#!/usr/bin/env bash
# archeflow-rollback.sh — Auto-revert a merge that fails post-merge tests.
#
# Usage: archeflow-rollback.sh <run_id> [--test-cmd <cmd>]
#
# If --test-cmd not provided, reads test_command from .archeflow/config.yaml.
# Returns 0 if tests pass, 1 if tests fail (merge reverted).

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
RUN_ID="${1:?Usage: archeflow-rollback.sh <run_id> [--test-cmd <cmd>]}"
shift

# Parse optional --test-cmd
TEST_CMD=""
while [[ $# -gt 0 ]]; do
  case "$1" in
    --test-cmd) TEST_CMD="$2"; shift 2 ;;
    *) echo "Unknown option: $1" >&2; exit 2 ;;
  esac
done

# Read test_command from config if not provided
if [[ -z "$TEST_CMD" ]]; then
  if [[ -f ".archeflow/config.yaml" ]]; then
    TEST_CMD=$(grep -E "^test_command:" .archeflow/config.yaml | sed 's/^test_command:\s*//' | tr -d '"' || true)
  fi
fi

if [[ -z "$TEST_CMD" ]]; then
  echo "ERROR: No test command specified (use --test-cmd or set test_command in .archeflow/config.yaml)" >&2
  exit 2
fi

# Verify HEAD is an ArcheFlow merge
HEAD_MSG=$(git log -1 --format=%s HEAD)
if [[ "$HEAD_MSG" != *"$RUN_ID"* ]] && [[ "$HEAD_MSG" != *"archeflow"* ]]; then
  echo "WARNING: HEAD commit does not appear to be an ArcheFlow merge: $HEAD_MSG" >&2
  echo "Proceeding anyway..." >&2
fi

echo "Running post-merge tests: $TEST_CMD"

if timeout 300 bash -c "$TEST_CMD"; then
  echo "Tests passed — merge is good."
  exit 0
fi

echo "Tests FAILED — reverting merge..."
git revert --no-edit --mainline 1 HEAD

# Emit event if event script exists
if [[ -x "$SCRIPT_DIR/archeflow-event.sh" ]]; then
  "$SCRIPT_DIR/archeflow-event.sh" "$RUN_ID" decision act "" \
    "{\"what\":\"post_merge_test\",\"chosen\":\"revert\",\"rationale\":\"test suite failed after merge\"}" ""
fi

REVERT_HASH=$(git rev-parse --short HEAD)
echo "Merge reverted (commit: $REVERT_HASH). Tests must pass before re-merging."
exit 1