import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
import japanize_matplotlib
import ipywidgets as widgets
from IPython.display import display, clear_output

# シミュレーション関数
def simulate_withdrawal(start_age, years, initial_assets, monthly_withdraw, annual_return, annual_risk, n_sim=1000):
    months = years * 12
    results = []
    for _ in range(n_sim):
        assets = initial_assets
        monthly_returns = np.random.normal(
            loc=(annual_return/100)/12,
            scale=(annual_risk/100)/np.sqrt(12),
            size=months
        )
        trajectory = []
        for r in monthly_returns:
            assets *= (1 + r)           
            assets -= monthly_withdraw  
            assets = max(0, assets)     
            trajectory.append(assets)
        results.append(trajectory)
    return pd.DataFrame(results).T  

# 実行関数
def run_simulation(b):
    clear_output(wait=True)
    display(ui)
    
    # 入力値取得
    start_age = age_slider.value
    years = years_slider.value
    initial_assets = assets_slider.value
    monthly_withdraw = withdraw_slider.value
    annual_return = return_slider.value
    annual_risk = risk_slider.value

    # シミュレーション実行
    df = simulate_withdrawal(start_age, years, initial_assets, monthly_withdraw, annual_return, annual_risk)
    mean_path = df.mean(axis=1)
    median_path = df.median(axis=1)
    best_path = df.max(axis=1)
    worst_path = df.min(axis=1)
    months = np.arange(1, years*12 + 1)

    # 最終結果テキスト
    final_assets = df.iloc[-1]
    print(
        f"最終結果:"
        f"  破産確率: {100 * (final_assets==0).mean():.1f}%"
        f"  平均資産額: {final_assets.mean():,.0f} 万円"
        f"  中央資産額: {final_assets.median():,.0f} 万円"
        f"  最良ケース: {final_assets.max():,.0f} 万円"
        f"  最悪ケース: {final_assets.min():,.0f} 万円"
    )

    # グラフ描画 (matplotlib)
    plt.figure(figsize=(10,6))
    #plt.plot(months, best_path, label="最良ケース", color="green")
    plt.plot(months, worst_path, label="最悪ケース", color="red")
    plt.plot(months, mean_path, label="平均ケース", color="blue")
    plt.plot(months, median_path, label="中央値ケース", color="orange")
    plt.title(f"資産取り崩しシミュレーション（開始年齢: {start_age}歳, 期間: {years}年）")
    plt.xlabel("経過月数")
    plt.ylabel("資産額 (万円)")
    plt.legend()
    plt.grid(True)
    plt.show()

# スライダーUI
age_slider = widgets.IntSlider(value=65, min=50, max=100, step=1, description="開始年齢")
years_slider = widgets.IntSlider(value=30, min=10, max=50, step=1, description="年数")
assets_slider = widgets.IntSlider(value=5000, min=1000, max=20000, step=100, description="資産(万円)")
withdraw_slider = widgets.IntSlider(value=20, min=10, max=100, step=1, description="月取崩(万円)")
return_slider = widgets.IntSlider(value=4, min=1, max=20, step=1, description="利回り%")
risk_slider = widgets.IntSlider(value=1, min=1, max=30, step=1, description="リスク%")

# 実行ボタン
run_button = widgets.Button(description="シミュレーション実行", button_style="success")
run_button.on_click(run_simulation)

# UIまとめて表示
ui = widgets.VBox([age_slider, years_slider, assets_slider,withdraw_slider, return_slider, risk_slider,run_button])
display(ui)