#!/bin/bash
# ============================================================
# PX360 Database Sync Script
# ============================================================
# Copies the local Docker PostgreSQL database + media files
# to a production DB server.
#
# Usage:
#   ./scripts/db_sync.sh                    # Dry-run: dump locally only
#   ./scripts/db_sync.sh --deploy user@host # Full: dump → scp → restore
#
# Prerequisites:
#   - Docker containers running locally (px360_db)
#   - SSH access to the DB server
#   - PostgreSQL client tools on the DB server (pg_restore, createdb)
#   - .env.production file with DB_HOST, DB_USER, DB_NAME
# ============================================================

set -euo pipefail

# Colors
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

# Paths
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PROJECT_DIR="$(dirname "$SCRIPT_DIR")"
BACKUP_DIR="$PROJECT_DIR/backups"

# Default config (overridden by .env.production if available)
LOCAL_DB_CONTAINER="px360_db"
LOCAL_DB_USER="px360"
LOCAL_DB_NAME="px360"

PROD_DB_HOST=""
PROD_DB_USER="px360"
PROD_DB_NAME="px360"
PROD_SSH=""

# Tables to exclude from dump (dev-only data)
EXCLUDE_TABLES=(
  "django_session"
  "simulator_hisrequestlog"
  "simulator_emaillog"
  "simulator_smslog"
)

# Flags
DEPLOY=false

# ============================================================
# Parse arguments
# ============================================================
while [[ $# -gt 0 ]]; do
  case $1 in
    --deploy)
      DEPLOY=true
      PROD_SSH="$2"
      shift 2
      ;;
    --help|-h)
      echo "Usage: ./scripts/db_sync.sh [--deploy user@db-server-ip]"
      echo ""
      echo "  Without --deploy: Creates a local dump only (dry-run)"
      echo "  With --deploy:    Dumps locally, copies to prod DB server, restores"
      echo ""
      echo "Example:"
      echo "  ./scripts/db_sync.sh                                    # local dump"
      echo "  ./scripts/db_sync.sh --deploy root@10.10.1.100           # full deploy"
      exit 0
      ;;
    *)
      echo -e "${RED}Unknown option: $1${NC}"
      exit 1
      ;;
  esac
done

# ============================================================
# Load production config
# ============================================================
if [ "$DEPLOY" = true ]; then
  if [ -z "$PROD_SSH" ]; then
    echo -e "${RED}Error: --deploy requires SSH target (user@host)${NC}"
    exit 1
  fi

  ENV_FILE="$PROJECT_DIR/.env.production"
  if [ -f "$ENV_FILE" ]; then
    PROD_DB_HOST=$(grep -E "^DB_HOST=" "$ENV_FILE" | cut -d= -f2 || echo "")
    PROD_DB_USER=$(grep -E "^DB_USER=" "$ENV_FILE" | cut -d= -f2 || echo "px360")
    PROD_DB_NAME=$(grep -E "^DB_NAME=" "$ENV_FILE" | cut -d= -f2 || echo "px360")
    if [ -z "$PROD_DB_HOST" ]; then
      PROD_DB_HOST=$(grep -E "^DATABASE_URL=" "$ENV_FILE" | sed -E 's/.*@([^:]+):.*/\1/' || echo "")
    fi
  fi

  if [ -z "$PROD_DB_HOST" ]; then
    echo -e "${YELLOW}Warning: DB_HOST not found in .env.production${NC}"
    echo -e "Enter DB server IP/hostname: "
    read -r PROD_DB_HOST
  fi

  echo -e "${BLUE}Production target:${NC}"
  echo -e "  SSH:       $PROD_SSH"
  echo -e "  DB Host:   $PROD_DB_HOST"
  echo -e "  DB User:   $PROD_DB_USER"
  echo -e "  DB Name:   $PROD_DB_NAME"
  echo ""
  echo -e "${YELLOW}This will OVERWRITE production database data. Continue? (y/N)${NC}"
  read -r CONFIRM
  if [[ ! "$CONFIRM" =~ ^[Yy]$ ]]; then
    echo "Aborted."
    exit 0
  fi
fi

# ============================================================
# Setup
# ============================================================
mkdir -p "$BACKUP_DIR"

