#!/bin/bash
set -euo pipefail

# ── PostgreSQL Backup Restore Verification Script ──
# Restores the latest backup to an isolated test database, verifies data
# integrity (table existence, row counts, key checksums), and reports pass/fail.
#
# SAFETY: Never touches the production database. Creates a temporary
# "goodgo_verify_<timestamp>" database and drops it on exit.
#
# Usage:
#   ./pg-verify-backup.sh                    # Verify latest backup
#   ./pg-verify-backup.sh <backup-file>      # Verify specific backup
#   SKIP_CLEANUP=1 ./pg-verify-backup.sh     # Keep test DB for inspection
#
# Environment variables:
#   BACKUP_DIR      — Directory containing backups (default: /backups)
#   PGHOST          — PostgreSQL host (default: postgres)
#   PGPORT          — PostgreSQL port (default: 5432)
#   PGUSER          — PostgreSQL user (default: goodgo)
#   PGPASSWORD      — PostgreSQL password (from environment)
#   PGDATABASE      — Source/production database name (default: goodgo)
#   SKIP_CLEANUP    — Set to 1 to keep test database after verification
#   REPORT_FILE     — Path for JSON report output (optional)
#
# Exit codes:
#   0 — All checks passed
#   1 — One or more checks failed
#   2 — Setup error (no backups found, restore failed, etc.)

# ── Configuration ──
BACKUP_DIR="${BACKUP_DIR:-/backups}"
PGHOST="${PGHOST:-postgres}"
PGPORT="${PGPORT:-5432}"
PGUSER="${PGUSER:-goodgo}"
PGDATABASE="${PGDATABASE:-goodgo}"
SKIP_CLEANUP="${SKIP_CLEANUP:-0}"
REPORT_FILE="${REPORT_FILE:-}"

TIMESTAMP=$(date +%Y%m%d_%H%M%S)
VERIFY_DB="goodgo_verify_${TIMESTAMP}"
PASSED=0
FAILED=0
WARNINGS=0
RESULTS=()

# ── Color output (if terminal) ──
if [ -t 1 ]; then
  GREEN='\033[0;32m'
  RED='\033[0;31m'
  YELLOW='\033[0;33m'
  BLUE='\033[0;34m'
  NC='\033[0m'
else
  GREEN=''
  RED=''
  YELLOW=''
  BLUE=''
  NC=''
fi

log_pass() {
  PASSED=$((PASSED + 1))
  RESULTS+=("{\"check\":\"$1\",\"status\":\"pass\",\"detail\":\"$2\"}")
  echo -e "${GREEN}[PASS]${NC} $1: $2"
}

log_fail() {
  FAILED=$((FAILED + 1))
  RESULTS+=("{\"check\":\"$1\",\"status\":\"fail\",\"detail\":\"$2\"}")
  echo -e "${RED}[FAIL]${NC} $1: $2"
}

log_warn() {
  WARNINGS=$((WARNINGS + 1))
  RESULTS+=("{\"check\":\"$1\",\"status\":\"warn\",\"detail\":\"$2\"}")
  echo -e "${YELLOW}[WARN]${NC} $1: $2"
}

log_info() {
  echo -e "${BLUE}[INFO]${NC} $1"
}

# ── Cleanup function ──
cleanup() {
  local exit_code=$?
  if [ "${SKIP_CLEANUP}" = "1" ]; then
    log_info "SKIP_CLEANUP=1 — keeping test database '${VERIFY_DB}' for inspection"
    log_info "Drop manually: psql -h ${PGHOST} -U ${PGUSER} -d postgres -c 'DROP DATABASE IF EXISTS \"${VERIFY_DB}\";'"
  else
    log_info "Cleaning up test database '${VERIFY_DB}'..."
    psql -h "${PGHOST}" -p "${PGPORT}" -U "${PGUSER}" -d postgres -c \
      "SELECT pg_terminate_backend(pid) FROM pg_stat_activity WHERE datname = '${VERIFY_DB}' AND pid <> pg_backend_pid();" \
      > /dev/null 2>&1 || true
    psql -h "${PGHOST}" -p "${PGPORT}" -U "${PGUSER}" -d postgres -c \
      "DROP DATABASE IF EXISTS \"${VERIFY_DB}\";" \
      > /dev/null 2>&1 || true
    log_info "Test database dropped."
  fi
  return $exit_code
}

