#!/usr/bin/env sh

# Description: Text based file previewer
#
# Note: This plugin needs a "NNN_FIFO" to work.
#
# Dependencies: tmux or xterm (or set $TERMINAL), file, tree
#
# How to use:
#   You need to set a NNN_FIFO path and set a key for the plugin,
#   then start `nnn`:
#
#     $ NNN_FIFO=/tmp/nnn.fifo nnn
#
#   Then in `nnn`, launch the `preview-tui` plugin.
#
#   If you provide the same NNN_FIFO to all nnn instances, there will be a
#   single common preview window. I you provide different FIFO path, they
#   will be independent.
#
# Authors: Todd Yamakawa and Léo Villeveygoux

TERMINAL="${TERMINAL:-xterm}"
NUKE="${XDG_CONFIG_HOME:-$HOME/.config}/nnn/plugins/nuke"

if [ ! -r "$NNN_FIFO" ] ; then
    echo "No FIFO available! (\$NNN_FIFO='$NNN_FIFO')" >&2
    exit 1
fi
if [ ! -x "$NUKE" ] ; then
    echo "Nuke not found!" >&2
    exit 1
fi

if [ "$PREVIEW_MODE" ] ; then
    exec < "$NNN_FIFO"
    while read -r selection ; do
        clear
        lines=$(($(tput lines)-1))
        cols=$(tput cols)
        mime="$(file -b --mime-type "$selection")"

        if [ "$mime" = "inode/directory" ] ; then
            # Print directory tree
            cd "$selection" && tree | head -n $lines | cut -c 1-"$cols"
        elif [ "${mime%%/*}" = "text" ] ; then
            # Print file head
            head -n $lines "$selection" | cut -c 1-"$cols"
        else
            # Binary file
            echo "-------- Binary file --------"
            file -b "$selection"
        fi
    done

    if [ -e "${TMUX%%,*}" ] ; then
        tmux kill-pane
    fi

    exit 0
fi

if [ -e "${TMUX%%,*}" ] ; then
    tmux split-window -e "NNN_FIFO=$NNN_FIFO" -e "PREVIEW_MODE=1" -dh "$0"
else
    PREVIEW_MODE=1 GUI=0 $TERMINAL -e "$0" &
fi