#!/usr/bin/env bash
# fzf-tmux: starts fzf in a tmux pane
# usage: fzf-tmux [-u|-d [HEIGHT[%]]] [-l|-r [WIDTH[%]]] [--] [FZF OPTIONS]

fail() {
  >&2 echo "$1"
  exit 2
}

fzf="$(command -v fzf 2> /dev/null)" || fzf="$(dirname "$0")/fzf"
[[ -x "$fzf" ]] || fail 'fzf executable not found'

args=()
opt=""
skip=""
swap=""
close=""
term=""
[[ -n "$LINES" ]] && lines=$LINES || lines=$(tput lines) || lines=$(tmux display-message -p "#{pane_height}")
[[ -n "$COLUMNS" ]] && columns=$COLUMNS || columns=$(tput cols) || columns=$(tmux display-message -p "#{pane_width}")

help() {
  >&2 echo 'usage: fzf-tmux [-u|-d [HEIGHT[%]]] [-l|-r [WIDTH[%]]] [--] [FZF OPTIONS]

  Layout
    -u [HEIGHT[%]]  Split above (up)
    -d [HEIGHT[%]]  Split below (down)
    -l [WIDTH[%]]   Split left
    -r [WIDTH[%]]   Split right

    (default: -d 50%)
'
  exit
}

while [[ $# -gt 0 ]]; do
  arg="$1"
  shift
  [[ -z "$skip" ]] && case "$arg" in
    -)
      term=1
      ;;
    --help)
      help
      ;;
    --version)
      echo "fzf-tmux (with fzf $("$fzf" --version))"
      exit
      ;;
    -w*|-h*|-d*|-u*|-r*|-l*)
      if [[ "$arg" =~ ^.[lrw] ]]; then
        opt="-h"
        if [[ "$arg" =~ ^.l ]]; then
          opt="$opt -d"
          swap="; swap-pane -D ; select-pane -L"
          close="; tmux swap-pane -D"
        fi
      else
        opt=""
        if [[ "$arg" =~ ^.u ]]; then
          opt="$opt -d"
          swap="; swap-pane -D ; select-pane -U"
          close="; tmux swap-pane -D"
        fi
      fi
      if [[ ${#arg} -gt 2 ]]; then
        size="${arg:2}"
      else
        if [[ "$1" =~ ^[0-9]+%?$ ]]; then
          size="$1"
          shift
        else
          continue
        fi
      fi

      if [[ "$size" =~ %$ ]]; then
        size=${size:0:((${#size}-1))}
        if [[ -n "$swap" ]]; then
          opt="$opt -p $(( 100 - size ))"
        else
          opt="$opt -p $size"
        fi
      else
        if [[ -n "$swap" ]]; then
          if [[ "$arg" =~ ^.l ]]; then
            max=$columns
          else
            max=$lines
          fi
          size=$(( max - size ))
          [[ $size -lt 0 ]] && size=0
          opt="$opt -l $size"
        else
          opt="$opt -l $size"
        fi
      fi
      ;;
    --)
      # "--" can be used to separate fzf-tmux options from fzf options to
      # avoid conflicts
      skip=1
      continue
      ;;
    *)
      args+=("$arg")
      ;;
  esac
  [[ -n "$skip" ]] && args+=("$arg")
done

if [[ -z "$TMUX" || "$opt" =~ ^-h && "$columns" -le 40 || ! "$opt" =~ ^-h && "$lines" -le 15 ]]; then
  "$fzf" "${args[@]}"
  exit $?
fi

# --height option is not allowed
args+=("--no-height")

# Handle zoomed tmux pane by moving it to a temp window
if tmux list-panes -F '#F' | grep -q Z; then
  zoomed=1
  original_window=$(tmux display-message -p "#{window_id}")
  tmp_window=$(tmux new-window -d -P -F "#{window_id}" "bash -c 'while :; do for c in \\| / - '\\;' do sleep 0.2; printf \"\\r\$c fzf-tmux is running\\r\"; done; done'")
  tmux swap-pane -t $tmp_window \; select-window -t $tmp_window
fi

set -e

# Clean up named pipes on exit
id=$RANDOM
argsf="${TMPDIR:-/tmp}/fzf-args-$id"
fifo1="${TMPDIR:-/tmp}/fzf-fifo1-$id"
fifo2="${TMPDIR:-/tmp}/fzf-fifo2-$id"
fifo3="${TMPDIR:-/tmp}/fzf-fifo3-$id"
cleanup() {
  \rm -f $argsf $fifo1 $fifo2 $fifo3

  # Restore tmux window options
  if [[ "${#tmux_win_opts[@]}" -gt 0 ]]; then
    eval "tmux ${tmux_win_opts[@]}"
  fi

  # Remove temp window if we were zoomed
  if [[ -n "$zoomed" ]]; then
    tmux display-message -p "#{window_id}" > /dev/null
    tmux swap-pane -t $original_window \; \
      select-window -t $original_window \; \
      kill-window -t $tmp_window \; \
      resize-pane -Z
  fi

  if [ $# -gt 0 ]; then
    trap - EXIT
    exit 130
  fi
}
trap 'cleanup 1' SIGUSR1
trap 'cleanup' EXIT

envs="env TERM=$TERM "
[[ -n "$FZF_DEFAULT_OPTS"    ]] && envs="$envs FZF_DEFAULT_OPTS=$(printf %q "$FZF_DEFAULT_OPTS")"
[[ -n "$FZF_DEFAULT_COMMAND" ]] && envs="$envs FZF_DEFAULT_COMMAND=$(printf %q "$FZF_DEFAULT_COMMAND")"

mkfifo -m o+w $fifo2
mkfifo -m o+w $fifo3

# Build arguments to fzf
opts=""
for arg in "${args[@]}"; do
  arg="${arg//\\/\\\\}"
  arg="${arg//\"/\\\"}"
  arg="${arg//\`/\\\`}"
  arg="${arg//$/\\$}"
  opts="$opts \"$arg\""
done

pppid=$$
echo -n "trap 'kill -SIGUSR1 -$pppid' EXIT SIGINT SIGTERM;" > $argsf
close="; trap - EXIT SIGINT SIGTERM $close"

tmux_win_opts=( $(tmux show-window-options remain-on-exit \; show-window-options synchronize-panes | sed '/ off/d; s/^/set-window-option /; s/$/ \\;/') )

if [[ -n "$term" ]] || [[ -t 0 ]]; then
  cat <<< "\"$fzf\" $opts > $fifo2; echo \$? > $fifo3 $close" >> $argsf
  TMUX=$(echo $TMUX | cut -d , -f 1,2) tmux set-window-option synchronize-panes off \;\
    set-window-option remain-on-exit off \;\
    split-window $opt "$envs bash -c 'cd $(printf %q "$PWD"); exec -a fzf bash $argsf'" $swap \
    > /dev/null 2>&1
else
  mkfifo $fifo1
  cat <<< "\"$fzf\" $opts < $fifo1 > $fifo2; echo \$? > $fifo3 $close" >> $argsf
  TMUX=$(echo $TMUX | cut -d , -f 1,2) tmux set-window-option synchronize-panes off \;\
    set-window-option remain-on-exit off \;\
    split-window $opt "$envs bash -c 'exec -a fzf bash $argsf'" $swap \
    > /dev/null 2>&1
  cat <&0 > $fifo1 &
fi
cat $fifo2
exit "$(cat $fifo3)"