#!/usr/bin/env bash
set -euo pipefail

ROOT_DIR="$(cd "$(dirname "$0")/.." && pwd)"
cd "$ROOT_DIR"

BASE_REF="${1:-}"
HEAD_REF="${2:-HEAD}"

if [[ -z "$BASE_REF" ]]; then
  BASE_REF="${GITHUB_BASE_REF:-}"
  if [[ -n "$BASE_REF" ]]; then
    BASE_REF="origin/$BASE_REF"
  elif git rev-parse --verify origin/master >/dev/null 2>&1; then
    BASE_REF="origin/master"
  elif git rev-parse --verify origin/main >/dev/null 2>&1; then
    BASE_REF="origin/main"
  else
    BASE_REF="HEAD~1"
  fi
fi

CHANGED="$(git diff --name-only "$BASE_REF"..."$HEAD_REF" || true)"
if [[ -z "$CHANGED" ]]; then
  echo "[contract-check] no changes detected"
  exit 0
fi

API_CHANGED=0
DOC_CHANGED=0
TS_CHANGED=0

if printf '%s\n' "$CHANGED" | grep -E -q '^(backend/app/api/|backend/app/schemas/|backend/app/services/signal_planner_service.py|backend/app/services/model_routing_service.py)'; then
  API_CHANGED=1
fi

if printf '%s\n' "$CHANGED" | grep -E -q '^(frontend/src/api/|frontend/src/types/|frontend/src/pages/ModelRoutingConfigPage.tsx)'; then
  TS_CHANGED=1
fi

if printf '%s\n' "$CHANGED" | grep -E -q '^docs/architecture/(MASTER_CONTRACT.md|API_CONTRACTS.md|DATAFLOW.md)$'; then
  DOC_CHANGED=1
fi

if [[ "$API_CHANGED" -eq 1 && "$TS_CHANGED" -eq 0 ]]; then
  echo "[contract-check] backend contract changed but frontend TS contract not updated"
  exit 1
fi

if [[ "$API_CHANGED" -eq 1 && "$DOC_CHANGED" -eq 0 ]]; then
  echo "[contract-check] backend contract changed but architecture docs not updated"
  exit 1
fi

echo "[contract-check] pass"