{
    config,
    lib,
    pkgs,
    ...
}: let
    cfg = config.poz.programs.git;
    inherit (config.poz.other.system) username;

    inherit (lib.meta) getExe;
    inherit (lib.modules) mkIf;
    inherit (lib.options) mkEnableOption mkOption;
    inherit (lib.types) nullOr str;

    delta = getExe pkgs.delta;
in {
    options.poz.programs.git = {
        enable = mkEnableOption "git";
        userName = mkOption {
            type = nullOr str;
            default = null;
            description = "git username";
        };
        userEmail = mkOption {
            type = nullOr str;
            default = null;
            description = "git email";
        };
        signingKey = mkOption {
            type = nullOr str;
            default = null;
            description = "git commit signing key";
        };
        editor = mkOption {
            type = str;
            default = "$EDITOR";
            description = "commit message editor";
        };
        defaultBranch = mkOption {
            type = str;
            default = "main";
            description = "default git branch";
        };
    };

    config = mkIf cfg.enable {
        home-manager.users.${username} = {
            programs.git = {
                enable = true;
                inherit (cfg) userName userEmail;
                extraConfig = {
                    core = {
                        inherit (cfg) editor;
                        pager = "${delta}";
                    };
                    init.defaultBranch = cfg.defaultBranch;
                    push.autoSetupRemote = true;
                    commit = {
                        verbose = true;
                        gpgsign = cfg.signingKey != null;
                    };
                    gpg.format = "ssh";
                    user.signingkey = mkIf (cfg.signingKey != null) "key::${cfg.signingKey}";
                    merge.conflictstyle = "zdiff3";
                    interactive.diffFilter = "${delta} --color-only";
                    diff.algorithm = "histogram";
                    transfer.fsckobjects = true;
                    fetch.fsckobjects = true;
                    receive.fsckobjects = true;
                };
            };
        };
    };
}