import mimetypes
import boto3
import os
import logging
from botocore.exceptions import ClientError

# 初始化 S3 客户端和资源对象
s3_client = boto3.client('s3',aws_access_key_id="", aws_secret_access_key="")
s3_resource = boto3.resource('s3',aws_access_key_id="", aws_secret_access_key="")

# 设置日志记录器
logger = logging.getLogger('S3-img-processing')
logger.addHandler(logging.StreamHandler())
logger.setLevel(getattr(logging, os.getenv('LOG_LEVEL', 'INFO')))

# 支持的图片文件扩展名
IMAGE_EXTENSIONS = {'.jpg', '.jpeg', '.png', '.gif', '.bmp', '.tiff', '.webp'}


def is_supported_image(key):
    """
    判断文件是否是支持的图片格式，根据文件扩展名。
    """
    extension = os.path.splitext(key)[-1].lower()
    return extension in IMAGE_EXTENSIONS


def resize_image(image_path, resized_path):
    """
    调整图像大小至原图的一半，并保存到指定路径。
    """
    from PIL import Image
    with Image.open(image_path) as image:
        image.thumbnail(tuple(x / 2 for x in image.size))
        image.save(resized_path)


def process_image(bucket_name, key):
    """
    处理指定 S3 文件，将其大小调整后保存到目标路径。
    """
    try:
        # 跳过非图片文件和目标目录中的文件
        if not is_supported_image(key):
            logger.info(f"文件 {key} 不是支持的图片格式，跳过处理")
            return
        if key.startswith('resized/'):
            logger.info(f"文件 {key} 位于 resized/ 目录中，跳过处理")
            return

        # 临时文件路径
        download_path = f'/tmp/{os.path.basename(key)}'
        resized_path = f'/tmp/resized_{os.path.basename(key)}'

        # 下载文件
        s3_client.download_file(bucket_name, key, download_path)

        # 调整图片大小
        resize_image(download_path, resized_path)

        # 构造上传路径
        resized_key = f'resized/{key}'

        # 上传文件到目标存储桶
        content_type, _ = mimetypes.guess_type(resized_path)
        if not content_type:
            logger.warning(f"无法检测文件 {resized_path} 的 MIME 类型，默认为 binary/octet-stream")
            content_type = "binary/octet-stream"

        with open(resized_path, "rb") as file_data:
            s3_client.upload_fileobj(
                file_data,
                bucket_name,
                resized_key,
                ExtraArgs={"ContentType": content_type}
            )
        logger.info(f'File uploaded to {bucket_name}/{resized_key} with ContentType {content_type}')

    except ClientError as e:
        logger.error(f"处理文件 {key} 时出错: {e}")


def scan_and_process_images(bucket_name, folder):
    """
    扫描 S3 存储桶中的指定文件夹，并处理支持的图片文件。
    """
    bucket = s3_resource.Bucket(bucket_name)
    prefix = folder.rstrip('/') + '/'  # 确保以 '/' 结尾

    for obj in bucket.objects.filter(Prefix=prefix):
        logger.info(f"Processing file: {obj.key}")
        process_image(bucket_name, obj.key)


if __name__ == "__main__":
    # 从环境变量获取存储桶名称和目标文件夹
    bucket_name = 'bucket_name'
    folder = 'folder'

    logger.info(f"开始扫描存储桶 {bucket_name} 中文件夹 {folder} 的文件")
    scan_and_process_images(bucket_name, folder)
    logger.info("所有文件处理完成")