trap cleanup EXIT

# ── Determine backup file ──
BACKUP_FILE="${1:-}"

if [ -z "${BACKUP_FILE}" ]; then
  log_info "Finding latest backup in ${BACKUP_DIR}..."
  BACKUP_FILE=$(ls -t "${BACKUP_DIR}"/goodgo_*.sql.gz 2>/dev/null | head -n1 || true)
  if [ -z "${BACKUP_FILE}" ]; then
    echo -e "${RED}[ERROR]${NC} No backup files found in ${BACKUP_DIR}"
    exit 2
  fi
fi

if [ ! -f "${BACKUP_FILE}" ]; then
  echo -e "${RED}[ERROR]${NC} Backup file not found: ${BACKUP_FILE}"
  exit 2
fi

BACKUP_SIZE=$(du -h "${BACKUP_FILE}" | cut -f1)
BACKUP_MTIME=$(stat -c '%Y' "${BACKUP_FILE}" 2>/dev/null || stat -f '%m' "${BACKUP_FILE}" 2>/dev/null || echo "unknown")

echo ""
echo "================================================================"
echo "  GoodGo Backup Restore Verification"
echo "================================================================"
echo "  Backup file : ${BACKUP_FILE}"
echo "  Backup size : ${BACKUP_SIZE}"
echo "  Source DB   : ${PGHOST}:${PGPORT}/${PGDATABASE}"
echo "  Test DB     : ${VERIFY_DB}"
echo "  Started at  : $(date -Iseconds)"
echo "================================================================"
echo ""

# ── Step 1: Create isolated test database ──
log_info "Step 1/5: Creating isolated test database '${VERIFY_DB}'..."
psql -h "${PGHOST}" -p "${PGPORT}" -U "${PGUSER}" -d postgres -c \
  "CREATE DATABASE \"${VERIFY_DB}\";" > /dev/null 2>&1

if ! psql -h "${PGHOST}" -p "${PGPORT}" -U "${PGUSER}" -d postgres -c \
  "SELECT 1 FROM pg_database WHERE datname = '${VERIFY_DB}';" 2>/dev/null | grep -q 1; then
  echo -e "${RED}[ERROR]${NC} Failed to create test database"
  exit 2
fi
log_pass "Database creation" "Test database '${VERIFY_DB}' created"

# ── Step 2: Restore backup into test database ──
log_info "Step 2/5: Restoring backup to test database..."
RESTORE_START=$(date +%s)

# Enable PostGIS extension before restore (required for geometry columns)
psql -h "${PGHOST}" -p "${PGPORT}" -U "${PGUSER}" -d "${VERIFY_DB}" -c \
  "CREATE EXTENSION IF NOT EXISTS postgis;" > /dev/null 2>&1

RESTORE_OUTPUT=$(pg_restore \
  -h "${PGHOST}" \
  -p "${PGPORT}" \
  -U "${PGUSER}" \
  -d "${VERIFY_DB}" \
  --no-owner \
  --no-privileges \
  --clean \
  --if-exists \
  "${BACKUP_FILE}" 2>&1) || true

RESTORE_END=$(date +%s)
RESTORE_DURATION=$((RESTORE_END - RESTORE_START))

