#!/bin/sh

# output functions from abuild/functions.sh
NORMAL="\033[1;0m"
STRONG="\033[1;1m"
RED="\033[1;31m"
GREEN="\033[1;32m"
YELLOW="\033[1;33m"
BLUE="\033[1;34m"

_prefix="${BLUE}${STRONG}apatch${NORMAL}:"

msg() {
  local prompt="$GREEN>>> ${_prefix}"
  printf "${prompt} %s\n" "$1" >&2
}

warning() {
    local prompt="${YELLOW}>>> WARNING: ${_prefix}"
    printf "${prompt} %s\n" "$1" >&2
}

error() {
    local prompt="${RED}>>> ERROR: ${_prefix}"
    printf "${prompt} %s\n" "$1" >&2
}

if [ ! -f APKBUILD ]; then
  error "please run this in a package directory"
  exit 1
fi

if [ "$1" == "" ]; then
  echo "usage: apatch <patch name>"
  exit 1
fi

set -e

msg "running abuild"
abuild clean fetch unpack default_prepare

# obtain builddir
startdir="$PWD"
srcdir="$startdir/src"
. APKBUILD
unset -f grep cut head git rm mv
[ -n "$builddir" ] || builddir="$srcdir/$pkgname-$pkgver"

patchpath="$startdir/$1"

for patch in $source; do
  if [ "$patch" = "$1" ]; then
    # if the patch was in source, it was already applied in prepare() above,
    # but we want the original src to not have it, so we can get a full diff of
    # its original changes + our new ones
    (
      msg "reversing $patch"
      cd "$builddir"
      patch -R -p1 < "$patchpath"
    )
    break
  fi
done

header=""
if [ -f "$patchpath" ]; then
  msg "patch exists, trying to extract existing message"
  # try to extract the original header from the patch
  patch_start=$(grep -En '^(diff --git|--- )' "$patchpath" | cut -d: -f1 | head -n 1)
  header_file="/tmp/$(mktemp -u apatch.XXXXXX)"
  head -n $(( patch_start - 1 )) "$patchpath" > "$header_file"
fi

(
  cd "$builddir"
  git init
  git add .
  git commit -m "$pkgver" >/dev/null

  # if file exists, try to apply
  if [ -e "$patchpath" ]; then
    git apply --reject --whitespace=fix "$patchpath" || {
      rejects="$(git status --porcelain | grep -F '??' | grep -F '.rej' | cut -c4-)"
      if [ -n "$rejects" ]; then
        warning "$1 partially applied with rejects"
        for reject in $rejects; do
          target="${reject%.rej}"
          msg "trying to wiggle $target"
          wiggle --merge --replace "$target" "$reject" || {
            warning "could not merge $target, fix manually"
          }
          rm "$reject"
          rm "$target.porig" # left by wiggle
        done
      else
        warning "$1 failed to apply"
      fi
    }
  fi
  msg "you can edit now!"

  $SHELL || true

  git add .

  msg "saving patch $1"
  echo -n > "$patchpath" # empty the file first
  if [ -n "$header_file" ]; then
     mv "$header_file" "$patchpath"
  fi
  git diff --cached >> "$patchpath"

  if [ ! -s "$patchpath" ]; then
    msg "patch is empty, removing"
    rm "$patchpath"
  fi

  rm -rf .git
)