.tmux.conf

## .tmux.conf
# Update the status bar by fetching an environment variable set earlier by a shell script.
# Requires Thomas Adam's hook patch for tmux
# https://github.com/ThomasAdam/tmux/tree/ta/hooks
set-hook -g -n 'after-select-window' 'run "tmux set -q status-left \"`tmux show -environment TMUX_STATUS_#I | cut -c 15-`\""'
set-hook -g -n 'after-kill-window' 'run "tmux set -q status-left \"`tmux show -environment TMUX_STATUS_#I | cut -c 15-`\""'

## .vimrc
" Update tmux statusbar
autocmd BufEnter * silent execute '!tmux_set_status.sh ' . expand("%:t") . ' ' . expand("%:h")
autocmd BufWinEnter * silent execute '!tmux_set_status.sh ' . expand("%:t") . ' ' . expand("%:h")
autocmd BufWritePost * silent execute '!tmux_set_status.sh ' . expand("%:t") . ' ' . expand("%:h")

## .zshrc
line_divider(){
  echo "${(l.$COLUMNS..—.)}"
}

PROMPT="%{$fg_bold[magenta]%}$(line_divider)\n%{$fg[white]%}➥%{$reset_color%} "

precmd () {
  # Check if tmux is running
  if [ "$TERM" = "screen-256color" ] && [ -n "$TMUX" ]; then
    # Run the script that sets the tmux statusbar and environment variable.
    tmux_set_status.sh
  fi
}

## tmux_set_status.sh
#!/bin/zsh

CURRENT_DIR=${PWD##*/}

FILENAME=$1
FILEPATH=$2

# Get filename if inside vim
file() {
  if [[ $FILENAME == "" ]]; then
    echo ""
  else
    if [[ $FILEPATH == "." ]]; then
      echo "#[default]#[fg=cyan]$FILENAME"
    else
      echo "$FILEPATH/#[default]#[fg=cyan]$FILENAME"
    fi
  fi
}

# Get the current git repo branch
branch() {
  echo $(git symbolic-ref HEAD 2>/dev/null | awk -F/ {'print $NF'})
}

# Get whether branch needs to be synced.
sync () {
  unpushed=$(git cherry -v @{upstream} 2>/dev/null)
  if [[ $unpushed == "" ]]; then
    echo ""
  else
    echo "⟳#[default]"
  fi
}

# Display git information
git() {
  st=$(git status 2>/dev/null | tail -n 1)
  if [[ $st == "" ]]; then
    echo ""
  else
    if [[ $st == "nothing to commit, working directory clean" ]]; then
      echo " #[fg=cyan]on #[fg=white,bold]$(branch)$(sync)"
    else
      echo " #[fg=cyan]on #[fg=black,bold]$(branch)$(sync)"
    fi
  fi
}

# Set tmux statusbar (remind me to refactor this)
# if the CWD begins with '/' ie. outside the CWD
if [[ `echo $FILEPATH | cut -c1` == '/' ]]; then
  # Set environment variable for retrieval later when switching windows.
  tmux setenv TMUX_STATUS_$(tmux display -p "#I") " #[fg=cyan,bold]$(file)#[default]"
  # Set tmux status line itself.
  tmux set -q status-left " #[fg=cyan,bold]$(file)#[default]"
else
  # Set environment variable for retrieval later when switching windows.
  tmux setenv TMUX_STATUS_$(tmux display -p "#I") " #[fg=cyan,bold]$CURRENT_DIR/$(file)#[default]$(git)"
  # Set tmux status line itself.
  tmux set -q status-left " #[fg=cyan,bold]$CURRENT_DIR/$(file)#[default]$(git)"
fi