"""Stack CRUD + lifecycle endpoints."""
from __future__ import annotations

import os
from dataclasses import asdict

from fastapi import APIRouter, Depends, File, HTTPException, Query, Request, UploadFile
from fastapi.responses import FileResponse
from sqlmodel import Session, select

from auth import get_current_user, require_admin
from database import get_session
from docker_client import DockerError
from models.stack import (
    ConvertRequest,
    ConvertResponse,
    Stack,
    StackCloneRequest,
    StackCreate,
    StackUpdate,
)
from models.setting import (
    EVENT_PULL_FAILED,
    EVENT_STACK_ERROR,
    EVENT_STACK_START,
    EVENT_STACK_STOP,
)
from models.auto_update import AutoUpdateRead, AutoUpdateWrite
from models.user import User
from services import (
    audit_service,
    auto_update_service,
    compose_service,
    icon_service,
    notify_service,
    stack_lock_service,
    stats_service,
    update_service,
)
from services.convert_service import convert_docker_run

router = APIRouter(prefix="/api/stacks", tags=["stacks"])


# --------------------------------------------------------------------------- #
# helpers
# --------------------------------------------------------------------------- #


def _client_ip(request: Request) -> str:
    return request.client.host if request.client else "unknown"


def sync_discovered_stacks(session: Session) -> None:
    """Register any on-disk stacks not yet in the database."""
    known = {s.id for s in session.exec(select(Stack)).all()}
    for stack_id in compose_service.discover_stacks():
        if stack_id not in known:
            stack = Stack(id=stack_id, name=stack_id)
            session.add(stack)
    session.commit()


def _get_stack_or_404(session: Session, stack_id: str) -> Stack:
    stack = session.get(Stack, stack_id)
    if not stack:
        raise HTTPException(status_code=404, detail=f"Stack '{stack_id}' not found")
    return stack


def _stack_summary(
    stack: Stack, summaries: dict | None = None, busy: dict[str, str] | None = None
) -> dict:
    """Build a list-row summary.

    Pass ``summaries`` (from :func:`compose_service.stack_status_summaries`) and
    ``busy`` (from :func:`stack_lock_service.active`) to serve the whole stacks
    list from one Docker call and one query. Without them (single
    create/update/clone responses), fall back to one direct query for this stack.
    """
    busy = busy or {}
    if summaries is None:
        try:
            containers = compose_service.containers_for_stack(stack.id)
            total = len(containers)
            running = sum(1 for c in containers if c.state == "running")
            status = compose_service.compute_status(stack.id, containers)
        except DockerError:
            total = running = 0
            status = "unknown"
    else:
        info = summaries.get(stack.id)
        total = info["total"] if info else 0
        running = info["running"] if info else 0
        if stack.id in busy:
            status = "updating"
        else:
            status = info["status"] if info else "stopped"
    return {
        "id": stack.id,
        "name": stack.name,
        "description": stack.description,
        "icon": stack.icon,
        "status": status,
        "service_count": total,
        "running_count": running,
        "created_at": stack.created_at,
        "updated_at": stack.updated_at,
    }


# --------------------------------------------------------------------------- #
# CRUD
# --------------------------------------------------------------------------- #


@router.get("")
def list_stacks(
    session: Session = Depends(get_session),
    _user: User = Depends(get_current_user),
) -> list[dict]:
    sync_discovered_stacks(session)
    stacks = session.exec(select(Stack)).all()
    try:
        summaries = compose_service.stack_status_summaries()
    except DockerError:
        summaries = {}
    busy = stack_lock_service.active(session)
    return [_stack_summary(s, summaries, busy) for s in stacks]


