{ config, lib, pkgs, ... }:
let
  inherit (lib)
    mkEnableOption mkOption types mkIf concatMap unique warn escapeShellArg;
  cfg = config.rsydn.aiTools;

  getPkgsPackage = name: lib.attrByPath [ name ] null pkgs;

  codexDefault = getPkgsPackage "codex";

  crushDefault = getPkgsPackage "crush";

  claudeDefault = getPkgsPackage "claude-code";

  toolOption = { name, description, defaultPackage, extraOptions ? { }
    , extraDefaults ? { } }:
    mkOption {
      type = types.submodule {
        options = {
          enable = mkOption {
            type = types.bool;
            default = true;
            description = "Enable the ${name} CLI.";
          };
          package = mkOption {
            type = types.nullOr types.package;
            default = defaultPackage;
            description =
              "Package providing ${name}. Set to null to skip installation.";
          };
        } // extraOptions;
      };
      default = {
        enable = true;
        package = defaultPackage;
      } // extraDefaults;
      description = description;
    };

  gatherToolPackages = tools:
    concatMap (tool:
      let
        name = tool.name;
        cfgTool = tool.cfg;
      in if cfgTool.enable then
        if cfgTool.package != null then
          [ cfgTool.package ]
        else
          warn "rsydn.aiTools.${name}: package is null, skipping install" [ ]
      else
        [ ]) tools;

  toolPackages = gatherToolPackages [
    {
      name = "codex";
      cfg = cfg.codex;
    }
    {
      name = "crush";
      cfg = cfg.crush;
    }
    {
      name = "claude";
      cfg = cfg.claude;
    }
  ];

  zaiWrapperPackages = let
    claudeCfg = cfg.claude;
    zaiCfg = claudeCfg.zai or { enable = false; };
  in if claudeCfg.enable && zaiCfg.enable then
    if claudeCfg.package != null then
      let
        claudeExe = lib.getExe claudeCfg.package;
        commandName = zaiCfg.commandName;
        baseUrl = zaiCfg.baseUrl;
        model = zaiCfg.model;
        tokenEnvVar = zaiCfg.tokenEnvVar;
      in [
        (pkgs.writeShellApplication {
          name = commandName;
          text = ''
            if [ -z "''${${tokenEnvVar}:-}" ]; then
              echo "${commandName}: environment variable ${tokenEnvVar} is not set" >&2
              exit 1
            fi

            export ANTHROPIC_BASE_URL=${escapeShellArg baseUrl}
            export ANTHROPIC_AUTH_TOKEN="''${${tokenEnvVar}}"
            export ANTHROPIC_MODEL=${escapeShellArg model}

            exec ${claudeExe} "$@"
          '';
        })
      ]
    else
      warn "rsydn.aiTools.claude: Z.AI wrapper requested but package is null"
      [ ]
  else
    [ ];

in {
  options.rsydn.aiTools = {
    enable = mkEnableOption "AI-oriented command line tooling";

    codex = toolOption {
      name = "Codex";
      description = "OpenAI Codex CLI packaged in nixpkgs.";
      defaultPackage = codexDefault;
    };

    crush = toolOption {
      name = "Crush";
      description = "Charmbracelet Crush CLI packaged in nixpkgs.";
      defaultPackage = crushDefault;
    };

    claude = toolOption {
      name = "Claude Code";
      description = "Anthropic Claude Code CLI packaged in nixpkgs.";
      defaultPackage = claudeDefault;
      extraOptions = {
        zai = mkOption {
          type = types.submodule {
            options = {
              enable = mkEnableOption
                "Expose the Z.AI Gateway wrapper command for Claude.";
              commandName = mkOption {
                type = types.str;
                default = "glm";
                description =
                  "Name of the wrapper command that launches Claude via Z.AI.";
              };
              baseUrl = mkOption {
                type = types.str;
                default = "https://api.z.ai/api/anthropic";
                description = "Gateway base URL used for the Anthropic client.";
              };
              model = mkOption {
                type = types.str;
                default = "glm-4.6";
                description = "Model identifier passed via ANTHROPIC_MODEL.";
              };
              tokenEnvVar = mkOption {
                type = types.str;
                default = "ZAI_API_KEY";
                description =
                  "Environment variable that stores the Z.AI API token.";
              };
            };
          };
          default = {
            enable = false;
            commandName = "glm";
            baseUrl = "https://api.z.ai/api/anthropic";
            model = "glm-4.6";
            tokenEnvVar = "ZAI_API_KEY";
          };
          description =
            "Configuration for the Claude wrapper that targets the Z.AI gateway.";
        };
      };
    };

    extraPackages = mkOption {
      type = types.listOf types.package;
      default = [ ];
      description =
        "Additional AI tooling packages to add alongside the defaults.";
    };
  };

  config = mkIf cfg.enable {
    home.packages =
      unique (toolPackages ++ zaiWrapperPackages ++ cfg.extraPackages);
  };
}