#!/bin/bash

# Script to fix "too many open files" error in Kubernetes
# This error occurs when the system hits inotify limits

echo "🔧 Fixing Kubernetes inotify limits..."

# Check if we're running on macOS (Docker Desktop) or Linux
if [[ "$(uname)" == "Darwin" ]]; then
    echo "🍎 Detected macOS - Docker Desktop environment"
    echo ""
    echo "For Docker Desktop on macOS, you need to:"
    echo "1. Open Docker Desktop settings"
    echo "2. Go to 'Resources' -> 'Advanced'"
    echo "3. Increase the memory allocation (recommended: 8GB+)"
    echo "4. Restart Docker Desktop"
    echo ""
    echo "Alternatively, you can run:"
    echo "docker system prune -a --volumes"
    echo "Then restart Docker Desktop"
    
    # Also check if we can adjust macOS system limits
    echo ""
    echo "Checking current macOS inotify limits..."
    sysctl kern.maxfilesperproc
    sysctl kern.maxfiles
    
    echo ""
    echo "To increase macOS limits permanently, add to /etc/sysctl.conf:"
    echo "kern.maxfiles=1048576"
    echo "kern.maxfilesperproc=65536"
    echo "Then run: sudo sysctl -w kern.maxfiles=1048576"
    echo "And: sudo sysctl -w kern.maxfilesperproc=65536"
    
elif [[ "$(uname)" == "Linux" ]]; then
    echo "🐧 Detected Linux environment"
    
    # Check if we're in a Kubernetes cluster
    if kubectl cluster-info >/dev/null 2>&1; then
        echo "🎯 Detected Kubernetes cluster"
        
        # Check current inotify limits
        echo ""
        echo "Current inotify limits:"
        sysctl fs.inotify.max_user_watches
        sysctl fs.inotify.max_user_instances
        sysctl fs.inotify.max_queued_events
        
        # Increase limits temporarily
        echo ""
        echo "Increasing inotify limits temporarily..."
        sudo sysctl -w fs.inotify.max_user_watches=524288
        sudo sysctl -w fs.inotify.max_user_instances=1024
        sudo sysctl -w fs.inotify.max_queued_events=16384
        
        # Verify changes
        echo ""
        echo "New inotify limits:"
        sysctl fs.inotify.max_user_watches
        sysctl fs.inotify.max_user_instances
        sysctl fs.inotify.max_queued_events
        
        # Check if we can make permanent changes
        if [[ -f /etc/sysctl.conf ]]; then
            echo ""
            echo "Making inotify limits permanent..."
            sudo bash -c 'cat >> /etc/sysctl.conf << EOF
# Increased inotify limits for Kubernetes
fs.inotify.max_user_watches=524288
fs.inotify.max_user_instances=1024
fs.inotify.max_queued_events=16384
EOF'
            sudo sysctl -p
        fi
        
        # Check for Docker containers that might need restarting
        echo ""
        echo "Checking for running containers that might need restarting..."
        docker ps --format "{{.Names}}" | while read container; do
            echo "Restarting container: $container"
            docker restart "$container" >/dev/null 2>&1 || echo "Failed to restart $container"
        done
        
    else
        echo "⚠️  Kubernetes cluster not detected"
        echo "This script should be run on a Kubernetes node or with kubectl access"
    fi
else
    echo "❓ Unsupported operating system: $(uname)"
fi

echo ""
echo "📋 Additional recommendations:"
echo "1. For Kind clusters: kind delete cluster && kind create cluster"
echo "2. For Minikube: minikube stop && minikube start"
echo "3. For production: Adjust node system limits and restart kubelet"
echo "4. Consider adding resource limits to your deployments"

echo ""
echo "✅ Inotify fix script completed!"