{ config, lib, moduleName, cfg, pkgs, capitalModuleName ? moduleName
, isGaps ? true }:

with lib;

let
  isI3 = moduleName == "i3";
  isSway = !isI3;

  fontOptions = types.submodule {
    options = {
      names = mkOption {
        type = types.listOf types.str;
        default = [ "monospace" ];
        defaultText = literalExample ''[ "monospace" ]'';
        description = ''
          List of font names list used for window titles. Only FreeType fonts are supported.
          The order here is important (e.g. icons font should go before the one used for text).
        '';
        example = literalExample ''[ "FontAwesome" "Terminus" ]'';
      };

      style = mkOption {
        type = types.str;
        default = "";
        description = ''
          The font style to use for window titles.
        '';
        example = "Bold Semi-Condensed";
      };

      size = mkOption {
        type = types.float;
        default = 8.0;
        description = ''
          The font size to use for window titles.
        '';
        example = 11.5;
      };
    };
  };

  startupModule = types.submodule {
    options = {
      command = mkOption {
        type = types.str;
        description = "Command that will be executed on startup.";
      };

      always = mkOption {
        type = types.bool;
        default = false;
        description = "Whether to run command on each ${moduleName} restart.";
      };
    } // optionalAttrs isI3 {
      notification = mkOption {
        type = types.bool;
        default = true;
        description = ''
          Whether to enable startup-notification support for the command.
          See <option>--no-startup-id</option> option description in the i3 user guide.
        '';
      };

      workspace = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = ''
          Launch application on a particular workspace. DEPRECATED:
          Use <varname><link linkend="opt-xsession.windowManager.i3.config.assigns">xsession.windowManager.i3.config.assigns</link></varname>
          instead. See <link xlink:href="https://github.com/nix-community/home-manager/issues/265"/>.
        '';
      };
    };

  };

  barModule = types.submodule {
    options = let
      versionAtLeast2009 = versionAtLeast config.home.stateVersion "20.09";
      mkNullableOption = { type, default, ... }@args:
        mkOption (args // optionalAttrs versionAtLeast2009 {
          type = types.nullOr type;
          default = null;
          example = default;
        } // {
          defaultText = literalExample ''
            ${
              if isString default then default else "See code"
            } for state version < 20.09,
            null for state version ≥ 20.09
          '';
        });
    in {
      fonts = mkOption {
        type = with types; either (listOf str) fontOptions;
        default = { };
        example = literalExample ''
          {
            names = [ "DejaVu Sans Mono" "FontAwesome5Free" ];
            style = "Bold Semi-Condensed";
            size = 11.0;
          }
        '';
        description = "Font configuration for this bar.";
      };

      extraConfig = mkOption {
        type = types.lines;
        default = "";
        description = "Extra configuration lines for this bar.";
      };

      id = mkOption {
        type = types.nullOr types.str;
        default = null;
        description = ''
          Specifies the bar ID for the configured bar instance.
          If this option is missing, the ID is set to bar-x, where x corresponds
          to the position of the embedding bar block in the config file.
        '';
      };

      mode = mkNullableOption {
        type = types.enum [ "dock" "hide" "invisible" ];
        default = "dock";
        description = "Bar visibility mode.";
      };

      hiddenState = mkNullableOption {
        type = types.enum [ "hide" "show" ];
        default = "hide";
        description = "The default bar mode when 'bar.mode' == 'hide'.";
      };

      position = mkNullableOption {
        type = types.enum [ "top" "bottom" ];
        default = "bottom";
        description = "The edge of the screen ${moduleName}bar should show up.";
      };

      workspaceButtons = mkNullableOption {
        type = types.bool;
        default = true;
        description = "Whether workspace buttons should be shown or not.";
      };

      workspaceNumbers = mkNullableOption {
        type = types.bool;
        default = true;
        description =
          "Whether workspace numbers should be displayed within the workspace buttons.";
      };