TIMESTAMP=$(date +%Y%m%d_%H%M%S)
DB_DUMP="$BACKUP_DIR/px360_${TIMESTAMP}.dump"
MEDIA_DUMP="$BACKUP_DIR/media_${TIMESTAMP}.tar.gz"

echo ""
echo -e "${BLUE}========================================${NC}"
echo -e "${BLUE}  PX360 Database Sync${NC}"
echo -e "${BLUE}  $(date '+%Y-%m-%d %H:%M:%S')${NC}"
echo -e "${BLUE}========================================${NC}"
echo ""

# ============================================================
# Step 1: Dump local database
# ============================================================
echo -e "${BLUE}[1/5] Dumping local database...${NC}"

# Build exclude flags
EXCLUDE_FLAGS=""
for table in "${EXCLUDE_TABLES[@]}"; do
  EXCLUDE_FLAGS="$EXCLUDE_FLAGS --exclude-table-data=$table"
done

# Check if Docker DB is running
if ! docker ps --format '{{.Names}}' | grep -q "^${LOCAL_DB_CONTAINER}$"; then
  echo -e "${YELLOW}Docker DB container not found. Trying local PostgreSQL...${NC}"
  # Fall back to local pg_dump (for SQLite → PG migration or local PG)
  if command -v pg_dump &> /dev/null; then
    PGPASSWORD="${LOCAL_DB_USER}" pg_dump -U "$LOCAL_DB_USER" -d "$LOCAL_DB_NAME" \
      --no-owner --no-privileges -Fc $EXCLUDE_FLAGS \
      -f "$DB_DUMP" 2>/dev/null || {
      echo -e "${RED}Failed to dump database. Neither Docker nor local PostgreSQL available.${NC}"
      exit 1
    }
  else
    echo -e "${RED}No Docker DB container and no pg_dump found.${NC}"
    exit 1
  fi
else
  docker exec "$LOCAL_DB_CONTAINER" pg_dump -U "$LOCAL_DB_USER" -d "$LOCAL_DB_NAME" \
    --no-owner --no-privileges -Fc $EXCLUDE_FLAGS > "$DB_DUMP"
fi

DB_SIZE=$(du -h "$DB_DUMP" | cut -f1)
echo -e "${GREEN}  Database dump: $DB_DUMP ($DB_SIZE)${NC}"

# Show table counts
echo -e "${BLUE}  Table counts:${NC}"
if docker ps --format '{{.Names}}' | grep -q "^${LOCAL_DB_CONTAINER}$"; then
  docker exec "$LOCAL_DB_CONTAINER" psql -U "$LOCAL_DB_USER" -d "$LOCAL_DB_NAME" -t -c "
    SELECT '  ' || relname || ': ' || n_live_tup
    FROM pg_stat_user_tables
    WHERE n_live_tup > 0
    ORDER BY n_live_tup DESC
    LIMIT 10;
  " 2>/dev/null || true
fi

# ============================================================
# Step 2: Dump media files
# ============================================================
echo ""
echo -e "${BLUE}[2/5] Dumping media files...${NC}"

if [ -d "$PROJECT_DIR/media" ] && [ "$(ls -A "$PROJECT_DIR/media" 2>/dev/null)" ]; then
  tar -czf "$MEDIA_DUMP" -C "$PROJECT_DIR/media" .
  MEDIA_SIZE=$(du -h "$MEDIA_DUMP" | cut -f1)
  echo -e "${GREEN}  Media dump: $MEDIA_DUMP ($MEDIA_SIZE)${NC}"
else
  echo -e "${YELLOW}  No media files found, skipping.${NC}"
  MEDIA_DUMP=""
fi

# ============================================================
# Step 3: Cleanup old local backups (keep last 3)
# ============================================================
echo ""
echo -e "${BLUE}[3/5] Cleaning old local backups (keeping last 3)...${NC}"

ls -t "$BACKUP_DIR"/px360_*.dump 2>/dev/null | tail -n +4 | while read -r old_file; do
  rm -f "$old_file"
  echo -e "  ${YELLOW}Removed: $(basename "$old_file")${NC}"
done
ls -t "$BACKUP_DIR"/media_*.tar.gz 2>/dev/null | tail -n +4 | while read -r old_file; do
  rm -f "$old_file"
  echo -e "  ${YELLOW}Removed: $(basename "$old_file")${NC}"
done

