flake: remove dependency to nixpkgs

.github/README.md → README.md

@@ -6,23 +6,23 @@ repository.
 
 ## Usage
 
-To use a wallpaper in wallpkgs, you add the flake to your flake inputs.
-You then may use each of the wallpapers however you please.
+To use a wallpaper in wallpkgs, you add the flake to your flake inputs. You then
+may use each of the wallpapers however you please.
 
 ```nix
 {
-    inputs = {
-        nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
-        wallpkgs.url = "github:NotAShelf/wallpkgs";
-    };
-
-    outputs = { wallpkgs, ... }: {
-        overlays.default = _final: prev: {
-            catppuccinWalls = prev.callPackage ./wallpapers.nix {
-                wallpapers = builtins.filter (wall: builtins.elem "catppuccin" wall.tags) (builtins.attrValues wallpkgs.wallpapers);
-            };
-        };
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    wallpkgs.url = "github:NotAShelf/wallpkgs";
+  };
+
+  outputs = {wallpkgs, ...}: {
+    overlays.default = _final: prev: {
+      catppuccinWalls = prev.callPackage ./wallpapers.nix {
+        wallpapers = builtins.filter (wall: builtins.elem "catppuccin" wall.tags) (builtins.attrValues wallpkgs.wallpapers);
+      };
     };
+  };
 }
 ```
 

flake.nix

@@ -3,44 +3,17 @@
     Pure and reproducible, and possibly curated collection of wallpapers.
   '';
 
-  inputs = {
-    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
-    systems.url = "github:nix-systems/default";
-  };
-
-  outputs = {
-    nixpkgs,
-    systems,
-    ...
-  }: let
-    inherit (nixpkgs) lib;
+  outputs = let
+    lib = import ./lib;
 
+    systems = ["x86_64-linux" "aarch64-linux"];
     genSystems = lib.genAttrs (import systems);
-    pkgsFor = nixpkgs.legacyPackages;
   in {
-    wallpapers = let
-      fileExts = ["png" "jpg" "jpeg" "gif"];
-    in
-      builtins.listToAttrs (map (n: let
-          findFile = builtins.filter builtins.pathExists (map (ext: ./wallpapers/${n}.${ext}) fileExts);
-          file =
-            if findFile == []
-            then builtins.throw "Either ${n} isn't a file or it doesn't have the ${builtins.concatStringsSep ", " (lib.init fileExts)} or ${lib.last fileExts} extensions."
-            else builtins.head findFile;
-        in {
-          name = n;
-          value = {
-            path = file;
-            tags = lib.splitString "-" n;
-            hash = builtins.hashFile "sha256" file;
-          };
-        })
-        (map (n: builtins.head (lib.splitString "." n)) (
-          builtins.attrNames (
-            lib.filterAttrs (n: _: n != "README.md") (builtins.readDir ./wallpapers)
-          )
-        )));
+    # Construct the wallpapers output for wallpkgs from a directory and a list of
+    # extensions allow.
+    wallpapers = lib.toWallpkgs ./wallpapers ["png" "jpg" "jpeg" "gif"];
 
+    # For backwards compatibility. This should re removed in the future.
     packages = genSystems (_:
       builtins.listToAttrs (map (n: {
           name = n;
@@ -68,8 +41,5 @@
           "monochrome"
           "nord"
         ]));
-
-    # I do not accept anything else.
-    formatter = genSystems (system: pkgsFor.${system}.alejandra);
   };
 }

lib/default.nix

@@ -0,0 +1,78 @@
+# This is the wallpkgs... un-extended library. It appends a few useful functions
+# based on their nixpkgs.lib variants, without any reliance on nixpkgs' own lib.
+# Idea is that we do not need to pull an input for nixpkgs library alone, since
+# wallpapers here are no longer packages. If implementing a new function, please
+# remember to keep it lib-free. If it *must* rely on lib, then implement the
+# function or functions you need as well as the main function.
+let
+  splitString = separator: str: let
+    # "Nix doesn't have for loops it's a functional programming language!"
+    # You know what it has now? For loops. Nerd.
+    loop = str: acc: currentPos: currentSegment:
+      if currentPos == builtins.stringLength str
+      then
+        # end of string: add the current segment (even if it's empty)
+        acc ++ [currentSegment]
+      else let
+        char = builtins.substring currentPos 1 str;
+      in
+        if char == separator
+        then
+          # separator; add the current segment (even if it's empty) to acc
+          # and start a new segment for the next part
+          loop str (acc ++ [currentSegment]) (currentPos + 1) ""
+        else loop str acc (currentPos + 1) (currentSegment + char);
+  in
+    loop str [] 0 "";
+
+  filterAttrs = f: attrs: let
+    names = builtins.attrNames attrs;
+    filteredNames = builtins.filter (name: f name (attrs.${name})) names;
+  in
+    builtins.listToAttrs (map (name: {
+        name = name;
+        value = attrs.${name};
+      })
+      filteredNames);
+
+  genAttrs = names: f:
+    builtins.listToAttrs (map (name: {
+        name = name;
+        value = f name;
+      })
+      names);
+
+  # TODO: This needs to be extensible, possibly in order to allow additional directories.
+  # In theory, we should only need to handle path*s* instead of a path, and search multiple
+  # paths by extension instead of just once, right?
+  toWallpkgs = path: extensions: let
+    fileExts = extensions;
+  in
+    builtins.listToAttrs (map (n: let
+        filesByExtension = builtins.filter builtins.pathExists (map (ext: ./${path}/${n}.${ext}) fileExts);
+        file =
+          if filesByExtension == []
+          then builtins.throw "Either ${n} is not a file or it does not have the ${builtins.concatStringsSep ", " fileExts} extensions."
+          else builtins.head filesByExtension;
+      in {
+        name = n;
+        value = {
+          path = file;
+          tags = splitString "-" n;
+          hash = builtins.hashFile "md5" file; # in theory, md5 is the fastest option because it produces a 128-bit hash instead of >= 160
+        };
+      })
+      (map (n: builtins.head (splitString "." n)) (
+        builtins.attrNames (
+          filterAttrs (n: _: n != "README.md") (builtins.readDir ./wallpapers)
+        )
+      )));
+in {
+  # Partial re-implementations of functions from Nixpkgs.
+  # They may not work as intended, as the implementation is *completely* different. If this is
+  # the case while contributing, please create an issue!
+  inherit splitString filterAttrs genAttrs;
+
+  # Main function to create the final collection of wallpapers from a given directory.
+  inherit toWallpkgs;
+}