"""Model-free Docker view helpers.

Kept separate from routes.py/models.py so tests can import it directly: importing
a module that re-imports plugins.docker.models AFTER the app has loaded the docker
plugin raises "Table 'docker_containers' is already defined". This module touches
no ORM models, so it's safe to import in either environment.
"""
from __future__ import annotations


def dedup_by_container_id(containers: list) -> list:
    """Collapse containers double-reported across hosts. Swarm-aware agents on
    every manager list cluster-wide tasks, so the same container (identical
    container_id) arrives once per manager and would otherwise be counted N times.
    Keep the first occurrence per non-empty container_id — callers order
    running-first, so a running report wins over a stale stopped one. Rows without
    a container_id (older agents) can't be matched, so they're kept as-is."""
    seen: set[str] = set()
    out = []
    for c in containers:
        cid = (c.container_id or "").strip()
        if cid:
            if cid in seen:
                continue
            seen.add(cid)
        out.append(c)
    return out