# This is a configuration entry-point called "Flake".
# Here you define your inputs (dependencies) and outputs (hosts).
{
  # Those are external dependencies.
  inputs = {
    # Core system.
    # Homepage: https://github.com/NixOS/nixpkgs
    # Manual:   https://nixos.org/manual/nixos/stable
    # Search:   https://search.nixos.org/packages and https://search.nixos.org/options
    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
    nixpkgsUnstable.url = "github:nixos/nixpkgs/nixos-unstable";
    nixpkgsStable.url = "github:nixos/nixpkgs/nixos-24.05";
    nixpkgsMaster.url = "github:nixos/nixpkgs/master";

    # This thing manages user's /home directroies. Because NixOS only manages system itself.
    # Homepage: https://github.com/nix-community/home-manager
    # Manual:   https://nix-community.github.io/home-manager
    # Search:   https://home-manager-options.extranix.com
    home-manager = {
      url = "github:nix-community/home-manager";

      # This means that home-manager and our Flake both depend on the same nixpkgs version.
      inputs.nixpkgs.follows = "nixpkgs";
    };

    # This allows automatic styling based on active Wallpaper.
    # Homepage: https://github.com/danth/stylix
    # Manual:   https://danth.github.io/stylix
    stylix.url = "github:danth/stylix";

    # I use this for a single container called jobber. WARN: Do not update.
    # You likely won't need this one, so just skip it for now.
    poetry2nixJobber.url = "github:nix-community/poetry2nix/304f8235fb0729fd48567af34fcd1b58d18f9b95";
    nixpkgsJobber.url = "github:nixos/nixpkgs/051f920625ab5aabe37c920346e3e69d7d34400e";

    # Nix on Android (inside Termux). It has no NixOS modules, but still allows the use of Nixpkgs arm packages with Home-Manager configurations.
    # Homepage: https://github.com/nix-community/nix-on-droid
    # Manual:   https://github.com/nix-community/nix-on-droid/blob/master/README.md
    nix-on-droid = {
      url = "github:t184256/nix-on-droid/release-23.11";
      inputs.nixpkgs.follows = "nixpkgs";
      inputs.home-manager.follows = "home-manager";
    };

    # Those are Nvim plugins. I do not use package managers like Packer or Lazy, instead I use Nix to download them and later configure in [Neovim module](module/common/Nvim.nix).
    nvimAlign = {
      url = "github:echasnovski/mini.align";
      flake = false;
    };
    nvimAutoclose = {
      url = "github:m4xshen/autoclose.nvim";
      flake = false;
    };
    nvimBufferline = {
      url = "github:akinsho/bufferline.nvim";
      flake = false;
    };
    nvimCloseBuffers = {
      url = "github:kazhala/close-buffers.nvim";
      flake = false;
    };
    nvimColorizer = {
      url = "github:brenoprata10/nvim-highlight-colors";
      flake = false;
    };
    nvimDevicons = {
      url = "github:nvim-tree/nvim-web-devicons";
      flake = false;
    };
    nvimDressing = {
      url = "github:stevearc/dressing.nvim";
      flake = false;
    };
    nvimGen = {
      url = "github:David-Kunz/gen.nvim";
      flake = false;
    };
    nvimGitsigns = {
      url = "github:lewis6991/gitsigns.nvim";
      flake = false;
    };
    nvimGruvboxMaterial = {
      url = "github:sainnhe/gruvbox-material";
      flake = false;
    };
    nvimIndentoMatic = {
      url = "github:Darazaki/indent-o-matic";
      flake = false;
    };
    nvimLspconfig = {
      url = "github:neovim/nvim-lspconfig";
      flake = false;
    };
    nvimPlenary = {
      url = "github:nvim-lua/plenary.nvim";
      flake = false;
    };
    nvimTelescope = {
      url = "github:nvim-telescope/telescope.nvim";
      flake = false;
    };
    nvimTodo = {
      url = "github:folke/todo-comments.nvim";
      flake = false;
    };
    nvimTree = {
      url = "github:nvim-tree/nvim-tree.lua";
      flake = false;
    };
    nvimTreesitter = {
      url = "github:nvim-treesitter/nvim-treesitter";
      flake = false;
    };
    nvimTrouble = {
      url = "github:folke/trouble.nvim";
      flake = false;
    };
  };

