"""Aliyun background-removal integration.

Aliyun Marketplace product cmapi00069648 exposes:
  POST https://bgrem.market.alicloudapi.com/api/v1/bg-remove/submit
  POST https://bgrem.market.alicloudapi.com/api/v1/bg-remove/query

The remote service requires a public image URL. Generated images from the
current gpt-image-2 gateway are usually b64-only, so the pipeline uses remote
matting only when a public URL is available. There is intentionally no local
fallback because local matting was not clean enough for production assets.
"""

import base64
import http.client
import io
import json
import time
import uuid
from urllib.parse import urlparse

from PIL import Image, ImageFilter

import config

ALIYUN_APP_CODE = config.get("ALIYUN_BGREM_APP_CODE", "")
HOST = "bgrem.market.alicloudapi.com"
SUBMIT_PATH = "/api/v1/bg-remove/submit"
QUERY_PATH = "/api/v1/bg-remove/query"


def _json_post(path, payload, timeout=60):
    if not ALIYUN_APP_CODE:
        raise RuntimeError("missing ALIYUN_BGREM_APP_CODE")
    body = json.dumps(payload, ensure_ascii=False).encode("utf-8")
    headers = {
        "Content-Type": "application/json; charset=utf-8",
        "Accept": "application/json",
        "Authorization": f"APPCODE {ALIYUN_APP_CODE}",
        "X-Ca-Nonce": uuid.uuid4().hex,
    }
    conn = http.client.HTTPSConnection(HOST, timeout=timeout)
    try:
        conn.request("POST", path, body=body, headers=headers)
        res = conn.getresponse()
        raw = res.read()
        res_headers = dict(res.getheaders())
    finally:
        conn.close()
    if res.status < 200 or res.status >= 300:
        msg = raw.decode("utf-8", "ignore") or res_headers.get("X-Ca-Error-Message", "")
        raise RuntimeError(f"HTTP {res.status}: {msg}")
    if not raw:
        raise RuntimeError("empty response")
    return json.loads(raw.decode("utf-8"))


def _download(url, timeout=120):
    parsed = urlparse(url)
    path = parsed.path or "/"
    if parsed.query:
        path += "?" + parsed.query
    conn_cls = http.client.HTTPSConnection if parsed.scheme == "https" else http.client.HTTPConnection
    conn = conn_cls(parsed.hostname, parsed.port, timeout=timeout)
    try:
        conn.request("GET", path)
        res = conn.getresponse()
        raw = res.read()
    finally:
        conn.close()
    if res.status < 200 or res.status >= 300:
        raise RuntimeError(f"download HTTP {res.status}")
    return raw


def _extract_result_key(data):
    payload = data.get("data", data)
    if isinstance(payload, str):
        try:
            payload = json.loads(payload)
        except Exception:
            return payload
    if isinstance(payload, dict):
        for key in ("result_key", "resultKey", "task_key", "taskKey"):
            if payload.get(key):
                return payload[key]
        tasks = payload.get("task_list") or payload.get("taskList")
        if isinstance(tasks, list) and tasks:
            return _extract_result_key(tasks[0])
    return None


def _extract_result_url(data):
    payload = data.get("data", data)
    if isinstance(payload, str):
        try:
            payload = json.loads(payload)
        except Exception:
            return payload if payload.startswith(("http://", "https://")) else None
    if isinstance(payload, dict):
        results = payload.get("results")
        if isinstance(results, list) and results:
            return results[0]
        for key in ("url", "result", "result_url", "resultUrl", "image_url", "imageUrl", "alpha", "alpha_url"):
            val = payload.get(key)
            if isinstance(val, str) and val:
                return val
        tasks = payload.get("task_list") or payload.get("taskList") or payload.get("result_list") or payload.get("resultList")
        if isinstance(tasks, list) and tasks:
            return _extract_result_url(tasks[0])
    return None


def _ensure_success(data):
    if data.get("success") is False:
        raise RuntimeError(data.get("message") or json.dumps(data, ensure_ascii=False)[:500])
    code = data.get("code")
    if code not in (None, 0, "0", 200, "200"):
        raise RuntimeError(data.get("message") or json.dumps(data, ensure_ascii=False)[:500])


def _remote_remove_by_url(image_url, model_type="general", log=None, label="image"):
    submit_body = {"data": {"task_list": [{"model_type": model_type, "image": image_url}]}}
    if log:
        log(f"🧼 [{label}] 去背景：提交阿里云任务…")
    submit = _json_post(SUBMIT_PATH, submit_body, timeout=60)
    _ensure_success(submit)
    result_key = _extract_result_key(submit)
    if not result_key:
        raise RuntimeError(f"提交接口未返回 result_key: {json.dumps(submit, ensure_ascii=False)[:500]}")
    if log:
        log(f"🧼 [{label}] 去背景：任务已提交 result_key={result_key}")

    query_body = {"data": {"result_key": result_key}}
    last = None
    for i in range(40):
        time.sleep(1.5 if i else 0.3)
        data = _json_post(QUERY_PATH, query_body, timeout=60)
        _ensure_success(data)
        last = data
        result_url = _extract_result_url(data)
        if result_url:
            if log:
                log(f"🧼 [{label}] 去背景：任务完成，下载透明 PNG…")
            return Image.open(io.BytesIO(_download(result_url))).convert("RGBA")
        if log and i in (0, 3, 10, 20):
            log(f"🧼 [{label}] 去背景：等待任务结果…")
    raise RuntimeError(f"查询超时，最后返回: {json.dumps(last, ensure_ascii=False)[:500]}")


def remove_background(img, log=None, label="image", enabled=True, image_url=None, model_type="general"):
    if not enabled:
        return img.convert("RGBA")
    if image_url and image_url.startswith(("http://", "https://")):
        try:
            out = _remote_remove_by_url(image_url, model_type=model_type, log=log, label=label)
            if log:
                log(f"✅ [{label}] 远端去背景完成：透明 PNG {out.size[0]}×{out.size[1]}")
            return out
        except Exception as e:
            if log:
                log(f"⚠️  [{label}] 远端去背景失败，保留原图：{e}")
    else:
        if log:
            log(f"ℹ️ [{label}] 去背景：当前图片没有公网 URL，跳过远端去背景并保留原图")
    return img.convert("RGBA")