import os
import io
import time
import json
import flask
import requests
import pandas as pd

from dotenv import load_dotenv

load_dotenv()

# cache get_finances() for 5 minutes

def get_finances():
    return requests.get(
        url=f'{os.environ["CORE_API_URL"]}/finances',
        headers={
            'Authorization': f'{os.environ["CORE_API_KEY"]}'
        },
        timeout=5
    ).json()

def register(app):
    @app.route('/finances')
    def finances_view():
        try:
            data = get_finances()
        except Exception:
            return flask.Response('Error fetching finances from database. This might be cause the data is still being processed. Please allow up to a few minutes.', status=500)

        donations = data['donations']
        expenses = data['expenses']

        finances = {
            'last_update': data['timestamp'],
            'donations_total': round(sum([i['amount_usd'] for i in donations])),
            'donations_num': len(donations),
            'donations_avg': round(sum([i['amount_usd'] for i in donations]) / len(donations), 2),
            'donations_max': round(max([i['amount_usd'] for i in donations])),
            'most_used_donation_currency': max(donations, key=lambda x: x['amount_usd'])['currency'],

            'expenses_total': round(sum([i['amount_usd'] for i in expenses])),
            'expenses_wages': round(sum([i['amount_usd'] for i in expenses if i['type'] == 'wage'])),
            'most_used_expense_currency': max(expenses, key=lambda x: x['amount_usd'])['currency'],
        }

        transaction_table = []

        transactions = [{'change': '+', **donation} for donation in donations] + [{'change': '-', **expense} for expense in expenses]
        transactions = sorted(transactions, key=lambda x: x['timestamp'], reverse=True)

        for transaction in transactions:
            description = ''

            if transaction['change'] == '+':
                description = f'Discord/{transaction["user"]}'

            if transaction['change'] == '-':
                description = f'{transaction["reason"]} -> {transaction["to"]}' 

            if transaction['currency'] in ['USD', 'EUR', 'GBP', 'CAD', 'AUD', 'NZD', 'CHF', 'JPY', 'CNY', 'HKD', 'SGD']:
                transaction['proof'] = ''

            if transaction['change'] == '-':
                transaction['amount_usd'] = -transaction['amount_usd']

            amount = f'{round(transaction["amount_usd"])}'

            transaction_table.append({
                'Amount (USD)': amount,
                'Currency': transaction['currency'],
                'Type': transaction.get('type', 'donation'),
                'Description': description,
                'Timestamp': time.strftime('%Y-%m-%d %H:%M', time.localtime(transaction['timestamp'])),
                'Proof': transaction['proof'],
            })

        # convert transaction_table to html
        transaction_table = pd.DataFrame(transaction_table).to_html(
            index=False,
            classes=['table', 'table-striped', 'table-hover'],
            table_id='transactionTable'
        )

        return flask.render_template('finances.html', finances=finances, transaction_table=transaction_table)

    @app.route('/finances/json')
    def finances_download():
        try:
            data = get_finances()
        except Exception:
            return flask.Response('Error fetching finances from database. This might be cause the data is still being processed. Please allow up to a few minutes.', status=500)

        virtual_file = io.StringIO()
        json.dump(data, virtual_file, indent=4)
        name = f'finances-{time.strftime("%Y-%m-%d")}.json'
        virtual_file.seek(0)

        return flask.send_file(
            io.BytesIO(virtual_file.read().encode('utf-8')),
            mimetype='application/json',
            as_attachment=True,
            download_name=name
        )