#!/usr/bin/env bash
# Show and preview git diffs through fzf. Anything you can pass to git diff
# you can pass to this script. It also supports passing in --side to configure
# delta to use side-by-side mode.
#
# Examples:
#   gd
#   gd --side
#   gd --staged
#   gd [any flag that git diff supports]

set -o errexit
set -o pipefail
set -o nounset

GIT_ARGS=("--color=always")

# Handle displaying side by side on demand.
for arg in "${@}"; do
  if [ "${arg}" = "--side" ]; then
    export DELTA_FEATURES="${DELTA_FEATURES:-} side-by-side"
  else
    GIT_ARGS+=("${arg}")
  fi
done

printf -v GIT_ARGS_STR "%q " "${GIT_ARGS[@]}"

git diff "${GIT_ARGS[@]}" --name-only |
  fzf \
    --preview "git diff ${GIT_ARGS_STR:-} -- ':(top){-1}' | delta --width=\${FZF_PREVIEW_COLUMNS}" \
    --preview-window="right,75%" || true