import re
from typing import Any

IMAGE_STATUS_PENDING = "pending"
IMAGE_STATUS_PROCESSING = "processing"
IMAGE_STATUS_COMPLETED = "completed"
IMAGE_STATUS_FAILED = "failed"

VALID_IMAGE_STATUSES = {
    IMAGE_STATUS_PENDING,
    IMAGE_STATUS_PROCESSING,
    IMAGE_STATUS_COMPLETED,
    IMAGE_STATUS_FAILED,
}

_PLACEHOLDER_DESCRIPTION_RE = re.compile(
    r"\{\{\{\{IMAGE:(.*?)\}\}\}\}|\{\{IMAGE:(.*?)\}\}"
)


def normalize_image_asset(asset: dict[str, Any] | None) -> dict[str, Any] | None:
    """归一化单条图片 dict。

    - 可解析 {{{{IMAGE:…}}}} / {{IMAGE:…}} 占位符中的 description。
    - 插图不嵌入 markdown 时可无占位符；已完成且带 url/storage_key 即可通过，
      description 缺省时用「插图」；pending/processing 至少要有 description、占位符或 prompt。
    """
    if not isinstance(asset, dict):
        return None

    ph_in = _as_non_empty_string(asset.get("placeholder"))
    desc_in = _as_non_empty_string(asset.get("description"))
    desc_from_ph = _extract_description_from_placeholder(ph_in) if ph_in else None
    merged_description = desc_in or desc_from_ph

    prompt_s = _as_non_empty_string(asset.get("prompt"))
    error_s = _as_optional_string(asset.get("error"))
    url_s = _as_optional_string(asset.get("url"))
    storage_key_s = _as_optional_string(asset.get("storage_key"))
    has_url_or_key = bool(url_s or storage_key_s)

    status = _as_non_empty_string(asset.get("status")) or IMAGE_STATUS_PENDING

    if ph_in and merged_description:
        placeholder_out = ph_in
        description_out = merged_description
    elif status == IMAGE_STATUS_COMPLETED and has_url_or_key:
        placeholder_out = ph_in or ""
        description_out = merged_description or "插图"
    elif status in (IMAGE_STATUS_PENDING, IMAGE_STATUS_PROCESSING):
        if not (merged_description or ph_in or prompt_s):
            return None
        placeholder_out = ph_in or ""
        description_out = merged_description or prompt_s or "插图"
    elif status == IMAGE_STATUS_FAILED:
        if not (merged_description or ph_in or error_s):
            return None
        placeholder_out = ph_in or ""
        description_out = merged_description or "插图"
    else:
        return None

    normalized = dict(asset)
    normalized["index"] = _coerce_int(asset.get("index"), default=0)
    normalized["placeholder"] = placeholder_out
    normalized["description"] = description_out
    if status not in VALID_IMAGE_STATUSES:
        normalized["status"] = IMAGE_STATUS_FAILED
        normalized["error"] = asset.get("error") or f"invalid image status: {status}"
        return normalized

    normalized["status"] = status
    normalized["prompt"] = _as_optional_string(asset.get("prompt"))
    normalized["url"] = _as_optional_string(asset.get("url"))
    normalized["storage_key"] = _as_optional_string(asset.get("storage_key"))
    normalized["provider"] = _as_optional_string(asset.get("provider"))
    normalized["style"] = _as_optional_string(asset.get("style"))
    normalized["size"] = _as_optional_string(asset.get("size"))
    normalized["error"] = _as_optional_string(asset.get("error"))
    normalized["created_at"] = _as_optional_string(asset.get("created_at"))
    normalized["updated_at"] = _as_optional_string(asset.get("updated_at"))
    normalized["retryable"] = _as_optional_bool(asset.get("retryable"))

    if normalized["status"] == IMAGE_STATUS_COMPLETED and not (
        normalized["url"] or normalized["storage_key"]
    ):
        normalized["status"] = IMAGE_STATUS_FAILED
        normalized["error"] = normalized["error"] or "missing image url"

    if normalized["status"] != IMAGE_STATUS_FAILED:
        normalized["retryable"] = None

    return normalized


def normalize_image_assets(images: list[dict[str, Any]] | None) -> list[dict[str, Any]]:
    normalized_assets: list[dict[str, Any]] = []
    for item in images or []:
        normalized = normalize_image_asset(item)
        if normalized:
            normalized_assets.append(normalized)
    return normalized_assets


def completed_image_assets(images: list[dict[str, Any]] | None) -> list[dict[str, Any]]:
    return [
        asset
        for asset in normalize_image_assets(images)
        if asset.get("status") == IMAGE_STATUS_COMPLETED
        and (asset.get("storage_key") or asset.get("url"))
    ]


def _as_non_empty_string(value: Any) -> str | None:
    if isinstance(value, str):
        stripped = value.strip()
        return stripped or None
    return None


def _as_optional_string(value: Any) -> str | None:
    if value is None:
        return None
    if isinstance(value, str):
        return value
    return str(value)


def _as_optional_bool(value: Any) -> bool | None:
    if value is None:
        return None
    if isinstance(value, bool):
        return value
    if isinstance(value, str):
        lowered = value.strip().lower()
        if lowered in {"true", "1", "yes"}:
            return True
        if lowered in {"false", "0", "no"}:
            return False
    return None


def _coerce_int(value: Any, default: int) -> int:
    try:
        return int(value)
    except (TypeError, ValueError):
        return default


def _extract_description_from_placeholder(placeholder: str | None) -> str | None:
    if not placeholder:
        return None
    match = _PLACEHOLDER_DESCRIPTION_RE.fullmatch(placeholder.strip())
    if not match:
        return None
    description = (match.group(1) or match.group(2) or "").strip()
    return description or None