      command = mkOption {
        type = types.str;
        default = let
          # If the user uses the "system" Sway (i.e. cfg.package == null) then the bar has
          # to come from a different package
          pkg = if isSway && isNull cfg.package then pkgs.sway else cfg.package;
        in "${pkg}/bin/${moduleName}bar";
        defaultText = "i3bar";
        description = "Command that will be used to start a bar.";
        example = if isI3 then
          "\${pkgs.i3-gaps}/bin/i3bar -t"
        else
          "\${pkgs.waybar}/bin/waybar";
      };

      statusCommand = mkOption {
        type = types.nullOr types.str;
        default =
          if versionAtLeast2009 then null else "${pkgs.i3status}/bin/i3status";
        example = "i3status";
        description = "Command that will be used to get status lines.";
      };

      colors = mkOption {
        type = types.submodule {
          options = {
            background = mkNullableOption {
              type = types.str;
              default = "#000000";
              description = "Background color of the bar.";
            };

            statusline = mkNullableOption {
              type = types.str;
              default = "#ffffff";
              description = "Text color to be used for the statusline.";
            };

            separator = mkNullableOption {
              type = types.str;
              default = "#666666";
              description = "Text color to be used for the separator.";
            };

            focusedWorkspace = mkNullableOption {
              type = barColorSetModule;
              default = {
                border = "#4c7899";
                background = "#285577";
                text = "#ffffff";
              };
              description = ''
                Border, background and text color for a workspace button when the workspace has focus.
              '';
            };

            activeWorkspace = mkNullableOption {
              type = barColorSetModule;
              default = {
                border = "#333333";
                background = "#5f676a";
                text = "#ffffff";
              };
              description = ''
                Border, background and text color for a workspace button when the workspace is active.
              '';
            };

            inactiveWorkspace = mkNullableOption {
              type = barColorSetModule;
              default = {
                border = "#333333";
                background = "#222222";
                text = "#888888";
              };
              description = ''
                Border, background and text color for a workspace button when the workspace does not
                have focus and is not active.
              '';
            };

            urgentWorkspace = mkNullableOption {
              type = barColorSetModule;
              default = {
                border = "#2f343a";
                background = "#900000";
                text = "#ffffff";
              };
              description = ''
                Border, background and text color for a workspace button when the workspace contains
                a window with the urgency hint set.
              '';
            };

            bindingMode = mkNullableOption {
              type = barColorSetModule;
              default = {
                border = "#2f343a";
                background = "#900000";
                text = "#ffffff";
              };
              description =
                "Border, background and text color for the binding mode indicator";
            };
          };
        };
        default = { };
        description = ''
          Bar color settings. All color classes can be specified using submodules
          with 'border', 'background', 'text', fields and RGB color hex-codes as values.
          See default values for the reference.
          Note that 'background', 'status', and 'separator' parameters take a single RGB value.

          See <link xlink:href="https://i3wm.org/docs/userguide.html#_colors"/>.
        '';
      };

      trayOutput = mkNullableOption {
        type = types.str;
        default = "primary";
        description = "Where to output tray.";
      };
    };
  };

  barColorSetModule = types.submodule {
    options = {
      border = mkOption {
        type = types.str;
        visible = false;
      };

      background = mkOption {
        type = types.str;
        visible = false;
      };

      text = mkOption {
        type = types.str;
        visible = false;
      };
    };
  };

  colorSetModule = types.submodule {
    options = {
      border = mkOption {
        type = types.str;
        visible = false;
      };

      childBorder = mkOption {
        type = types.str;
        visible = false;
      };

      background = mkOption {
        type = types.str;
        visible = false;
      };

      text = mkOption {
        type = types.str;
        visible = false;
      };

      indicator = mkOption {
        type = types.str;
        visible = false;
      };
    };
  };

  windowCommandModule = types.submodule {
    options = {
      command = mkOption {
        type = types.str;
        description = "${capitalModuleName}wm command to execute.";
        example = "border pixel 1";
      };

      criteria = mkOption {
        type = criteriaModule;
        description =
          "Criteria of the windows on which command should be executed.";
        example = { title = "x200: ~/work"; };
      };
    };
  };