# ============================================================
# Dry-run check
# ============================================================
if [ "$DEPLOY" = false ]; then
  echo ""
  echo -e "${GREEN}========================================${NC}"
  echo -e "${GREEN}  Dry-run complete!${NC}"
  echo -e "${GREEN}  Dump saved locally.${NC}"
  echo -e "${GREEN}  Run with --deploy user@host to push to prod.${NC}"
  echo -e "${GREEN}========================================${NC}"
  echo ""
  echo -e "Database: ${DB_DUMP} (${DB_SIZE})"
  if [ -n "$MEDIA_DUMP" ]; then
    echo -e "Media:    ${MEDIA_DUMP} (${MEDIA_SIZE})"
  fi
  exit 0
fi

# ============================================================
# Step 4: Copy to production DB server
# ============================================================
echo ""
echo -e "${BLUE}[4/5] Copying to production server ($PROD_SSH)...${NC}"

echo -e "  Copying database dump..."
scp -q "$DB_DUMP" "${PROD_SSH}:/tmp/px360_restore.dump"
echo -e "${GREEN}  Database dump uploaded.${NC}"

if [ -n "$MEDIA_DUMP" ]; then
  echo -e "  Copying media files..."
  scp -q "$MEDIA_DUMP" "${PROD_SSH}:/tmp/px360_media.tar.gz"
  echo -e "${GREEN}  Media files uploaded.${NC}"
fi

# ============================================================
# Step 5: Restore on production DB server
# ============================================================
echo ""
echo -e "${BLUE}[5/5] Restoring on production database...${NC}"

ssh "$PROD_SSH" bash -s << REMOTE_SCRIPT
  set -e
  DB_USER="${PROD_DB_USER}"
  DB_NAME="${PROD_DB_NAME}"
  DB_HOST="${PROD_DB_HOST}"

  echo "  Creating database if not exists..."
  createdb -U "\$DB_USER" "\$DB_NAME" 2>/dev/null || echo "  Database already exists."

  echo "  Restoring database (this may take a minute)..."
  pg_restore -U "\$DB_USER" -d "\$DB_NAME" \
    --no-owner --no-privileges --clean --if-exists \
    --no-tablespaces \
    /tmp/px360_restore.dump 2>&1 | grep -v "does not exist" || true

  echo "  Verifying restore..."
  psql -U "\$DB_USER" -d "\$DB_NAME" -t -c "
    SELECT '  Total tables: ' || count(*) FROM pg_stat_user_tables;
  " 2>/dev/null || true

  psql -U "\$DB_USER" -d "\$DB_NAME" -t -c "
    SELECT '  ' || relname || ': ' || n_live_tup
    FROM pg_stat_user_tables
    WHERE n_live_tup > 0
    ORDER BY n_live_tup DESC
    LIMIT 10;
  " 2>/dev/null || true

  echo "  Cleaning up temp files..."
  rm -f /tmp/px360_restore.dump /tmp/px360_media.tar.gz

  echo "  Restore complete."
REMOTE_SCRIPT

# ============================================================
# Media restore on app server (if separate from DB server)
# ============================================================
if [ -n "$MEDIA_DUMP" ]; then
  echo ""
  echo -e "${YELLOW}Note: Media files were uploaded to the DB server at /tmp/px360_media.tar.gz${NC}"
  echo -e "${YELLOW}If your app server is separate, copy and extract there:${NC}"
  echo -e "  scp ${PROD_SSH}:/tmp/px360_media.tar.gz app-server:/tmp/"
  echo -e "  ssh app-server 'mkdir -p /path/to/media && tar -xzf /tmp/px360_media.tar.gz -C /path/to/media'"
fi

# ============================================================
# Summary
# ============================================================
echo ""
echo -e "${GREEN}========================================${NC}"
echo -e "${GREEN}  Sync complete!${NC}"
echo -e "${GREEN}  $(date '+%Y-%m-%d %H:%M:%S')${NC}"
echo -e "${GREEN}========================================${NC}"
echo ""
echo -e "Local backup: ${DB_DUMP} (${DB_SIZE})"
if [ -n "$MEDIA_DUMP" ]; then
  echo -e "Media backup: ${MEDIA_DUMP} (${MEDIA_SIZE})"
fi
echo ""
echo -e "${YELLOW}Next steps:${NC}"
echo -e "  1. Run migrations on app server: docker compose -f docker-compose.prod.yml exec web python manage.py migrate"
echo -e "  2. Clear sessions: docker compose -f docker-compose.prod.yml exec web python manage.py shell -c \"from django.contrib.sessions.models import Session; Session.objects.all().delete()\""
echo -e "  3. Restart services: docker compose -f docker-compose.prod.yml restart"