install.sh

#!/bin/sh -e

# DOTFILES          Files that will be installed by this script.
# DOTFILES_DEPS     Files that should be installed via the systems package
#                   manager prior to installing the dotfiles.  Currently only
#                   dnf is supported.
# DOTFILES_DESTDIR  Directory to install the dotfiles to.
#                   Default: $HOME
# DOTFILES_CONFDIR  Directory where this script will store stuff like backups
#                   and a list of previously installed files.
#                   Default: $DOTFILES_DESTDIR/.dotfiles

DOTFILES_DESTDIR=${DOTFILES_DESTDIR:-"$HOME"}
DOTFILES_CONFDIR=${DOTFILES_CONFDIR:-"$DOTFILES_DESTDIR/.dotfiles"}

CONFFILE="$DOTFILES_CONFDIR/dotfiles"
BACKUPDIR="$DOTFILES_CONFDIR/backup"

if [ -n "$DOTFILES_DEPS" ]; then
    sudo dnf install $DOTFILES_DEPS
fi

mkdir -p "$DOTFILES_CONFDIR" "$BACKUPDIR"
touch "$CONFFILE"

echo "Installing dotfiles (I=install, B=backup, R=rollback, D=delete)"

echo "$DOTFILES" |
while IFS= read -r f; do
    dest="$DOTFILES_DESTDIR/$f"

    # skip empty lines
    if [ -z "$f" ]; then
        continue
    fi

    if [ ! -e "$PWD/$f" ]; then
        >&2 echo "$0: cannot install '$PWD/$f': No such file or directory."
        exit 1
    fi

    # create a backup if file already exists
    if [ -f "$dest" ] || [ -d "$dest" ]; then
        if [ -h "$dest" ] && [ "$(readlink "$dest" == "$PWD/$f")" ]; then
            continue
        else
            mkdir -p "$(dirname "$BACKUPDIR/$f")"
            mv "$dest" "$BACKUPDIR/$f"
            echo "B $f"
        fi
    fi

    # install file by creating symlink to it
    mkdir -p "$(dirname "$dest")"
    if ln -s "$PWD/$f" "$dest"; then
        echo "$f" >> "$CONFFILE"
        echo "I $f"
    else
        echo "ERROR: Linking of $f failed" 1>&2
        if [ -f "$BACKUPDIR/$f" ]; then
            mv "$BACKUPDIR/$f" "$dest"
            echo "R $f"
        fi
    fi
done

# remove files that shouldn't be installed
touch "$CONFFILE.swp"
while IFS= read -r f; do
    dest="$DOTFILES_DESTDIR/$f"
    if ! echo "$DOTFILES" | grep -q "^\s*$f\s*$"; then
        if [ -h "$dest" ] && [ "$(readlink "$dest" == "$PWD/$f")" ]; then
            rm "$dest"
            echo "D $f"
        fi
        if [ -f "$BACKUPDIR/$f" ]; then
            mv "$BACKUPDIR/$f" "$dest"
            echo "R $f"
        fi
    else
        echo "$f" >> "$CONFFILE.swp"
    fi
done < "$CONFFILE"

mv "$CONFFILE.swp" "$CONFFILE"