  criteriaModule = types.attrsOf types.str;
in {
  fonts = mkOption {
    type = with types; either (listOf str) fontOptions;
    default = { };
    example = literalExample ''
      {
        names = [ "DejaVu Sans Mono" "FontAwesome5Free" ];
        style = "Bold Semi-Condensed";
        size = 11.0;
      }
    '';
    description = "Font configuration for window titles, nagbar...";
  };

  window = mkOption {
    type = types.submodule {
      options = {
        titlebar = mkOption {
          type = types.bool;
          default = !isGaps;
          defaultText = if isI3 then
            "xsession.windowManager.i3.package != nixpkgs.i3-gaps (titlebar should be disabled for i3-gaps)"
          else
            "false";
          description = "Whether to show window titlebars.";
        };

        border = mkOption {
          type = types.int;
          default = 2;
          description = "Window border width.";
        };

        hideEdgeBorders = mkOption {
          type = types.enum [ "none" "vertical" "horizontal" "both" "smart" ];
          default = "none";
          description = "Hide window borders adjacent to the screen edges.";
        };

        commands = mkOption {
          type = types.listOf windowCommandModule;
          default = [ ];
          description = ''
            List of commands that should be executed on specific windows.
            See <option>for_window</option> ${moduleName}wm option documentation.
          '';
          example = [{
            command = "border pixel 1";
            criteria = { class = "XTerm"; };
          }];
        };
      };
    };
    default = { };
    description = "Window titlebar and border settings.";
  };

  floating = mkOption {
    type = types.submodule {
      options = {
        titlebar = mkOption {
          type = types.bool;
          default = !isGaps;
          defaultText = if isI3 then
            "xsession.windowManager.i3.package != nixpkgs.i3-gaps (titlebar should be disabled for i3-gaps)"
          else
            "false";
          description = "Whether to show floating window titlebars.";
        };

        border = mkOption {
          type = types.int;
          default = 2;
          description = "Floating windows border width.";
        };

        modifier = mkOption {
          type =
            types.enum [ "Shift" "Control" "Mod1" "Mod2" "Mod3" "Mod4" "Mod5" ];
          default = cfg.config.modifier;
          defaultText = "${moduleName}.config.modifier";
          description =
            "Modifier key that can be used to drag floating windows.";
          example = "Mod4";
        };

        criteria = mkOption {
          type = types.listOf criteriaModule;
          default = [ ];
          description =
            "List of criteria for windows that should be opened in a floating mode.";
          example = [
            { "title" = "Steam - Update News"; }
            { "class" = "Pavucontrol"; }
          ];
        };
      };
    };
    default = { };
    description = "Floating window settings.";
  };

  focus = mkOption {
    type = types.submodule {
      options = {
        newWindow = mkOption {
          type = types.enum [ "smart" "urgent" "focus" "none" ];
          default = "smart";
          description = ''
            This option modifies focus behavior on new window activation.

            See <link xlink:href="https://i3wm.org/docs/userguide.html#focus_on_window_activation"/>
          '';
          example = "none";
        };

        followMouse = mkOption {
          type = if isSway then
            types.either (types.enum [ "yes" "no" "always" ]) types.bool
          else
            types.bool;
          default = if isSway then "yes" else true;
          description = "Whether focus should follow the mouse.";
          apply = val:
            if (isSway && isBool val) then
              (if val then "yes" else "no")
            else
              val;
        };

        forceWrapping = mkOption {
          type = types.bool;
          default = false;
          description = ''
            Whether to force focus wrapping in tabbed or stacked container.