@router.post("", status_code=201)
def create_stack(
    body: StackCreate,
    request: Request,
    session: Session = Depends(get_session),
    user: User = Depends(require_admin),
) -> dict:
    stack_id = compose_service.slugify(body.name)
    if session.get(Stack, stack_id) or os.path.isdir(compose_service.stack_dir(stack_id)):
        raise HTTPException(status_code=409, detail=f"Stack '{stack_id}' already exists")
    try:
        icon = icon_service.normalize_choice(body.icon or "")
    except icon_service.IconError as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc
    compose_service.write_compose(stack_id, body.yaml or "services:\n")
    if body.env:
        compose_service.write_env(stack_id, body.env)
    stack = Stack(
        id=stack_id, name=body.name, description=body.description, icon=icon
    )
    session.add(stack)
    session.commit()
    session.refresh(stack)
    audit_service.record(
        session, user=user.username, action="stack.create", target=stack_id,
        ip=_client_ip(request),
    )
    return _stack_summary(stack)


@router.get("/stats")
def stacks_stats(_user: User = Depends(get_current_user)) -> dict:
    """Live CPU (cores) and memory usage per stack, with assigned limits."""
    return stats_service.stack_stats()


@router.get("/updates")
def stacks_updates(_user: User = Depends(get_current_user)) -> dict:
    """Per-stack image-update availability, read from the cached registry
    digests (no live registry calls — safe for the list to poll)."""
    return update_service.stacks_update_summary()


@router.get("/{stack_id}")
def get_stack(
    stack_id: str,
    session: Session = Depends(get_session),
    user: User = Depends(get_current_user),
) -> dict:
    stack = _get_stack_or_404(session, stack_id)
    try:
        raw = compose_service.containers_for_stack(stack_id)
        containers = [asdict(c) for c in raw]
        status = compose_service.compute_status(stack_id, raw)
    except DockerError:
        containers = []
        status = "unknown"
    # An operation in flight outranks whatever the containers currently say.
    if stack_lock_service.is_busy(session, stack_id):
        status = "updating"
    return {
        "id": stack.id,
        "name": stack.name,
        "description": stack.description,
        "icon": stack.icon,
        "status": status,
        "yaml": compose_service.read_compose(stack_id),
        # The .env is where credentials live by convention, so it is withheld
        # from the read-only role — same reasoning as the admin-only file
        # browser. Non-admins still get status, services and the compose file.
        "env": compose_service.read_env(stack_id) if user.role == "admin" else "",
        "containers": containers,
        "created_at": stack.created_at,
        "updated_at": stack.updated_at,
    }


@router.put("/{stack_id}")
def update_stack(
    stack_id: str,
    body: StackUpdate,
    request: Request,
    session: Session = Depends(get_session),
    user: User = Depends(require_admin),
) -> dict:
    stack = _get_stack_or_404(session, stack_id)
    if body.yaml is not None:
        compose_service.write_compose(stack_id, body.yaml)
    if body.env is not None:
        compose_service.write_env(stack_id, body.env)
    if body.name is not None:
        stack.name = body.name
    if body.description is not None:
        stack.description = body.description
    if body.icon is not None:
        try:
            icon = icon_service.normalize_choice(body.icon)
        except icon_service.IconError as exc:
            raise HTTPException(status_code=400, detail=str(exc)) from exc
        # Switching to a built-in icon (or back to automatic) makes any
        # uploaded image dead weight, so it goes with the choice.
        if icon_service.custom_ext(stack.icon) and icon != stack.icon:
            icon_service.remove(stack_id)
        stack.icon = icon
    stack.updated_at = compose_service.now()
    session.add(stack)
    session.commit()
    session.refresh(stack)
    audit_service.record(
        session, user=user.username, action="stack.update", target=stack_id,
        ip=_client_ip(request),
    )
    return _stack_summary(stack)


@router.delete("/{stack_id}")
async def delete_stack(
    stack_id: str,
    request: Request,
    delete_files: bool = Query(True),
    session: Session = Depends(get_session),
    user: User = Depends(require_admin),
) -> dict:
    stack = _get_stack_or_404(session, stack_id)
    try:
        await compose_service.down(stack_id)
    except Exception:  # noqa: BLE001 - best-effort teardown
        pass
    if delete_files:
        compose_service.delete_stack_files(stack_id)
    icon_service.remove(stack_id)
    session.delete(stack)
    session.commit()
    audit_service.record(
        session, user=user.username, action="stack.delete", target=stack_id,
        detail=f"delete_files={delete_files}", ip=_client_ip(request),
    )
    return {"ok": True}


