setup.sh

#!/bin/bash
# Symlinks into $HOME

### Preamble

set -euo pipefail
shopt -s failglob

case "$OSTYPE" in
    darwin*)
        BREW="$(brew --prefix 2>/dev/null || /opt/homebrew/bin/brew --prefix)"
        READLINK="$BREW/bin/greadlink"
        if [[ ! -x $READLINK ]]; then
            echo "$0: error: $READLINK could not be found. Run \`brew install coreutils\`" >&2
            exit 1
        fi
        GETOPT="$BREW/opt/util-linux/bin/getopt"
        if [[ ! -x $GETOPT ]]; then
            echo "$0: error: $GETOPT could not be found. Run \`brew install util-linux\`" >&2
            exit 1
        fi
        ;;
    *)
        READLINK=readlink
        GETOPT=getopt
        ;;
esac

SCRIPT="$($READLINK -f "${BASH_SOURCE[0]}")"
SCRIPT_NAME="$(basename "$SCRIPT")"
SCRIPT_DIR="$(dirname "$SCRIPT")"

### Usage

usage()
{
    cat <<END >&2
Usage: $SCRIPT_NAME [-h|--help] [-n|--dry-run] [-a value|--argument value] [file...]
    -h|--help: get help
    -n|--dry-run: don't make any modifications
    -f|--force: overwrite symlinks
END
    exit 1
}

### Option defaults

opt_dry_run=
opt_force=

### Options

opts=$($GETOPT --options hnf --long help,dry-run,force --name "$SCRIPT_NAME" -- "$@")
[ $? != 0 ] && usage
eval set -- "$opts"

while true; do
    case "$1" in
        -h | --help) usage ;;
        -n | --dry-run) opt_dry_run=1; shift ;;
        -f | --force) opt_force=f; shift ;;
        --) shift; break ;;
        *) echo "$SCRIPT_NAME: Internal error!" >&2; exit 1 ;;
    esac
done

[[ $# -gt 0 ]] && usage

### Function

function symlink {
    target="$1"
    link_name="$2"

    if [[ -h "$link_name" ]]; then
        link_target="$(readlink "$link_name")"
        if [[ "$link_target" != "$target" ]]; then
            if [[ -z $opt_force ]]; then
                echo "$SCRIPT_NAME: error: $link_name is pointing to $link_target instead of $target" >&2
                return 1
            fi
        else
            return 0
        fi
    elif [[ -e "$link_name" ]]; then
        echo "$SCRIPT_NAME: error: $link_name already exists" >&2
        return 1
    fi

    echo ln -s$opt_force "$1" "$2"
    [[ -z $opt_dry_run ]] && ln -s$opt_force "$1" "$2"
}

### Entire subdir

relative_dir="${SCRIPT_DIR#"$HOME/"}"

symlink "$relative_dir" ~/.vim
[[ -d ~/.config ]] || mkdir ~/.config
symlink ~/.vim ~/.config/nvim

### Contents of base

cd ~
for i in .vimrc .gvimrc .ideavimrc .exrc; do
    target=".vim/$i"
    link_name="$(basename "$target")"
    symlink "$target" "$link_name"
done

### Decrypt

cd "$SCRIPT_DIR"

# This is only for me
vimrc_post=.vimrc.post
if [[ -e "$vimrc_post.age" && ! -e "$vimrc_post" ]]; then
    if command -v age &>/dev/null; then
        age -d -i ~/.age/github-public-files-key.age -o "$vimrc_post" "$vimrc_post.age"
    else
        echo "$SCRIPT_NAME: warning: age not found. Cannot decrypt $vimrc_post.age" >&2
    fi
fi