import json
import re
from datetime import datetime, timedelta
from decimal import Decimal
from http import HTTPStatus

import aiohttp
import yaml

from utils.format_number import format_number

config = yaml.safe_load(open("../config.yaml", "r", encoding="utf-8"))


class Converter:
    def __init__(self):
        self.amount: float = 1.0
        self.conv_amount: float = 0.0
        self.from_currency: str = ""
        self.conv_currency: str = ""

    async def convert(self) -> None:
        if not await self.kekkai():
            await self.ddg()

        self.conv_amount = format_number(Decimal(self.conv_amount))

    async def get_lastdate(self) -> str:
        async with aiohttp.ClientSession(
            timeout=aiohttp.ClientTimeout(total=3)
        ) as session:
            async with session.get(f"{config['kekkai_instance']}/api/metadata") as res:

                if not HTTPStatus(res.status).is_success:
                    return (datetime.now() - timedelta(1)).strftime("%Y-%m-%d")

                data = await res.json()

                return data.get(
                    "last_date", (datetime.now() - timedelta(1)).strftime("%Y-%m-%d")
                )

    async def kekkai(self) -> bool:
        date = await self.get_lastdate()

        async with aiohttp.ClientSession(
            timeout=aiohttp.ClientTimeout(total=3)
        ) as session:
            async with session.get(
                f"{config['kekkai_instance']}/api/getRate/",
                params={
                    "from_currency": self.from_currency,
                    "conv_currency": self.conv_currency,
                    "date": date,
                    "conv_amount": self.amount,
                },
            ) as res:
                if not HTTPStatus(res.status).is_success:
                    return False

                data = await res.json()
                self.conv_amount = data.get("conv_amount", 0.0)

                return True

    async def ddg(self) -> None:
        async with aiohttp.ClientSession(
            timeout=aiohttp.ClientTimeout(total=3)
        ) as session:
            async with session.get(
                "https://duckduckgo.com/js/spice/currency/"
                f"{self.amount}/{self.from_currency}/{self.conv_currency}"
            ) as res:

                data_text = await res.text()

                data = json.loads(re.findall(r"\(\s*(.*)\s*\);$", data_text)[0])

                for key in ["terms", "privacy", "timestamp"]:
                    data.pop(key, None)

                if not data.get("to"):
                    raise RuntimeError(
                        "Failed to get the exchange rate from DuckDuckGo"
                    )

                conv = data.get("to")[0]
                conv_amount = conv.get("mid")

                if conv_amount is None:
                    raise RuntimeError("Error when converting currency via DuckDuckGo")

                self.conv_amount = float(conv_amount)