#!/bin/bash
set -e

# ----------------------------------------------------------------------------------------------
# --------------------------- ZFS ARC & Memory Snapshot for Unraid -----------------------------
# ----------------------------------------------------------------------------------------------

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

source "$SCRIPT_DIR/../Master.conf"
source "$SCRIPT_DIR/../common.sh"

parse_args "$@"

# STATUS MODE
if [[ "$SHOW_STATUS" == true ]]; then
    echo
    echo "=================================================="
    echo " ℹ️ ZFS + MEMORY SNAPSHOT STATUS"
    echo "--------------------------------------------------"
    echo " 📊 Mode:       Read-only diagnostics"
    echo " 🧪 Dry Run:    $DRY_RUN"
    echo "=================================================="
    exit 0
fi

# HEADER
echo
echo "============================================================"
echo " 📊 ZFS ARC + MEMORY SNAPSHOT"
echo "------------------------------------------------------------"
echo " 🕒 Time:      $(date)"
echo " 🧪 Dry Run:   $DRY_RUN"
echo "============================================================"

log "ℹ️ Collecting ZFS ARC + memory statistics"

# FUNCTIONS
show_zfs_arc() {

    echo
    echo "==================== ZFS ARC STATS ===================="

    if [[ ! -r /proc/spl/kstat/zfs/arcstats ]]; then
        warn "🔴 ZFS arcstats not available on this system"
        return
    fi

    grep -iE '^(c|size|hits|misses|arc_meta_used|demand_metadata_misses|mru_ghost_metadata|mfu_ghost_metadata)' \
        /proc/spl/kstat/zfs/arcstats 2>/dev/null || warn "🟡 Unable to read ARC stats"
}

show_memory_status() {

    echo
    echo "==================== MEMORY STATUS ===================="

    if command -v free >/dev/null 2>&1; then
        free -h | awk '
        NR==1 {print $0}
        /Mem:/ {print $0}
        /Swap:/ {print $0}'
    else
        warn "🔴 free command not available"
    fi
}

# EXECUTION
START_TIME=$(date +%s)

if [[ "$DRY_RUN" == true ]]; then
    warn "🧪 Dry run enabled - no system data collected"
else
    show_zfs_arc
    show_memory_status
fi

END_TIME=$(date +%s)
DURATION=$((END_TIME - START_TIME))

# SUMMARY
echo
echo "============================================================"

echo " 📊 SNAPSHOT SUMMARY"
echo "------------------------------------------------------------"
echo " ⏱ Duration:   ${DURATION}s"
echo " 📡 Mode:       READ-ONLY"
echo " 🧠 Source:     ZFS ARC + system memory"
echo "============================================================"

info "ℹ️ Snapshot complete"