#!/bin/bash

set -eux

src=${EMACS_SRC:-.}
build=${EMACS_BUILD:-.}
config_h=${build}/src/config.h

make="make -j$(nproc --all)"
configure_flags=(
    --prefix=${HOME}/apps/.emacs.$(date +%F)
    --with-cairo
    --with-sqlite3
    --with-xinput2
)

is-rolling-distro ()
{
    (
        . /etc/os-release
        case "${ID}"
        in
            opensuse-tumbleweed) return 0;;
        esac
        return 1
    )
}

cache-file ()
{
    local -r cachedir=${XDG_CACHE_HOME:-~/.cache}/emacs
    test -d "${cachedir}" || mkdir -p "${cachedir}"

    local builddesc=${PWD}
    builddesc=${builddesc#~}
    builddesc=${builddesc//\//,}
    echo ${cachedir}/config${builddesc}
}

if ! is-rolling-distro
then
    configure_flags=(
        --cache-file="$(cache-file)"
        "${configure_flags[@]}"
    )
fi

if test "${DEBUG:-}"
then
    configure_flags+=(
        --enable-checking=yes,glyphs
        --enable-check-lisp-object-type
        CFLAGS='-O0 -g3'
    )
fi

if ! test -f "${src}"/Makefile
then
        ${make} -C "${src}" configure
fi

check-config ()
{
    if ! test -f "${config_h}"
    then
        return 1
    fi

    local pattern="#define EMACS_CONFIG_OPTIONS \"${configure_flags[@]}\""
    grep "${pattern}" "${config_h}"
}

cd "${build}"

if ! check-config
then
    "${src}"/configure "${configure_flags[@]}"
fi

${make} "$@"