#!/bin/bash

# Database backup script with S3 upload
# Runs every 12 hours and keeps last 7 local backups

BACKUP_DIR="/backups"
DB_HOST="${DB_HOST:-db}"
DB_USER="${DB_USER:-root}"
DB_PASSWORD="${MYSQL_ROOT_PASSWORD}"
KEEP_BACKUPS="${KEEP_BACKUPS:-7}"
S3_BUCKET="${S3_BUCKET:-selectel:backup_db}"
S3_PATH="${S3_PATH:-dot}"
ENVIRONMENT="${ENVIRONMENT:-prod}"

while true; do
    echo "[$(date)] Starting database backup process..."

    # Get list of databases (exclude system databases)
    DATABASES=$(mysql -h "${DB_HOST}" -u"${DB_USER}" -p"${DB_PASSWORD}" -s -AN -e 'show databases' | grep -vE "information_schema|performance_schema|sys")

    if [ $? -ne 0 ]; then
        echo "[$(date)] ERROR: Failed to get database list!"
        sleep 43200
        continue
    fi

    # Backup each database separately
    for database in ${DATABASES}; do
        TIMESTAMP=$(date +%Y%m%d_%H%M%S)
        DAY_NAME=$(date +%a)
        BACKUP_FILE="${BACKUP_DIR}/${database}.${DAY_NAME}.sql.gz"

        echo "[$(date)] Backing up database: ${database}..."

        # Create backup with compression (MariaDB compatible)
        mysqldump -h "${DB_HOST}" \
                  -u"${DB_USER}" \
                  -p"${DB_PASSWORD}" \
                  --max-allowed-packet=1G \
                  --add-drop-table \
                  --single-transaction \
                  --extended-insert \
                  --quick \
                  --lock-tables=false \
                  --skip-add-locks \
                  --skip-comments \
                  "${database}" | gzip -c > "${BACKUP_FILE}"

        if [ $? -eq 0 ]; then
            # Get file size for logging
            BACKUP_SIZE=$(du -h "${BACKUP_FILE}" | cut -f1)
            echo "[$(date)] Backup completed: ${database} (${BACKUP_SIZE})"

            # Upload to S3 if rclone is configured
            if [ -f /root/.config/rclone/rclone.conf ]; then
                echo "[$(date)] Uploading ${database} to S3..."
                rclone copy "${BACKUP_FILE}" "${S3_BUCKET}/${S3_PATH}/${ENVIRONMENT}/" --progress

                if [ $? -eq 0 ]; then
                    echo "[$(date)] Successfully uploaded ${database} to S3"
                    # Optional: remove local backup after successful upload
                    # rm -f "${BACKUP_FILE}"
                else
                    echo "[$(date)] WARNING: Failed to upload ${database} to S3"
                fi
            else
                echo "[$(date)] Rclone not configured, keeping backup locally only"
            fi
        else
            echo "[$(date)] ERROR: Failed to backup ${database}!"
            [ -f "${BACKUP_FILE}" ] && rm -f "${BACKUP_FILE}"
        fi
    done

    # Clean old local backups (keep last N days for each database)
    echo "[$(date)] Cleaning old local backups..."
    for database in ${DATABASES}; do
        ls -t ${BACKUP_DIR}/${database}.*.sql.gz 2>/dev/null | tail -n +$((KEEP_BACKUPS + 1)) | xargs -r rm -f
    done

    # List current backups
    echo "[$(date)] Current local backups:"
    ls -lah ${BACKUP_DIR}/*.sql.gz 2>/dev/null || echo "No backups found"

    echo "[$(date)] Next backup will run in 12 hours..."
    echo "========================================="

    # Sleep for 12 hours (43200 seconds)
    sleep 43200
done