#!/usr/bin/env zsh

# I'll just leave this here...
__setup_clang_ubuntu() {
    local site="http://apt.llvm.org"
    local name="$(lsb_release -c | cut -f2)"
    local version=10 # NOTE: no longer decimal-based
    local priority=$(( version * 100 ))
    # TODO: use https? this is sketchy
    echo wget -O - "$site/llvm-snapshot.gpg.key" \| apt-key add -
    echo echo -n \""\
deb $site/$name/ llvm-toolchain-$name main\n\
# deb-src $site/$name/ llvm-toolchain-$name main\n\
# $version\n\
deb $site/$name/ llvm-toolchain-$name-$version main\n\
# deb-src $site/$name/ llvm-toolchain-$name-$version main\n\
"\" \> "/etc/apt/sources.list.d/llvm-toolchain-$name.list"
    echo apt-get update
    echo apt-get install clang-$version
    echo apt-get install lld-$version
    echo update-alternatives --install /usr/bin/clang clang /usr/bin/clang-$version $priority
    echo update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-$version $priority
    echo update-alternatives --install /usr/bin/llvm-symbolizer llvm-symbolizer /usr/bin/llvm-symbolizer-$version $priority
}

compile() {
    local gcc="$(whence -p gcc 2>/dev/null)"
    local clang="$(whence -p clang 2>/dev/null)"
    local clang_flags=() # currently just for clang-msvc

    local cl
    local vc
    if [ -n "$MSYSTEM" ]; then # using msys2?
        if [ -z "$clang" ]; then # don't have native clang?
            # then maybe we have clang-msvc installed.
            local dir
            printf "%s\n" "/c/Program Files/LLVM"*(On/N[1]) | read -r dir
            if [ -d "$dir" ] && [ -e "$dir/bin/clang" ]; then
                clang="$dir/bin/clang"

                # not sure if i'll need this:
                #local clang_include
                #printf "%s\n" "$dir/lib/clang/"*(On/N[1]) | read -r clang_include
                #[ -n "$clang_include" ] || { echo "failed glob; missing clang include" >&2; return 1 }
                #clang_flags+=(-I"$clang_include/include")

                export PATH="$PATH:$dir/bin/"
            fi
        fi

        local winkit
        printf "%s\n" "/c/Program Files (x86)/Windows Kits/"*(on/N[1]) | read -r winkit
        [ -n "$winkit" ] || { echo "failed glob; missing winkit" >&2; return 1 }
        printf "%s\n" "$winkit/Lib/"*(On/N[1]) | read -r winkit
        [ -n "$winkit" ] || { echo "failed glob; missing winkit" >&2; return 1 }

        # detect MSVC.
        local clarch
        local arch
        local msvc_dig_deep
        [ "$MSYSTEM" = MINGW64 ] && clarch="/amd64" || clarch=""
        [ "$MSYSTEM" = MINGW64 ] && arch="x64" || arch="x86"
        if [ -d "/c/Program Files (x86)/Microsoft Visual Studio" ]; then # 2017+
            printf "%s\n" "/c/Program Files (x86)/Microsoft Visual Studio/20"*(On/N[1]) | read vc
            printf "%s\n" "$vc"/*/VC | read vc
            printf "%s\n" "$vc/Tools/MSVC/"*(On/N[1]) | read vc
            msvc_dig_deep="yes"
        else # older versions
            printf "%s\n" "/c/Program Files (x86)/Microsoft Visual Studio "*(On/N[1]) | read vc
            vc="$vc/VC"
        fi

        # setup MSVC.
        if [ -n "$msvc_dig_deep" ] && [ -e "$vc/bin/Host$arch/$arch/cl" ]; then
            cl="$vc/bin/Host$arch/$arch/cl"
            export PATH="$PATH:$vc/bin/Host$arch/$arch"
            export LIB="$(cygpath -w "$vc/lib/$arch")"
            export LIBPATH="$(cygpath -w "$vc/lib/$arch")"
        elif [ -d "$vc/bin$clarch" ] && [ -e "$vc/bin$clarch/$cl" ]; then
            cl="$vc/bin$clarch/cl"
            export PATH="$PATH:$vc/bin$clarch"
            export LIB="$(cygpath -w "$vc/LIB$clarch")"
            export LIBPATH="$(cygpath -w "$vc/LIB$clarch")"
        fi

