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

import os
from dataclasses import asdict

from fastapi import APIRouter, Depends, HTTPException, Query, Request
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.user import User
from services import audit_service, compose_service, notify_service, stats_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) -> dict:
    try:
        containers = compose_service.containers_for_stack(stack.id)
        status = compose_service.compute_status(stack.id)
    except DockerError:
        containers = []
        status = "unknown"
    return {
        "id": stack.id,
        "name": stack.name,
        "description": stack.description,
        "status": status,
        "service_count": len(containers),
        "running_count": sum(1 for c in containers if c.state == "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()
    return [_stack_summary(s) 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")
    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)
    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("/{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:
        containers = [asdict(c) for c in compose_service.containers_for_stack(stack_id)]
        status = compose_service.compute_status(stack_id)
    except DockerError as exc:
        containers = []
        status = "unknown"
    return {
        "id": stack.id,
        "name": stack.name,
        "description": stack.description,
        "status": status,
        "yaml": compose_service.read_compose(stack_id),
        "env": compose_service.read_env(stack_id),
        "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
    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)
    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:
    _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)
    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)


# --------------------------------------------------------------------------- #
# 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)
    result = await action_fn(stack_id)
    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)):
    return await _lifecycle(compose_service.pull, "pull", stack_id, request, session, user)


@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)):
    return await _lifecycle(compose_service.update, "update", stack_id, request, session, user)


@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),
    _user: User = Depends(get_current_user),
):
    import io
    import tarfile
    import tempfile

    stack = _get_stack_or_404(session, stack_id)
    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