################################################################################
#### Unbreak things

# Prevent tmux from messing up keybindings and colors.
# This is witchcraft, I have no explanation for the following commands.
set-option -g xterm-keys on
set-window-option -g xterm-keys on
set-option -g default-terminal "xterm-256color"

# Prevent tmux from waiting half a second before processing the ESC key, see:
# http://unix.stackexchange.com/a/25638/176805
set-option -s escape-time 0

# Enable proper mouse support:
# http://www.hamvocke.com/blog/a-guide-to-customizing-your-tmux-conf/
set-option -g mouse on
bind-key m set-option -g mouse on
bind-key M set-option -g mouse off

# The following line prevents a weird OS X problem that otherwise
# keeps the "open" command from working (and has several other
# undesirable properties; see issue #120). For more details on the
# issue, see [1]-[5].
#
# The exact version of the solution below is the only way I have found
# to satisfy all of the following properties:
#
# * It fixes the problem, i.e. "open" works correctly.
#
# * When opening a new window in tmux, the window name is correctly
#   set to zsh initially. It does not briefly flash
#   "reattach-to-user-namespace", and it does not display
#   "/usr/local/bin/zsh" either.
#
# * The "automatic-rename" property is still set to "on" in new tmux
#   windows, meaning that if you run another program, the window name
#   will change to reflect that (unless you manually rename the
#   window).
#
# * Exiting the shell (e.g. with Control+D) will immediately kill the
#   tmux window instead of dropping you into another shell.
#
# * It works for all shells, and doesn't hardcode any particular one.
#
# * It still works when reattach-to-user-namespace is unavailable.
#
# Yes, it's horrible. I think we can all agree on that, no need to
# point it out.
#
# Unfortunately, tmux appears to be remarkably unintelligent when it
# comes to determining the string to show as the window title.
# Basically, about as unintelligent as shebang parsing, and anyone
# involved in the virtualenv-can't-handle-spaces fiasco will know
# that's pretty darn unintelligent. In particular, it grabs characters
# literally from the beginning of the command string until it hits a
# space, then discards until the first slash, if there is one. This
# means it's impossible to quote the executable name, so if your shell
# has spaces in its name, you're screwed. Making this whole fiasco
# work for paths with double quotes in it is an exercise in futility,
# I think.
#
# [1]: http://superuser.com/q/834525/326239
# [2]: http://www.economyofeffort.com/2013/07/29/reattach-to-user-namespace-the-fix-for-your-tmux-in-os-x-woes/
# [3]: https://www.elmund.io/osx/2015/07/10/open-command-in-osx-tmux/
# [4]: https://github.com/ChrisJohnsen/tmux-MacOSX-pasteboard
# [5]: https://github.com/ChrisJohnsen/tmux-MacOSX-pasteboard/issues/10

run-shell 'command -v reattach-to-user-namespace > /dev/null && tmux set-option -g default-command "$SHELL -c \"reattach-to-user-namespace -l \\\"$(basename "$SHELL")\\\"\"" || true'

################################################################################
#### Keybindings

# Use ` instead of C-b as prefix key, see:
# http://www.hamvocke.com/blog/a-guide-to-customizing-your-tmux-conf/
unbind-key C-b
set-option -g prefix `
bind-key ` send-prefix

# Force tmux to use Emacs keybindings, see:
# http://stackoverflow.com/q/18240683/3538165
# http://stackoverflow.com/a/18247437/3538165
set-option -g status-keys emacs
set-window-option -g mode-keys emacs

# Turn off repeatability for moving between panes. Otherwise, if you split
# horizontally and switch panes, you will have to wait for the 'repeat period'
# to expire before you can use <Up> and <Down> to page through shell history.
#
# Doing it this way instead of using 'set-option -g repeat-time 0' makes it
# so that Control+Arrows and Meta+Arrows (for resizing panes) are still
# repeatable.
#
# See: http://superuser.com/a/325579/326239
bind-key Up select-pane -U
bind-key Down select-pane -D
bind-key Left select-pane -L
bind-key Right select-pane -R

# Keybinding for reloading .tmux.conf.
bind-key R source-file ~/.tmux.conf

# Keybinding for swapping the current and marked windows.
bind-key \ swap-window

# Keybindings for swapping adjacent windows.
bind-key < swap-window -t -1
bind-key > swap-window -t +1

# Keybinding for inserting a window.
# Adapted from http://superuser.com/a/704551/326239
bind-key I command-prompt -p 'Insert window at:' '      \
    run-shell "                                     \
        if tmux select-window -t %1; then           \
            tmux new-window -a;                     \
            tmux swap-window -s %1 -t \$((%1+1));   \
        else                                        \
            tmux new-window;                        \
            tmux move-window -t %1;                 \
        fi;                                         \
        tmux select-window -t #{window_id};         \
        tmux select-window -t %1;                   \
    "'

################################################################################
#### Status bar

# The following code is adapted from:
# https://coderwall.com/p/trgyrq/make-your-tmux-status-bar-responsive
# It provides the same appearance as https://github.com/powerline/powerline,
# but sidesteps the environment/configuration hell which that project
# introduces.

