install

#!/bin/sh

scriptdir="$(dirname "$(readlink -f "$0")")"

do_mkdir() {
    local dirname="$1"
    # dirname 'foo' -> '.'
    if [ ! "$dirname" = '.' ]; then
        mkdir -p "$HOME/$dirname"
    fi
}

do_symlink() {
    local filename="$1"
    local linkname="$HOME/$filename"
    local targetname="$scriptdir/$filename"
    local reltarget="$(realpath --relative-to="$(dirname "$linkname")" "$targetname")"
    #echo "Symlinking ~/$filename to $targetname ($reltarget)"
    echo "Symlinking ~/$filename"
    if [ -f "$linkname" ]; then
        if ! diff "$targetname" "$linkname" >/dev/null; then
            echo "\e[33mWarning: Overwriting ~/$filename!\e[m"
            echo "Creating backup as ~/$filename.save"
            # TODO: Find usable name if save file already exists.
            mv "$linkname" "$linkname.save"
        fi
    fi
    ln -sf "$reltarget" "$linkname"
}

link_file() {
    local filename="$1"
    local mode="$2"
    local dirname="$(dirname "$filename")"
    # Make sure the directory exists.
    do_mkdir "$dirname"
    # Symlink the file.
    do_symlink "$filename"
    if [ ! -z "$mode" ]; then
      chmod "$mode" "$filename"
    fi
}

link_files() {
    local dirname="$1"
    local mode="$2"
    # Make sure the directory exists.
    do_mkdir "$dirname"
    # Symlink all files.
    for f in "$dirname"/*; do
        [ -f "$f" ] || continue
        do_symlink "$f"
        if [ ! -z "$mode" ]; then
          chmod "$mode" "$f"
        fi
    done
}

main() {
    cd "$scriptdir"

    local dist_id="$(lsb_release -si)"
    local dist_name="$(lsb_release -sc)"

    # Install only the bare minimum. Other stuff like ansible and terraform is
    # only used if available.
    local prereq_no_tmux='zsh git neovim jq'
    local prereq="$prereq_no_tmux tmux"
    if [ "$dist_id" = 'Debian' ] && [ "$dist_name" = 'bullseye' ]; then
      echo "Installing prerequisites: $prereq"
      sudo apt install -y $prereq # no quotes!
    elif [ "$dist_id" = 'Debian' ] && [ "$dist_name" = 'buster' ]; then
      echo "Installing prerequisites: $prereq"
      sudo apt install -y $prereq_no_tmux # no quotes!
      # tmux from buster repos is too old, install from backports.
      sudo apt install -y -t "$(lsb_release -sc)-backports" tmux
    else
      >&2 echo '\e[33mWarning: Your distro is untested.\e[m'
      read -p 'Continue anyway? [yes/no] ' reply
      if [ "$reply" != 'yes' ]; then
        return 1
      fi
    fi

    link_files '.config/coreutils'
    link_files '.config/git'
    link_files '.config/htop'
    link_files '.config/nvim'
    link_files '.config/nvim/init.vim.d'
    link_files '.config/postgresql'
    link_files '.config/tmux'
    link_files '.config/wget'
    link_files '.config/zsh'
    link_file '.config/zsh/.zlogin'
    link_file '.config/zsh/.zlogout'
    link_file '.config/zsh/.zprofile'
    link_file '.config/zsh/.zshenv'
    link_file '.config/zsh/.zshrc'
    link_files '.config/zsh/zlogin.d'
    link_files '.config/zsh/zlogout.d'
    link_files '.config/zsh/zprofile.d'
    link_files '.config/zsh/zshenv.d'
    link_files '.config/zsh/zshrc.d'
    link_file '.zshenv'
    link_files '.local/bin' '+x'
}

main