#!/usr/bin/env bash
# Git merge driver for .beads/issues.jsonl. Reasoning: context/code/tooling.md.
set -eu

BASE="$1"; OURS="$2"; THEIRS="$3"; PATHNAME="${4:-.beads/issues.jsonl}"

say() { echo "beads-merge: $*" >&2; }

if ! command -v bd >/dev/null 2>&1; then
  say "bd is not on PATH; leaving $PATHNAME conflicted"
  exit 1
fi

# Opt-in, because a merge driver that reaches the network fails in ways a merge
# cannot report. Off by default; the export alone is enough for a git merge.
if [ "${BEADS_MERGE_PULL:-0}" = "1" ]; then
  bd dolt pull "${BEADS_MERGE_REMOTE:-gh}" >&2 || say "dolt pull failed; continuing from local"
fi

# Both sides, not just theirs: `bd import` skips any row whose updated_at is not
# strictly newer than the local one, so neither call can move the database
# backwards, and importing OURS restores a database that has lost rows.
for side in "$OURS" "$THEIRS"; do
  [ -s "$side" ] || continue
  bd import "$side" >&2 || { say "import failed; leaving $PATHNAME conflicted"; exit 1; }
done

bd export -o "$OURS" || { say "export failed; leaving $PATHNAME conflicted"; exit 1; }

if grep -qE '^(<<<<<<<|=======|>>>>>>>)' "$OURS"; then
  say "export produced conflict markers; refusing"
  exit 1
fi

say "resolved $PATHNAME from the database ($(wc -l < "$OURS" | tr -d ' ') rows)"
exit 0