        # finish up.
        if [ -n "$cl" ]; then
            export INCLUDE="$(cygpath -w "$vc/INCLUDE")"
            export INCLUDE="$INCLUDE;$(cygpath -w "${winkit/Lib/Include}/ucrt")"
            export LIB="$LIB;$(cygpath -w "$winkit/um/$arch")"
            export LIB="$LIB;$(cygpath -w "$winkit/ucrt/$arch")"

            for d in "${(@s/;/)INCLUDE}"; do
                clang_flags+=(-I"$d")
            done
            # ignore MSVC's non-standard deprecation warnings.
            clang_flags+=(-D_CRT_SECURE_NO_WARNINGS)
        fi
    fi

    local sep_once=
    print_separated() {
        echo -n "${sep_once:+|}$1" >&2
        sep_once=1
    }

    if [ $# -eq 0 ]; then
        echo -n "usage: compile [" >&2
        [ -n "$clang" ] && print_separated "clang"
        [ -n "$gcc" ] && print_separated "gcc"
        [ -n "$cl" ] && print_separated "msvc"
        echo "] [debug|derelease|release|hardened] [flags...] {source file}" >&2
        return 1
    fi

    # set some defaults.
    local sepples=0
    [ -n "$clang" ] && local CC=clang || local CC=gcc
    [ -n "$clang" ] && local CXX=clang++ || local CXX=g++
    local our_flags=(-I.)

    # guess if we're compiling C++ by the file extension.
    local file=${@[-1]}
    [ "${file##*.}" = "c" ] || [ "${file##*.}" = "h" ] || sepples=1

    # select the appropriate executable if a compiler name is given.
    { [ "$1" = clang ] && CC="clang" && CXX="clang++" && shift } || \
    { [ "$1" = gcc ] && CC="gcc" && CXX="g++" && shift } || \
    { [ "$1" = msvc ] && CC="cl" && CXX="cl" && shift }

    # always color outputs.
    [ "$CC" = cl ] || our_flags+=-fdiagnostics-color=always

    # add our clang-specific flags. (currently just for clang-msvc)
    if [ $CC = clang ] && [ -n "$clang_flags" ]; then
        for flag in $clang_flags; do
            our_flags+=($flag)
        done
    fi

    # if they exist, include some directories that contain useful headers.
    maybe_include() {
        [ -d "$1" ] && our_flags+=("-I$1")
    }
    maybe_include "$HOME/opt/local/include"
    maybe_include "$HOME/src/ustl"

    # set the build flags for each mode.
    if [ $CC = cl ]; then
        our_flags+=(-nologo -utf-8)
        local debug_flags=(-Od -ZI -sdl);
        local release_flags=(-Ox)
        local dr_flags=(-Ox -Zi)
        local hardened_flags=(-Ox -sdl)
    else
        if [ $CC = clang ]; then
            # clang doesn't like -march=native on ARM for some reason.
            our_flags+=(-mcpu=native)
        else
            our_flags+=(-march=native)
        fi
        local debug_flags=(-O1 -g -D_DEBUG);
        local release_flags=(-Ofast -fwhole-program -fweb -mtune=native -g0 -fomit-frame-pointer -s -DNDEBUG)
        local dr_flags=(-Ofast -g -fomit-frame-pointer -DNDEBUG)
        local hardened_flags=(-O3 -g0 -s
                              -DNDEBUG -D_FORTIFY_SOURCE=2
                              -Wformat -Wformat-security -Werror=format-security)

        if [ -z "$MSYSTEM" ]; then
            hardened_flags+=(-fPIE -pie)
            hardened_flags+=(-Wl,-O1,--sort-common,--as-needed,-z,relro,-z,now)
        fi

        local nomalloc=(-fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-free)
        if [ -e /usr/bin/pprof ]; then
            #debug_flags+=(-ltcmalloc $nomalloc)
            dr_flags+=(-lprofiler $nomalloc)
        elif [ -e /usr/bin/google-pprof ]; then
            #debug_flags+=(-l:libtcmalloc.so.4 $nomalloc)
            dr_flags+=(-l:libtcmalloc_and_profiler.so.4 $nomalloc)
        fi
    fi

