#!/usr/bin/env sh

# Description: Only works inside a tmux session - Opens files in Neovim.
#              If $NVIM is set and its server is alive, files are opened
#              in that server. Otherwise, a new pane is split on the left
#              and files are opened there until the nnn pane is closed.
#
# Dependencies: tmux neovim
#
# Tip: Exec nnn inside Neovim pane via a leader key
#
#        vim.keymap.set("n", "<Leader>n", function()
#          if vim.env.TMUX then
#            vim.fn.system({
#              "tmux", "split-window", "-h",
#              "-c", vim.fn.getcwd(),
#              "-e", "NVIM=" .. vim.v.servername,
#              "exec nnn"
#            })
#          end
#        end)
#
# Shell: POSIX compliant
# Author: 8lackfish

fpath="${2:+$2/}$1"

if [ -n "$TMUX" ]; then
    if [ -S "$NVIM" ]; then
        svname="$NVIM"
        nvim --server "$svname" --remote "$fpath"
    else
        id=$(tmux display-message -p '#{pane_id}.#{window_id}.#{session_id}' | tr -d '%@$')
        svname="${XDG_RUNTIME_DIR:-/tmp}/nvim.nnn-tnp.$id"
        if [ -S "$svname" ]; then
            nvim --server "$svname" --remote "$fpath"
        else
            tmux split-pane -bdh "nvim --listen \"${svname}\" \"${fpath}\""
        fi
    fi
    until nvim --headless --server "$svname" \
        --remote-expr "execute('%argdelete')" >/dev/null 2>&1
    do :; done
else
    printf "\n'%s' only works inside a tmux session" "$(basename "$0")"
    printf "\n\n'Enter' to return"; read -r _
fi