import matplotlib.pyplot as plt
import matplotlib.dates as mdates
from io import BytesIO
import pandas as pd

def plot_candlestick(df):
    try:
        df = df.tail(50).copy()
        df['timestamp'] = pd.to_datetime(df['timestamp'])

        fig, ax = plt.subplots(figsize=(8, 4))
        for _, row in df.iterrows():
            color = 'green' if row['close'] >= row['open'] else 'red'
            ax.plot([row['timestamp'], row['timestamp']], [row['low'], row['high']], color='black')
            ax.plot([row['timestamp'], row['timestamp']], [row['open'], row['close']], color=color, linewidth=5)

        ax.xaxis.set_major_formatter(mdates.DateFormatter('%H:%M'))
        ax.xaxis.set_major_locator(mdates.AutoDateLocator())
        plt.xticks(rotation=45)
        plt.title('Candlestick Chart (MEXC)')
        plt.tight_layout()

        buf = BytesIO()
        plt.savefig(buf, format='png')
        buf.seek(0)
        plt.close(fig)
        return buf
    except Exception as e:
        print("Chart error:", e)
        raise e