#!/bin/bash
# ==============================================================================================
# ============================= Docker Prune Images ============================================
# ==============================================================================================
#
# PURPOSE
# ─────────────────────────────────────────────────────────────────────────────
# Removes dangling Docker images — images no longer tagged or referenced by any
# container. These accumulate after container updates pull a new image version,
# leaving the old image behind with no tag.
#
# Safe to run at any time. Only removes images with no tag and no container
# reference — running containers are never affected.
#
# ==============================================================================================
# RUNTIME MODES
# ==============================================================================================
#
# docker_prune_images.sh
#     Show dangling images and remove them.
#
# docker_prune_images.sh --dry-run
#     Show what would be removed without removing anything.
#
# docker_prune_images.sh --status
#     Show current dangling images and disk usage. No changes.
#
# ==============================================================================================

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

source "$SCRIPT_DIR/../load_config.sh"

parse_args "$@"

# ==============================================================================================
# ━━━ Setup ━━━
# ==============================================================================================
if [[ "$EUID" -ne 0 ]]; then
    error "Must be run as root"
    exit 1
fi

acquire_lock

# ==============================================================================================
# ━━━ Status ━━━
# ==============================================================================================
if [[ "$SHOW_STATUS" == true ]]; then
    echo ""
    echo "━━━━━ $ICON_SUMMARY DOCKER PRUNE IMAGES STATUS ━━━━━"
    DANGLING=$(docker images -f "dangling=true" --format "{{.ID}}\t{{.Size}}\t{{.CreatedSince}}" 2>/dev/null)
    if [[ -z "$DANGLING" ]]; then
        echo "$ICON_DONE  No dangling images."
    else
        COUNT=$(echo "$DANGLING" | wc -l)
        echo "$ICON_CONTAINERS  $COUNT dangling image(s):"
        echo "$DANGLING" | while IFS=$'\t' read -r id size age; do
            echo "    $id   $size   created $age"
        done
    fi
    echo "━━━━━━━━━━━━━━━━━━━━━━━"
    exit 0
fi

# ==============================================================================================
# ━━━ Run ━━━
# ==============================================================================================
echo "━━━ $ICON_CONTAINERS Docker Prune Images — $(date '+%Y-%m-%d %H:%M:%S') ━━━"

DANGLING_IDS=$(docker images -f "dangling=true" -q 2>/dev/null)

if [[ -z "$DANGLING_IDS" ]]; then
    success "No dangling images — nothing to do"
    exit 0
fi

COUNT=$(echo "$DANGLING_IDS" | wc -l)
log "Found $COUNT dangling image(s)"

if [[ "$DRY_RUN" == true ]]; then
    warn "DRY RUN — would remove $COUNT dangling image(s):"
    docker images -f "dangling=true" --format "  {{.ID}}   {{.Size}}   created {{.CreatedSince}}" 2>/dev/null
    exit 0
fi

OUTPUT=$(docker image prune -f 2>&1)
echo "$OUTPUT"

RECLAIMED=$(echo "$OUTPUT" | grep -E "^Total reclaimed" || echo "")
if [[ -n "$RECLAIMED" ]]; then
    success "Done — $RECLAIMED"
else
    success "Done — $COUNT image(s) removed"
fi