#!/usr/bin/env bash
# -----------------------------------------------------------------------------
# Build automation script designed to work with autotools.
# -----------------------------------------------------------------------------
set -e

# -----------------------------------------------------------------------------
# Functions used by Build.rc
#
declare prefix
function setPrefix () {
    if (( $# != 1 )); then
        echo "Usage: $0 PREFIX" >&2
        return 1
    fi
    prefix="$1"
}

function setPath () {
    if (( $# == 0 )); then
        echo "Usage: $0 VAR [PATH, ...]" >&2
        return 1
    fi

    local -r var="$1"
    local paths=("${@:2}")

    case ${#paths[@]} in
        0)
            unset $var;;
        1)
            export $var="$paths";;
        *)
            export $var="${paths[0]}"
            local path
            for path in "${paths[@]:1}"; do
                local val=$(eval echo \$$var)
                export $var="$val:$path"
            done
    esac

    # Special case for PATH: we prepend "$prefix/bin" to it.
    if [[ $var = "PATH" ]]; then
        PATH="$prefix/bin:$PATH"
    fi
}

declare -a configArgs
function setConfigArgs () {
    configArgs=( \
        --prefix="$prefix" \
        PATH="$PATH" \
        "$@" \
        )
}

declare buildTarget
function setBuildTarget () {
    if (( $# != 1 )); then
        echo "Usage: $0 TARGET" >&2
        return 1
    fi
    buildTarget="$1"
}

declare docDirectory
function setDocDirectory () {
    if (( $# != 1 )); then
        echo "Usage: $0 DIRECTORY" >&2
        return 1
    fi
    docDirectory="$1"
}

declare docTarget
function setDocTarget () {
    if (( $# != 1 )); then
        echo "Usage: $0 TARGET" >&2
        return 1
    fi
    docTarget="$1"
}

# -----------------------------------------------------------------------------
# Setting variables
#
setPrefix "/usr/local"
setPath PATH "/usr/bin" "/bin"
setConfigArgs
setBuildTarget "all"
setDocDirectory "."
setDocTarget "all"

if [ -f "Build.rc" ]; then
    . "Build.rc"
fi

# -----------------------------------------------------------------------------
# Main
#
function run () {
    if (( $# == 0 )); then
        echo "run: Usage: run CMD [ARG...]" >&2
        return 1
    fi

    if [[ -t 1 ]]; then
        # Bold + Green
        echo -ne "\e[1;32m"
        echo "$@"
        echo -ne "\e[0m"
    else
        echo "$@"
    fi

    $@
}

function detectNumCPUs () {
    if sysctl -n "hw.ncpu" 2>/dev/null; then
        # This works for most BSDs.
        :
    elif grep -qF processor /proc/cpuinfo 2>/dev/null; then
        # Linux sucks...
        grep -cF processor /proc/cpuinfo
    else
        echo "WARNING: I don't know how to detect the number of processors on this platform." >&2
        echo 1
    fi
}

function runMake () {
    run gmake -w -j $(detectNumCPUs) $@
}

function configure () {
    if [[ ! -f configure.ac && ! -f configure.in ]]; then
        echo "ERROR: Neither configure.ac nor configure.in exists in the current directory." >&2
        return 1
    fi

    if [[ ! -f configure ]]; then
        run autoreconf -v -i -f
    fi

    if [[ ! -f "_build/Makefile" ]]; then
        run mkdir -p _build
        run pushd _build
        run ../configure "${configArgs[@]}"
        run popd
    fi
}

function build () {
    configure
    runMake -C "_build" $buildTarget
}

function doc () {
    configure
    runMake -C "_build/$docDirectory" $docTarget
}

function check () {
    build
    runMake -C "_build" check
}

function clean () {
    run rm -rf "_build"
}

function dist () {
    configure
    runMake -C "_build" dist
}

function install () {
    build
    runMake -C "_build" install
}

case "$1" in
    ""|"build") build  ;;
    "doc"     ) doc    ;;
    "check"   ) check  ;;
    "clean"   ) clean  ;;
    "dist"    ) dist   ;;
    "install" ) install;;
    *)
        echo "Usage: $0 [build | doc | check | clean | dist | install]" >&2
        exit 1
esac