    # select appropriate version and executable for the language.
    local compiler=
    if [ $sepples -eq 1 ]; then
        compiler=$CXX
        [ $CC = cl ] && std="-TP" || std="-std=gnu++1z"
    else
        compiler=$CC
        [ $CC = cl ] && std="-TC" || std="-std=gnu11"
    fi

    local clang_msvc=0
    if [ $CC = clang ]; then
        if $compiler --version | grep -q windows-msvc; then
            clang_msvc=1
        fi
    fi

    # utilize clang's vast debugging and hardening features where available.
    if [ $CC = clang ]; then
        debug_flags+=(-ftrapv)
        [ -z "$MSYSTEM" ] && local gold=gold || local gold=lld
        [ -n "$MSYSTEM" ] && our_flags+=(-fansi-escape-codes) || true
        if [ $clang_msvc -eq 1 ] || [ -z "$MSYSTEM" ]; then
            debug_flags+=(-fsanitize=undefined) # this SHOULD work with mingw,
                                                # but it fails to link.
            debug_flags+=(-fsanitize=address)
            debug_flags+=(-fvisibility=hidden -fuse-ld=$gold -flto -fsanitize=cfi)

            hardened_flags+=(-fsanitize=safe-stack)
            hardened_flags+=(-fstack-protector-strong)
            hardened_flags+=(-fvisibility=hidden -fuse-ld=$gold -flto -fsanitize=cfi)
        else
        fi
    fi

    # select and merge the flags for our build mode.
    # TODO: add static option.
    { [ "$1" = debug ] && our_flags+=($debug_flags) && shift } || \
    { [ "$1" = release ] && our_flags+=($release_flags) && shift } || \
    { [ "$1" = derelease ] && our_flags+=($dr_flags) && shift } || \
    { [ "$1" = hardened ] && our_flags+=($hardened_flags) && shift } || \
    { our_flags+=($debug_flags) } # our default

    local flags=(${@[1,-2]})

    # drop everything past the first dot and use that as our output filename.
    local out=/tmp/${${file##*/}%%.*}
    if [ -n "$MSYSTEM" ]; then
        # explicitly output as .exe to avoid weirdness.
        out="$out.exe"
    fi

    # TODO: naive idea:
    # allow multiple source files (using the firstmost to determine the program name)
    # by generating a file that #includes each given file.

    local final_flags=()
    local libraries=()
    local warnings=()
    for flag in $our_flags $flags; do
        # move -l flags to the end because gcc won't respect them otherwise.
        if [[ $flag == -l* ]]; then
            libraries+=($flag)

        # split warning flags so they don't spam the console.
        elif [[ $flag == -W* ]] && [[ $flag != -Wl* ]] || [[ $flag == -Wlogical-op ]]; then
            warnings+=($flag)

            if [ $sepples -eq 0 ] && [[ $flag == -Wextra ]] then
                # enable some warnings just for C. too annoying in C++.
                warnings+=(-Wshadow -Winline)
                # these ones only work with C.
                warnings+=(-Wjump-misses-init)
            fi

            if [ $CC = cl ] && [ $flag = -Wall ]; then
                # disable some obnoxious msvc warnings.
                warnings+=(
                    -wd4505 # unreferenced local function has been removed
                    -wd4514 # unreferenced inline function has been removed
                    -wd4625 # copy constructor was implicitly defined as deleted because a base class copy constructor is inaccessible or deleted
                    -wd4626 # assignment operator was implicitly defined as deleted because a base class assignment operator is inaccessible or deleted
                    -wd4710 # function not inlined
                    -wd4711 # function selected for automatic inline expansion
                )
            fi

        else
            if [ $CC = clang ]; then
                # these are specific to gcc. (for now)
                if [ $flag = "-findirect-inlining" ] \
                || [ $flag = "-finline-small-functions" ]; then
                    continue
                fi
            fi

            if [ $clang_msvc -eq 1 ]; then
                # remove linker-related flags from our compiler-only clang.
                if [ $flag = "-Wl,--gc-sections" ] \
                || [ $flag = "-s" ]; then
                    continue
                fi
            fi

            final_flags+=($flag)
        fi
    done

    # do the thing!
    [ $CC = cl ] && local outflag=-Fe: || local outflag=-o
    echo $compiler $std ${final_flags[@]} $file ${libraries[@]} $outflag $out >&2
    $compiler $std ${final_flags[@]} $file ${libraries[@]} ${warnings[@]} $outflag $out
}

compile "$@"