#!/usr/bin/env bash
#
# USAGE
#   [targets='...'] [spectre_feature=0|1 ...] [CFLAGS='...'] [LDFLAGS='...'] ./build [-v|-d|-h|--] [cc arguments ...]
#
#   By default, you should only need to run ./build
#
#   -v: verbose mode, outputs state information and compiler commands.
#   -d: debug build, modifies default build flags to produce binaries best suited for debugging.
#   -h: show this usage information.
#
#   You can customize the targets that are built using targets='...'. Use targets='all' to build all targets.
#   By default, we only build the 'spectre' target.  
#   See targets_all for all possible targets as well as the features they support and require.
#
#   Several features can be enabled or disabled using feature flags.
#   See the Features section for an overview of the features, their default setting, their meaning and their dependencies.
#   You will need to have each of the feature's dependencies installed for the build to succeed with that feature enabled.
#
#   Finally, the C compiler can be tuned using CFLAGS, LDFLAGS and compiler arguments passed to the script.
#
# BUGS
#   support@spectre.app
#
# AUTHOR
#   Maarten Billemont
#
cd "${BASH_SOURCE%/*}"
shopt -s extglob
set -e


### CONFIGURATION
verbose=0

# Options
while getopts :vdh opt; do
    case $opt in
        v)      verbose=1 ;;
        d)      debug=1 ;;
        h|?)    sed -n '/^[^#]/q;p' "${BASH_SOURCE##*/}"; exit ;;
    esac
done
shift "$(( OPTIND - 1 ))"

# Targets to build
targets_all=(
    spectre                     # C CLI version of Spectre (needs: spectre_sodium, optional: spectre_color, spectre_json).
    spectre-bench               # C CLI Spectre benchmark utility (needs: spectre_sodium).
    spectre-tests               # C Spectre algorithm test suite (needs: spectre_sodium, spectre_xml).
)
targets_default='spectre'       # Override with: targets='...' ./build
targets=${targets[*]:-$targets_default} 

# Features
spectre_sodium=${spectre_sodium:-1} # Implement crypto functions with sodium (depends on libsodium).
spectre_json=${spectre_json:-1}     # Support JSON-based user configuration format (depends on libjson-c).
spectre_color=${spectre_color:-1}   # Colorized identicon (depends on libncurses).
spectre_xml=${spectre_xml:-1}       # XML parsing (depends on libxml2).

# Default build flags
cflags=( -O3 $CFLAGS ); unset CFLAGS
ldflags=( $LDFLAGS ); unset LDFLAGS
if (( debug )); then
    cflags+=( -O0 -g )
fi

# Version
if { spectre_version=$(git describe --match '*-cli*' --long --dirty) || spectre_version=$(<VERSION); } 2>/dev/null; then
    cflags+=( -D"MP_VERSION=$spectre_version" )
fi
echo "Current spectre source version ${spectre_version:-<unknown>}..."

# Meta
if (( verbose )); then
    echo "spectre_sodium=${spectre_sodium}, spectre_json=${spectre_json}, spectre_color=${spectre_color}, spectre_xml=${spectre_xml}"
    echo "CFLAGS: ${cflags[*]}"
    echo "LDFLAGS: ${ldflags[*]}"
    echo "targets: ${targets[*]}"
fi


### TARGET: SPECTRE
spectre() {
    # dependencies
    use_spectre_sodium required
    use_spectre_color optional
    use_spectre_json optional

    # target
    cflags=(
        "${cflags[@]}"

        # spectre paths
        -I"api/c" -I"src"
    )
    ldflags=(
        "${ldflags[@]}"
    )

    # build
    cc "${cflags[@]}" "$@" \
       "api/c/aes.c" "api/c/spectre-algorithm.c" \
       "api/c/spectre-algorithm_v0.c" "api/c/spectre-algorithm_v1.c" "api/c/spectre-algorithm_v2.c" "api/c/spectre-algorithm_v3.c" \
       "api/c/spectre-types.c" "api/c/spectre-util.c" "api/c/spectre-marshal-util.c" "api/c/spectre-marshal.c" "src/spectre-cli-util.c" \
       "${ldflags[@]}" "src/spectre-cli.c" -o "spectre"
    echo "done!  You can now run ./spectre-cli-tests, ./install or use ./$_"
}


