#!/bin/bash
#
# Database Replication Setup for PostgreSQL Streaming Replication
# Run on PRIMARY server first, then on SECONDARY
#

set -eu

MODE="${1:-help}"
PRIMARY_IP="192.168.1.100"  # Update with primary server IP
SECONDARY_IP="72.62.39.24"
POSTGRES_PASSWORD="your_postgres_password"  # Update from .env
REPLICATION_USER="replicator"
REPLICATION_PASSWORD="your_replication_password"  # Generate strong password

log() {
  echo "[$(date +'%Y-%m-%d %H:%M:%S')] $*"
}

setup_primary() {
  log "🔧 Setting up PRIMARY database for replication..."
  
  # Create replication user
  docker exec trading-bot-postgres psql -U postgres -d trading_bot_v4 <<-EOF
    -- Create replication user
    CREATE USER ${REPLICATION_USER} WITH REPLICATION ENCRYPTED PASSWORD '${REPLICATION_PASSWORD}';
    
    -- Grant necessary privileges
    GRANT CONNECT ON DATABASE trading_bot_v4 TO ${REPLICATION_USER};
EOF

  log "✅ Replication user created"
  
  # Configure pg_hba.conf for replication
  docker exec trading-bot-postgres bash -c "cat >> /var/lib/postgresql/data/pg_hba.conf <<EOF
# Replication connection from secondary
host    replication     ${REPLICATION_USER}     ${SECONDARY_IP}/32     md5
EOF"

  # Configure postgresql.conf for replication
  docker exec trading-bot-postgres bash -c "cat >> /var/lib/postgresql/data/postgresql.conf <<EOF
# Replication settings
wal_level = replica
max_wal_senders = 3
wal_keep_size = 64
EOF"

  log "✅ PostgreSQL configured for replication"
  log "⚠️  Restart PostgreSQL container: docker restart trading-bot-postgres"
}

setup_secondary() {
  log "🔧 Setting up SECONDARY database (replica)..."
  
  # Stop secondary postgres if running
  docker compose stop trading-bot-postgres || true
  
  # Remove old data
  log "⚠️  Removing old PostgreSQL data on secondary..."
  docker volume rm traderv4_postgres-data || true
  
  # Create base backup from primary
  log "📦 Creating base backup from primary..."
  docker run --rm \
    -e PGPASSWORD="${REPLICATION_PASSWORD}" \
    postgres:16-alpine \
    pg_basebackup -h ${PRIMARY_IP} -U ${REPLICATION_USER} -D /backup -Fp -Xs -P -R
  
  # Restore to secondary
  # ... (needs volume mounting, complex - see simplified approach below)
  
  log "✅ Secondary database configured as replica"
}

simplified_sync() {
  log "📋 Simplified approach: Database sync via pg_dump/restore"
  log "Run on PRIMARY to create backup:"
  echo "  docker exec trading-bot-postgres pg_dump -U postgres trading_bot_v4 > /tmp/trading_bot_backup.sql"
  echo "  rsync -avz /tmp/trading_bot_backup.sql ${SECONDARY_IP}:/tmp/"
  log "Run on SECONDARY to restore:"
  echo "  docker exec -i trading-bot-postgres psql -U postgres trading_bot_v4 < /tmp/trading_bot_backup.sql"
}

case "$MODE" in
  primary)
    setup_primary
    ;;
  secondary)
    setup_secondary
    ;;
  sync)
    simplified_sync
    ;;
  help|*)
    echo "Usage: $0 {primary|secondary|sync}"
    echo ""
    echo "primary   - Configure primary DB for replication"
    echo "secondary - Configure secondary DB as replica"
    echo "sync      - Show commands for manual DB sync"
    echo ""
    echo "⚠️  IMPORTANT: Update IP addresses and passwords in script first!"
    exit 1
    ;;
esac