single key click session switcher

tmux-sessions.sh

#!/usr/bin/env bash

fetch_tmux_sessions() {
  # list session ids and names, each on a new line, ordered by session_id
  tmux list-sessions -F "#{session_id} #{session_name}" | sort -n
}

# read tmux sessions into an array
mapfile -t SESSIONS < <(fetch_tmux_sessions)
declare -A KEY_SESSION_ID_MAP
declare -a SHORTCUT_KEYS=( 1 2 3 4 5 6 7 8 9 0 '!' '@' '#' '$' '%' '^' '&' '\*' '(' ')' '-' '=' \\ '`'  '_' '+' '|' '~' )

FZF_LINES=""
FZF_KEYS=""

fzf_map_keys_to_sessions() {
  for (( i=0; i<${#SESSIONS[@]}; i++ )); do
    if [ $i -lt "${#SHORTCUT_KEYS[@]}" ]; then
      session_id="${SESSIONS[$i]%% *}"
      session_name="${SESSIONS[$i]#* }"
      # session_id="${session_line%% *}"
      # session_name="${session_line#* }"
      key="${SHORTCUT_KEYS[$i]}"
      KEY_SESSION_ID_MAP["$key"]="$session_id"
      FZF_LINES+="$key: $session_id $session_name"$'\n'
      FZF_KEYS+="$key,"
    else
      FZF_LINES+="  $session_id $session_name"$'\n'
    fi
    # i=$((i+1))
  done
  FZF_KEYS+="N" # new session key.
  # remove trailing empty line
  FZF_LINES=$(echo "$FZF_LINES" | sed '/^$/d')
}

fzf_display_sessions() {
  # display sessions with fzf
  echo "$FZF_LINES" | fzf --reverse \
    --prompt="Select tmux session: " \
    --scrollbar='' \
    --expect="${FZF_KEYS}" \
    --preview-window=bottom:50%:wrap:border-top \
    --preview='
      session_id=''{}''
      session_id="${session_id#*: }"
      session_id="${session_id%% *}"
      tmux list-windows -t "${session_id}" -F "#{window_index}" \
      | while read window; do
          tmux capture-pane -t "${session_id}:${window}" -p
          echo "-------"
        done
    '
}

handle_fzf_output() {
  # Check if any selection was made
  if [[ "${#FZF_OUTPUT[@]}" -le 0 ]]; then
    tmux display-message "No session selected."
    exit 0
  fi

  if [[ "${#FZF_OUTPUT[@]}" -eq 1 ]]; then
    # a result has been selected using <enter>
    session_id="${FZF_OUTPUT[0]#*: }"
    session_id="${session_id%% *}"
  else
    # a result has been selected using an expected key
    expected_key="${FZF_OUTPUT[0]}"
    session_id="${KEY_SESSION_ID_MAP["$expected_key"]}"
  fi

  # Add: handle Shift-N (new session)
  if [[ "$expected_key" == "N" ]]; then
    read -rp "New session name: " new_session_name
    if [[ -n "$new_session_name" ]]; then
      tmux new-session -d -s "$new_session_name"
      tmux switch-client -t "$new_session_name"
    fi
    exit 0
  fi

  echo >&2
  for key in "${!KEY_SESSION_ID_MAP[@]}"; do
    echo "key: $key, value: ${KEY_SESSION_ID_MAP["$key"]}" >&2
  done
  echo >&2

  echo "expected_key: _${expected_key}_ ; session_id: _${session_id}_ ; fzf_output: _${FZF_OUTPUT[*]}_" >&2

  # If a session was selected, switch to it
  if [ -n "$session_id" ]; then
    tmux switch-client -t "$session_id"
  else
    tmux display-message "No session selected."
  fi
}

fzf_session_selector() {
  if [ "${#SESSIONS[@]}" -le 0 ]; then
    tmux display-message "No tmux sessions found."
    exit 1
  fi

  fzf_map_keys_to_sessions

  IFS=$'\n' read -r -d '' -a FZF_OUTPUT <<< "$(fzf_display_sessions)"
  handle_fzf_output "$FZF_OUTPUT"
}

# Invoke the selector in a tmux popup window
if [[ "$1" == "popup" ]]; then
  tmux popup -E -h 80% "$(readlink -f "${BASH_SOURCE[0]}")"
else
  fzf_session_selector
fi