chore: format and add meta module

lib/flake.nix

@@ -1,5 +1,5 @@
 {
-  outputs = i: {
+  outputs = _i: {
     lib = import ./.;
   };
 }

lib/modules/default.nix

@@ -2,5 +2,6 @@
   imports = [
     ./main.nix
     ./env.nix
+    ./meta.nix
   ];
 }

lib/modules/env.nix

@@ -13,7 +13,7 @@
     prefix,
     ...
   } @ args: let
-    vals = filter (key: args.${key} != null && args.${key} != false) [
+    vals = filter (key: args.${key} != null && args.${key}) [
       "eval"
       "prefix"
       "unset"
@@ -122,5 +122,14 @@ in {
     };
     enterShellCommands."env".text = concatStringsSep "\n" (map envToBash (builtins.attrValues config.env));
     # TODO: collect all env vars, then add them to the menu if they have a description and "visibile == true"
+
+    meta = {
+      sections."Environment Variables".color = "red";
+      entries."XDG_DATA_DIRS" = {
+        description = "Hello world";
+        section = "Environment Variables";
+        subEntries."Usage" = "hello world";
+      };
+    };
   };
 }

lib/modules/main.nix

@@ -124,8 +124,12 @@ in {
       meta.mainProgram = "devshell-${config.name}";
     };
     finalPackage = mkNakedShell {
-      name = config.name;
+      inherit (config) name;
       profile = config.shell.finalProfile;
+      passthru = {
+        metadata = config.meta.finalMetadata;
+        metadataJson = config.meta.finalJson;
+      };
     };
   };
 }

