🚀 Day 4：打造「具備持久化與完整 CRUD 功能的自動存檔記帳系統」

"""
 Day 4 最終成果：具備持久化與完整 CRUD 功能的自動存檔記帳系統
 核心概念：JSON 檔案序列化/反序列化 -> 開機自動讀檔 -> CRUD 操作 -> 報表匯出
"""
import json
import os
import datetime

DATA_FILE = "expenses.json"

# ==========================================
# 💾 資料持久化模組 (對應 DB Access & ORM Persistence)
# ==========================================

def load_data():
    """ 開機自動讀檔 (模擬 DB Connection & QuerySet Fetch) """
    if not os.path.exists(DATA_FILE):
        return []
    try:
        with open(DATA_FILE, "r", encoding="utf-8") as f:
            return json.load(f)
    except (json.JSONDecodeError, Exception) as e:
        print(f"⚠️ 資料檔讀取異常或格式損毀 ({e})，已啟動預防性備份並重置清單。")
        return []

def save_data(records):
    """ 寫入 JSON 檔案 (模擬 DB .save() 寫入與 Commit) """
    with open(DATA_FILE, "w", encoding="utf-8") as f:
        json.dump(records, f, ensure_ascii=False, indent=4)

# ==========================================
# 🚀 系統主程式與 CRUD 路由
# ==========================================

records = load_data()
print(f"📂 開機成功！已自動從 [{DATA_FILE}] 載入 {len(records)} 筆歷史紀錄。")

while True:
    print("\n" + "=" * 45)
    print("      💾 持久化 CRUD 終端機記帳系統 💾      ")
    print("=" * 45)
    print("  [1] ➕ 新增消費紀錄 (Create)")
    print("  [2] 📊 查看所有明細 (Read)")
    print("  [3] ✏️ 修改紀錄金額 (Update)")
    print("  [4] ❌ 刪除特定紀錄 (Delete)")
    print("  [5] 📑 匯出財務月報表 (.txt)")
    print("  [6] 🚪 儲存並離開系統")
    print("=" * 45)

    choice = input("👉 請選擇功能選項 (1-6): ").strip()

    if choice == "1":
        # --- [C]reate 新增 ---
        item = input("👉 請輸入品項名稱: ").strip()
        if not item:
            print("⚠️ 名稱不能為空！")
            continue
        try:
            price = int(input("👉 請輸入金額: "))
        except ValueError:
            print("❌ 錯誤：金額必須是純數字！")
            continue
        
        cat = input("👉 請輸入分類 (預設: 一般): ").strip() or "一般"
        today = datetime.date.today().strftime("%Y-%m-%d")

        records.append({"name": item, "price": price, "category": cat, "date": today})
        save_data(records)
        print(f"✅ 已新增並自動存檔：{item} ${price} 元 [{cat}]")

    elif choice == "2":
        # --- [R]ead 讀取列表 ---
        if not records:
            print("📭 目前尚無任何記帳紀錄！")
            continue
        print("\n--- 📊 完整記帳明細列表 ---")
        total = 0
        for idx, r in enumerate(records, start=1):
            print(f"[{idx}] {r['date']} | {r['name']:<10} | ${r['price']:<5} | [{r['category']}]")
            total += r["price"]
        print("-" * 45)
        print(f"💵 總計累計金額：${total} 元")

    elif choice == "3":
        # --- [U]pdate 修改 ---
        if not records:
            print("📭 沒有可修改的資料！")
            continue
        print("\n--- ✏️ 修改紀錄金額 ---")
        for idx, r in enumerate(records, start=1):
            print(f"[{idx}] {r['name']} - 當前金額: ${r['price']}")
        try:
            target_idx = int(input("👉 請輸入要修改的編號: ")) - 1
            if 0 <= target_idx < len(records):
                new_price = int(input(f"👉 請輸入 [{records[target_idx]['name']}] 的新金額: "))
                records[target_idx]["price"] = new_price
                save_data(records)
                print("✅ 修改完成並已更新檔案！")
            else:
                print("⚠️ 輸入編號超出範圍！")
        except ValueError:
            print("❌ 錯誤：請輸入有效的數字編號與金額！")

    elif choice == "4":
        # --- [D]elete 刪除 ---
        if not records:
            print("📭 沒有可刪除的資料！")
            continue
        print("\n--- ❌ 刪除特定紀錄 ---")
        for idx, r in enumerate(records, start=1):
            print(f"[{idx}] {r['name']} - ${r['price']} ({r['category']})")
        try:
            target_idx = int(input("👉 請輸入要刪除的編號: ")) - 1
            if 0 <= target_idx < len(records):
                deleted = records.pop(target_idx)
                save_data(records)
                print(f"🗑️ 已成功刪除：{deleted['name']} ${deleted['price']} 元")
            else:
                print("⚠️ 輸入編號超出範圍！")
        except ValueError:
            print("❌ 錯誤：請輸入有效的數字編號！")

    elif choice == "5":
        # --- 匯出文字報表 ---
        report_file = "monthly_report.txt"
        with open(report_file, "w", encoding="utf-8") as f:
            f.write("=== 📊 個人財務月報表 ===\n")
            f.write(f"匯出日期: {datetime.date.today()}\n")
            f.write("-----------------------------------\n")
            tot = 0
            for r in records:
                f.write(f"• {r['date']} | {r['name']:<10} | ${r['price']}\n")
                tot += r["price"]
            f.write("-----------------------------------\n")
            f.write(f"總累計花費: ${tot} 元\n")
        print(f"📄 成功匯出財務報表至檔名：[{report_file}]")

    elif choice == "6":
        save_data(records)
        print("\n💾 系統資料已保存，期待下次運算！再見！👋")
        break

    else:
        print("⚠️ 無效的選項，請輸入數字 1 至 6！")