from __future__ import annotations

import os
from pathlib import Path
import paramiko


def _sftp_client() -> tuple[paramiko.SFTPClient, paramiko.Transport]:
    host = (os.environ.get("SFTP_HOST") or "").strip()
    user = (os.environ.get("SFTP_USER") or "").strip()
    port = int((os.environ.get("SFTP_PORT") or "22").strip() or "22")
    password = os.environ.get("SFTP_PASS")

    if not host or not user:
        raise RuntimeError("Missing SFTP_HOST or SFTP_USER")
    if not password:
        raise RuntimeError("Missing SFTP_PASS")

    t = paramiko.Transport((host, port))
    # force password-only auth
    t.connect(username=user, password=password)
    return paramiko.SFTPClient.from_transport(t), t


def _mkdir_p(sftp: paramiko.SFTPClient, remote_dir: str) -> None:
    parts = [p for p in remote_dir.strip("/").split("/") if p]
    cur = ""
    for part in parts:
        cur += "/" + part
        try:
            sftp.stat(cur)
        except FileNotFoundError:
            sftp.mkdir(cur)


def store_to_sftp(
    pdf_id: str,
    template_id: str,
    cfg_json_bytes: bytes,
    pdf_bytes: bytes,
    pdf_name: str,
) -> str:
    """
    Remote layout:
      <base>/<template_id>/<pdf_id>/
        trainer_config_<pdf_id>__<template_id>.json
        <pdf_name or <pdf_id>.pdf>
    """
    base = (os.environ.get("SFTP_BASE_DIR") or "/").strip()
    if not base.startswith("/"):
        base = "/" + base
    base = base.rstrip("/") or "/"

    sftp, transport = _sftp_client()
    try:
        remote_dir = f"{base}/{template_id}/{pdf_id}".replace("//", "/")
        _mkdir_p(sftp, remote_dir)

        remote_cfg = f"{remote_dir}/trainer_config_{pdf_id}__{template_id}.json"
        remote_pdf_name = (pdf_name or f"{pdf_id}.pdf").lstrip("/")
        remote_pdf = f"{remote_dir}/{remote_pdf_name}"

        with sftp.open(remote_cfg, "wb") as f:
            f.write(cfg_json_bytes)
        with sftp.open(remote_pdf, "wb") as f:
            f.write(pdf_bytes)

        return remote_dir
    finally:
        try:
            sftp.close()
        finally:
            transport.close()