app/utils/helpers.py

"""
通用工具函数模块
"""
import json
import re
import base64
import requests
from typing import Dict, Any, List, Optional, Tuple
from pathlib import Path
import logging

from app.core.constants import DATA_URL_PATTERN, IMAGE_URL_PATTERN, VALID_IMAGE_RATIOS

helper_logger = logging.getLogger("app.utils")

PROJECT_ROOT = Path(__file__).resolve().parent.parent.parent
VERSION_FILE_PATH = PROJECT_ROOT / "VERSION"


def extract_mime_type_and_data(base64_string: str) -> Tuple[Optional[str], str]:
    """
    从 base64 字符串中提取 MIME 类型和数据
    
    Args:
        base64_string: 可能包含 MIME 类型信息的 base64 字符串
        
    Returns:
        tuple: (mime_type, encoded_data)
    """
    # 检查字符串是否以 "data:" 格式开始
    if base64_string.startswith('data:'):
        # 提取 MIME 类型和数据
        pattern = DATA_URL_PATTERN
        match = re.match(pattern, base64_string)
        if match:
            mime_type = "image/jpeg" if match.group(1) == "image/jpg" else match.group(1)
            encoded_data = match.group(2)
            return mime_type, encoded_data
    
    # 如果不是预期格式，假定它只是数据部分
    return None, base64_string


def convert_image_to_base64(url: str) -> str:
    """
    将图片URL转换为base64编码
    
    Args:
        url: 图片URL
        
    Returns:
        str: base64编码的图片数据
        
    Raises:
        Exception: 如果获取图片失败
    """
    response = requests.get(url)
    if response.status_code == 200:
        # 将图片内容转换为base64
        img_data = base64.b64encode(response.content).decode('utf-8')
        return img_data
    else:
        raise Exception(f"Failed to fetch image: {response.status_code}")


def format_json_response(data: Dict[str, Any], indent: int = 2) -> str:
    """
    格式化JSON响应
    
    Args:
        data: 要格式化的数据
        indent: 缩进空格数
        
    Returns:
        str: 格式化后的JSON字符串
    """
    return json.dumps(data, indent=indent, ensure_ascii=False)


def parse_prompt_parameters(prompt: str, default_ratio: str = "1:1") -> Tuple[str, int, str]:
    """
    从prompt中解析参数
    
    支持的格式:
    - {n:数量} 例如: {n:2} 生成2张图片
    - {ratio:比例} 例如: {ratio:16:9} 使用16:9比例
    
    Args:
        prompt: 提示文本
        default_ratio: 默认比例
        
    Returns:
        tuple: (清理后的提示文本, 图片数量, 比例)
    """
    # 默认值
    n = 1
    aspect_ratio = default_ratio
    
    # 解析n参数
    n_match = re.search(r'{n:(\d+)}', prompt)
    if n_match:
        n = int(n_match.group(1))
        if n < 1 or n > 4:
            raise ValueError(f"Invalid n value: {n}. Must be between 1 and 4.")
        prompt = prompt.replace(n_match.group(0), '').strip()
        
    # 解析ratio参数    
    ratio_match = re.search(r'{ratio:(\d+:\d+)}', prompt)
    if ratio_match:
        aspect_ratio = ratio_match.group(1)
        if aspect_ratio not in VALID_IMAGE_RATIOS:
            raise ValueError(
                f"Invalid ratio: {aspect_ratio}. Must be one of: {', '.join(VALID_IMAGE_RATIOS)}"
            )
        prompt = prompt.replace(ratio_match.group(0), '').strip()
        
    return prompt, n, aspect_ratio


def extract_image_urls_from_markdown(text: str) -> List[str]:
    """
    从Markdown文本中提取图片URL
    
    Args:
        text: Markdown文本
        
    Returns:
        List[str]: 图片URL列表
    """
    pattern = IMAGE_URL_PATTERN
    matches = re.findall(pattern, text)
    return [match[1] for match in matches]


def is_valid_api_key(key: str) -> bool:
    """
    检查API密钥格式是否有效
    
    Args:
        key: API密钥
        
    Returns:
        bool: 如果密钥格式有效则返回True
    """
    # 检查Gemini API密钥格式
    if key.startswith('AIza'):
        return len(key) >= 30
    
    # 检查OpenAI API密钥格式
    if key.startswith('sk-'):
        return len(key) >= 30
    
    return False



def get_current_version(default_version: str = "0.0.0") -> str:
    """Reads the current version from the VERSION file."""
    version_file = VERSION_FILE_PATH
    try:
        with version_file.open('r', encoding='utf-8') as f:
            version = f.read().strip()
        if not version:
            helper_logger.warning(f"VERSION file ('{version_file}') is empty. Using default version '{default_version}'.")
            return default_version
        return version
    except FileNotFoundError:
        helper_logger.warning(f"VERSION file not found at '{version_file}'. Using default version '{default_version}'.")
        return default_version
    except IOError as e:
        helper_logger.error(f"Error reading VERSION file ('{version_file}'): {e}. Using default version '{default_version}'.")
        return default_version