# Check if any critical errors occurred (ignore warnings about objects not existing)
RESTORE_ERRORS=$(echo "${RESTORE_OUTPUT}" | grep -ci "ERROR" || true)
if [ "${RESTORE_ERRORS}" -gt 0 ]; then
  # Filter out harmless "does not exist" errors from --clean --if-exists
  CRITICAL_ERRORS=$(echo "${RESTORE_OUTPUT}" | grep -i "ERROR" | grep -cv "does not exist" || true)
  if [ "${CRITICAL_ERRORS}" -gt 0 ]; then
    log_fail "Restore" "pg_restore completed with ${CRITICAL_ERRORS} critical error(s) in ${RESTORE_DURATION}s"
    echo "${RESTORE_OUTPUT}" | grep -i "ERROR" | grep -v "does not exist" | head -5
  else
    log_pass "Restore" "pg_restore completed in ${RESTORE_DURATION}s (non-critical warnings only)"
  fi
else
  log_pass "Restore" "pg_restore completed cleanly in ${RESTORE_DURATION}s"
fi

# ── Step 3: Verify table existence ──
log_info "Step 3/5: Verifying table existence..."

# Expected tables from Prisma schema (22 models + Prisma migration tracking)
EXPECTED_TABLES=(
  "User"
  "RefreshToken"
  "OAuthAccount"
  "Agent"
  "Property"
  "PropertyMedia"
  "Listing"
  "SavedSearch"
  "Transaction"
  "Inquiry"
  "Lead"
  "Payment"
  "Plan"
  "Subscription"
  "UsageRecord"
  "Valuation"
  "MarketIndex"
  "NotificationLog"
  "NotificationPreference"
  "AdminAuditLog"
  "Review"
  "_prisma_migrations"
)

ACTUAL_TABLES=$(psql -h "${PGHOST}" -p "${PGPORT}" -U "${PGUSER}" -d "${VERIFY_DB}" \
  -t -A -c "SELECT tablename FROM pg_tables WHERE schemaname = 'public' ORDER BY tablename;" 2>/dev/null)

MISSING_TABLES=()
for table in "${EXPECTED_TABLES[@]}"; do
  if echo "${ACTUAL_TABLES}" | grep -qx "${table}"; then
    : # Table exists
  else
    MISSING_TABLES+=("${table}")
  fi
done

ACTUAL_COUNT=$(echo "${ACTUAL_TABLES}" | grep -c . || true)
EXPECTED_COUNT=${#EXPECTED_TABLES[@]}

if [ ${#MISSING_TABLES[@]} -eq 0 ]; then
  log_pass "Table existence" "All ${EXPECTED_COUNT} expected tables present (${ACTUAL_COUNT} total)"
else
  log_fail "Table existence" "Missing ${#MISSING_TABLES[@]} table(s): ${MISSING_TABLES[*]}"
fi

# ── Step 4: Row count comparison ──
log_info "Step 4/5: Comparing row counts between source and restored databases..."

ROW_MISMATCHES=0
ROW_REPORT=""

for table in "${EXPECTED_TABLES[@]}"; do
  if [ "${table}" = "_prisma_migrations" ]; then
    continue  # Skip migration tracking table for row comparison
  fi

  # Skip missing tables
  if [[ " ${MISSING_TABLES[*]} " =~ " ${table} " ]]; then
    continue
  fi

  SOURCE_COUNT=$(psql -h "${PGHOST}" -p "${PGPORT}" -U "${PGUSER}" -d "${PGDATABASE}" \
    -t -A -c "SELECT count(*) FROM \"${table}\";" 2>/dev/null || echo "ERROR")
  VERIFY_COUNT=$(psql -h "${PGHOST}" -p "${PGPORT}" -U "${PGUSER}" -d "${VERIFY_DB}" \
    -t -A -c "SELECT count(*) FROM \"${table}\";" 2>/dev/null || echo "ERROR")

  if [ "${SOURCE_COUNT}" = "ERROR" ] || [ "${VERIFY_COUNT}" = "ERROR" ]; then
    log_warn "Row count: ${table}" "Could not query row count"
    continue
  fi

  ROW_REPORT="${ROW_REPORT}\n  ${table}: source=${SOURCE_COUNT} restored=${VERIFY_COUNT}"

  if [ "${SOURCE_COUNT}" != "${VERIFY_COUNT}" ]; then
    ROW_MISMATCHES=$((ROW_MISMATCHES + 1))
    log_fail "Row count: ${table}" "Mismatch — source=${SOURCE_COUNT} restored=${VERIFY_COUNT}"
  fi
done

if [ "${ROW_MISMATCHES}" -eq 0 ]; then
  log_pass "Row counts" "All tables match between source and restored database"
else
  log_fail "Row counts" "${ROW_MISMATCHES} table(s) have row count mismatches"
fi