lib/modules/meta.nix

@@ -0,0 +1,211 @@
+{
+  pkgs,
+  lib,
+  config,
+  ...
+}: let
+  inherit (lib) mkOption types optional mkIf concatMapStrings concatMapStringsSep toUpper splitString;
+  cfg = config.meta;
+
+  printSubtext = subtext:
+  # sh
+  ''
+    printf "  $FG_GRAY ↳ $RESET''${BOLD}${subtext.text}$RESET: ${subtext.desc}\n"
+  '';
+
+  printEntry = entry:
+  # sh
+  ''
+    printf " $FG_${entry.color}› %-*s$RESET  $FG_GRAY%s$RESET\n" "${maxWidth}" "${entry.text}" "${entry.desc}"
+    ${concatMapStrings printSubtext entry.subtexts}
+  '';
+  printGroup = group:
+  # sh
+  ''
+    printf " $FG_WHITE$RESET$BG_WHITE$FG_BLACK %s $RESET$FG_WHITE$RESET\n" "${group.title}"
+    ${concatMapStrings printEntry group.entries}
+  '';
+
+  calculateMaxWidth = groups: let
+    lengths = builtins.concatLists (builtins.map (
+        group:
+          builtins.map (entry: builtins.stringLength entry.text) group.entries
+      )
+      groups);
+
+    max = a: b:
+      if a > b
+      then a
+      else b;
+    maxLength =
+      if lengths == []
+      then 0
+      else builtins.foldl' max 0 lengths;
+  in
+    maxLength;
+  maxWidth = builtins.toString (calculateMaxWidth result);
+
+  printHeaderDescription = text:
+    concatMapStringsSep "\n" (line:
+      # sh
+      ''
+        printf " $FG_BLUE│$RESET  $FG_WHITE%s$RESET\n" "${line}"
+      '') (splitString "\n" text);
+
+  menuPackage = pkgs.writeTextFile {
+    name = "menu";
+    destination = "/bin/menu";
+    executable = true;
+    text =
+      # sh
+      ''
+        BOLD=$(tput bold)
+        RESET=$(tput sgr0)
+        FG_BLACK=$(tput setaf 0)
+        FG_RED=$(tput setaf 1)
+        FG_GREEN=$(tput setaf 2)
+        FG_YELLOW=$(tput setaf 3)
+        FG_BLUE=$(tput setaf 4)
+        FG_MAGENTA=$(tput setaf 5)
+        FG_CYAN=$(tput setaf 6)
+        FG_WHITE=$(tput setaf 7)
+        BG_WHITE=$(tput setab 7)
+        FG_GRAY=$(tput setaf 8)
+
+        printf " $FG_BLUE╭─┄┄┈┈$RESET\n"
+        printf " $FG_BLUE│$RESET $FG_YELLOW$BOLD%s$RESET\n" "${config.name}"
+        ${printHeaderDescription cfg.description}
+        printf " $FG_BLUE╰─┄┄┈┈$RESET\n"
+        printf "\n"
+
+        ${concatMapStringsSep "printf '\n'\n" printGroup result}
+      '';
+  };
+
+  groupedEntries = builtins.foldl' (
+    acc: entryName: let
+      entry = cfg.entries.${entryName};
+      sectionName = entry.section;
+      section = cfg.sections.${sectionName} or {};
+
+      newEntry = {
+        text = entry.name;
+        desc = entry.description or "";
+        color = section.color or "BLUE";
+        subtexts = map (name: {
+          text = name;
+          desc = entry.subEntries.${name};
+        }) (builtins.attrNames entry.subEntries);
+      };
+
+      updatedSection =
+        if acc ? ${sectionName}
+        then acc.${sectionName} ++ [newEntry]
+        else [newEntry];
+    in
+      acc // {${sectionName} = updatedSection;}
+  ) {} (builtins.attrNames cfg.entries);
+
+  result = builtins.map (sectionName: {
+    title = sectionName;
+    entries = groupedEntries.${sectionName} or [];
+  }) (builtins.attrNames groupedEntries);
+in {
+  options.meta = {
+    enableMenu = mkOption {
+      type = types.bool;
+      default = true;
+      description = ''
+        Add a `menu` command which shows a nice overview/summary of the devshell.
+      '';
+    };
+    showMenu = mkOption {
+      type = types.enum ["always" "once" "never"];
+      default = "once";
+      description = ''
+        When to show the devshell menu. `once` uses a state file in `$REN_STATE`
+        to keep track of the first time.
+      '';
+    };
+    description = mkOption {
+      type = types.str;
+      default = "Welcome to the devshell.";
+      description = '''';
+    };
+    sections = mkOption {
+      type = types.attrsOf (types.submodule ({name, ...}: {
+        options = {
+          name = mkOption {
+            type = types.str;
+            default = name;
+          };
+          color = mkOption {
+            type = types.nullOr types.str;
+            default = "blue";
+            apply = toUpper;
+          };
+        };
+      }));
+      default = {
+        "general" = {};
+      };
+    };
+    entries = mkOption {
+      type = types.attrsOf (types.submodule ({name, ...}: {
+        options = {
+          name = mkOption {
+            type = types.str;
+            default = name;
+          };
+          section = mkOption {
+            type = types.str;
+            default = "general";
+          };
+          description = mkOption {
+            type = types.nullOr types.str;
+            default = null;
+          };
+          subEntries = mkOption {
+            type = types.attrs;
+            default = {};
+          };
+        };
+      }));
+      default = {};
+    };
+    finalMetadata = mkOption {
+      type = types.attrs;
+      internal = true;
+    };
+    finalJson = mkOption {
+      type = types.package;
+      internal = true;
+    };
+  };
+
+  config = {
+    meta = rec {
+      finalMetadata = {
+        inherit (config) name;
+        # inherit (cfg) sections entries;
+        sections = result;
+      };
+      finalJson = builtins.toFile "meta.json" (builtins.toJSON finalMetadata);
+    };
+
+    packages = optional cfg.enableMenu menuPackage;
+    # shows the menu when entering the devshell
+    enterShellCommands."menu".text = mkIf (cfg.enableMenu && cfg.showMenu != "never") (
+      if cfg.showMenu == "always"
+      then "menu"
+      else
+        # sh
+        ''
+          if [[ ! -f "$REN_STATE/${config.name}_menu_shown" ]]; then
+            touch "$REN_STATE/${config.name}_menu_shown"
+            menu
+          fi
+        ''
+    );
+  };
+}

lib/utils/mkNakedShell.nix

@@ -30,7 +30,7 @@ in
     (derivation {
       inherit name;
 
-      system = stdenv.hostPlatform.system;
+      inherit (stdenv.hostPlatform) system;
 
       # `nix develop` actually checks and uses builder. And it must be bash.
       builder = bashPath;

nix/repo/devShells.nix

@@ -13,10 +13,15 @@ in {
         };
       })
     ];
-    env."HELLO".value = "world!";
-    enterShellCommands.test = {
-      text = "echo Hello $HELLO";
-      deps = ["env"];
+    meta = {
+      enableMenu = true;
+      showMenu = "always";
+      entries = {
+        "World" = {
+          section = "Hello";
+          description = "meow";
+        };
+      };
     };
   };
 }