Kekkai/chart/function/create_chart.py

65 lines
1.7 KiB
Python

from datetime import datetime
from matplotlib import pyplot as plt
from chart.function.gen_unique_name import generate_unique_name
from ..database.server import create_pool
async def create_chart(from_currency: str, conv_currency: str, start_date: str, end_date: str) -> (str, None):
pool = await create_pool()
if not validate_date(start_date) or not validate_date(end_date):
return None
start_date_obj = datetime.strptime(start_date, '%Y-%m-%d').date()
end_date_obj = datetime.strptime(end_date, '%Y-%m-%d').date()
async with pool.acquire() as conn:
data = await conn.fetch(
'SELECT date, rate FROM currency '
'WHERE (date BETWEEN $1 AND $2) AND from_currency = $3 AND conv_currency = $4',
start_date_obj,
end_date_obj,
from_currency.upper(),
conv_currency.upper()
)
if not data or len(data) <= 1:
return None
date, rate = [], []
for row in data:
date.append(str(row['date']))
rate.append(row['rate'])
if rate[0] < rate[-1]:
plt.plot(date, rate, color='green', marker='o')
elif rate[0] > rate[-1]:
plt.plot(date, rate, color='red', marker='o')
else:
plt.plot(date, rate, color='grey')
plt.xlabel('Date')
plt.ylabel('Rate')
fig = plt.gcf()
fig.set_size_inches(18.5, 9.5)
name = await generate_unique_name(
f'{from_currency.upper()}_{conv_currency.upper()}',
datetime.now()
)
fig.savefig(f'../charts/{name}.png')
fig.clear()
return name
def validate_date(date_str: str) -> bool:
try:
datetime.strptime(date_str, '%Y-%m-%d')
return True
except ValueError:
return False