# Format to display on the left-hand side of the status bar.
# Note that the conditional #{?cond,true,false} operator does not do any
# fancy parsing, so you can't have literal commas in the conditions --
# this will cause the conditions to be split up. So we have to use multiple
# style #[attr=value] directives.
set-option -g status-left '#{?client_prefix,#[fg=colour254]#[bg=colour31],#[fg=colour16]#[bg=colour254]#[bold]} #{=80:session_name} #{?client_prefix,#[fg=colour31],#[fg=colour254]}#[bg=colour234,nobold] '

# Maximum length of the format displayed on the left-hand side.
# Since the maximum length of the session name is limited in the above
# format string, this number is unimportant -- it just needs to be a
# bit larger than what is allocated for the session name, to allow for
# the surrounding characters.
set-option -g status-left-length 90

# Format to display on the right-hand side of the status bar.
set-option -g status-right '#{?mouse,#[fg=colour254]#[bg=colour31],#[fg=colour244,bg=colour234]} Mouse #[fg=colour254,bg=colour234] #H'

# Format to display for the current window.
set-option -g window-status-current-format '#[fg=colour117,bg=colour31] #{window_index}#{window_flags} #[fg=colour231,bold]#(tmux display-message -p "#{pane_current_path}" | sed "s#$HOME#~#g") #{?#{m:*#{b:SHELL}*, #{pane_current_command}},| #{pane_current_command} }#[fg=colour31,bg=colour234,nobold]'

# Format to display for other windows.
set-option -g window-status-format '#[fg=colour244,bg=colour234]#{window_index}#{window_flags} #[fg=colour249]#(tmux display-message -p "#{pane_current_path}" | sed "s#$HOME#~#g") #{?#{m:*#{b:SHELL}*, #{pane_current_command}},| #{pane_current_command} }'

# Background color for parts of the status bar not specified by the above
# formats. For instance, the empty space to the right, and the single
# spaces between instances of window-status-format.
set-option -g status-bg colour234

# Inhibit the default styling for windows with unseen activity, which
# looks blatantly incorrect with the "powerline" theme we are trying to
# emulate.
set-window-option -g window-status-activity-attr none

# Update the status bar every second, instead of the default 15(!)
# seconds. It doesn't look like it's possible to update more than
# once per second, unfortunately.
set-option -g status-interval 1

################################################################################
#### Appearance

# Attempt to set the title of the terminal emulator.
set-option -g set-titles on
set-option -g set-titles-string '#{session_name} - #{window_name}'

# Show an indicator in the status bar on windows with unseen activity.
set-option -g monitor-activity on

# Make the borders of the current pane the same color as the borders
# of other panes. This is because the borders of the marked pane are
# *inverted*, and while different foreground colors in different parts
# of the frame are not too objectionable, different background colors
# look very bad.
set-option -g pane-active-border-style none

################################################################################
#### Miscellaneous

# When the current session is killed, switch to another session instead of
# detaching.
set-option -g detach-on-destroy off

# Show messages until they are dismissed, instead of for 750 milliseconds(!).
# Actually it is only for an hour, because it doesn't seem like you can turn
# off the time limit.
set-option -g display-time 36000000

# Open new windows in the same directory as the current pane.
bind-key c new-window -c "#{pane_current_path}"

# Automatically renumber windows when one is deleted, see:
# http://unix.stackexchange.com/a/51879/176805
set-option -g renumber-windows on

# Number windows and panes from 1, instead of 0; see:
# http://unix.stackexchange.com/a/35932/176805
set-option -g base-index 1
set-window-option -g pane-base-index 1

# Open new panes in the same directory as the current pane.
bind-key % split-window -h -c "#{pane_current_path}"
bind-key '"' split-window -v -c "#{pane_current_path}"

# Increase the scrollback buffer size from 2000 to a larger size, but
# not one so large that tmux begins to lag.
set-option -g history-limit 10000

################################################################################
#### Local overrides

if-shell "[[ -f ~/.tmux.local.conf ]]" "source ~/.tmux.local.conf"