@router.post("/{stack_id}/clone")
def clone_stack(
    stack_id: str,
    body: StackCloneRequest,
    request: Request,
    session: Session = Depends(get_session),
    user: User = Depends(require_admin),
) -> dict:
    source = _get_stack_or_404(session, stack_id)
    new_id = compose_service.slugify(body.name)
    if session.get(Stack, new_id):
        raise HTTPException(status_code=409, detail=f"Stack '{new_id}' already exists")
    try:
        compose_service.clone_stack_files(stack_id, new_id)
    except compose_service.StackFileError as exc:
        raise HTTPException(status_code=409, detail=str(exc)) from exc
    stack = Stack(
        id=new_id,
        name=body.name,
        icon=icon_service.copy(stack_id, new_id, source.icon),
    )
    session.add(stack)
    session.commit()
    session.refresh(stack)
    audit_service.record(
        session, user=user.username, action="stack.clone",
        target=new_id, detail=f"from {stack_id}", ip=_client_ip(request),
    )
    return _stack_summary(stack)


# --------------------------------------------------------------------------- #
# icon
# --------------------------------------------------------------------------- #


@router.get("/{stack_id}/icon")
def get_stack_icon(
    stack_id: str,
    session: Session = Depends(get_session),
    _user: User = Depends(get_current_user),
) -> FileResponse:
    """Serve a stack's uploaded icon.

    Authenticated like everything else, which is why the frontend fetches it
    through the API client and renders the blob rather than pointing an
    ``<img src>`` straight at this URL (that request would carry no token).
    """
    stack = _get_stack_or_404(session, stack_id)
    path = icon_service.file_for(stack_id, stack.icon)
    if not path:
        raise HTTPException(status_code=404, detail="This stack has no custom icon")
    ext = icon_service.custom_ext(stack.icon) or ""
    return FileResponse(
        path,
        media_type=icon_service.content_type(ext),
        # An SVG opened as a top-level document would run its own script in the
        # API's origin. Nothing here is ever meant to be a document.
        headers={"Content-Disposition": f'attachment; filename="{stack_id}.{ext}"'},
    )


@router.post("/{stack_id}/icon")
async def upload_stack_icon(
    stack_id: str,
    request: Request,
    file: UploadFile = File(...),
    session: Session = Depends(get_session),
    user: User = Depends(require_admin),
) -> dict:
    """Replace a stack's icon with an uploaded image."""
    stack = _get_stack_or_404(session, stack_id)
    data = await file.read(icon_service.MAX_ICON_BYTES + 1)
    try:
        stack.icon = icon_service.store_upload(stack_id, data)
    except icon_service.IconError as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc
    stack.updated_at = compose_service.now()
    session.add(stack)
    session.commit()
    session.refresh(stack)
    audit_service.record(
        session, user=user.username, action="stack.icon", target=stack_id,
        detail=f"uploaded {file.filename or 'image'}", ip=_client_ip(request),
    )
    return _stack_summary(stack)


@router.delete("/{stack_id}/icon")
def reset_stack_icon(
    stack_id: str,
    request: Request,
    session: Session = Depends(get_session),
    user: User = Depends(require_admin),
) -> dict:
    """Drop any explicit choice and go back to the name-derived icon."""
    stack = _get_stack_or_404(session, stack_id)
    icon_service.remove(stack_id)
    stack.icon = None
    stack.updated_at = compose_service.now()
    session.add(stack)
    session.commit()
    session.refresh(stack)
    audit_service.record(
        session, user=user.username, action="stack.icon", target=stack_id,
        detail="reset to automatic", ip=_client_ip(request),
    )
    return _stack_summary(stack)


