#!/bin/bash
# shellcheck disable=SC1090
#
# Library for operating system actions

# Load Generic Libraries
. "${BITNAMI_SCRIPTS_DIR:-}"/liblog.sh

# Functions

########################
# Check if an user exists in the system
# Arguments:
#   $1 - user
# Returns:
#   Boolean
#########################
user_exists() {
    local user="${1:?user is missing}"
    id "$user" >/dev/null 2>&1
}

########################
# Check if a group exists in the system
# Arguments:
#   $1 - group
# Returns:
#   Boolean
#########################
group_exists() {
    local group="${1:?group is missing}"
    getent group "$group" >/dev/null 2>&1
}

########################
# Create a group in the system if it does not exist already
# Arguments:
#   $1 - group
# Returns:
#   None
#########################
ensure_group_exists() {
    local group="${1:?group is missing}"

    if ! group_exists "$group"; then
        groupadd "$group" >/dev/null 2>&1
    fi
}

########################
# Create an user in the system if it does not exist already
# Arguments:
#   $1 - user
#   $2 - group
# Returns:
#   None
#########################
ensure_user_exists() {
    local user="${1:?user is missing}"
    local group="${2:-}"

    if ! user_exists "$user"; then
        useradd "$user" >/dev/null 2>&1
    fi

    if [[ -n "$group" ]]; then
        ensure_group_exists "$group"
        usermod -a -G "$group" "$user" >/dev/null 2>&1
    fi
}

########################
# Check if the script is currently running as root
# Arguments:
#   $1 - user
#   $2 - group
# Returns:
#   Boolean
#########################
am_i_root() {
    if [[ "$(id -u)" = "0" ]]; then
        true
    else
	false
    fi
}

########################
# Get total memory available
# Arguments:
#   None
# Returns:
#   Memory in bytes
#########################
get_total_memory() {
    echo $(($(grep MemTotal /proc/meminfo | awk '{print $2}') / 1024))
}

########################
# Get machine size depending on specified memory
# Globals:
#   None
# Arguments:
#   $1 - memory size (optional)
# Returns:
#   Detected instance size
#########################
get_machine_size() {
    local memory="${1:-}"
    if [[ -z "$memory" ]]; then
        debug "Memory was not specified, detecting available memory automatically"
        memory="$(get_total_memory)"
    fi
    sanitized_memory=$(convert_to_mb "$memory")
    if [[ "$sanitized_memory" -gt 26000 ]]; then
        echo 2xlarge
    elif [[ "$sanitized_memory" -gt 13000 ]]; then
        echo xlarge
    elif [[ "$sanitized_memory" -gt 6000 ]]; then
        echo large
    elif [[ "$sanitized_memory" -gt 3000 ]]; then
        echo medium
    elif [[ "$sanitized_memory" -gt 1500 ]]; then
        echo small
    else
        echo micro
    fi
}

########################
# Get machine size depending on specified memory
# Globals:
#   None
# Arguments:
#   $1 - memory size (optional)
# Returns:
#   Detected instance size
#########################
get_supported_machine_sizes() {
    echo micro small medium large xlarge 2xlarge
}

########################
# Convert memory size from string to amount of megabytes (i.e. 2G -> 2048)
# Globals:
#   None
# Arguments:
#   $1 - memory size
# Returns:
#   Result of the conversion
#########################
convert_to_mb() {
    local amount="${1:-}"
    if [[ $amount =~ ^([0-9]+)(M|G) ]]; then
        size="${BASH_REMATCH[1]}"
        unit="${BASH_REMATCH[2]}"
        if [[ "$unit" = "G" ]]; then
           amount="$((size * 1024))"
        else
            amount="$size"
        fi
    fi
    echo "$amount"
}


#########################
# Redirects output to /dev/null if debug mode is disabled
# Globals:
#   BITNAMI_DEBUG
# Arguments:
#   $@ - Command to execute
# Returns:
#   None
#########################
debug_execute() {
    if ${BITNAMI_DEBUG:-false}; then
        "$@"
    else
        "$@" >/dev/null 2>&1
    fi
}

########################
# Retries a command a given number of times
# Arguments:
#   $1 - cmd (as a string)
#   $2 - max retries. Default: 12
#   $3 - sleep between retries (in seconds). Default: 5
# Returns:
#   Boolean
#########################
retry_while() {
    local -r cmd="${1:?cmd is missing}"
    local -r retries="${2:-12}"
    local -r sleep_time="${3:-5}"
    local return_value=1

    read -r -a command <<< "$cmd"
    for ((i = 1 ; i <= retries ; i+=1 )); do
        "${command[@]}" && return_value=0 && break
        sleep "$sleep_time"
    done
    return $return_value
}