lua.lib: use toLua in generateLuarocksConfig

{ pkgs, lib, lua }:

let

  inherit (lib.generators) toLua;

  requiredLuaModules = drvs: with lib; let

    modules =  filter hasLuaModule drvs;

  in unique ([lua] ++ modules ++ concatLists (catAttrs "requiredLuaModules" modules));

    , rocksSubdir

    }: let

      rocksTrees = lib.imap0

        (i: dep: "{ name = [[dep-${toString i}]], root = '${dep}', rocks_dir = '${dep}/${dep.rocksSubdir}' }")

        (i: dep: { name = "dep-${toString i}"; root = "${dep}"; rocks_dir = "${dep}/${dep.rocksSubdir}"; })

        requiredLuaRocks;

      # Explicitly point luarocks to the relevant locations for multiple-output

      # derivations that are external dependencies, to work around an issue it has

      # (https://github.com/luarocks/luarocks/issues/766)

      depVariables = lib.concatMap ({name, dep}: [

        "${name}_INCDIR='${lib.getDev dep}/include';"

        "${name}_LIBDIR='${lib.getLib dep}/lib';"

        "${name}_BINDIR='${lib.getBin dep}/bin';"

      ]) externalDeps';

      depVariables = zipAttrsWithLast (lib.lists.map ({name, dep}: {

        "${name}_INCDIR" = "${lib.getDev dep}/include";

        "${name}_LIBDIR" = "${lib.getLib dep}/lib";

        "${name}_BINDIR" = "${lib.getBin dep}/bin";

      }) externalDeps');

      zipAttrsWithLast = lib.attrsets.zipAttrsWith (name: lib.lists.last);

      # example externalDeps': [ { name = "CRYPTO"; dep = pkgs.openssl; } ]

      externalDeps' = lib.filter (dep: !lib.isDerivation dep) externalDeps;

      externalDepsDirs = map

        (x: "'${builtins.toString x}'")

        (x: builtins.toString x)

        (lib.filter (lib.isDerivation) externalDeps);

      extraVariablesStr = lib.concatStringsSep "\n "

        (lib.mapAttrsToList (k: v: "${k}='${v}';") extraVariables);

  in ''

    local_cache = ""

    -- To prevent collisions when creating environments, we install the rock

    -- files into per-package subdirectories

    rocks_subdir = '${rocksSubdir}'

    rocks_subdir = ${toLua {} rocksSubdir}

    -- first tree is the default target where new rocks are installed,

    -- any other trees in the list are treated as additional sources of installed rocks for matching dependencies.

    rocks_trees = {

      {name = "current", root = '${placeholder "out"}', rocks_dir = "current" },

      ${lib.concatStringsSep "\n, " rocksTrees}

    }

    rocks_trees = ${toLua {} (

      [{name = "current"; root = "${placeholder "out"}"; rocks_dir = "current"; }] ++

      rocksTrees

    )}

  '' + lib.optionalString lua.pkgs.isLuaJIT ''

    -- Luajit provides some additional functionality built-in; this exposes

    -- that to luarock's dependency system

    rocks_provided = {

      jit='${lua.luaversion}-1';

      ffi='${lua.luaversion}-1';

      luaffi='${lua.luaversion}-1';

      bit='${lua.luaversion}-1';

    }

    rocks_provided = ${toLua {} {

      jit = "${lua.luaversion}-1";

      ffi = "${lua.luaversion}-1";

      luaffi = "${lua.luaversion}-1";

      bit = "${lua.luaversion}-1";

    }}

  '' + ''

    -- For single-output external dependencies

    external_deps_dirs = {

      ${lib.concatStringsSep "\n, " externalDepsDirs}

    }

    variables = {

    external_deps_dirs = ${toLua {} externalDepsDirs}

    -- Some needed machinery to handle multiple-output external dependencies,

    -- as per https://github.com/luarocks/luarocks/issues/766

      ${lib.optionalString (lib.length depVariables > 0) ''

        ${lib.concatStringsSep "\n  " depVariables}''}

      ${extraVariablesStr}

    }

    variables = ${toLua {} (depVariables // extraVariables)}

  '';

}