#!/bin/bash

# Test if the named environment variable is set and not zero length
# is_set env-var
function is_set {
    local var=\$"$1"
    eval "[[ -n \"$var\" ]]"
}

# Prints backtrace info
# filename:lineno:function
# backtrace level
function backtrace {
    local level=$1
    local deep
    deep=$((${#BASH_SOURCE[@]} - 1))
    echo "[Call Trace]"
    while [ $level -le $deep ]; do
        echo "${BASH_SOURCE[$deep]}:${BASH_LINENO[$deep-1]}:${FUNCNAME[$deep-1]}"
        deep=$((deep - 1))
    done
}

# Prints line number and "message" in error format
# err $LINENO "message"
function err {
    local exitcode=$?
    local xtrace
    xtrace=$(set +o | grep xtrace)
    set +o xtrace
    local msg="[ERROR] ${BASH_SOURCE[2]}:$1 $2"
    echo $msg 1>&2;
    if [[ -n ${LOGDIR} ]]; then
        echo $msg >> "${LOGDIR}/error.log"
    fi
    $xtrace
    return $exitcode
}

# Prints line number and "message" then exits
# die $LINENO "message"
function die {
    local exitcode=$?
    local xtrace
    xtrace=$(set +o | grep xtrace)
    set +o xtrace
    local line=$1; shift
    if [ $exitcode == 0 ]; then
        exitcode=1
    fi
    backtrace 2
    err $line "$*"
    # Give buffers a second to flush
    sleep 1
    $xtrace
    exit $exitcode
}

# Checks an environment variable is not set or has length 0 OR if the
# exit code is non-zero and prints "message" and exits
# NOTE: env-var is the variable name without a '$'
# die_if_not_set $LINENO env-var "message"
function die_if_not_set {
    local exitcode=$?
    local xtrace
    xtrace=$(set +o | grep xtrace)
    set +o xtrace
    local line=$1; shift
    local evar=$1; shift
    if ! is_set $evar || [ $exitcode != 0 ]; then
        die $line "$*"
    fi
    $xtrace
}

# Wait until the condition is met.
# wait_until condition timeout interval
function wait_until {
    local condition="$1"
    local timeout=$2
    local interval=$3

    while eval ${condition}
    do
        sleep ${interval}
        timeout=$((${timeout} - ${interval}))
        if [[ ${timeout} < 0 ]]; then
            err $LINENO "timed out ($condition)..."
            return 1
        fi
    done
}