# ABOUTME: Flake for running the Moonarch desktop on NixOS.
# ABOUTME: Pulls the Moonarch project repos as sources and builds them with Nix.

{
  description = "NixOS configuration for a niri and Quickshell Wayland desktop";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    nixos-hardware.url = "github:NixOS/nixos-hardware";

    # Declarative partitioning. Consumed by modules/disk.nix.
    disko = {
      url = "github:nix-community/disko/latest";
      inputs.nixpkgs.follows = "nixpkgs";
    };

    # Project sources. These repos are not flakes themselves, they are
    # consumed as plain source trees pinned to a release tag.
    moonarch = {
      url = "git+https://gitea.moonarch.de/nevaforget/moonarch.git";
      flake = false;
    };
    sweet-cursors = {
      url = "git+https://gitea.moonarch.de/nevaforget/Sweet-cursors.git";
      flake = false;
    };
    # Not packaged in nixpkgs.
    stasis = {
      url = "github:saltnpepper97/stasis/v1.4.1";
      flake = false;
    };
  };

  outputs = { self, nixpkgs, ... }@inputs:
    let
      system = "x86_64-linux";
      pkgs = nixpkgs.legacyPackages.${system};

      moonarchPackages = {
        sweet-cursors = pkgs.callPackage ./pkgs/sweet-cursors.nix {
          src = inputs.sweet-cursors;
          version = "0-unstable";
        };

        stasis = pkgs.callPackage ./pkgs/stasis.nix {
          src = inputs.stasis;
          version = "1.4.1";
        };

        moonarch-scripts = pkgs.callPackage ./pkgs/moonarch-scripts.nix {
          src = inputs.moonarch;
        };
      };

      # disko kills the whole format script when the two passphrase entries
      # differ: `exit 1` sits inside a function called from the `until` loop
      # that was meant to repeat the prompt
      # (share/disko/lib/types/luks.nix:151). A typo therefore means starting
      # the install over. One word changes that.
      diskoRetryingPassphrase = inputs.disko.packages.${system}.disko.overrideAttrs (old: {
        postFixup = (old.postFixup or "") + ''
          substituteInPlace $out/share/disko/lib/types/luks.nix \
            --replace-fail 'exit 1' 'return 1'
        '';
      });

      # Colloid overrides, used by the desktop session and by the greeter.
      # Defined once so the two cannot drift apart.
      themePackages = {
        gtk = pkgs.colloid-gtk-theme.override {
          themeVariants = [ "grey" ];
          colorVariants = [ "dark" ];
          tweaks = [ "catppuccin" ];
        };

        icons = pkgs.colloid-icon-theme.override {
          schemeVariants = [ "catppuccin" ];
          colorVariants = [ "grey" ];
        };
      };
    in
    {
      packages.${system} = moonarchPackages // {
        # Installer image: `nix build .#installer-iso`.
        installer-iso = self.nixosConfigurations.installer.config.system.build.isoImage;
      };

      # Makes the packages and the moonarch source tree available to every
      # module without threading arguments through by hand.
      nixosModules.moonarch = { ... }: {
        imports = [
          inputs.disko.nixosModules.disko
          ./modules/user.nix
          ./modules/disk.nix
          ./modules/desktop.nix
          ./modules/greetd.nix
          ./modules/services.nix
        ];

        _module.args = {
          moonarchSrc = inputs.moonarch;
          moonarchPkgs = moonarchPackages;
          moonarchThemes = themePackages;
        };
      };

      nixosConfigurations = {
        # Installer image. Carries this flake and disko, so installing needs
        # neither a clone nor the Gitea reference.
        installer = nixpkgs.lib.nixosSystem {
          inherit system;
          modules = [ ./hosts/installer ];
          specialArgs = {
            moonixSrc = self;
            disko = diskoRetryingPassphrase;
          };
        };

        # QEMU/KVM test VM.
        testvm = nixpkgs.lib.nixosSystem {
          inherit system;
          modules = [
            ./hosts/testvm
            self.nixosModules.moonarch
          ];
        };

        # Desktop: 512G system disk, 1T disk for /home.
        desktop = nixpkgs.lib.nixosSystem {
          inherit system;
          modules = [
            ./hosts/desktop
            self.nixosModules.moonarch
          ];
        };

        # ThinkPad T14 Gen 3 (AMD Ryzen 7 PRO 6850U).
        thinkpad = nixpkgs.lib.nixosSystem {
          inherit system;
          modules = [
            inputs.nixos-hardware.nixosModules.lenovo-thinkpad-t14-amd-gen3
            ./hosts/thinkpad
            self.nixosModules.moonarch
          ];
        };
      };

      devShells.${system}.default = pkgs.mkShell {
        packages = with pkgs; [ nixpkgs-fmt ];
      };
    };
}