"""ASI Bridge plugin — CIFS mount watcher + FITS file scanner."""

import asyncio
import logging
import os
import time
from pathlib import Path
from typing import Optional

from fastapi import APIRouter, Depends, HTTPException, WebSocket, WebSocketDisconnect
from pydantic import BaseModel

from backend.auth import get_current_user, ws_authenticate
from backend.config import load_config, save_config

router = APIRouter(prefix="/api/plugins/asi-bridge", tags=["asi-bridge"])
log = logging.getLogger("atlus.asi_bridge")


class MountConfig(BaseModel):
    cifs_share: Optional[str] = None
    mount_point: Optional[str] = None
    cifs_user: Optional[str] = None
    cifs_pass: Optional[str] = None


async def _run(cmd: list[str]) -> tuple[int, str, str]:
    proc = await asyncio.create_subprocess_exec(
        *cmd,
        stdout=asyncio.subprocess.PIPE,
        stderr=asyncio.subprocess.PIPE,
    )
    stdout, stderr = await proc.communicate()
    return proc.returncode, stdout.decode(), stderr.decode()


def _is_mounted(mount_point: str) -> bool:
    """Check if a path is a mount point."""
    try:
        return os.path.ismount(mount_point)
    except OSError:
        return False


def _scan_fits(mount_point: str) -> list[dict]:
    """Scan for FITS files in the mount point."""
    fits_files = []
    mp = Path(mount_point)
    if not mp.is_dir():
        return fits_files

    for root, dirs, files in os.walk(str(mp)):
        for fname in files:
            if fname.lower().endswith((".fit", ".fits", ".fts")):
                fp = Path(root) / fname
                try:
                    st = fp.stat()
                    fits_files.append({
                        "name": fname,
                        "path": str(fp),
                        "size": st.st_size,
                        "modified": st.st_mtime,
                        "relative": str(fp.relative_to(mp)),
                    })
                except OSError:
                    continue
    fits_files.sort(key=lambda x: x["modified"], reverse=True)
    return fits_files


@router.get("/status")
async def bridge_status(_user: str = Depends(get_current_user)):
    """Get current ASI Bridge status."""
    cfg = load_config().get("asi_bridge", {})
    mount_point = cfg.get("mount_point", "/mnt/asiair")
    mounted = _is_mounted(mount_point)

    fits_count = 0
    total_size = 0
    latest_file = None
    if mounted:
        fits = _scan_fits(mount_point)
        fits_count = len(fits)
        total_size = sum(f["size"] for f in fits)
        if fits:
            latest_file = fits[0]

    return {
        "mounted": mounted,
        "mount_point": mount_point,
        "cifs_share": cfg.get("cifs_share", ""),
        "fits_count": fits_count,
        "total_size": total_size,
        "latest_file": latest_file,
    }


@router.get("/files")
async def list_fits(_user: str = Depends(get_current_user)):
    """List all FITS files on the mount."""
    cfg = load_config().get("asi_bridge", {})
    mount_point = cfg.get("mount_point", "/mnt/asiair")
    if not _is_mounted(mount_point):
        raise HTTPException(503, "ASI Air share not mounted")
    return _scan_fits(mount_point)


@router.post("/mount")
async def mount_share(_user: str = Depends(get_current_user)):
    """Mount the ASI Air CIFS share."""
    cfg = load_config().get("asi_bridge", {})
    mount_point = cfg.get("mount_point", "/mnt/asiair")
    share = cfg.get("cifs_share", "")
    user = cfg.get("cifs_user", "anonymous")
    password = cfg.get("cifs_pass", "")

    if not share:
        raise HTTPException(400, "CIFS share not configured")

    Path(mount_point).mkdir(parents=True, exist_ok=True)

    creds = f"username={user}"
    if password:
        creds += f",password={password}"

    rc, out, err = await _run([
        "mount", "-t", "cifs", share, mount_point,
        "-o", f"{creds},iocharset=utf8,vers=3.0",
    ])
    if rc != 0:
        raise HTTPException(500, f"Mount failed: {err}")
    return {"mounted": True, "mount_point": mount_point}


@router.post("/unmount")
async def unmount_share(_user: str = Depends(get_current_user)):
    cfg = load_config().get("asi_bridge", {})
    mount_point = cfg.get("mount_point", "/mnt/asiair")
    rc, out, err = await _run(["umount", mount_point])
    if rc != 0:
        raise HTTPException(500, f"Unmount failed: {err}")
    return {"mounted": False, "mount_point": mount_point}


@router.get("/config")
async def get_bridge_config(_user: str = Depends(get_current_user)):
    cfg = load_config()
    return cfg.get("asi_bridge", {})


@router.put("/config")
async def update_bridge_config(update: MountConfig, _user: str = Depends(get_current_user)):
    cfg = load_config()
    bridge = cfg.get("asi_bridge", {})
    for field, value in update.model_dump(exclude_none=True).items():
        bridge[field] = value
    cfg["asi_bridge"] = bridge
    save_config(cfg)
    return bridge


@router.websocket("/ws")
async def bridge_ws(websocket: WebSocket):
    """Stream mount status and new FITS file events."""
    username = await ws_authenticate(websocket)
    await websocket.accept()

    cfg = load_config().get("asi_bridge", {})
    mount_point = cfg.get("mount_point", "/mnt/asiair")
    seen_files: set[str] = set()
    last_mounted = None

    try:
        while True:
            mounted = _is_mounted(mount_point)

            if mounted != last_mounted:
                await websocket.send_json({
                    "type": "mount_status",
                    "mounted": mounted,
                })
                last_mounted = mounted

            if mounted:
                fits = _scan_fits(mount_point)
                current_paths = {f["path"] for f in fits}
                new_files = current_paths - seen_files
                if new_files and seen_files:
                    for f in fits:
                        if f["path"] in new_files:
                            await websocket.send_json({
                                "type": "new_file",
                                "file": f,
                            })
                seen_files = current_paths

            await asyncio.sleep(5)
    except WebSocketDisconnect:
        pass
    except Exception:
        log.exception("ASI Bridge WS error")