#!/bin/bash

# Get the total or free amount of RAM+swap on the system
#
# usage: ynh_get_ram [--free|--total] [--ignore_swap|--only_swap]
# | arg: -f, --free         - Count free RAM+swap
# | arg: -t, --total        - Count total RAM+swap
# | arg: -s, --ignore_swap  - Ignore swap, consider only real RAM
# | arg: -o, --only_swap    - Ignore real RAM, consider only swap
# | ret: the amount of free ram, in MB (MegaBytes)
#
# Requires YunoHost version 3.8.1 or higher.
ynh_get_ram() {
    # Declare an array to define the options of this helper.
    local legacy_args=ftso
    local -A args_array=([f]=free [t]=total [s]=ignore_swap [o]=only_swap)
    local free
    local total
    local ignore_swap
    local only_swap
    # Manage arguments with getopts
    ynh_handle_getopts_args "$@"
    ignore_swap=${ignore_swap:-0}
    only_swap=${only_swap:-0}
    free=${free:-0}
    total=${total:-0}

    if [ $free -eq $total ]; then
        ynh_print_warn --message="You have to choose --free or --total when using ynh_get_ram"
        ram=0
    # Use the total amount of ram
    elif [ $free -eq 1 ]; then
        local free_ram=$(LC_ALL=C vmstat --stats --unit M | grep "free memory" | awk '{print $1}')
        local free_swap=$(LC_ALL=C vmstat --stats --unit M | grep "free swap" | awk '{print $1}')
        local free_ram_swap=$((free_ram + free_swap))

        # Use the total amount of free ram
        local ram=$free_ram_swap
        if [ $ignore_swap -eq 1 ]; then
            # Use only the amount of free ram
            ram=$free_ram
        elif [ $only_swap -eq 1 ]; then
            # Use only the amount of free swap
            ram=$free_swap
        fi
    elif [ $total -eq 1 ]; then
        local total_ram=$(LC_ALL=C vmstat --stats --unit M | grep "total memory" | awk '{print $1}')
        local total_swap=$(LC_ALL=C vmstat --stats --unit M | grep "total swap" | awk '{print $1}')
        local total_ram_swap=$((total_ram + total_swap))

        local ram=$total_ram_swap
        if [ $ignore_swap -eq 1 ]; then
            # Use only the amount of free ram
            ram=$total_ram
        elif [ $only_swap -eq 1 ]; then
            # Use only the amount of free swap
            ram=$total_swap
        fi
    fi

    echo $ram
}

# Return 0 or 1 depending if the system has a given amount of RAM+swap free or total
#
# usage: ynh_require_ram --required=RAM [--free|--total] [--ignore_swap|--only_swap]
# | arg: -r, --required=    - The amount to require, in MB
# | arg: -f, --free         - Count free RAM+swap
# | arg: -t, --total        - Count total RAM+swap
# | arg: -s, --ignore_swap  - Ignore swap, consider only real RAM
# | arg: -o, --only_swap    - Ignore real RAM, consider only swap
# | ret: 1 if the ram is under the requirement, 0 otherwise.
#
# Requires YunoHost version 3.8.1 or higher.
ynh_require_ram() {
    # Declare an array to define the options of this helper.
    local legacy_args=rftso
    local -A args_array=([r]=required= [f]=free [t]=total [s]=ignore_swap [o]=only_swap)
    local required
    local free
    local total
    local ignore_swap
    local only_swap
    # Manage arguments with getopts
    ynh_handle_getopts_args "$@"
    # Dunno if that's the right way to do, but that's some black magic to be able to
    # forward the bool args to ynh_get_ram easily?
    # If the variable $free is not empty, set it to '--free'
    free=${free:+--free}
    total=${total:+--total}
    ignore_swap=${ignore_swap:+--ignore_swap}
    only_swap=${only_swap:+--only_swap}

    local ram=$(ynh_get_ram $free $total $ignore_swap $only_swap)

    if [ $ram -lt $required ]; then
        return 1
    else
        return 0
    fi
}
