#!/bin/bash
set -euo pipefail

# ==========================================
# LOGGER — source the shared library
# ==========================================
# shellcheck source=lib/logger.sh
source "$(dirname "$0")/lib/logger.sh" "backup"
trap 'log_error "Failure at line $LINENO. See $LOG_FILE"' ERR

# ==========================================
# VARIABLES
# ==========================================
NAMESPACE="vigimeteo"
DB_LABEL="app=vigimeteo-db"
DB_USER_OVERRIDE="${DB_USER:-postgres}"
DB_NAME="postgres"
OUTPUT_DIR="$(dirname "$0")/sql"
TIMESTAMP="$(date +%Y%m%d_%H%M%S)"
OUTPUT_FILE="${OUTPUT_DIR}/backup_${TIMESTAMP}.sql"

# ==========================================
log_info "========================================"
log_info "  Vigimétéo – Database Backup"
log_info "  Full log : $LOG_FILE"
log_info "========================================"

# ==========================================
log_info "STEP 1 — Locate the PostgreSQL pod"
# ==========================================

log_debug "Looking for a running pod with label '$DB_LABEL' in namespace '$NAMESPACE'..."

POD=$(kubectl get pod \
  --namespace "$NAMESPACE" \
  --selector "$DB_LABEL" \
  --field-selector="status.phase=Running" \
  -o jsonpath='{.items[0].metadata.name}' 2>/dev/null || true)

if [ -z "$POD" ]; then
  log_error "No running pod found with label '$DB_LABEL' in namespace '$NAMESPACE'."
  log_error "Is the cluster running?  kubectl get pods -n $NAMESPACE"
  exit 1
fi

log_info "Target pod: $POD"

# ==========================================
log_info "STEP 2 — Verify database readiness"
# ==========================================

log_debug "Checking pg_isready on pod '$POD'..."
if ! kubectl exec --namespace "$NAMESPACE" "$POD" -- \
    pg_isready -U "$DB_USER_OVERRIDE" -d "$DB_NAME" -q; then
  log_error "PostgreSQL is not ready on pod '$POD'. Aborting backup."
  exit 1
fi
log_info "PostgreSQL is ready."

# ==========================================
log_info "STEP 3 — Run pg_dump and save to $OUTPUT_FILE"
# ==========================================

mkdir -p "$OUTPUT_DIR"

log_info "Dumping database '$DB_NAME' (user: $DB_USER_OVERRIDE)..."
kubectl exec --namespace "$NAMESPACE" "$POD" -- \
  pg_dump \
    --username "$DB_USER_OVERRIDE" \
    --dbname "$DB_NAME" \
    --clean \
    --if-exists \
    --no-password \
  > "$OUTPUT_FILE"

# Verify the file was produced and is non-empty
if [ ! -s "$OUTPUT_FILE" ]; then
  log_error "Backup file '$OUTPUT_FILE' is empty or was not created."
  rm -f "$OUTPUT_FILE"
  exit 1
fi

FILESIZE=$(du -sh "$OUTPUT_FILE" | cut -f1)
log_info "Backup written: $OUTPUT_FILE ($FILESIZE)"

# ==========================================
log_info "========================================"
log_info "BACKUP COMPLETE"
log_info "  File : $OUTPUT_FILE"
log_info "  Size : $FILESIZE"
log_info "  Log  : $LOG_FILE"
log_info ""
log_info "To restore:"
log_info "  bash backup.sh                   # create a new backup first"
log_info "  kubectl exec -i -n $NAMESPACE $POD -- \\"
log_info "    psql -U $DB_USER_OVERRIDE -d $DB_NAME < $OUTPUT_FILE"
log_info "========================================"