# ── Step 5: Key data checksums ──
log_info "Step 5/5: Verifying data checksums on critical tables..."

# Checksum key tables by hashing sorted IDs + key fields
verify_checksum() {
  local table="$1"
  local query="$2"
  local label="$3"

  # Skip if table is missing
  if [[ " ${MISSING_TABLES[*]} " =~ " ${table} " ]]; then
    log_warn "Checksum: ${label}" "Table '${table}' missing, skipped"
    return
  fi

  SOURCE_HASH=$(psql -h "${PGHOST}" -p "${PGPORT}" -U "${PGUSER}" -d "${PGDATABASE}" \
    -t -A -c "${query}" 2>/dev/null || echo "ERROR")
  VERIFY_HASH=$(psql -h "${PGHOST}" -p "${PGPORT}" -U "${PGUSER}" -d "${VERIFY_DB}" \
    -t -A -c "${query}" 2>/dev/null || echo "ERROR")

  if [ "${SOURCE_HASH}" = "ERROR" ] || [ "${VERIFY_HASH}" = "ERROR" ]; then
    log_warn "Checksum: ${label}" "Could not compute checksum"
    return
  fi

  if [ "${SOURCE_HASH}" = "${VERIFY_HASH}" ]; then
    log_pass "Checksum: ${label}" "Hashes match (${SOURCE_HASH:0:16}...)"
  else
    log_fail "Checksum: ${label}" "Hash mismatch — source=${SOURCE_HASH:0:16}... restored=${VERIFY_HASH:0:16}..."
  fi
}

# Checksum queries for critical tables
verify_checksum "User" \
  "SELECT md5(string_agg(id || email || phone || \"fullName\" || role::text || \"kycStatus\"::text, '|' ORDER BY id)) FROM \"User\";" \
  "User identities"

verify_checksum "Property" \
  "SELECT md5(string_agg(id || title || district || city || \"propertyType\"::text || \"areaM2\"::text, '|' ORDER BY id)) FROM \"Property\";" \
  "Property records"

verify_checksum "Listing" \
  "SELECT md5(string_agg(id || \"propertyId\" || \"sellerId\" || status::text || \"priceVND\"::text || \"transactionType\"::text, '|' ORDER BY id)) FROM \"Listing\";" \
  "Listing records"

verify_checksum "Payment" \
  "SELECT md5(string_agg(id || \"userId\" || provider::text || type::text || \"amountVND\"::text || status::text, '|' ORDER BY id)) FROM \"Payment\";" \
  "Payment records"

verify_checksum "Subscription" \
  "SELECT md5(string_agg(id || \"userId\" || \"planId\" || status::text, '|' ORDER BY id)) FROM \"Subscription\";" \
  "Subscription records"

verify_checksum "Transaction" \
  "SELECT md5(string_agg(id || \"listingId\" || \"buyerId\" || status::text, '|' ORDER BY id)) FROM \"Transaction\";" \
  "Transaction records"

verify_checksum "Plan" \
  "SELECT md5(string_agg(id || tier::text || name || \"priceMonthlyVND\"::text, '|' ORDER BY id)) FROM \"Plan\";" \
  "Plan records"

verify_checksum "_prisma_migrations" \
  "SELECT md5(string_agg(id || migration_name || checksum, '|' ORDER BY started_at)) FROM \"_prisma_migrations\";" \
  "Migration history"

# ── PostGIS extension check ──
POSTGIS_CHECK=$(psql -h "${PGHOST}" -p "${PGPORT}" -U "${PGUSER}" -d "${VERIFY_DB}" \
  -t -A -c "SELECT extname FROM pg_extension WHERE extname = 'postgis';" 2>/dev/null || echo "")

if [ "${POSTGIS_CHECK}" = "postgis" ]; then
  log_pass "PostGIS extension" "PostGIS is available in restored database"
else
  log_fail "PostGIS extension" "PostGIS extension not found in restored database"
fi

