"""
千问视觉：只读图上可见原文。

本文件职责：把图片交给 qwen3-vl-plus，抄出看得见的文字。
属于 llm 包。依赖：LlmHttpClient（生产）；单测注入 chat_fn。
禁止：填询价字段 JSON、算最终缺项、发明港口/重量/日期；禁止在回调线程长等（由 Worker 槽调用）。
"""

from __future__ import annotations

import logging
from typing import Any, Optional

from agent.llm.modes import LlmMode

logger = logging.getLogger(__name__)

MODE = LlmMode.VISION

VISION_SYSTEM = (
    "只读出图片上能看见的文字和数字，原样抄写，一行不漏。"
    "英文、机场三字码、航线（如 SZX-CGK、SZX/CGK）必须保持原样，禁止翻译成中文城市名。"
    "看不清的字不要猜。不要补询价缺项，不要发明港口、重量或日期。"
    "只有整张图完全没有文字时才输出空；只要看得见字就必须抄出来。"
)


def sniff_image_mime(raw: bytes) -> str:
    """
    按文件头认图片类型。企微截图经常是 PNG，不能一律当 JPEG 送给千问。
    """
    blob = raw or b""
    if len(blob) < 12:
        return ""
    if blob.startswith(b"\x89PNG\r\n\x1a\n"):
        return "image/png"
    if blob.startswith(b"\xff\xd8\xff"):
        return "image/jpeg"
    if blob[:4] == b"RIFF" and blob[8:12] == b"WEBP":
        return "image/webp"
    if blob.startswith(b"GIF87a") or blob.startswith(b"GIF89a"):
        return "image/gif"
    if blob[4:8] == b"ftyp":
        return "image/heic"
    if blob.startswith(b"BM"):
        return "image/bmp"
    return ""


def mode_meta() -> dict[str, Any]:
    return {
        "mode": MODE.value,
        "provider": "qwen",
        "purpose": "vision",
        "implemented": True,
    }


def _pack_text(text: str, *, stub: bool = False) -> dict[str, Any]:
    body = (text or "").strip()
    return {
        "ok": True,
        "stub": stub,
        "mode": MODE.value,
        "text": body,
        "empty": not bool(body),
        "error": "",
    }


def invoke_shell(*, payload: dict[str, Any]) -> dict[str, Any]:
    """
    无网/单测入口：assistant_text 当作图上可见原文。

    没有该键时保持失败码，避免假装已经读图。
    """
    if "assistant_text" in (payload or {}):
        packed = _pack_text(str(payload.get("assistant_text") or ""), stub=True)
        return packed
    return {
        "ok": False,
        "stub": True,
        "mode": MODE.value,
        "text": "",
        "empty": True,
        "error": "vision_shell_not_implemented",
        "echo_keys": sorted((payload or {}).keys()),
    }


def _vision_messages(*, image_b64: str, mime: str, image_url: str) -> list[dict[str, Any]]:
    """拼兼容 OpenAI 的图文消息。优先 data URL，其次 http 图链。"""
    url = (image_url or "").strip()
    if not url and image_b64:
        kind = (mime or "image/jpeg").strip() or "image/jpeg"
        url = f"data:{kind};base64,{image_b64}"
    user_content: list[dict[str, Any]] = []
    if url:
        user_content.append({"type": "image_url", "image_url": {"url": url}})
    user_content.append({"type": "text", "text": "请只抄写图上可见文字。"})
    return [
        {"role": "system", "content": VISION_SYSTEM},
        {"role": "user", "content": user_content},
    ]


def invoke_vision(
    *,
    payload: dict[str, Any],
    chat_fn: Optional[Any] = None,
    allow_network: bool = False,
) -> dict[str, Any]:
    """
    读一张图，返回可见原文。

    chat_fn：单测注入，签名同 LlmHttpClient.chat。
    allow_network=False 且无 chat_fn：走 invoke_shell，不打真网。
    """
    data = dict(payload or {})
    image_b64 = str(data.get("image_b64") or "")
    image_url = str(data.get("image_url") or "")
    mime = str(data.get("mime") or "").strip() or "image/jpeg"
    if chat_fn is None and not allow_network:
        return invoke_shell(payload=data)
    if not image_b64 and not image_url:
        logger.info("vision 拒绝：没有图")
        return {
            "ok": False,
            "stub": False,
            "mode": MODE.value,
            "text": "",
            "empty": True,
            "error": "no_image",
        }
    if chat_fn is None:
        from agent.llm.http_client import LlmHttpClient

        client = LlmHttpClient.from_settings()
        chat_fn = client.chat
    messages = _vision_messages(
        image_b64=image_b64,
        mime=mime,
        image_url=image_url,
    )
    result = chat_fn(mode=MODE, messages=messages)
    if not getattr(result, "ok", False):
        err = str(getattr(result, "error", "") or "vision_failed")
        logger.info("vision 失败 err=%s", err)
        return {
            "ok": False,
            "stub": False,
            "mode": MODE.value,
            "text": "",
            "empty": True,
            "error": err,
        }
    packed = _pack_text(str(getattr(result, "content", "") or ""))
    packed["stub"] = False
    logger.info(
        "vision 读完 ok=%s empty=%s text_len=%s mime=%s",
        True,
        packed.get("empty"),
        len(str(packed.get("text") or "")),
        mime,
    )
    return packed