  # Those are outputs (hosts, configurations) that can be produced by this whole config.
  # Here you see a set of inputs we defined above, like nixpkgs, home-manager and so on.
  # `...` at the end of a set means "ignore other arguments provided to this function".
  # @inputs means aliasing all the inputs to the `inputs` name, so we can pass them all at once later.
  outputs =
    {
      self,
      nixpkgs,
      nixpkgsUnstable,
      nixpkgsStable,
      nixpkgsMaster,
      nix-on-droid,
      home-manager,
      stylix,
      poetry2nixJobber,
      nixpkgsJobber,
      ...
    }@inputs:
    {
      # Constant values.
      const = {
        droidStateVersion = "23.11";
        stateVersion = "24.05";
        timeZone = "Europe/Moscow";
        url = "https://git.voronind.com/voronind/nix.git";
      };

      # Hack to use <container/Change.nix> in other files.
      # Need to add __findFile to args tho.
      __findFile = _: p: ./${p};

      # List all files in a dir.
      findFiles =
        path:
        map (f: "${path}/${f}") (
          builtins.filter (i: builtins.readFileType "${path}/${i}" == "regular") (
            builtins.attrNames (builtins.readDir path)
          )
        );

      # Dev shell for this repo.
      devShells =
        let
          system = "x86_64-linux";
          lib = nixpkgs.lib;
          pkgs = nixpkgs.legacyPackages.${system};
        in
        {
          ${system}.default = pkgs.mkShell {
            nativeBuildInputs = with pkgs; [
              nixd
              nixfmt-rfc-style
              treefmt
            ];
            # buildInputs = with pkgs; [ ];

            # LD_LIBRARY_PATH   = "${lib.makeLibraryPath buildInputs}";
            # SOURCE_DATE_EPOCH = "${toString self.lastModified}";
          };
        };

      # Nixos systems.
      nixosConfigurations =
        let
          # Function to create a host. It does basic setup, like adding common modules.
          mkHost =
            { system, hostname }:
            nixpkgs.lib.nixosSystem {
              # `Inherit` is just an alias for `system = system;`, which means that
              # keep the `system` argument as a property in a resulting set.
              inherit system;

              # List of modules to use by defualt for all the hosts.
              modules =
                [
                  # Make a device hostname match the one from this config.
                  { networking.hostName = hostname; }

                  # Specify current release version.
                  { system.stateVersion = self.const.stateVersion; }

                  # Add Home Manager module.
                  home-manager.nixosModules.home-manager

                  # Add Stylix module.
                  stylix.nixosModules.stylix

                  # HM config.
                  ./home/NixOs.nix
                ]
                ++ (self.findFiles ./host/${system}/${hostname})
                ++ (self.findFiles ./config)
                ++ (self.findFiles ./container)
                ++ (self.findFiles ./module)
                ++ (self.findFiles ./system)
                ++ (self.findFiles ./overlay);

              # SpecialArgs allows you to pass objects down to other NixOS modules.
              specialArgs =
                let
                  pkgs = nixpkgs.legacyPackages.${system}.pkgs;
                  lib = nixpkgs.lib;
                  config = self.nixosConfigurations.${hostname}.config;
                in
                {
                  inherit inputs self;
                  inherit (self) const __findFile;

                  pkgsJobber = nixpkgsJobber.legacyPackages.${system}.pkgs;
                  pkgsStable = nixpkgsStable.legacyPackages.${system}.pkgs;
                  pkgsUnstable = nixpkgsUnstable.legacyPackages.${system}.pkgs;
                  pkgsMaster = nixpkgsMaster.legacyPackages.${system}.pkgs;

                  secret = import ./secret { }; # Secrets (public keys).
                  container = import ./lib/Container.nix {
                    inherit lib pkgs config;
                    inherit (self) const;
                  }; # Container utils.
                  util = import ./lib/Util.nix { inherit lib; }; # Util functions.

