where((Message.timestamp >= start_date) & (Message.timestamp <= end_date))
        .group_by(fn.date_trunc(group_by, Message.timestamp))
        .order_by(SQL("range"))
    )
    
    for record in query:
        data.append({
            "datetime": record.range.strftime(date_format),
            "count": record.count,
        })

    return jsonify(data)


@statistics_api.route("/last-user-activity", methods=["GET"])
def last_user_activity():
    """
    /last-user-activity - user activity selected range
    :param user_id: user id
    :param startDate: datetime at which start(optional)
    :param endDate: datetime at which end
    :param groupBy: year, month, day, hour
    :param formatDatetime: format string datetime object(default: %Y-%m-%d)
    """
    data = []
    
    user_id = request.args.get("user_id")
    user = Member.get_or_none(Member.user_id == user_id)

    start_date = request.args.get("startDate")
    end_date = request.args.get("endDate")
    
    if not start_date or not end_date:
        return jsonify({
            "err": "startDate/endDate must be defined"
        }), 422
    
    date_format = request.args.get("formatDatetime")
    if not date_format:
        date_format = "%Y-%m-%d"
    
    groupby_keys = ["year", "month", "week", "day"]
    group_by = request.args.get("groupBy")
    if not group_by or not (group_by in groupby_keys):
        return jsonify({
            "err": "invalid groupBy parametr(year, month, day, hour)"
        }), 422
    
    try:
        start_date = datetime.strptime(start_date, date_format)
        end_date = datetime.strptime(end_date, date_format)
    except ValueError:
        return jsonify({
            "err": "Can't unparse start_date and end_date"
        }), 422
    
    query = (Message
        .select(fn.date_trunc(group_by, Message.timestamp).alias("range"), fn.count(Message.id).alias("count"))
        .where((Message.user == user) & (Message.timestamp >= start_date) & (Message.timestamp <= end_date))
        .group_by(fn.date_trunc(group_by, Message.timestamp))
        .order_by(SQL("range"))
    )
    
    for record in query:
        data.append({
            "datetime": record.range.strftime(date_format),
            "count": record.count,
        })

    return jsonify(data)