### TARGET: SPECTRE-BENCH
spectre-bench() {
    # dependencies
    use_spectre_sodium required

    # target
    cflags=(
        "${cflags[@]}"

        # spectre paths
        -I"api/c" -I"src"
    )
    ldflags=(
        "${ldflags[@]}"
    )

    # build
    cc "${cflags[@]}" "$@" \
       "api/c/aes.c" "api/c/spectre-algorithm.c" \
       "api/c/spectre-algorithm_v0.c" "api/c/spectre-algorithm_v1.c" "api/c/spectre-algorithm_v2.c" "api/c/spectre-algorithm_v3.c" \
       "api/c/spectre-types.c" "api/c/spectre-util.c" \
       "${ldflags[@]}" "src/spectre-bench.c" -o "spectre-bench"
    echo "done!  You can now use ./$_"
}


### TARGET: SPECTRE-TESTS
spectre-tests() {
    # dependencies
    use_spectre_sodium required
    use_spectre_xml required

    # target
    cflags=(
        "${cflags[@]}"

        # spectre paths
        -I"api/c" -I"src"
    )
    ldflags=(
        "${ldflags[@]}"
    )

    # build
    cc "${cflags[@]}" "$@" \
       "api/c/aes.c" "api/c/spectre-algorithm.c" \
       "api/c/spectre-algorithm_v0.c" "api/c/spectre-algorithm_v1.c" "api/c/spectre-algorithm_v2.c" "api/c/spectre-algorithm_v3.c" \
       "api/c/spectre-types.c" "api/c/spectre-util.c" "src/spectre-tests-util.c" \
       "${ldflags[@]}" "src/spectre-tests.c" -o "spectre-tests"
    echo "done!  You can now use ./$_"
}


### TOOLS
haslib() {
    cc -x c "${ldflags[@]}" -l"$1" -o /dev/null - <<< 'int main() { return 0; }' &>/dev/null
}
cc() (
    (( verbose )) && set -x

    if { hash "$CC"; } 2>/dev/null; then
        "$CC" -std=c11 "$@"
    elif { hash clang; } 2>/dev/null; then
        clang -std=c11 "$@"
    elif { hash llvm-gcc; } 2>/dev/null; then
        llvm-gcc -std=c11 "$@"
    elif { hash gcc; } 2>/dev/null; then
        gcc -std=c11 "$@"
    else
        echo >&2 "Need a compiler.  Please install GCC or LLVM."
        exit 1
    fi
)


### DEPENDENCIES
use() {
    local option=$1 requisite=$2 lib=$3; shift 3
    local enabled=${!option} found=0 _cflags _ldflags

    if (( enabled )); then
        for lib in "$lib" "$@"; do
            if _cflags=$(pkg-config --cflags "$lib" 2>/dev/null) && _ldflags=$(pkg-config --libs "$lib" 2>/dev/null); then
                cflags+=( $_cflags ) ldflags+=( $_ldflags ); found=1
            elif _cflags=$(pkg-config --cflags "lib$lib" 2>/dev/null) && _ldflags=$(pkg-config --libs "lib$lib" 2>/dev/null); then
                cflags+=( $_cflags ) ldflags+=( $_ldflags ); found=1
            elif haslib "$lib"; then
                ldflags+=( -l"$lib" ); found=1
            fi
        done

        if (( found )); then
            echo "INFO:     Enabled $option (lib$lib)."
            return 0

        elif [[ $requisite == required ]]; then
            echo >&2 "ERROR:    $option was enabled but is missing $lib library.  Please install this library before continuing."
            exit 1

        else
            echo >&2 "WARNING:  $option was enabled but is missing $lib library.  Will continue with $option disabled!"
            return 1

        fi

    elif [[ $requisite == required ]]; then
        echo >&2 "ERROR:    $option was required but is not enabled.  Please enable the option or remove this target before continuing."
        exit 1

    else
        echo "INFO:     $option is supported but not enabled."
        return 1
    fi
}
use_spectre_sodium() {
    local requisite=$1
    use spectre_sodium "$requisite" sodium && cflags+=( -D"SPECTRE_SODIUM=1" ) ||:
}
use_spectre_color() {
    local requisite=$1
    use spectre_color "$requisite" curses tinfo && cflags+=( -D"SPECTRE_COLOR=1" ) ||:
}
use_spectre_json() {
    local requisite=$1
    use spectre_json "$requisite" json-c && cflags+=( -D"SPECTRE_JSON=1" ) ||:
}
use_spectre_xml() {
    local requisite=$1
    use spectre_xml "$requisite" xml2 && cflags+=( $(xml2-config --cflags) ) ldflags+=( $(xml2-config --libs) ) ||:
}


### BUILD TARGETS
for target in "${targets_all[@]}"; do
    if [[ $targets == 'all' || " $targets " = *" $target "*  ]]; then
        echo
        echo "Building target: $target..."
        ( "$target" "$@" )
    fi
done