flake.nix

{
  description = "My wallpaper collection";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
    flake-parts.url = "github:hercules-ci/flake-parts";
  };

  outputs = inputs @ {
    self,
    nixpkgs,
    flake-parts,
    ...
  }:
    flake-parts.lib.mkFlake {inherit inputs;} {
      systems = ["aarch64-linux" "x86_64-linux" "aarch64-darwin" "x86_64-darwin"];
      perSystem = {
        config,
        self',
        inputs',
        pkgs,
        system,
        ...
      }: {
        packages = {
          chwallpaper = pkgs.writeShellApplication {
            name = "chwallpaper";
            runtimeInputs = with pkgs; [bash fzf feh kitty];
            text = ''
              #!/usr/bin/env bash
              set -euo pipefail

              echo "Choose a wallpaper from the following options:"
              # Default folder for images
              DEFAULT_DIR="${self}/images"
              if [[ -n "''${1-}" ]]; then
                IMAGE_DIR="$1"
                echo "Using directory $IMAGE_DIR"
              else
                IMAGE_DIR="$DEFAULT_DIR"
              fi

              # Get the operating system name
              OS_NAME=$(uname -s)

              # Function to display error and exit
              function error_exit {
                echo "Error: $1" >&2
                exit 1
              }

              # Check if the folder exists
              if [[ ! -d "$IMAGE_DIR" ]]; then
                error_exit "The directory '$IMAGE_DIR' does not exist."
              fi

              # Find jpg and png images in the folder
              mapfile -t IMAGES < <(find "$IMAGE_DIR" -type f \( -iname "*.jpg" -o -iname "*.jpeg" -o -iname "*.png" \) | sort)

              # Check if any images were found
              if [ ''${#IMAGES[@]} -eq 0 ]; then
                error_exit "No jpg or png images found in '$IMAGE_DIR'."
              fi

              # Function to set the wallpaper
              function set_wallpaper_macos {
                local image="$1"
                osascript -e "tell application \"System Events\" to set picture of every desktop to POSIX file \"$image\""
                killall Finder
                echo "Wallpaper set to $image."
              }

              function set_wallpaper_linux {
                local image="$1"
                feh --no-fehbg --bg-fill "$image"
                echo "Wallpaper set to $image."
              }

              # Main workflow
              function set_wallpaper {
                # Use fixed dimensions for the preview, can be overridden by environment variables
                # shellcheck disable=SC2016
                selected_image=$(printf '%s\n' "''${IMAGES[@]}" | awk -v dir="$IMAGE_DIR" '{print $0, substr($0, length(dir) + 2)}' | fzf --with-nth=2 --preview='kitty icat --clear --transfer-mode=memory --stdin=no --place=''${FZF_PREVIEW_COLUMNS}x''${FZF_PREVIEW_LINES}@0x0 {1}')
                selected_image=''${selected_image%% *}
                kitty icat --clear
                if [[ -z "$selected_image" ]]; then
                    error_exit "No image selected."
                fi
                echo "Selected image: $selected_image"
                read -r -p "Do you want to set this image as your wallpaper? [y/n, default is y]: " confirm
                confirm=''${confirm:-y}  # Default to 'y' if no input
                if [[ "$confirm" =~ ^[Yy]$ ]]; then
                    if [[ "$OS_NAME" == "Darwin" ]]; then
                        set_wallpaper_macos "$selected_image"
                    elif [[ "$OS_NAME" == "Linux" ]]; then
                        set_wallpaper_linux "$selected_image"
                    else
                        error_exit "Unsupported operating system: $OS_NAME"
                    fi
                    echo "Wallpaper set to $(basename "$selected_image")"
                else
                    echo "Wallpaper not changed."
                fi
              }
              # Run the set_wallpaper function
              set_wallpaper
            '';
          };
          default = self'.packages.chwallpaper;
        };

        formatter = pkgs.alejandra;

        devShells.default = pkgs.mkShell {
          packages = [self'.packages.chwallpaper pkgs.feh pkgs.fzf pkgs.kitty];
        };
      };
    };
}