home-manager/git/default.nix

{ pkgs, userName, userEmail, gpgSigningKey, ... }:

{
  programs = {
    less.enable = true;
    git-credential-oauth.enable = true;

    git = {
      enable = true;

      inherit userName;
      inherit userEmail;

      signing = {
        key = gpgSigningKey;
        signByDefault = true;
      };

      difftastic = {
        enable = true;
        background = "light";
      };

      lfs = {
        enable = true;
      };

      extraConfig = {
        core.editor = "nvim";
        core.pager = "less -FX";

        diff.ignoreSubmodules = "none";

        fetch.parallel = 8;
        fetch.writeCommitGraph = true;
        fetch.recurseSubmodules = true;

        format.pretty = "format:%C(yellow)%h %Cblue%>(12)%ad %C(red)%G? %Cgreen%<(7,trunc)%aN%Cred%d %Creset%s";

        init.defaultBranch = "main";

        log.date = "relative";

        merge.ff = false;
        merge.tool = "nvim";

        mergetool.nvim.cmd = "nvim -f -c \"Gdiffsplit!\" \"$MERGED\"";
        mergetool.prompt = false;

        pager.difftool = true;

        pull.rebase = true;

        push.recurseSubmodules = "on-demand";

        rebase.autostash = true;

        rerere.enabled = true;

        status.submoduleSummary = true;

        submodule.fetchJobs = 8;
        submodule.recurse = true;

        worktree.guessRemote = true;
      };

      aliases = {
        graph = "log --graph";
      };

      ignores = [
        ".env"
        ".direnv"
        "*.swp"
      ];
    };
  };

  home.packages = with pkgs; [
    (writeShellScriptBin "git-clone-worktree" ''

      uri=''${1}
      dir=''${2}

      if [[ -z ''${dir} ]]; then
        dir=''$(basename ''${1} .git)
      fi

      if [[ -e ''${dir} ]]; then
        echo "error: directory ''${dir} already exists"
        exit 1
      fi

      mkdir ''${dir}
      git clone ''${uri} ''${dir}/.base

      branch=`git -C ''${dir}/.base symbolic-ref --short HEAD`
      echo "default branch is ''${branch}"

      git -C ''${dir}/.base checkout --detach HEAD
      git -C ''${dir}/.base worktree add ../''${branch}
    '')

    (writeShellScriptBin "git-make-relative" ''

      gitfile=''${1}

      if [[ -z ''${gitfile} ]]; then
        gitfile=".git"
      fi

      if [[ ! -f ''${gitfile} ]]; then
        echo "file ''${gitfile} does not exist"
        exit 1
      fi

      gitdir=$(grep "gitdir:" ''${gitfile} | cut -d: -f2 | xargs)
      rel_gitdir=$(realpath -s --relative-to=. ''${gitdir})

      echo "relative path: ''${rel_gitdir}"

      sed -i -e "s,gitdir:.*,gitdir: ''${rel_gitdir}," ''${gitfile}
    '')
  ];
}