default.nix

{ pkgs, ... }:

let
  maybeSwitch = pkgs.writeShellScript "tmux-maybe-switch" ''
    set -e
    set -u

    if [[ "$1" =~ ^=[0-9]+:[0-9]+ ]]; then
      exec tmux link-window -s "$1"
    else
      exec tmux display-message "A session was selected; please pick a window."
    fi
  '';
in
{
  # Merges defaults with our customizations.
  environment.etc."tmux.conf".text = ''
    # Custom tmux configuration
    # =========================

    # Look and feel
    # -------------

    # ### Colours
    # Colours follow default fg/bg of term, inverted for selected window.
    set -g status-bg default
    set -g status-fg default
    # Boldened
    set-window-option -g window-status-current-style reverse
    set-window-option -g window-status-style default

    # ### Statusbar
    set-option -g status-left ""
    set-option -g status-left-length 25
    set-option -g status-right "@#H %H:%M"
    set-option -g status-justify left
    # Refresh the status at 1s interval for a more dynamic clock.
    set-option -g status-interval 10
    set-option -g window-status-current-format " #I #W "
    set-option -g window-status-format         " #I#{?window_flags,#F, }#W "

    # Behaviour
    # ---------

    # Setting the title
    set-option -g set-titles on
    set-option -g set-titles-string "#I:#T"

    # Bell
    set-option -g bell-action any
    set-option -g visual-bell off

    # Sets tmux's reported TERM to screen-256color
    # This gets us some vim color goodness.
    set -g default-terminal "screen-256color"

    # ### Additional bindings

    # [^b j] Splits, but instead of creating a new pane, joins another pane.
    bind-key j command-prompt -p "join pane from:"  "join-pane -s '%%'"

    # [^/M + PageUp] to switch to previous tab
    bind-key -n C-PPage previous-window
    bind-key -n M-PPage previous-window

    # [^/M + PageDown] to switch to next tab
    bind-key -n C-NPage next-window
    bind-key -n M-NPage next-window

    # Open new windows and splits with the current pane's path.
    bind '"' split-window -c "#{pane_current_path}"
    bind % split-window -h -c "#{pane_current_path}"
    bind c new-window -c "#{pane_current_path}"

    bind -n C-t new-window -c "#{pane_current_path}"

    # Linking windows through a menu
    bind l choose-tree 'run-shell "${maybeSwitch} %%"'
    bind u unlink-window

    # For neovim.
    # See https://github.com/neovim/neovim/wiki/FAQ#esc-in-tmux-or-gnu-screen-is-delayed
    set -g escape-time 10

    run-shell ${pkgs.tmuxPlugins.sensible}/share/tmux-plugins/sensible/sensible.tmux
    run-shell ${pkgs.tmuxPlugins.sessionist}/share/tmux-plugins/sessionist/sessionist.tmux
  '';

}