from flask import Blueprint
from flask import request, jsonify

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

from datetime import datetime

group_stat_api = Blueprint('group_stat_api', __name__)


@group_stat_api.route("/top_users", methods=["GET"])
def top_users():
    number = request.args.get("number")

    if not number: number = 3

    number = int(number)

    members = []
    counts = []

    query = (Member
        .select(fn.count(Message.id).alias("count"), Member)
        .join(Message)
        .group_by(Member)
        .order_by(SQL("count").desc())
    )

    for group in query:
        members.append(group.first_name)
        counts.append(group.count)

    members.insert(0, "Others")
    counts.insert(0, sum(counts[number:]))

    return jsonify({
        "members": members[:number + 1],
        "counts": counts[:number + 1]
    })

@group_stat_api.route("/chat_activity", methods=["GET"])
def chat_activity():
    dates = []
    counts = []
    
    from_date = request.args.get("from_date")
    to_date = request.args.get("to_date")
    
    if not from_date or not to_date:
        return jsonify({
            "err": "from_date/to_date empty"
        }),422

    date_format = request.args.get("date_format")
    date_format = date_format if date_format else "%Y-%m-%d"
    
    group_by = request.args.get("group_by")
    group_by = group_by if group_by else "day"
    
    try:
        from_date = datetime.strptime(from_date, date_format)
        to_date   = datetime.strptime(to_date, date_format)
    except ValueError:
        return jsonify({
            "from_date": from_date,
            "to_date": to_date,
            "date_format": date_format,
            "err":"can't format datatime obj"
        }),422
    
    if not group_by in ["day","week","month","year"]:
        return jsonify({
            "err":"invalid group_by"
        }),422

    query = (Message
        .select(fn.date_trunc(group_by, Message.timestamp).alias('range'), fn.count(Message.id).alias('count'))
        .where((Message.timestamp >= from_date) & (Message.timestamp <= to_date))
        .group_by(fn.date_trunc(group_by, Message.timestamp))
        .order_by(SQL("range"))
    )

    for row in query:
        dates.append(row.range.strftime(date_format))
        counts.append(row.count)

    return jsonify({
        "date": dates,
        "counts": counts
    })

@group_stat_api.route("/user_activity", methods=["GET"])
def user_activity():
    dates = []
    counts = []

    user_id = request.args.get("user_id")
    user = Member.get_or_none(Member.user_id == user_id)
    
    if not user:
        return jsonify({
            "err":"invalid user_id"
        }),422

    from_date   = request.args.get("from_date")
    to_date     = request.args.get("to_date")
    
    if not from_date or not to_date:
        return jsonify({
            "err": "from_date/to_date empty"
        }),422

    group_by  = request.args.get("group_by")
    group_by = group_by if group_by else "day"

    date_format = request.args.get("date_format")
    date_format = date_format if date_format else "%Y-%m-%d" 

    try:
        from_date = datetime.strptime(from_date,date_format)
        to_date   = datetime.strptime(to_date,  date_format)
    except ValueError:
        return jsonify({
            "from_date": from_date,
            "to_date": to_date,
            "date_format": date_format,
            "err":"can't format datatime obj"
        }),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 >= from_date) & (Message.timestamp <= to_date))
        .group_by(fn.date_trunc(group_by, Message.timestamp))
        .order_by(SQL("range"))
    )
    
    for row in query:
        dates.append(row.range.strftime(date_format))
        counts.append(row.count)

    return jsonify({
        "date": dates,
        "counts": counts
    })