import io
import json
import os
import pickle
import threading
import time
import uuid
from enum import Enum

import pandas as pd
import requests
from flask import Flask, jsonify, render_template, request, redirect, make_response


app = Flask(__name__)

TREASURY_URL = "https://home.treasury.gov/resource-center/data-chart-center/interest-rates/daily-treasury-rates.csv/2024/all?type=daily_treasury_yield_curve&field_tdr_date_value=2024&page&_format=csv"

CURRENT_DATE = 20240524  # Set to friday since market is closed

RATES = None


class Side(str, Enum):
    BUY = "BUY"
    SELL = "SELL"


# Since we know all the types of treasuries, just enumerate them
class Instrument(str, Enum):
    I_1MO = "1 Mo"
    I_2MO = "2 Mo"
    I_3MO = "3 Mo"
    I_4MO = "4 Mo"
    I_6MO = "6 Mo"
    I_1YR = "1 Yr"
    I_2YR = "2 Yr"
    I_3YR = "3 Yr"
    I_5YR = "5 Yr"
    I_7YR = "7 Yr"
    I_10YR = "10 Yr"
    I_20YR = "12 Yr"
    I_30YR = "30 Yr"

    @classmethod
    def from_text(cls, txt):
        if txt == "1 Mo":
            return Instrument.I_1MO
        elif txt == "2 Mo":
            return Instrument.I_2MO
        elif txt == "3 Mo":
            return Instrument.I_3MO
        elif txt == "4 Mo":
            return Instrument.I_4MO
        elif txt == "6 Mo":
            return Instrument.I_6MO
        elif txt == "1 Yr":
            return Instrument.I_1YR
        elif txt == "2 Yr":
            return Instrument.I_2YR
        elif txt == "3 Yr":
            return Instrument.I_3YR
        elif txt == "5 Yr":
            return Instrument.I_5YR
        elif txt == "7 Yr":
            return Instrument.I_7YR
        elif txt == "10 Yr":
            return Instrument.I_20YR
        elif txt == "12 Yr":
            return Instrument.I_20YR
        return Instrument.I_30YR


class Transaction:
    def __init__(
        self, user: str, instrument: Instrument, quantity: int, date: int, side: Side, rate: float
    ):
        self.user = user
        self.instrument: str = str(instrument.value)
        self.side: str = str(side.value)
        self.quantity = quantity
        self.date = date
        self.rate = rate


class User:
    def __init__(self, balance: int = 100000) -> None:
        self.ID = str(uuid.uuid4())
        self.balance = balance


USERS: dict[str, User] = {}
TRANSACTIONS: dict[str, list[Transaction]] = {}


def background_saver():
    while True:
        with open("users.p", "wb") as fp:
            pickle.dump(USERS, fp)
        with open("transactions.p", "wb") as fp:
            pickle.dump(TRANSACTIONS, fp)

        time.sleep(5)


def get_treasury_rates_for_year(year: int) -> pd.DataFrame | None:
    global RATES

    use_cache = False
    if RATES is None:
        if os.path.isfile("./cache.csv"):
            if time.time() - os.path.getmtime("./cache.csv") < 60000:
                use_cache = True
    else:
        use_cache = True

    if use_cache:
        csv: pd.DataFrame = pd.read_csv("./cache.csv")
        RATES = csv
    else:
        response = requests.get(TREASURY_URL)
        response.raise_for_status()
        raw_csv = response.content.decode("UTF-8")
        csv_io = io.StringIO(raw_csv)
        csv: pd.DataFrame = pd.read_csv(csv_io)
        csv.to_csv("./cache.csv", index=False)
        RATES = csv

    ret = {}
    cols = list(RATES.columns.values)
    for col in cols:
        ret[col] = RATES[col].tolist()

    dates = ret["Date"]
    del ret["Date"]
    return ret, dates


@app.route("/api/transactions/<id>")
def get_transactions_for_user(id):
    t = TRANSACTIONS.get(id)
    if t is None:
        return jsonify([])

    return jsonify([{"term": tx.instrument, "quantity": tx.quantity, "side": tx.side, "date": tx.date, "rate": tx.rate} for tx in t])


@app.route("/api/buy", methods=["POST"])
def buy():
    content = request.json
    print(content)
    q = int(content["quantity"])
    i = content["instrument"]
    user_id = content["user_id"]
    cost = q * 100
    if USERS.get(user_id) is not None:
        if cost > USERS[user_id].balance:
            return "You do not have the funds for this transaction", 400
    else:
        return "User does not exist", 404

    current_rate = RATES[i].tolist()[-1]

    USERS[user_id].balance = USERS[user_id].balance - cost
    t = Transaction(user_id, Instrument.from_text(i), q, time.time(), Side.BUY, current_rate)

    if TRANSACTIONS.get(user_id) is None:
        TRANSACTIONS[user_id] = [t]
    else:
        TRANSACTIONS[user_id].append(t)

    return jsonify(t)


@app.route("/api/login", methods=["POST"])
def login():
    content = request.json
    id = content.get("id")
    if id is None:
        return "ID cannot be empty", 400
    u = USERS.get(id)
    if u is None:
        return "User does not exist", 404
    resp = make_response(redirect("/"))
    resp.set_cookie("userid", u.ID)
    return resp


@app.route("/api/createuser", methods=["POST"])
def createuser():
    u = User()
    USERS[u.ID] = u
    resp = make_response(redirect("/"))
    resp.set_cookie("userid", u.ID)
    return resp


@app.route("/register")
def register():
    if "userid" in request.cookies:
        return redirect("/")
    return render_template("register.html")


@app.route("/logout")
def logout():
    if "userid" not in request.cookies:
        return redirect("/register")
    resp = make_response(redirect("/register"))
    resp.set_cookie("userid", "", expires=0)
    return resp


@app.route("/")
def index():
    if "userid" not in request.cookies:
        return redirect("/register")
    uid = request.cookies.get("userid")
    if uid not in USERS:
        resp = make_response(redirect("/register"))
        resp.set_cookie("userid", "", expires=0)
        return resp
    rates, dates = get_treasury_rates_for_year(2024)
    return render_template("index.html", rates=[rates], dates=dates, userid=uid, balance=USERS[uid].balance)


if __name__ == "__main__":
    # Load up files if they exist
    if os.path.isfile("./users.p"):
        print("Loading users")
        with open("./users.p", "rb") as fp:
            USERS = pickle.load(fp)

    if os.path.isfile("./transactions.p"):
        print("Loading transactions")
        with open("./transactions.p", "rb") as fp:
            TRANSACTIONS = pickle.load(fp)

    # Start persistence
    thread = threading.Thread(target=background_saver)
    thread.start()

    # Start Server
    app.run(host='0.0.0.0', port=8008)


thread = threading.Thread(target=background_saver)
thread.start()