"""
seaweed_store.py
Sdileny helper pro ukladani priloh do SeaweedFS Fileru na Tower1 (192.168.1.50).

Pouzivaji:
    - 3_download_attachments_v1.5.py  (Graph pipeline, dalsi behy)
    - seaweed_attachments_backfill_graph.py  (jednorazovy backfill jiz stazenych priloh)
    - mailstore/mailstore_attachments_poc.py  (mailstore vetev — stejne schema cesty)

Schema cesty je content-addressed dle SHA-256 obsahu:
    /mail-attachments/<ab>/<cd>/<plny-hash>
=> identicky obsah z libovolneho zdroje (Graph i mailstore) skonci na stejne
ceste a deduplikuje se globalne.

Upload: PUT raw telo (POST multipart na prvni zapis do Fileru timeoutuje!).
"""

import requests

SEAWEED_FILER = "http://192.168.1.50:8888"
BASE_PATH     = "/mail-attachments"
HTTP_TIMEOUT  = 60

# Lazy modulova session — znovupouziti spojeni napric volanimi v ramci procesu.
_SESSION: requests.Session | None = None


def _session() -> requests.Session:
    global _SESSION
    if _SESSION is None:
        _SESSION = requests.Session()
    return _SESSION


def seaweed_path(sha256: str) -> str:
    """Cesta deduplikovana podle obsahu: /mail-attachments/ab/cd/<hash>."""
    return f"{BASE_PATH}/{sha256[:2]}/{sha256[2:4]}/{sha256}"


def seaweed_url(sha256: str) -> str:
    return SEAWEED_FILER + seaweed_path(sha256)


def exists(path: str, sess: requests.Session | None = None) -> bool:
    sess = sess or _session()
    try:
        r = sess.head(SEAWEED_FILER + path, timeout=HTTP_TIMEOUT)
        return r.status_code == 200
    except requests.RequestException:
        return False


def put(path: str, data: bytes, mime: str, sess: requests.Session | None = None) -> bool:
    sess = sess or _session()
    r = sess.put(SEAWEED_FILER + path, data=data,
                 headers={"Content-Type": mime or "application/octet-stream"},
                 timeout=HTTP_TIMEOUT)
    return r.status_code in (200, 201)


def store(sha256: str, data: bytes, mime: str,
          sess: requests.Session | None = None) -> tuple[str, str, bool]:
    """Ulozi obsah do SeaweedFS (idempotentne, dedup dle hashe).

    Vraci (path, url, uploaded):
        uploaded=True  pokud byl objekt nove nahran
        uploaded=False pokud uz na ceste existoval (dedup hit)
    Vyhazuje requests.RequestException / RuntimeError pri selhani zapisu —
    volajici si osetri (pipeline nesmi spadnout, jen preskoci seaweed pole).
    """
    sess = sess or _session()
    path = seaweed_path(sha256)
    if exists(path, sess):
        return path, SEAWEED_FILER + path, False
    if not put(path, data, mime, sess):
        raise RuntimeError(f"SeaweedFS PUT selhal pro {path}")
    return path, SEAWEED_FILER + path, True