from flask import Flask, render_template, request, jsonify
from backtester import Backtester
import pandas as pd
import io

app = Flask(__name__)

# Configure max upload size (e.g., 16MB)
app.config['MAX_CONTENT_LENGTH'] = 16 * 1024 * 1024

# Configure Jinja2 delimiters to avoid conflict with Vue.js
app.jinja_env.variable_start_string = '[['
app.jinja_env.variable_end_string = ']]'

@app.errorhandler(413)
def request_entity_too_large(error):
    return jsonify({'status': 'error', 'message': '文件太大，请上传小于 16MB 的文件'}), 413

@app.errorhandler(404)
def page_not_found(error):
    if request.path.startswith('/api/'):
        return jsonify({'status': 'error', 'message': 'API 端点未找到'}), 404
    return render_template('index.html'), 404 # Handle SPA routing if needed, or just 404 page

@app.errorhandler(500)
def internal_server_error(error):
    return jsonify({'status': 'error', 'message': '服务器内部错误'}), 500

@app.route('/')
def index():
    return render_template('index.html')

@app.route('/api/backtest', methods=['POST'])
def backtest():
    try:
        # Check if it's a file upload (multipart/form-data)
        custom_data = None
        
        if request.content_type and 'multipart/form-data' in request.content_type:
            short_window = int(request.form.get('short_window', 20))
            long_window = int(request.form.get('long_window', 50))
            initial_capital = float(request.form.get('initial_capital', 10000))
            
            if 'file' in request.files:
                file = request.files['file']
                if file.filename != '':
                    try:
                        if file.filename.endswith('.csv'):
                            custom_data = pd.read_csv(file)
                        elif file.filename.endswith('.xlsx') or file.filename.endswith('.xls'):
                            custom_data = pd.read_excel(file)
                        else:
                            return jsonify({'status': 'error', 'message': '不支持的文件格式，请上传 CSV 或 Excel 文件'}), 400
                    except Exception as e:
                        return jsonify({'status': 'error', 'message': f'文件读取失败: {str(e)}'}), 400
        else:
            # JSON request
            data = request.json
            short_window = int(data.get('short_window', 20))
            long_window = int(data.get('long_window', 50))
            initial_capital = float(data.get('initial_capital', 10000))
        
        bt = Backtester()
        results = bt.run_strategy(short_window, long_window, initial_capital, custom_data=custom_data)
        
        return jsonify({'status': 'success', 'data': results})
    except Exception as e:
        return jsonify({'status': 'error', 'message': str(e)}), 500

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=7860, debug=True)