nix-dots/home/modules/desktop/hyprland/modules/config-builder.nix

{ config, lib, pkgs, ... }:

with lib;

let
  cfg = config.programs.hyprlandLua;

  mkMonitorLua = m: 
    let 
      mirrorStr = if (m ? mirror && m.mirror != null) then ", mirror = \"${m.mirror}\"" else "";
    in
      ''hl.monitor({ output = "${m.output}", mode = "${m.mode}", position = "${m.position}", scale = ${toString m.scale}${mirrorStr} })'';

  mkBindLua = b:
    ''hl.bind("${b.key}", ${b.action})'';

  mkWorkspaceRules = rules: concatMapStringsSep "\n" (r: ''
    for i = ${toString r.startIdx}, ${toString r.endIdx} do
        hl.workspace_rule({ workspace = ${r.formula}, monitor = "${r.monitor}", default = ${boolToString r.default} })
    end
  '') rules;

  generatedLua = ''
    -- Auto-generated by Nix
    ${optionalString (cfg.shellCommand != "") ''
      hl.on("hyprland.start", function ()
          hl.exec_cmd("${cfg.shellCommand}")
      end)
    ''}

    mainMod = "${cfg.mainMod}"
    secMod = "${cfg.secMod}"

    ${concatMapStringsSep "\n" mkBindLua cfg.bindings}

    -- Monitors Configuration
    ${concatMapStringsSep "\n" mkMonitorLua cfg.monitors}

    -- Workspace Rules
    ${mkWorkspaceRules cfg.workspaceRules}

    ${optionalString (cfg.defaultCursorMonitor != "") ''
      hl.config({
          cursor = {
              default_monitor = "${cfg.defaultCursorMonitor}"
          }
      })
    ''}

    ${cfg.extraLua}
  '';

in {
  options.programs.hyprlandLua = {
    enable = mkEnableOption "Nix-generated Hyprland Lua configuration";

    shellCommand = mkOption {
      type = types.str;
      default = "";
      example = "dms run";
      description = "Command executed on hyprland start (e.g. dms-shell, waybar, etc.)";
    };

    mainMod = mkOption { type = types.str; default = "ALT"; };
    secMod = mkOption { type = types.str; default = "SUPER"; };

    bindings = mkOption {
      type = types.listOf (types.submodule {
        options = {
          key = mkOption { type = types.str; };
          action = mkOption { type = types.str; example = ''hl.dsp.exec_cmd("dms screenshot")''; };
        };
      });
      default = [];
    };

    monitors = mkOption {
      type = types.listOf (types.submodule {
        options = {
          output = mkOption { type = types.str; default = ""; };
          mode = mkOption { type = types.str; default = "preferred"; };
          position = mkOption { type = types.str; default = "auto"; };
          scale = mkOption { type = types.int; default = 1; };
          mirror = mkOption { type = types.nullOr types.str; default = null; };
        };
      });
      default = [];
    };

    workspaceRules = mkOption {
      type = types.listOf (types.submodule {
        options = {
          startIdx = mkOption { type = types.int; };
          endIdx = mkOption { type = types.int; };
          formula = mkOption { type = types.str; example = "i % 10"; };
          monitor = mkOption { type = types.str; };
          default = mkOption { type = types.bool; default = true; };
        };
      });
      default = [];
    };

    defaultCursorMonitor = mkOption { type = types.str; default = ""; };
    extraLua = mkOption { type = types.lines; default = ""; };
  };

  config = mkIf cfg.enable {
    xdg.configFile."hypr/host_specific.lua".text = generatedLua;
  };
}