from flask import Flask, request, jsonify
import math
import numpy as np

app = Flask(__name__)

# 定义计算解冻时间的函数
def calculate_thaw_time(mass, specific_heat, thermal_conductivity, length, width, height, T_thaw, T_env, T_initial, alpha=1.2):
    """
    mass: 煤矿质量 (kg)
    specific_heat: 比热容 (kJ/(kg·°C))
    thermal_conductivity: 热传导系数 (W/m·°C)
    length: 煤矿堆积的长度 (m)
    width: 煤矿堆积的宽度 (m)
    height: 煤矿堆积的高度 (m)
    T_thaw: 需要解冻的温度 (°C)
    T_env: 解冻库库温 (°C)
    T_initial: 煤矿初始温度 (°C)
    alpha: 修正系数 (默认 1.2)
    """
    # 1. 计算煤矿堆的外部表面积 (A)
    external_area = 2 * (length * width + length * height + width * height)

    # 2. 修正表面积 (A_effective)
    effective_area = alpha * external_area

    # 3. 避免计算中 log 的负值和分母为零的情况
    print(f"T_initial: {T_initial}")
    if T_initial == T_env or (T_thaw - T_env) / (T_initial - T_env) <= 0:
        return None

    # 4. 计算解冻时间
    thaw_time = - (mass * specific_heat) / (thermal_conductivity * effective_area) * \
                math.log((T_thaw - T_env) / (T_initial - T_env))

    return thaw_time

# 定义 REST API 路由
@app.route('/calculate-thaw-time', methods=['POST'])
def calculate():
    try:
        # 获取 JSON 参数
        data = request.json
        # 打印接收到的 JSON 数据
        print("Received data:", data)
        print("Request Headers:", request.headers)

        # 必填字段校验
        required_fields = ['mass', 'specific_heat', 'thermal_conductivity', 'length', 'width', 'height', 'T_thaw', 'T_env', 'T_initial']
        for field in required_fields:
            if field not in data:
                return jsonify({"error": f"Missing field: {field}"}), 400

        # 提取参数
        mass = data['mass']
        specific_heat = data['specific_heat']
        thermal_conductivity = data['thermal_conductivity']
        length = data['length']
        width = data['width']
        height = data['height']
        T_thaw = data['T_thaw']
        T_env = data['T_env']
        T_initial = data['T_initial']
        alpha = data.get('alpha', 1.2)  # 默认修正系数

        # 计算解冻时间
        thaw_time = calculate_thaw_time(mass, specific_heat, thermal_conductivity, length, width, height, T_thaw, T_env, T_initial, alpha)

        # 返回结果
        if thaw_time is None:
            return jsonify({"error": "Invalid input values for calculation"}), 400

        # 返回的解冻时间是小时
        return jsonify({"thaw_time": thaw_time})

    except Exception as e:
        return jsonify({"error": str(e)}), 500

if __name__ == '__main__':
    app.run(port=9996, debug=True)