# --------------------------------------------------------------------------- #
# lifecycle
# --------------------------------------------------------------------------- #


# which lifecycle actions emit a notification on success
_START_ACTIONS = {"start", "restart", "update"}
_STOP_ACTIONS = {"stop", "down"}


async def _notify_lifecycle(action_name: str, stack_id: str, ok: bool, detail: str, session) -> None:
    try:
        if not ok:
            event = EVENT_PULL_FAILED if action_name in ("pull", "update") else EVENT_STACK_ERROR
            await notify_service.notify(
                event,
                f"Stack '{stack_id}' {action_name} failed",
                detail or f"compose {action_name} returned a non-zero exit code.",
                session,
            )
        elif action_name in _START_ACTIONS:
            await notify_service.notify(
                EVENT_STACK_START, f"Stack '{stack_id}' started",
                f"compose {action_name} completed successfully.", session,
            )
        elif action_name in _STOP_ACTIONS:
            await notify_service.notify(
                EVENT_STACK_STOP, f"Stack '{stack_id}' stopped",
                f"compose {action_name} completed successfully.", session,
            )
    except Exception:  # noqa: BLE001 - notifications are best-effort
        pass


async def _lifecycle(action_fn, action_name, stack_id, request, session, user):
    _get_stack_or_404(session, stack_id)
    # One compose operation per stack. Without this two tabs (or auto-update
    # landing on a stack somebody just clicked) both run pull + up -d against
    # the same project and race over recreating containers.
    try:
        with stack_lock_service.hold(session, stack_id, action_name, user.username):
            result = await action_fn(stack_id)
    except stack_lock_service.StackBusy as exc:
        raise HTTPException(
            status_code=409,
            detail=f"Stack '{stack_id}' is busy: {exc.action} in progress",
        ) from exc
    audit_service.record(
        session, user=user.username, action=f"stack.{action_name}", target=stack_id,
        detail=f"rc={result.get('returncode')}", ip=_client_ip(request),
    )
    ok = result.get("returncode") in (0, None)
    stderr = result.get("stderr", "").strip()[-2000:]
    await _notify_lifecycle(action_name, stack_id, ok, stderr, session)
    if not ok:
        raise HTTPException(
            status_code=500,
            detail={
                "error": f"compose {action_name} failed",
                "detail": stderr,
            },
        )
    return result


@router.post("/{stack_id}/start")
async def start_stack(stack_id: str, request: Request, session: Session = Depends(get_session), user: User = Depends(require_admin)):
    return await _lifecycle(compose_service.up, "start", stack_id, request, session, user)


@router.post("/{stack_id}/stop")
async def stop_stack(stack_id: str, request: Request, session: Session = Depends(get_session), user: User = Depends(require_admin)):
    return await _lifecycle(compose_service.stop, "stop", stack_id, request, session, user)


@router.post("/{stack_id}/restart")
async def restart_stack(stack_id: str, request: Request, session: Session = Depends(get_session), user: User = Depends(require_admin)):
    return await _lifecycle(compose_service.restart, "restart", stack_id, request, session, user)


@router.post("/{stack_id}/pull")
async def pull_stack(stack_id: str, request: Request, session: Session = Depends(get_session), user: User = Depends(require_admin)):
    result = await _lifecycle(compose_service.pull, "pull", stack_id, request, session, user)
    update_service.refresh_stack_local(stack_id)
    return result


@router.post("/{stack_id}/update")
async def update_stack_images(stack_id: str, request: Request, session: Session = Depends(get_session), user: User = Depends(require_admin)):
    result = await _lifecycle(compose_service.update, "update", stack_id, request, session, user)
    update_service.refresh_stack_local(stack_id)
    return result


@router.post("/{stack_id}/down")
async def down_stack(stack_id: str, request: Request, session: Session = Depends(get_session), user: User = Depends(require_admin)):
    return await _lifecycle(compose_service.down, "down", stack_id, request, session, user)