                  # Stuff for Jobber container, skip this part.
                  inherit poetry2nixJobber;
                };
            };

          mkSystem = system: hostname: { "${hostname}" = mkHost { inherit system hostname; }; };
        in
        nixpkgs.lib.foldl' (acc: h: acc // h) { } (
          map (
            system:
            nixpkgs.lib.foldl' (acc: h: acc // h) { } (
              map (host: mkSystem system host) (builtins.attrNames (builtins.readDir ./host/${system}))
            )
          ) (builtins.attrNames (builtins.readDir ./host))
        );

      # Home manager (distro-independent).
      # Install nix: sh <(curl -L https://nixos.org/nix/install) --no-daemon
      # Or with --daemon for multi-user (as root).
      # $ nix run home-manager/master -- init --switch
      # $ nix shell '<home-manager>' -A install
      # Add to /etc/nix/nix.conf > experimental-features = nix-command flakes
      # And then # systemctl restart nix-daemon.service
      # $ home-manager switch --flake ~/hmconf
      homeConfigurations =
        let
          lib = nixpkgs.lib;
          secret = import ./secret { };
          util = import ./lib/Util.nix { inherit lib; };

          mkCommonHome =
            username: system:
            let
              pkgs = nixpkgs.legacyPackages.${system};
              pkgsStable = nixpkgsStable.legacyPackages.${system};
              pkgsUnstable = nixpkgsUnstable.legacyPackages.${system};
              pkgsMaster = nixpkgsMaster.legacyPackages.${system};
            in
            {
              ${username} = home-manager.lib.homeManagerConfiguration {
                inherit pkgs;

                extraSpecialArgs = {
                  inherit
                    self
                    inputs
                    secret
                    util
                    pkgs
                    pkgsStable
                    pkgsMaster
                    ;
                  inherit (self) const __findFile;
                };
                modules = [
                  ./home/HomeManager.nix
                  {
                    home.hm = {
                      inherit username;
                      enable = true;
                    };
                  }

                  { nixpkgs.config.allowUnfree = true; }
                  { nixpkgs.config.allowUnfreePredicate = (pkg: true); }
                  { nix.package = pkgs.nix; }
                  {
                    nix.settings.experimental-features = [
                      "nix-command "
                      "flakes"
                    ];
                  }

                  inputs.stylix.homeManagerModules.stylix
                ] ++ (self.findFiles ./home/user/${system}/${username}) ++ (self.findFiles ./config);
              };
            };
        in
        nixpkgs.lib.foldl' (acc: h: acc // h) { } (
          map (
            system:
            nixpkgs.lib.foldl' (acc: h: acc // h) { } (
              map (username: mkCommonHome username system) (
                builtins.attrNames (builtins.readDir ./home/user/${system})
              )
            )
          ) (builtins.attrNames (builtins.readDir ./home/user))
        );

      # Android.
      nixOnDroidConfigurations.default =
        let
          system = "aarch64-linux";
          config = self.nixOnDroidConfigurations.default.config;
          lib = nixpkgs.lib;
          pkgs = nixpkgs.legacyPackages.${system}.pkgs;
          pkgsStable = nixpkgsStable.legacyPackages.${system}.pkgs;
          pkgsUnstable = nixpkgsUnstable.legacyPackages.${system}.pkgs;
          pkgsMaster = nixpkgsMaster.legacyPackages.${system}.pkgs;
        in
        nix-on-droid.lib.nixOnDroidConfiguration {
          modules = [
            # Android release version.
            { system.stateVersion = self.const.droidStateVersion; }

            # I put all my Android configuration there.
            ./home/Android.nix
            { home.android.enable = true; }

            # { nixpkgs.config.allowUnfree = true; }
            # { nixpkgs.config.allowUnfreePredicate = (pkg: true); }
            { nix.extraOptions = "experimental-features = nix-command flakes"; }
            { home-manager.config.stylix.autoEnable = lib.mkForce false; }

            # Some common modules.
            ./config/Setting.nix
            ./config/Wallpaper.nix
            (import ./config/Style.nix {
              inherit (config.home-manager) config;
              inherit (self) __findFile;
              inherit lib pkgs;
            })
          ];

          # SpecialArgs allows you to pass objects down to other configuration.
          extraSpecialArgs = {
            inherit inputs self;
            inherit (self) const __findFile;

            secret = import ./secret { }; # Secrets (public keys).
            util = import ./lib/Util.nix { inherit lib; }; # Util functions.
          };
        };
    };
}
# That's it!