#!/bin/bash
# -----------------------------------------------------------------------------------------------
# --------------------------------- inotify Tuning --------------------------------------------
# -----------------------------------------------------------------------------------------------
# Increases Linux inotify limits to prevent "too many open files" and inotify exhaustion.
# Run once at array start via ARRAY_START_SCRIPTS in Master.conf.
#
# Why this matters:
#   Each Docker container that watches files (Sonarr, Radarr, Lidarr, NextCloud etc.)
#   consumes inotify instances and watches. unRAID defaults are very low — with many
#   containers running you can exhaust the limit silently, causing containers to miss
#   file events (new downloads not detected, library not updated etc.)
#
#   max_user_instances = max number of inotify instances per user (default: 128)
#   max_user_watches   = max number of files/dirs watched per instance (default: 8192)
#   max_queued_events  = max events queued before dropping (default: 16384)
#
# These settings are lost on reboot — this script reapplies them at every array start.
# All values configurable in Master.conf under unRAID Essentials.
# -----------------------------------------------------------------------------------------------

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

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

parse_args "$@"

# -----------------------------------------------------------------------------------------------
# ━━━ $ICON_GEAR Setup ━━━
# -----------------------------------------------------------------------------------------------
echo ""
echo "━━━ $ICON_GEAR inotify Tuning ━━━"

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

success "Running as root"

# -----------------------------------------------------------------------------------------------
# ━━━ Current Values ━━━
# -----------------------------------------------------------------------------------------------
CURRENT_INSTANCES=$(sysctl -n fs.inotify.max_user_instances 2>/dev/null || echo "?")
CURRENT_WATCHES=$(sysctl -n fs.inotify.max_user_watches 2>/dev/null || echo "?")
CURRENT_EVENTS=$(sysctl -n fs.inotify.max_queued_events 2>/dev/null || echo "?")

info "Current: instances=$CURRENT_INSTANCES watches=$CURRENT_WATCHES queued=$CURRENT_EVENTS"
info "Target:  instances=${INOTIFY_MAX_INSTANCES} watches=${INOTIFY_MAX_WATCHES} queued=${INOTIFY_MAX_QUEUED_EVENTS}"

if [[ "$SHOW_STATUS" == true ]]; then
    echo ""
    echo "━━━━━ $ICON_SUMMARY INOTIFY STATUS ━━━━━"
    echo "  max_user_instances:  $CURRENT_INSTANCES (target: ${INOTIFY_MAX_INSTANCES})"
    echo "  max_user_watches:    $CURRENT_WATCHES (target: ${INOTIFY_MAX_WATCHES})"
    echo "  max_queued_events:   $CURRENT_EVENTS (target: ${INOTIFY_MAX_QUEUED_EVENTS})"
    echo ""
    echo "  Active inotify instances in use:"
    find /proc/*/fd -lname "anon_inode:inotify" 2>/dev/null | \
        awk -F/ '{print $3}' | sort -u | while read -r pid; do
            cmd=$(cat /proc/$pid/comm 2>/dev/null || echo "?")
            echo "    PID $pid ($cmd)"
        done | head -20
    echo "━━━━━━━━━━━━━━━━━━━━━━━"
    exit 0
fi

# -----------------------------------------------------------------------------------------------
# ━━━ Apply Settings ━━━
# -----------------------------------------------------------------------------------------------
echo ""
CHANGED=0
FAILED=0

apply_sysctl() {
    local key="$1"
    local value="$2"
    local current
    current=$(sysctl -n "$key" 2>/dev/null || echo 0)

    if [[ "$current" -eq "$value" ]]; then
        success "$key = $value (already set)"
        return
    fi

    if [[ "$DRY_RUN" == true ]]; then
        warn "DRY RUN — would set $key = $value (currently $current)"
        return
    fi

    if sysctl -w "${key}=${value}" >/dev/null 2>&1; then
        success "$key = $value (was $current)"
        ((CHANGED++))
    else
        error "Failed to set $key = $value"
        ((FAILED++))
    fi
}

apply_sysctl "fs.inotify.max_user_instances" "$INOTIFY_MAX_INSTANCES"
apply_sysctl "fs.inotify.max_user_watches"   "$INOTIFY_MAX_WATCHES"
apply_sysctl "fs.inotify.max_queued_events"  "$INOTIFY_MAX_QUEUED_EVENTS"

# -----------------------------------------------------------------------------------------------
# ━━━ $ICON_SUMMARY Summary ━━━
# -----------------------------------------------------------------------------------------------
echo ""
echo "━━━━━ $ICON_SUMMARY INOTIFY TUNING SUMMARY ━━━━━"
echo "  max_user_instances:  $(sysctl -n fs.inotify.max_user_instances 2>/dev/null)"
echo "  max_user_watches:    $(sysctl -n fs.inotify.max_user_watches 2>/dev/null)"
echo "  max_queued_events:   $(sysctl -n fs.inotify.max_queued_events 2>/dev/null)"
echo ""

if [[ "$DRY_RUN" == true ]]; then
    echo "$ICON_WARN  Status: DRY RUN — no changes made"
elif [[ "$FAILED" -gt 0 ]]; then
    echo "$ICON_ERROR Status: $FAILED setting(s) failed"
    notify "inotify tuning failed on $(hostname) — $FAILED setting(s) could not be applied" "inotify Tuning" "warning"
    exit 1
elif [[ "$CHANGED" -gt 0 ]]; then
    echo "$ICON_DONE  Status: $ICON_SUCCESS $CHANGED setting(s) applied"
else
    echo "$ICON_DONE  Status: $ICON_SUCCESS All settings already correct"
fi
echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"