#!/bin/bash
# Automated Database Backup Script
# Runs as a Kubernetes CronJob for daily backups

set -e

# Configuration
BACKUP_DIR="${BACKUP_DIR:-/backups/postgres}"
DB_NAME="${DB_NAME:-sankofa}"
DB_HOST="${DB_HOST:-postgres}"
DB_PORT="${DB_PORT:-5432}"
DB_USER="${DB_USER:-postgres}"
RETENTION_DAYS="${RETENTION_DAYS:-7}"
TIMESTAMP=$(date +%Y%m%d_%H%M%S)
BACKUP_FILE="${BACKUP_DIR}/${DB_NAME}_${TIMESTAMP}.sql"

# Colors
GREEN='\033[0;32m'
RED='\033[0;31m'
YELLOW='\033[1;33m'
NC='\033[0m'

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

log_error() {
    echo -e "${RED}[ERROR]${NC} $1"
}

log_warn() {
    echo -e "${YELLOW}[WARN]${NC} $1"
}

# Create backup directory if it doesn't exist
mkdir -p "$BACKUP_DIR"

# Perform backup
perform_backup() {
    log_info "Starting database backup..."
    log_info "Database: ${DB_NAME}"
    log_info "Backup file: ${BACKUP_FILE}"
    
    # Check if pg_dump is available
    if ! command -v pg_dump &> /dev/null; then
        log_error "pg_dump not found. Install PostgreSQL client tools."
        exit 1
    fi
    
    # Perform backup
    if pg_dump -h "$DB_HOST" -p "$DB_PORT" -U "$DB_USER" -d "$DB_NAME" \
        -F p -f "$BACKUP_FILE" 2>&1; then
        log_info "Backup completed successfully"
        
        # Compress backup
        log_info "Compressing backup..."
        gzip "$BACKUP_FILE"
        BACKUP_FILE="${BACKUP_FILE}.gz"
        
        # Get backup size
        BACKUP_SIZE=$(du -h "$BACKUP_FILE" | cut -f1)
        log_info "Backup size: ${BACKUP_SIZE}"
        
        # Verify backup integrity
        if gzip -t "$BACKUP_FILE" 2>/dev/null; then
            log_info "Backup integrity verified"
        else
            log_error "Backup integrity check failed"
            exit 1
        fi
        
        return 0
    else
        log_error "Backup failed"
        exit 1
    fi
}

# Clean up old backups
cleanup_old_backups() {
    log_info "Cleaning up backups older than ${RETENTION_DAYS} days..."
    
    local deleted_count=0
    while IFS= read -r -d '' backup_file; do
        log_info "Deleting old backup: $(basename "$backup_file")"
        rm -f "$backup_file"
        ((deleted_count++))
    done < <(find "$BACKUP_DIR" -name "${DB_NAME}_*.sql.gz" -type f -mtime +$RETENTION_DAYS -print0)
    
    if [ $deleted_count -gt 0 ]; then
        log_info "Deleted ${deleted_count} old backup(s)"
    else
        log_info "No old backups to delete"
    fi
}

# Upload to S3 (optional)
upload_to_s3() {
    if [ -n "$S3_BUCKET" ] && command -v aws &> /dev/null; then
        log_info "Uploading backup to S3..."
        
        S3_PATH="s3://${S3_BUCKET}/postgres-backups/$(basename "$BACKUP_FILE")"
        
        if aws s3 cp "$BACKUP_FILE" "$S3_PATH"; then
            log_info "Backup uploaded to S3: ${S3_PATH}"
        else
            log_warn "Failed to upload backup to S3"
        fi
    fi
}

# Send notification (optional)
send_notification() {
    if [ -n "$WEBHOOK_URL" ]; then
        local status="$1"
        local message="Database backup ${status}: ${BACKUP_FILE}"
        
        curl -X POST "$WEBHOOK_URL" \
            -H "Content-Type: application/json" \
            -d "{\"text\": \"${message}\"}" \
            > /dev/null 2>&1 || true
    fi
}

# Main execution
main() {
    log_info "=========================================="
    log_info "Database Backup Automation"
    log_info "=========================================="
    log_info ""
    
    # Perform backup
    if perform_backup; then
        # Clean up old backups
        cleanup_old_backups
        
        # Upload to S3 if configured
        upload_to_s3
        
        # Send success notification
        send_notification "succeeded"
        
        log_info "Backup process completed successfully"
        exit 0
    else
        # Send failure notification
        send_notification "failed"
        
        log_error "Backup process failed"
        exit 1
    fi
}

main "$@"