#!/usr/bin/env bash
# Reclaim Docker's unused cache so host storage stays bounded.
#
# Modes:
#   (default) — gentle, age-windowed (keeps rollback + rebuild speed):
#     - BuildKit cache older than 72h, hard-capped at 4 GB (Debian /pnpm store
#       is shared across builds; everything newer speeds up rebuilds).
#     - Images referenced by NO container and older than 7 days.
#     - Containers stopped for more than 24h.
#   --force — emergency mode ("never let the disk max out"): drops every age
#     window and reclaims all unused bytes Docker can free:
#     - ALL unreferenced build cache,
#     - ALL unreferenced images (no 7-day grace),
#     - ALL stopped containers.
#     Trade-off: waiting rebuilds re-fetch deps/images later.
#
# Volumes are NEVER pruned in either mode: mariadb-turbo-data is a database.
# Idempotent; exits 0 when Docker is unavailable.
set -Eeuo pipefail
DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
LOG_DIR="${LOG_DIR:-$DIR/logs}"
mkdir -p "$LOG_DIR"
LOG_FILE="$LOG_DIR/docker-prune.log"
now() { date '+%Y-%m-%d %H:%M:%S'; }

FORCE=0
if [[ "${1:-}" == "--force" ]]; then
  FORCE=1
fi

command -v docker >/dev/null 2>&1 || {
  printf '[%s] docker CLI unavailable; nothing to prune\n' "$(now)" >>"$LOG_FILE"
  exit 0
}

printf '\n[%s] === docker prune start%s ===\n' "$(now)" "$( (( FORCE )) && printf ' (FORCE)' )" >>"$LOG_FILE"
docker system df >>"$LOG_FILE" 2>&1 || true

if (( FORCE )); then
  docker builder prune -af >>"$LOG_FILE" 2>&1 || true
  docker image prune -af >>"$LOG_FILE" 2>&1 || true
  docker container prune -f >>"$LOG_FILE" 2>&1 || true
else
  docker builder prune -af --filter "until=72h" --max-used-space=4g >>"$LOG_FILE" 2>&1 || true
  docker image prune -af --filter "until=168h" >>"$LOG_FILE" 2>&1 || true
  docker container prune -f --filter "until=24h" >>"$LOG_FILE" 2>&1 || true
fi

printf '\n[%s] === docker prune complete%s ===\n' "$(now)" "$( (( FORCE )) && printf ' (FORCE)' )" >>"$LOG_FILE"
docker system df >>"$LOG_FILE" 2>&1 || true