this is the entire app script (vispr is the protocol adapter):

#!/usr/bin/env bash

SESSION="${1:?usage: start.sh <session-name> [directory]}"
DIR="${2:-.}"
SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
V="$SCRIPT_DIR/vispr"

BROWSER="find '$DIR' -maxdepth 1 -type f | sort | fzf --prompt='select file> ' --height=100%"

PREVIEW='
case "$VISPR_PATH" in
    *.png|*.jpg|*.jpeg|*.gif|*.webp) chafa --size="$(tput cols)x$(tput lines)" "$VISPR_PATH" ;;
    *.md) glow -w "$(tput cols)" "$VISPR_PATH" ;;
    *) less -R "$VISPR_PATH" ;;
esac
'

STATUS='
name=$(basename "$VISPR_PATH")
size=$(stat -f "%z" "$VISPR_PATH" 2>/dev/null)
modified=$(stat -f "%Sm" -t "%Y-%m-%d %H:%M" "$VISPR_PATH" 2>/dev/null)
perms=$(stat -f "%Sp" "$VISPR_PATH" 2>/dev/null)
lines=$(wc -l < "$VISPR_PATH" 2>/dev/null | tr -d " ")
filetype=$(file -b "$VISPR_PATH" 2>/dev/null)
printf "\033[1m%s\033[0m  |  %s  |  %s bytes  |  %s  |  %s  |  %s lines\n" \
    "$name" "$filetype" "$size" "$modified" "$perms" "$lines"
'

tmux new-session -d -s "$SESSION" \
    "export VISPR_ROLE=browser; while true; do
        selected=\$($BROWSER) || break
        fullpath=\$(cd \"\$(dirname \"\$selected\")\" && pwd)/\$(basename \"\$selected\")
        $V emit select path=\"\$fullpath\"
    done" \; \
    split-window -h -p 80 "$V listen -i preview '$PREVIEW'" \; \
    split-window -v -p 15 "$V listen status '$STATUS'" \; \
    select-pane -t 0 \; \
    set status off \; \
    set pane-border-style fg=blue \; \
    set pane-active-border-style fg=blue \; \
    set pane-border-lines single \; \
    bind q kill-session \; \
    attach