            See <link xlink:href="https://i3wm.org/docs/userguide.html#_focus_wrapping"/>
          '';
        };

        mouseWarping = mkOption {
          type = types.bool;
          default = true;
          description = ''
            Whether mouse cursor should be warped to the center of the window when switching focus
            to a window on a different output.
          '';
        };
      };
    };
    default = { };
    description = "Focus related settings.";
  };

  assigns = mkOption {
    type = types.attrsOf (types.listOf criteriaModule);
    default = { };
    description = ''
      An attribute set that assigns applications to workspaces based
      on criteria.
    '';
    example = literalExample ''
      {
      "1: web" = [{ class = "^Firefox$"; }];
      "0: extra" = [{ class = "^Firefox$"; window_role = "About"; }];
      }
    '';
  };

  modifier = mkOption {
    type = types.enum [ "Shift" "Control" "Mod1" "Mod2" "Mod3" "Mod4" "Mod5" ];
    default = "Mod1";
    description = "Modifier key that is used for all default keybindings.";
    example = "Mod4";
  };

  workspaceLayout = mkOption {
    type = types.enum [ "default" "stacked" "tabbed" ];
    default = "default";
    example = "tabbed";
    description = ''
      The mode in which new containers on workspace level will
      start.
    '';
  };

  workspaceAutoBackAndForth = mkOption {
    type = types.bool;
    default = false;
    example = true;
    description = ''
      Assume you are on workspace "1: www" and switch to "2: IM" using
      mod+2 because somebody sent you a message. You don’t need to remember
      where you came from now, you can just press $mod+2 again to switch
      back to "1: www".
    '';
  };

  keycodebindings = mkOption {
    type = types.attrsOf (types.nullOr types.str);
    default = { };
    description = ''
      An attribute set that assigns keypress to an action using key code.
      See <link xlink:href="https://i3wm.org/docs/userguide.html#keybindings"/>.
    '';
    example = { "214" = "exec /bin/script.sh"; };
  };

  colors = mkOption {
    type = types.submodule {
      options = {
        background = mkOption {
          type = types.str;
          default = "#ffffff";
          description = ''
            Background color of the window. Only applications which do not cover
            the whole area expose the color.
          '';
        };

        focused = mkOption {
          type = colorSetModule;
          default = {
            border = "#4c7899";
            background = "#285577";
            text = "#ffffff";
            indicator = "#2e9ef4";
            childBorder = "#285577";
          };
          description = "A window which currently has the focus.";
        };

        focusedInactive = mkOption {
          type = colorSetModule;
          default = {
            border = "#333333";
            background = "#5f676a";
            text = "#ffffff";
            indicator = "#484e50";
            childBorder = "#5f676a";
          };
          description = ''
            A window which is the focused one of its container,
            but it does not have the focus at the moment.
          '';
        };

        unfocused = mkOption {
          type = colorSetModule;
          default = {
            border = "#333333";
            background = "#222222";
            text = "#888888";
            indicator = "#292d2e";
            childBorder = "#222222";
          };
          description = "A window which is not focused.";
        };

        urgent = mkOption {
          type = colorSetModule;
          default = {
            border = "#2f343a";
            background = "#900000";
            text = "#ffffff";
            indicator = "#900000";
            childBorder = "#900000";
          };
          description = "A window which has its urgency hint activated.";
        };

        placeholder = mkOption {
          type = colorSetModule;
          default = {
            border = "#000000";
            background = "#0c0c0c";
            text = "#ffffff";
            indicator = "#000000";
            childBorder = "#0c0c0c";
          };
          description = ''
            Background and text color are used to draw placeholder window
            contents (when restoring layouts). Border and indicator are ignored.
          '';
        };
      };
    };
    default = { };
    description = ''
      Color settings. All color classes can be specified using submodules
      with 'border', 'background', 'text', 'indicator' and 'childBorder' fields
      and RGB color hex-codes as values. See default values for the reference.
      Note that '${moduleName}.config.colors.background' parameter takes a single RGB value.

