go_commands=(go vim)

_go-installed() {
  which go > /dev/null 2>&1
}

_within-go-project() {
  local check_dir=$PWD
  local next_check_dir=${check_dir%/*}
  while [ "$next_check_dir" != "" ]; do
    if [ -f "$check_dir/.gopath" ]; then
        echo "$check_dir"
        return
    fi
    check_dir="$next_check_dir"
    next_check_dir=${check_dir%/*}
  done
  false
}

_run-with-gopath() {
  local go_path
  if _go-installed && go_path=$(_within-go-project); then
    env PATH="$PATH:$go_path/bin" GOPATH="$go_path" "$@"
  else
    "$@"
  fi
}

for cmd in "${go_commands[@]}"; do
  eval "function gopath_$cmd () { _run-with-gopath $cmd \$@; }"
  alias $cmd=gopath_$cmd

  if [[ -n $ZSH_VERSION ]]; then
    if which _$cmd > /dev/null 2>&1; then
      compdef _$cmd gopath_$cmd=$cmd
    fi
  fi
done

# vim: ft=sh