#!/usr/bin/env bash
# {{PROJECT_NAME}} — pin the ONE Docker engine every {{PROJECT_NAME}} tool targets
# (single-engine policy). With more than one engine installed (e.g. OrbStack + Docker
# Desktop), "which daemon am I talking to" otherwise depends on the caller: the docker CLI
# follows the selected context while docker-py/testcontainers follow DOCKER_HOST or fall back
# to /var/run/docker.sock. That split can put staging stacks on one VM and the integration
# testcontainers on another. Pinning a single context keeps every tool on the same engine.
#
# Resolution order:
#   1. DOCKER_HOST or DOCKER_CONTEXT already set -> respected unchanged (explicit override wins).
#   2. The pinned context ({{DOCKER_CONTEXT}}) if it exists -> exported via DOCKER_CONTEXT.
#   3. Otherwise -> print nothing; Docker's own defaults apply.
#
# Usage:
#   eval "$(bash scripts/ops/docker-env.sh)"   # exports DOCKER_CONTEXT (or nothing)
#   bash scripts/ops/docker-env.sh --print     # bare context name, for Makefile $(shell ...)
set -euo pipefail

MODE="eval"
case "${1:-}" in
  --print) MODE="print" ;;
  "") ;;
  *) printf "usage: docker-env.sh [--print]\n" >&2; exit 2 ;;
esac

PINNED_CONTEXT="{{DOCKER_CONTEXT}}"

resolve() {
  # An explicit engine selection by the caller always wins — never override it.
  if [[ -n "${DOCKER_HOST:-}" || -n "${DOCKER_CONTEXT:-}" ]]; then
    return 0
  fi
  command -v docker >/dev/null 2>&1 || return 0
  [[ -n "$PINNED_CONTEXT" ]] || return 0
  # Only pin a context that actually exists, so this never redirects tooling at a
  # non-existent engine (a fresh machine that hasn't created the context yet).
  docker context inspect "$PINNED_CONTEXT" >/dev/null 2>&1 || return 0
  printf '%s' "$PINNED_CONTEXT"
}

ctx="$(resolve)"
[[ -n "$ctx" ]] || exit 0
if [[ "$MODE" == "print" ]]; then
  printf '%s\n' "$ctx"
else
  # %q so a mangled context value can never break out of the eval'd assignment.
  printf 'export DOCKER_CONTEXT=%q\n' "$ctx"
fi