#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
License 验证模块
"""

import sys
import json
import base64
import os
from datetime import datetime
from pathlib import Path

try:
    from cryptography.hazmat.primitives import hashes, serialization
    from cryptography.hazmat.primitives.asymmetric import padding
    from cryptography.hazmat.backends import default_backend
    from cryptography.exceptions import InvalidSignature
except ImportError:
    print("错误: 缺少 cryptography 库")
    sys.exit(1)

PRODUCT_NAME = "laser_cal"


def _get_base_dir():
    """获取程序基础目录"""
    if getattr(sys, 'frozen', False) or '__compiled__' in dir():
        # 如果是被打包的程序，寻找当前执行路径的目录
        return Path(sys.executable).parent
    # 开发环境下，如果是从共享库加载，__file__ 指向当前文件
    return Path(__file__).parent


def _find_file(filename):
    """在可能的位置查找文件"""
    # 1. 尝试当前执行文件目录
    base = _get_base_dir()
    if (base / filename).exists():
        return base / filename
    
    # 2. 尝试当前工作目录
    cwd = Path.cwd()
    if (cwd / filename).exists():
        return cwd / filename
        
    # 3. 尝试开发环境下的 dist/license 目录
    dev_path = Path(__file__).parent / "dist" / "license" / filename
    if dev_path.exists():
        return dev_path
        
    return None


def verify_license(verbose=False):
    """验证 License 文件"""
    license_path = _find_file("license.lic")
    pubkey_path = _find_file("public_key.pem")

    if not license_path:
        if verbose:
            print(f"[授权错误] License 文件 (license.lic) 不存在")
        return False

    if not pubkey_path:
        if verbose:
            print(f"[授权错误] 公钥文件 (public_key.pem) 不存在")
        return False

    try:
        license_content = json.loads(license_path.read_text(encoding="utf-8"))
        license_data = license_content["license_data"]
        signature_b64 = license_content["signature"]
    except (json.JSONDecodeError, KeyError):
        if verbose:
            print("[授权错误] License 文件格式无效")
        return False

    try:
        public_key = serialization.load_pem_public_key(
            pubkey_path.read_bytes(), backend=default_backend()
        )
    except Exception:
        if verbose:
            print("[授权错误] 公钥加载失败")
        return False

    # 验证 RSA 签名
    try:
        license_json = json.dumps(license_data, sort_keys=True, ensure_ascii=False)
        signature = base64.b64decode(signature_b64)
        public_key.verify(
            signature, license_json.encode("utf-8"), padding.PKCS1v15(), hashes.SHA256()
        )
    except InvalidSignature:
        if verbose:
            print("[授权错误] License 签名验证失败，文件可能被篡改")
        return False
    except Exception:
        if verbose:
            print("[授权错误] 签名验证过程出错")
        return False

    # 检查过期日期
    expire_str = license_data.get("expire_date", "")
    if expire_str.lower() != "never":
        try:
            expire_date = datetime.strptime(expire_str, "%Y-%m-%d")
            if datetime.now() > expire_date:
                if verbose:
                    print(f"[授权错误] License 已过期: {expire_str}")
                return False
        except ValueError:
            if verbose:
                print("[授权错误] 过期日期格式无效")
            return False

    # 检查产品名
    if license_data.get("product", "") != PRODUCT_NAME:
        if verbose:
            print("[授权错误] License 产品不匹配")
        return False

    if verbose:
        print(f"[授权验证] 通过 | {license_data.get('licensee')} | 过期: {expire_str}")
    return True


def get_license_info():
    """获取 License 信息"""
    license_path = _find_file("license.lic")
    if not license_path:
        return {}
    try:
        content = json.loads(license_path.read_text(encoding="utf-8"))
        return content.get("license_data", {})
    except Exception:
        return {}


if __name__ == "__main__":
    verify_license(verbose=True)