#!/usr/bin/env bash
# Fetch a rusty-kaspa release tag into the Igneum node fork and open the merge on a branch.
# Commits nothing. A person reads the conflicts, runs the tests in tools/upstream/README.md,
# does the consensus review against docs/spec, and commits.
#
# Usage:
#   tools/upstream/sync-upstream.sh <tag> [fork-dir] [upstream-url]
#     tag           a rusty-kaspa release tag, for example v2.2.0
#     fork-dir      default: vendor/igneum-node (relative to the repository root)
#     upstream-url  used only if the fork has no remote named "upstream";
#                   default: https://github.com/kaspanet/rusty-kaspa.git
#
# Refuses: a dirty working tree, a merge already in progress, a missing tag,
# an existing merge branch. Never touches master and never runs the devnet.
set -euo pipefail

tag="${1:-}"
if [[ -z "$tag" ]]; then
  echo "usage: $0 <tag> [fork-dir] [upstream-url]" >&2
  exit 2
fi

root="$(cd "$(dirname "$0")/../.." && pwd)"
fork="${2:-$root/vendor/igneum-node}"
url="${3:-https://github.com/kaspanet/rusty-kaspa.git}"
branch="merge/upstream-$tag"
base="master"

if [[ ! -d "$fork/.git" ]]; then
  echo "no git repository at $fork" >&2
  exit 1
fi
cd "$fork"

if [[ -n "$(git status --porcelain)" ]]; then
  echo "refusing: working tree is not clean in $fork" >&2
  git status --short >&2
  exit 1
fi
if [[ -f .git/MERGE_HEAD ]]; then
  echo "refusing: a merge is already in progress in $fork" >&2
  exit 1
fi
if git show-ref --verify --quiet "refs/heads/$branch"; then
  echo "refusing: branch $branch already exists" >&2
  exit 1
fi
if ! git show-ref --verify --quiet "refs/heads/$base"; then
  echo "refusing: no local branch $base" >&2
  exit 1
fi

if ! git remote get-url upstream >/dev/null 2>&1; then
  echo "adding remote upstream -> $url"
  git remote add upstream "$url"
fi
echo "upstream is $(git remote get-url upstream)"

echo "fetching tags from upstream"
git fetch upstream --tags --prune

if ! git rev-parse --verify --quiet "refs/tags/$tag^{commit}" >/dev/null; then
  echo "refusing: tag $tag not found after fetch. Known release tags:" >&2
  git tag --list 'v*' | sort -V | tail -10 >&2
  exit 1
fi

echo
echo "upstream changes in the consensus directories since the fork base (01b532e8):"
git log --oneline "01b532e8..$tag" -- consensus crypto/hashes crypto/txscript crypto/addresses protocol/p2p/proto mining || true
echo

git checkout -q -b "$branch" "$base"
echo "on branch $branch (from $base)"

set +e
git merge --no-commit --no-ff "$tag"
status=$?
set -e

echo
conflicts="$(git diff --name-only --diff-filter=U)"
if [[ -n "$conflicts" ]]; then
  echo "merge opened with conflicts in:"
  echo "$conflicts" | sed 's/^/  /'
  echo
  echo "expected conflict files and how to resolve each: tools/upstream/README.md"
elif [[ $status -eq 0 ]]; then
  echo "merge opened cleanly, nothing committed"
else
  echo "git merge exited $status without conflict markers; read the output above" >&2
  exit $status
fi

cat <<EOF

Nothing has been committed. Next:
  1. Resolve the conflicts, keeping every Igneum change (tools/upstream/README.md, "Where conflicts are expected").
  2. Review every upstream change under consensus/, crypto/hashes, crypto/txscript, crypto/addresses,
     protocol/p2p/proto and mining/ against docs/spec. A consensus-rule change needs a spec change first.
  3. Run the tests listed in tools/upstream/README.md.
  4. Commit on $branch with the tag, the conflicted files and the review result in the message.
To abandon: git merge --abort && git checkout $base && git branch -D $branch
EOF