# coding=utf-8
"""本地对象存储（静态文件目录）。

图片落到本目录，通过 GET /media/... 对外访问。
生产可把 data/media 挂到 Nginx / OSS，接口形态不变。
"""

from __future__ import annotations
import os
import re
import time
from pathlib import Path

_FOLDER = os.path.dirname(os.path.abspath(__file__))
MEDIA_ROOT = os.environ.get("DISH_MEDIA_ROOT") or os.path.join(_FOLDER, "data", "media")
MEDIA_PUBLIC_BASE = os.environ.get("DISH_MEDIA_PUBLIC_BASE", "http://127.0.0.1:9000/media").rstrip("/")

_SAFE = re.compile(r"[^A-Za-z0-9._-]+")
ALLOWED_TYPES = ("source", "labeled", "crop")
ALLOWED_EXT = {".jpg", ".jpeg", ".png", ".bmp", ".webp"}


def _safe_token(value, fallback="x"):
    text = _SAFE.sub("_", str(value or "").strip())[:80]
    return text or fallback


def public_url(rel_path):
    rel = str(rel_path or "").replace("\\", "/").lstrip("/")
    return f"{MEDIA_PUBLIC_BASE}/{rel}"


def local_path(rel_path):
    rel = str(rel_path or "").replace("\\", "/").lstrip("/")
    return os.path.normpath(os.path.join(MEDIA_ROOT, *rel.split("/")))


def is_http_url(value):
    text = (value or "").strip().lower()
    return text.startswith("http://") or text.startswith("https://")


class MediaStore:
    """按 基地 / 请求号 归档图片。"""

    def __init__(self, root=None, public_base=None):
        self.root = os.path.abspath(root or MEDIA_ROOT)
        self.public_base = (public_base or MEDIA_PUBLIC_BASE).rstrip("/")
        os.makedirs(self.root, exist_ok=True)

    def save_bytes(self, data, filename, media_type="source", base_id="BASE", request_id=None):
        if not data:
            raise ValueError("empty file")
        media_type = (media_type or "source").strip().lower()
        if media_type not in ALLOWED_TYPES:
            media_type = "source"
        ext = Path(filename or "").suffix.lower() or ".jpg"
        if ext not in ALLOWED_EXT:
            ext = ".jpg"
        req = _safe_token(request_id or f"REQ_{int(time.time() * 1000)}")
        base = _safe_token(base_id or "BASE")
        stem = _safe_token(Path(filename or media_type).stem, media_type)
        rel = f"{base}/{req}/{media_type}_{stem}{ext}"
        dest = local_path_under(self.root, rel)
        os.makedirs(os.path.dirname(dest), exist_ok=True)
        with open(dest, "wb") as fh:
            fh.write(data)
        rel_url = rel.replace("\\", "/")
        return {
            "rel_path": rel_url,
            "path": dest,
            "url": f"{self.public_base}/{rel_url}",
            "type": media_type,
        }

    def save_file(self, src_path, media_type="source", base_id="BASE", request_id=None):
        if not src_path or not os.path.isfile(src_path):
            return None
        with open(src_path, "rb") as fh:
            data = fh.read()
        return self.save_bytes(
            data,
            filename=os.path.basename(src_path),
            media_type=media_type,
            base_id=base_id,
            request_id=request_id,
        )


def local_path_under(root, rel_path):
    dest = os.path.normpath(os.path.join(root, *str(rel_path).replace("\\", "/").split("/")))
    root_abs = os.path.abspath(root)
    dest_abs = os.path.abspath(dest)
    if dest_abs != root_abs and not dest_abs.startswith(root_abs + os.sep):
        raise ValueError("invalid media path")
    return dest_abs


def copy_if_local(src_path, media_type, base_id, request_id, store=None):
    if not src_path:
        return src_path
    if is_http_url(src_path):
        return src_path
    store = store or MediaStore()
    saved = store.save_file(src_path, media_type=media_type, base_id=base_id, request_id=request_id)
    return saved["url"] if saved else src_path