#!/bin/bash
# Purge files from the backup trash directory.
#
# Usage:
#   ./purge-backup-trash.sh [--dry-run]
#
# Environment:
#   TRASH_DIR=/backup/trash          Directory containing trash files to purge
#   DRY_RUN=false                    If true, only report what would be deleted

set -euo pipefail

BASEPATH="$(cd "$(dirname "$0")" && pwd)"
# shellcheck source=volume-utils.sh
source "$BASEPATH/volume-utils.sh"

TRASH_DIR="${TRASH_DIR:-/backup/trash}"

DRY_RUN=false
if [[ "${1:-}" == "--dry-run" ]]; then
    DRY_RUN=true
elif [[ -n "${1:-}" ]]; then
    echo "Usage: $0 [--dry-run]" >&2
    exit 1
fi

log() {
    echo "[$(date '+%Y-%m-%d %H:%M:%S')] $*" >&2
}

# Main purge function
purge_trash() {
    local total_bytes=0
    local file_count=0
    local delete_list=()

    if [[ ! -d "$TRASH_DIR" ]]; then
        log "Trash directory does not exist: $TRASH_DIR"
        echo "0 0"
        return
    fi

    # Find all files in the trash directory and build delete list with FULL paths
    while IFS= read -r -d '' file; do
        # Use full path, not just basename, to avoid stat() looking in wrong directory
        delete_list+=("$file")
    done < <(find "$TRASH_DIR" -maxdepth 1 -type f -print0 2>/dev/null)

    # Process each file with full path
    for file in "${delete_list[@]}"; do
        if [[ ! -f "$file" ]]; then
            continue
        fi

        local size
        size=$(stat -c%s "$file" 2>/dev/null || echo 0)
        total_bytes=$((total_bytes + size))
        file_count=$((file_count + 1))

        if $DRY_RUN; then
            log "DRY-RUN would purge: $file (${size} bytes)"
        else
            rm -f -- "$file"
            log "Purged: $file (${size} bytes)"
        fi
    done

    echo "$file_count $total_bytes"
}

main() {
    log "Starting trash purge from $TRASH_DIR (dry_run=$DRY_RUN)"

    local count bytes
    read -r count bytes < <(purge_trash)

    local bytes_human
    bytes_human=$(numfmt --to=iec-i --suffix=B "$bytes" 2>/dev/null || echo "${bytes}B")

    log "Trash purge complete: deleted=$count files, freed≈$bytes_human"
}

main "$@"