import logging
import os
from pathlib import Path
from typing import Optional
try:
    import alibabacloud_oss_v2 as oss
except Exception:  # pragma: no cover - import guard for optional dependency
    oss = None

logger = logging.getLogger("oss.upload")


class OssUploadError(RuntimeError):
    pass


def _get_env(*keys: str, required: bool = False) -> Optional[str]:
    for key in keys:
        value = os.getenv(key)
        if value:
            return value
    if required:
        raise OssUploadError(f"missing env: {keys[0]}")
    return None


def _build_object_key(
    html_path: Path,
    object_key: Optional[str],
    prefix: Optional[str],
    task_id: Optional[str],
) -> str:
    if object_key:
        key = object_key
    elif task_id:
        key = f"{task_id}.html"
    else:
        key = html_path.name
    if prefix:
        prefix_clean = prefix.strip().strip("/")
        if prefix_clean:
            return f"{prefix_clean}/{key.lstrip('/')}"
    return key.lstrip("/")


def upload_html_to_oss(
    html_path: Path,
    *,
    object_key: Optional[str] = None,
    task_id: Optional[str] = None,
) -> str:
    """
    Upload a generated HTML file to OSS and return a public URL.
    """
    if not html_path.exists():
        raise OssUploadError(f"html not found: {html_path}")

    if html_path.suffix.lower() != ".html":
        raise OssUploadError(f"invalid html suffix: {html_path}")

    if oss is None:
        raise OssUploadError("alibabacloud-oss-v2 not installed")

    access_key_id = _get_env("ALIYUN_OSS_ACCESS_KEY_ID")
    access_key_secret = _get_env("ALIYUN_OSS_ACCESS_KEY_SECRET")

    if not access_key_id:
        raise OssUploadError("missing env: ALIYUN_OSS_ACCESS_KEY_ID")
    if not access_key_secret:
        raise OssUploadError("missing env: ALIYUN_OSS_ACCESS_KEY_SECRET")
    bucket_name = _get_env("ALIYUN_OSS_BUCKET")
    if not bucket_name:
        raise OssUploadError("missing env: ALIYUN_OSS_BUCKET")
    region = _get_env("ALIYUN_OSS_REGION")
    if not region:
        raise OssUploadError("missing env: ALIYUN_OSS_REGION")
    prefix = _get_env("ALIYUN_OSS_PREFIX")
    if not prefix:
        raise OssUploadError("missing env: ALIYUN_OSS_PREFIX")
    public_base_url = _get_env("ALIYUN_OSS_PUBLIC_BASE_URL")
    if not public_base_url:
        raise OssUploadError("missing env: ALIYUN_OSS_PUBLIC_BASE_URL")

    key = _build_object_key(html_path, object_key, prefix, task_id)
    logger.info(
        "oss upload start",
        extra={
            "bucket": bucket_name,
            "region": region,
            "key": key,
            "html_path": str(html_path),
        },
    )

    credentials_provider = oss.credentials.StaticCredentialsProvider(
        access_key_id=access_key_id,
        access_key_secret=access_key_secret,
    )
    cfg = oss.config.load_default()
    cfg.credentials_provider = credentials_provider
    cfg.region = region
    client = oss.Client(cfg)
    request = oss.PutObjectRequest(bucket=bucket_name, key=key)
    result = client.put_object_from_file(request, str(html_path))
    if result.status_code >= 300:
        logger.error(
            "oss upload failed",
            extra={
                "bucket": bucket_name,
                "region": region,
                "key": key,
                "status_code": result.status_code,
            },
        )
        raise OssUploadError(f"oss upload failed: status={result.status_code}")
    logger.info(
        "oss upload success",
        extra={
            "bucket": bucket_name,
            "region": region,
            "key": key,
            "status_code": result.status_code,
        },
    )

    base = public_base_url.rstrip("/")
    return f"{base}/{key}"