#!/usr/bin/env bash
#
# sync-upstream.sh — look at what upstream Feather has done since our pin, and
# optionally fold it in.
#
# FTStore is a HARD FORK. This script is not part of any routine: it runs when
# someone asks for a sync, not on a schedule and not "because we're behind".
# .upstream-sync.json is a pin recording where we last synced, so this has a
# sensible place to diff from — it is not a promise to stay current.
#
# Workflow:
#   1. Fetch upstream and report what has landed since the pin.
#   2. Optionally merge upstream/main (pass --merge).
#   3. Re-apply the FTStore rebrand (scripts/apply-rebrand.sh).
#   4. Remind you to update .upstream-sync.json once the merge is committed.
#
# Run with no args for a read-only report — that is the normal use. `--merge`
# takes upstream wholesale; because the trees have diverged on purpose,
# cherry-picking the commits you actually want is usually the better move.
#
# Monorepo note: upstream's tree is rooted at the repo root, ours lives in ios/.
# A merge therefore lands Feather's files *next to* ios/, and apply-rebrand.sh
# relocates them in its first step — so always let the script run before judging
# what the merge did. web/ is ours alone and upstream never touches it.
#
set -euo pipefail
cd "$(git rev-parse --show-toplevel)"

SYNC_FILE=".upstream-sync.json"
REMOTE="upstream"
BRANCH="main"
DO_MERGE=0
[ "${1:-}" = "--merge" ] && DO_MERGE=1

bold() { printf '\033[1m%s\033[0m\n' "$*"; }

# Ensure the upstream remote exists.
if ! git remote get-url "$REMOTE" >/dev/null 2>&1; then
  bold "Adding '$REMOTE' remote -> claration/Feather"
  git remote add "$REMOTE" https://github.com/claration/Feather.git
fi

bold "Fetching $REMOTE …"
git fetch "$REMOTE" --tags

LAST="$(jq -r '.lastMerged.commit' "$SYNC_FILE")"
HEAD_UP="$(git rev-parse "$REMOTE/$BRANCH")"
COUNT="$(git rev-list --count "${LAST}..${REMOTE}/${BRANCH}")"

echo
bold "Last merged upstream commit: $LAST  (version $(jq -r '.lastMerged.upstreamVersion' "$SYNC_FILE"), synced $(jq -r '.lastMerged.syncedAt' "$SYNC_FILE"))"
bold "Upstream $REMOTE/$BRANCH HEAD:  $HEAD_UP"
bold "$COUNT upstream commit(s) since the pin. FTStore is a hard fork -- not a defect."
echo

if [ "$COUNT" -eq 0 ]; then
  echo "Nothing new upstream since the pin."
  exit 0
fi

bold "New upstream commits:"
git log --oneline --no-decorate "${LAST}..${REMOTE}/${BRANCH}"
echo

if [ "$DO_MERGE" -eq 0 ]; then
  echo "Read-only report. To fold something in, prefer cherry-picking the commits you"
  echo "actually want. For a wholesale catch-up: scripts/sync-upstream.sh --merge"
  exit 0
fi

bold "Merging $REMOTE/$BRANCH …"
if ! git merge --no-edit "$REMOTE/$BRANCH"; then
  echo
  bold "Merge conflicts detected. Resolve them, then:"
  echo "  - keep FTStore branding in app-repo.json / README.md / project.pbxproj"
  echo "  - keep OURS in .gitmodules (upstream says Zsign, we say ios/Zsign)"
  echo "  - keep OURS in .gitignore and .github/workflows/ (monorepo layout)"
  echo "  - run: bash scripts/apply-rebrand.sh   # relocates root files into ios/"
  echo "  - commit, then update $SYNC_FILE (commit=$HEAD_UP) and re-run validation"
  exit 1
fi

bold "Re-applying FTStore rebrand …"
bash scripts/apply-rebrand.sh

echo
bold "Merge + rebrand complete. Next:"
echo "  1. Review:  git status && git diff"
echo "  2. Update $SYNC_FILE:"
echo "       lastMerged.commit          = $HEAD_UP"
echo "       lastMerged.upstreamVersion = <new upstream version>"
echo "       lastMerged.syncedAt        = $(date +%F)"
echo "  3. Commit the merge + rebrand + sync-file bump."