      See <link xlink:href="https://i3wm.org/docs/userguide.html#_changing_colors"/>.
    '';
  };

  bars = mkOption {
    type = types.listOf barModule;
    default = if versionAtLeast config.home.stateVersion "20.09" then [{
      mode = "dock";
      hiddenState = "hide";
      position = "bottom";
      workspaceButtons = true;
      workspaceNumbers = true;
      statusCommand = "${pkgs.i3status}/bin/i3status";
      fonts = {
        names = [ "monospace" ];
        size = 8.0;
      };
      trayOutput = "primary";
      colors = {
        background = "#000000";
        statusline = "#ffffff";
        separator = "#666666";
        focusedWorkspace = {
          border = "#4c7899";
          background = "#285577";
          text = "#ffffff";
        };
        activeWorkspace = {
          border = "#333333";
          background = "#5f676a";
          text = "#ffffff";
        };
        inactiveWorkspace = {
          border = "#333333";
          background = "#222222";
          text = "#888888";
        };
        urgentWorkspace = {
          border = "#2f343a";
          background = "#900000";
          text = "#ffffff";
        };
        bindingMode = {
          border = "#2f343a";
          background = "#900000";
          text = "#ffffff";
        };
      };
    }] else
      [ { } ];
    description = ''
      ${capitalModuleName} bars settings blocks. Set to empty list to remove bars completely.
    '';
  };

  startup = mkOption {
    type = types.listOf startupModule;
    default = [ ];
    description = ''
      Commands that should be executed at startup.

      See <link xlink:href="https://i3wm.org/docs/userguide.html#_automatically_starting_applications_on_i3_startup"/>.
    '';
    example = if isI3 then
      literalExample ''
        [
        { command = "systemctl --user restart polybar"; always = true; notification = false; }
        { command = "dropbox start"; notification = false; }
        { command = "firefox"; workspace = "1: web"; }
        ];
      ''
    else
      literalExample ''
        [
        { command = "systemctl --user restart waybar"; always = true; }
        { command = "dropbox start"; }
        { command = "firefox"; }
        ]
      '';
  };

  gaps = mkOption {
    type = types.nullOr (types.submodule {
      options = {
        inner = mkOption {
          type = types.nullOr types.int;
          default = null;
          description = "Inner gaps value.";
          example = 12;
        };

        outer = mkOption {
          type = types.nullOr types.int;
          default = null;
          description = "Outer gaps value.";
          example = 5;
        };

        horizontal = mkOption {
          type = types.nullOr types.int;
          default = null;
          description = "Horizontal gaps value.";
          example = 5;
        };

        vertical = mkOption {
          type = types.nullOr types.int;
          default = null;
          description = "Vertical gaps value.";
          example = 5;
        };

        top = mkOption {
          type = types.nullOr types.int;
          default = null;
          description = "Top gaps value.";
          example = 5;
        };

        left = mkOption {
          type = types.nullOr types.int;
          default = null;
          description = "Left gaps value.";
          example = 5;
        };

        bottom = mkOption {
          type = types.nullOr types.int;
          default = null;
          description = "Bottom gaps value.";
          example = 5;
        };

        right = mkOption {
          type = types.nullOr types.int;
          default = null;
          description = "Right gaps value.";
          example = 5;
        };

        smartGaps = mkOption {
          type = types.bool;
          default = false;
          description = ''
            This option controls whether to disable all gaps (outer and inner)
            on workspace with a single container.
          '';
          example = true;
        };

        smartBorders = mkOption {
          type = types.enum [ "on" "off" "no_gaps" ];
          default = "off";
          description = ''
            This option controls whether to disable container borders on
            workspace with a single container.
          '';
        };
      };
    });
    default = null;
    description = if isSway then ''
      Gaps related settings.
    '' else ''
      i3Gaps related settings. The i3-gaps package must be used for these features to work.
    '';
  };

  terminal = mkOption {
    type = types.str;
    default = if isI3 then
      "i3-sensible-terminal"
    else
      "${pkgs.rxvt-unicode-unwrapped}/bin/urxvt";
    description = "Default terminal to run.";
    example = "alacritty";
  };

  menu = mkOption {
    type = types.str;
    default = if isSway then
      "${pkgs.dmenu}/bin/dmenu_path | ${pkgs.dmenu}/bin/dmenu | ${pkgs.findutils}/bin/xargs swaymsg exec --"
    else
      "${pkgs.dmenu}/bin/dmenu_run";
    description = "Default launcher to use.";
    example = "bemenu-run";
  };
}