#!/usr/bin/env bash
# fzf-tmux: starts fzf in a tmux pane
# usage: fzf-tmux [-h HEIGHT[%]] [-w WIDTH[%]] [--] [FZF OPTIONS]

args=()
opt=""
while [ $# -gt 0 ]; do
  arg="$1"
  case "$arg" in
    -w*|-h*)
      if [ ${#arg} -gt 2 ]; then
        size="${arg:2}"
      else
        shift
        size="$1"
      fi
      [[ "$arg"  =~ ^-w ]] && opt="-h"
      [[ "$size" =~ %$  ]] && opt="$opt -p ${size:0:-1}" ||
                              opt="$opt -l $size"
      ;;
    --)
      # "--" can be used to separate fzf-tmux options from fzf options to
      # avoid conflicts
      break
      ;;
    *)
      args+=("$1")
      ;;
  esac
  shift
done

if [ -z "$TMUX_PANE" ]; then
  fzf "${args[@]}"
  exit $?
fi

set -e

# Build arguments to fzf
[ ${#args[@]} -gt 0 ] && fzf_args=$(printf '\\"%s\\" ' "${args[@]}"; echo '')

# Clean up named pipes on exit
id=$RANDOM
fifo1=/tmp/fzf-fifo1-$id
fifo2=/tmp/fzf-fifo2-$id
fifo3=/tmp/fzf-fifo3-$id
cleanup() {
  rm -f $fifo1 $fifo2 $fifo3
}
trap cleanup EXIT SIGINT SIGTERM

fail() {
  >&2 echo "$1"
  exit 1
}
fzf=$(which fzf 2> /dev/null) || fail "fzf executable not found"

mkfifo $fifo2
mkfifo $fifo3
if [ -t 0 ]; then
  tmux split-window $opt 'sh -c "'$fzf' '"$fzf_args"' > '$fifo2'; echo \$? > '$fifo3'"'
else
  mkfifo $fifo1
  tmux split-window $opt 'sh -c "'$fzf' '"$fzf_args"' < '$fifo1' > '$fifo2'; echo \$? > '$fifo3'"'
  cat <&0 > $fifo1 &
fi
cat $fifo2
[ "$(cat $fifo3)" = '0' ]