#!/bin/sh -e
# sdn-install: integrate sdn with the shell, binding to M-o
# vim: set sw=2 ts=2 sts=2 et tw=80:

zsh() {
cat <<'EOF'
sdn-navigate () {
  # optionally: zle zle-line-finish
  while eval "`SDN=1 sdn "$BUFFER" "$CURSOR"`"
  do
    [ -z "$cd" ] || cd "$cd"
    [ -z "$insert" ] || LBUFFER="$LBUFFER$insert "
    [ -z "$helper" ] && break

    # Workaround for "zsh: suspended (tty output)" when invoking
    # helpers after the terminal has been resized while running sdn
    command true

    # Add to history, see https://www.zsh.org/mla/workers/2020/msg00633.html
    fc -R =(print -- "$helper")

    /bin/sh -c "$helper" </dev/tty || break
  done
  # optionally: zle zle-line-init
  zle reset-prompt
}

zle -N sdn-navigate
bindkey '\eo' sdn-navigate
EOF
}

bash() {
cat <<'EOF'
# We can't make the shell update the prompt on directory changes
# since there's no way to invoke `prompt_again()` from a `bind -x`
# handler but we can work around it by submitting a blank line.
sdn-cursor () {
  if [[ $BASH_VERSINFO -lt 5 ]]
  then echo -n "$SDN_L" | wc -m
  else echo "$SDN_P"
  fi
}

sdn-navigate () {
  SDN_L=$READLINE_LINE SDN_P=$READLINE_POINT
  READLINE_LINE=

  while eval "`SDN=1 sdn "$SDN_L" "$(sdn-cursor)"`"
  do
    [[ -z $cd ]] || cd "$cd"
    [[ -z $insert ]] || {
      SDN_L="${SDN_L:0:$SDN_P}$insert ${SDN_L:$SDN_P}"
      ((SDN_P=SDN_P+${#insert}+1))
    }
    [[ -z $helper ]] && break
    history -s -- "$helper"
    /bin/sh -c "$helper" || break
  done
}

sdn-restore () {
  READLINE_LINE=$SDN_L READLINE_POINT=$SDN_P
  unset SDN_L SDN_P
}

# These never occur in UTF-8: \300-\301 \365-\367 \370-\377
bind -x '"\300": sdn-navigate'
bind -x '"\301": sdn-restore'
bind '"\eo": "\300\C-m\301"'
EOF
}

fish() {
cat <<'EOF'
function sdn-navigate
  set --local IFS
  set --local buffer (commandline)
  set --local cursor (commandline --cursor)
  while eval (SDN=1 sdn $buffer $cursor | \
    string replace -ar '^(.*?)=' 'set --$1 ')
    test -z "$cd" || cd "$cd"
    test -z "$insert" || commandline --insert "$insert "
    test -z "$helper" && break
    /bin/sh -c "$helper" || break
  end
  commandline --function repaint
end
bind \eo sdn-navigate
EOF
}

elvish() {
cat <<'EOF'
edit:insert:binding[Alt-o] = {
  use str
  local:reesc = [posix]{ str:replace "'\\''"  "''" $posix }
  local:posix = [cmd]{ /bin/sh -c $cmd </dev/tty >/dev/tty 2>&1 }

  # XXX: the -dot is not a stable API, and may hence break soon
  # https://elv.sh/ref/builtin.html#do-not-use-functions-and-variables
  local:buffer = $edit:current-command
  local:cursor = (str:to-codepoints $buffer[0..$edit:-dot] | count)
  local:ns = (ns [&])
  while ?(eval ($reesc (E:SDN=1 sdn $buffer $cursor |
    sed 's/^local //' | slurp)) &ns=$ns) {
    if (not-eq $ns[cd] "") { cd $ns[cd] }
    if (not-eq $ns[insert] "") { edit:insert-at-dot $ns[insert]" " }
    if (or (eq $ns[helper] "") (not ?($posix $ns[helper]))) { break }
  }
  edit:redraw &full=$true
}
EOF
}

shell= path=
while getopts s:f:h opt
do
  case $opt in
  s) shell=$OPTARG;;
  f) path=$OPTARG;;
  *) echo "Usage: $0 [-s SHELL] [-f RCPATH | -]"; exit 2
  esac
done

# Figure out the shell to integrate with
login=$(basename "$SHELL")
actual=$(ps -p $$ -o ppid= | xargs ps -o comm= -p)
if [ -z "$shell" ]
then
  if [ "$login" != "$actual" ]
  then
    echo "Conflict between login ($login) and invoking ($actual) shell."
    echo "Specify the shell with the -s option."
    exit 1
  fi
  shell=$actual
fi

# Figure out the default initialisation file
case "$shell" in
zsh|bash)
  rc=~/.${shell}rc;;
fish)
  rc=${XDG_CONFIG_HOME:-$HOME/.config}/fish/conf.d/sdn.fish;;
elvish)
  rc=~/.elvish/rc.elv;;
*)
  echo "$shell is not supported."
  exit 1
esac

# Just print out the snippet if requested
if [ "$path" = "-" ]
then
  $shell
  exit 0
fi

# Finally append to or update the appropriate file
b="# sdn-install begin"
e="# sdn-install end"
[ -z "$path" ] && path=$rc
mkdir -p "$(dirname "$path")"
touch "$path"

if ! grep -q "^$b" "$path" 2>/dev/null || ! grep -q "^$e" "$path" 2>/dev/null
then
  printf "\n$b\n%s\n$e\n" "$($shell)" >> "$path"
  echo "The snippet has been added to $path"
  exit 0
fi

# POSIX-compliant in-place sed, trying to retain permissions here
temp=$path.sdn.new
cp -p -- "$path" "$temp"
sed < "$path" > "$temp" "/^$b/,/^$e/c\\
$b\\
$($shell | sed 's/\\/&&/g; s/$/\\/')
$e"
mv -- "$temp" "$path"
echo "The snippet in $path has been updated."