#!/usr/bin/env bash

set -e

script_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

# Use the current directory (set via display-popup -d)
dir="${PWD:-$HOME}"
# Use the directory basename as window name
window_name=$dir

# The client that opened the popup, recorded by the `bind A` binding. Its
# current window is the root window <prefix>A was pressed in; the popup cannot
# pass that through itself, so resolve it here before attaching.
popup_client=$(tmux display-message -p '#{@agent_popup_client}' 2>/dev/null || true)
origin_window=""
if [ -n "$popup_client" ]; then
  origin_window=$(tmux list-clients -F $'#{client_name}\x1f#{window_id}' \
    | awk -v FS=$'\x1f' -v client="$popup_client" '$1 == client { print $2; exit }')
fi

# Create the agent session if it doesn't exist
if ! tmux has-session -t agent; then
  tmux new-session -ds agent -c "$dir" -n "$window_name" "$script_dir/agent-cmd.sh"
  # Store the directory in a window option for later matching
  tmux set-window-option -t agent @agent_dir "$dir"
fi

# Apply session options on every invocation so updates propagate to live sessions
tmux set-option -t agent status off
tmux set-option -t agent remain-on-exit on
tmux set-option -t agent default-command "$script_dir/agent-cmd.sh"
# Session-scoped (not -g) so the root-session window changes agent-sync.sh makes
# cannot re-trigger it.
tmux set-hook -t agent session-window-changed "run -b '$script_dir/agent-sync.sh'"

# Search for an existing window with matching directory
target_window=""
for window_id in $(tmux list-windows -t agent -F '#{window_id}'); do
  window_dir=$(tmux show-window-option -t "$window_id" -v @agent_dir 2>/dev/null || true)
  if [ "$window_dir" = "$dir" ]; then
    target_window="$window_id"
    break
  fi
done

if [ -n "$target_window" ]; then
  # Remember which root window this agent window came from, refreshed on every
  # invocation. Recorded *before* selecting, so the sync hook select-window
  # fires sees this invocation's origin rather than the previous one's.
  if [ -n "$origin_window" ]; then
    tmux set-window-option -t "$target_window" @agent_origin_window "$origin_window"
  fi
  # Select the existing window
  tmux select-window -t "$target_window"
else
  # Create a new window; default-command runs agent-cmd.sh
  tmux new-window -t agent -c "$dir" -n "$window_name"
  # Store the directory in a window option for later matching
  tmux set-window-option -t agent @agent_dir "$dir"
  if [ -n "$origin_window" ]; then
    tmux set-window-option -t agent @agent_origin_window "$origin_window"
  fi
fi

# Prune windows whose recorded directory no longer exists. This runs after the
# current directory's window is guaranteed to exist, so the session always
# keeps at least one live window and is never killed out from under us.
for window_id in $(tmux list-windows -t agent -F '#{window_id}'); do
  window_dir=$(tmux show-window-option -t "$window_id" -v @agent_dir 2>/dev/null || true)
  # Skip windows with no recorded directory rather than risk pruning them.
  [ -n "$window_dir" ] || continue
  if [ ! -d "$window_dir" ]; then
    tmux kill-window -t "$window_id" 2>/dev/null || true
  fi
done

# Attach to the session
tmux attach-session -t agent