# --------------------------------------------------------------------------- #
# logs / export / convert
# --------------------------------------------------------------------------- #


@router.get("/{stack_id}/logs")
async def stack_logs(
    stack_id: str,
    tail: int = Query(200, le=2000),
    session: Session = Depends(get_session),
    _user: User = Depends(get_current_user),
) -> dict:
    _get_stack_or_404(session, stack_id)
    result = await compose_service.logs(stack_id, tail=tail)
    return {"logs": result.get("stdout", "") + result.get("stderr", "")}


@router.get("/{stack_id}/services/{service}/logs")
async def service_logs(
    stack_id: str,
    service: str,
    tail: int = Query(200, le=2000),
    session: Session = Depends(get_session),
    _user: User = Depends(get_current_user),
) -> dict:
    _get_stack_or_404(session, stack_id)
    result = await compose_service.logs(stack_id, service=service, tail=tail)
    return {"logs": result.get("stdout", "") + result.get("stderr", "")}


@router.get("/{stack_id}/export")
def export_stack(
    stack_id: str,
    session: Session = Depends(get_session),
    _admin: User = Depends(require_admin),
):
    """Download the whole stack folder as a tarball. Admin only: the archive
    contains the ``.env`` and every ``.secrets/*`` file verbatim."""
    import tarfile
    import tempfile

    _get_stack_or_404(session, stack_id)  # 404s if unknown
    directory = compose_service.stack_dir(stack_id)
    if not os.path.isdir(directory):
        raise HTTPException(status_code=404, detail="Stack directory missing")
    tmp = tempfile.NamedTemporaryFile(delete=False, suffix=".tar.gz")
    with tarfile.open(tmp.name, "w:gz") as tar:
        tar.add(directory, arcname=stack_id)
    date = compose_service.now().strftime("%Y%m%d")
    return FileResponse(
        tmp.name,
        media_type="application/gzip",
        filename=f"stack-{stack_id}-{date}.tar.gz",
    )


@router.post("/convert", response_model=ConvertResponse)
def convert(
    body: ConvertRequest,
    _user: User = Depends(get_current_user),
) -> ConvertResponse:
    try:
        return ConvertResponse(yaml=convert_docker_run(body.command))
    except ValueError as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc


# --------------------------------------------------------------------------- #
# Auto-update policy (Watchtower-style) — local stacks
# --------------------------------------------------------------------------- #


@router.get("/{stack_id}/auto-update", response_model=AutoUpdateRead)
def get_auto_update(
    stack_id: str,
    session: Session = Depends(get_session),
    _user: User = Depends(get_current_user),
) -> dict:
    policy = auto_update_service.get_policy(session, stack_id)
    return auto_update_service.to_read(policy, stack_id)


@router.put("/{stack_id}/auto-update", response_model=AutoUpdateRead)
def set_auto_update(
    stack_id: str,
    body: AutoUpdateWrite,
    request: Request,
    session: Session = Depends(get_session),
    user: User = Depends(require_admin),
) -> dict:
    policy = auto_update_service.upsert_policy(session, stack_id, body.enabled, body.redeploy)
    audit_service.record(
        session, user=user.username, action="stack.auto_update",
        target=stack_id, detail=f"enabled={body.enabled} redeploy={body.redeploy}",
        ip=_client_ip(request),
    )
    return auto_update_service.to_read(policy, stack_id)


@router.post("/{stack_id}/auto-update/run", response_model=AutoUpdateRead)
async def run_auto_update(
    stack_id: str,
    session: Session = Depends(get_session),
    user: User = Depends(require_admin),
) -> dict:
    policy = auto_update_service.get_policy(session, stack_id)
    if policy is None:
        raise HTTPException(status_code=404, detail="No auto-update policy for this stack")
    await auto_update_service.run_policy(session, policy)
    session.refresh(policy)
    return auto_update_service.to_read(policy, stack_id)