# ── Index verification ──
SOURCE_INDEX_COUNT=$(psql -h "${PGHOST}" -p "${PGPORT}" -U "${PGUSER}" -d "${PGDATABASE}" \
  -t -A -c "SELECT count(*) FROM pg_indexes WHERE schemaname = 'public';" 2>/dev/null || echo "0")
VERIFY_INDEX_COUNT=$(psql -h "${PGHOST}" -p "${PGPORT}" -U "${PGUSER}" -d "${VERIFY_DB}" \
  -t -A -c "SELECT count(*) FROM pg_indexes WHERE schemaname = 'public';" 2>/dev/null || echo "0")

if [ "${SOURCE_INDEX_COUNT}" = "${VERIFY_INDEX_COUNT}" ]; then
  log_pass "Index count" "All ${SOURCE_INDEX_COUNT} indexes restored"
else
  log_warn "Index count" "Source has ${SOURCE_INDEX_COUNT} indexes, restored has ${VERIFY_INDEX_COUNT}"
fi

# ── Enum type verification ──
SOURCE_ENUM_COUNT=$(psql -h "${PGHOST}" -p "${PGPORT}" -U "${PGUSER}" -d "${PGDATABASE}" \
  -t -A -c "SELECT count(*) FROM pg_type WHERE typtype = 'e';" 2>/dev/null || echo "0")
VERIFY_ENUM_COUNT=$(psql -h "${PGHOST}" -p "${PGPORT}" -U "${PGUSER}" -d "${VERIFY_DB}" \
  -t -A -c "SELECT count(*) FROM pg_type WHERE typtype = 'e';" 2>/dev/null || echo "0")

if [ "${SOURCE_ENUM_COUNT}" = "${VERIFY_ENUM_COUNT}" ]; then
  log_pass "Enum types" "All ${SOURCE_ENUM_COUNT} enum types restored"
else
  log_fail "Enum types" "Source has ${SOURCE_ENUM_COUNT} enums, restored has ${VERIFY_ENUM_COUNT}"
fi

# ── Summary ──
echo ""
echo "================================================================"
echo "  Verification Summary"
echo "================================================================"
echo "  Backup file  : ${BACKUP_FILE}"
echo "  Restore time : ${RESTORE_DURATION}s"
TOTAL=$((PASSED + FAILED))
echo "  Checks       : ${TOTAL} total, ${PASSED} passed, ${FAILED} failed, ${WARNINGS} warnings"
echo "  Finished at  : $(date -Iseconds)"

if [ "${FAILED}" -eq 0 ]; then
  echo -e "  Result       : ${GREEN}ALL CHECKS PASSED${NC}"
  echo "================================================================"
else
  echo -e "  Result       : ${RED}${FAILED} CHECK(S) FAILED${NC}"
  echo "================================================================"
fi
echo ""

# ── Write JSON report (if requested) ──
if [ -n "${REPORT_FILE}" ]; then
  RESULTS_JSON=$(printf '%s,' "${RESULTS[@]}")
  RESULTS_JSON="[${RESULTS_JSON%,}]"

  cat > "${REPORT_FILE}" << JSONEOF
{
  "timestamp": "$(date -Iseconds)",
  "backupFile": "${BACKUP_FILE}",
  "backupSize": "${BACKUP_SIZE}",
  "testDatabase": "${VERIFY_DB}",
  "restoreDurationSeconds": ${RESTORE_DURATION},
  "passed": ${PASSED},
  "failed": ${FAILED},
  "warnings": ${WARNINGS},
  "result": "$([ ${FAILED} -eq 0 ] && echo "pass" || echo "fail")",
  "checks": ${RESULTS_JSON}
}
JSONEOF
  log_info "JSON report written to ${REPORT_FILE}"
fi

# Exit with appropriate code
if [ "${FAILED}" -gt 0 ]; then
  exit 1
fi
exit 0