install.sh

#!/bin/sh

set -e
set -u

cd "$(dirname "$0")"
umask 027

my_find() {
    find "$@" \
        | awk '($0 ~ /^\.\/\./ && $0 !~ /^\.\/\.git/) { print }'
}

ask_overwrite() {
    local fn=$1; shift
    local default_answer=${1:-N}
    case $default_answer in
        Y) local answers="(Y/n)" ;;
        *) local answers="(y/N)" ;;
    esac
    while true; do
	    echo
	    grep -viE '\bpass(word|wd|)\b' "$fn" | head -n 10
	    printf "OK to overwrite this $fn? $answers "
	    read ans
	    ans=$(echo "${ans:-$default_answer}" | tr '[:upper:]' '[:lower:]')
        case "$ans" in
            n|no) return 1 ;;
            y|yes) return 0 ;;
        esac
    done
}

can_overwrite() {
    local fn=$1; shift
    local target=$1; shift
    local overwrite_default=N
    test -e "$target" || return 0
    case "$fn" in
        # Files that start with standard settings
        .config/hg/hgrc|.config/mutt/muttrc)
            local linecount=$(wc -l <"$fn")
            head -n "$linecount" "$target" | cmp -s "$fn" - && return 1
            ;;
        .config/screen/local)
            return 1
            ;;
        *)
            cmp -s "$fn" "$target" && return 1
            overwrite_default=Y
            ;;
    esac
    ask_overwrite "$target" $overwrite_default
}

link_if_ok() {
    local source="$1"; shift
    local target="$1"; shift
    if [ -h "$target" ] \
       && [ "$(readlink -e "$source")" = "$(readlink -e "$target")" ]; then
        true
    elif can_overwrite "$source" "$target"; then
        ln -srb "$source" "$target"
    fi
}

destdir=${1:-$HOME}

for dn in $(my_find -type d); do
    test -d "$destdir/$dn" || mkdir "$destdir/$dn"
done

for fn in $(my_find -type f); do
    target="$destdir/$fn"
    if can_overwrite "$fn" "$target"; then
        cp -b "$fn" "$target"
    fi
done

shelldir=".config/bcsh"
cd "$shelldir"
for fn in $(my_find -type f -name .\* ); do
    link_if_ok "$destdir/$shelldir/$fn" "$destdir/$fn"
done
for fn in .bash_profile .bashrc; do
    link_if_ok "$destdir/$shelldir/bashrc" "$destdir/$fn"
done
link_if_ok "$destdir/.config/emacs" "$destdir/.emacs.d"  # Obsolete by Emacs 27
link_if_ok "$destdir/.config/mutt" "$destdir/.mutt"  # Obsolete by mutt 2.0
cd - >/dev/null

if [ -z "${1:-}" ] && [ -d /run/systemd/system ] && { \
       [ -e "/var/lib/systemd/linger/$(id -nu)" ] \
       || loginctl enable-linger; } ; then
    cd .config/systemd/user
    systemctl --user daemon-reload
    systemctl --user enable --now systemd-tmpfiles-setup.service systemd-tmpfiles-clean.timer
    ls -1 | while read service_name; do
        case "$service_name" in
            emacs.service|tmpfiles-*.*)
                systemctl --user disable "$service_name"
                rm "$service_name"
                continue
                ;;
            *@.*) pattern='^DefaultInstance *=' ;;
            *) pattern='^\[Install\]$' ;;
        esac
        if grep -qr "$pattern" "$service_name" \
                && [ "$(systemctl --user is-enabled "$service_name" || true)" = disabled ]; then
            systemctl --user enable "$service_name"
        fi
    done
    cd - >/dev/null
fi