#!/bin/bash

# Function to check for sudo access
check_sudo_access() {
    sudo -l &> /dev/null || { echo "Error: No sudo access. Exiting."; exit 1; }
    echo "User $(whoami) has sudo access."
}

# Function to set ulimit values
set_ulimit() {
    local limits_file="/etc/security/limits.conf"
    grep -qE "^\* soft nofile\s+65536" "$limits_file" || {
        echo -e "* soft nofile 65536\n* hard nofile 65536" | sudo tee -a "$limits_file" > /dev/null
        echo "Ulimit values set."
    }
    sleep 5
}

# Function to install Java
install_java() {
    echo "Preparing to install Java..."
    sleep 5  

    local os_name
    os_name=$(grep '^NAME=' /etc/os-release | cut -d'=' -f2 | tr -d '"')
    case $os_name in
        "Amazon Linux") sudo yum install -y java-17-amazon-corretto-devel.x86_64 ;;
        "Red Hat Enterprise Linux" | "Oracle Linux Server") sudo yum install -y java-17-openjdk-devel.x86_64 ;;
        *) echo "Error: Unsupported OS: $os_name"; exit 1 ;;
    esac
    echo "Java 17 installation complete."
    sleep 5
}

# Function to set Java path
set_java_path() {
    local java_home bashrc_file user_home
    user_home=$(eval echo "~$1")
    bashrc_file="${user_home:-$HOME}/.bashrc"

    if ! cd /usr/lib/jvm || ! java_home=$(find . -maxdepth 1 -type d -name "java-17*" ! -type l | head -n 1); then
        echo "Error: Java installation directory not found. Exiting."; exit 1
    fi
    java_home=$(realpath "$java_home")

    # Ensure Java is a developer version
    if [[ ! -f "$java_home/bin/jps" || ! -f "$java_home/bin/jar" ]]; then
        echo "ERROR: Installed Java is not a developer version."; exit 1
    fi

    # Set JAVA_HOME and PATH if not already set
    grep -q "export JAVA_HOME=$java_home" "$bashrc_file" || {
        echo -e "export JAVA_HOME=$java_home\nexport PATH=\$JAVA_HOME/bin:\$PATH" >> "$bashrc_file"
        source "$bashrc_file"
        echo "JAVA_HOME set to: $java_home for user $(basename $user_home)"
    }
}

# Script execution
check_sudo_access
set_ulimit
install_java
set_java_path "$1"  # Pass username argument