#!/bin/bash
set -x

# ==========================================================
# CONFIGURATION
# ==========================================================
CONTAINER_NAME="MongoDB"
MONGO_HOST="localhost"
MONGO_PORT="27017"

UNRAID_NAME="tower"
BASE_PATH="/mnt/user/Backup/Critical/MongoDBBackup"

KEEP_DAYS=3
KEEP_COUNT=3   # počet posledních záloh k udržení (mimo time-based)

# Databases to back up (+ admin DB pro credentials a roles)
WHAT_TO_BACKUP=("admin" "edc")

# ==========================================================
# START
# ==========================================================
echo "Starting scheduled backup for: ${WHAT_TO_BACKUP[*]}"
START_TS=$(date '+%Y-%m-%d %H:%M:%S')

for DB_NAME in "${WHAT_TO_BACKUP[@]}"; do
    echo "------------------------------------------"
    echo "Processing database: $DB_NAME"

    DATE=$(date +%Y-%m-%d_%H%M)
    FINAL_PATH="$BASE_PATH/$UNRAID_NAME/$DB_NAME/$DATE"
    mkdir -p "$FINAL_PATH"

    DUMP_FILE="$FINAL_PATH/$DB_NAME.archive.gz"
    ERR_FILE="$FINAL_PATH/$DB_NAME.err"

    # ======================================================
    # DUMP + GZIP (streamuje přes stdout, nepotřebuje volume mount)
    # Zachovává: indexy, metadata, validators, all collections
    # ======================================================
    docker exec "$CONTAINER_NAME" mongodump \
        --host="$MONGO_HOST" \
        --port="$MONGO_PORT" \
        --db="$DB_NAME" \
        --archive \
        --gzip \
        --numParallelCollections=4 \
        > "$DUMP_FILE" 2> "$ERR_FILE"

    EXIT_CODE=$?

    # ======================================================
    # VALIDATION
    # ======================================================
    if [ $EXIT_CODE -eq 0 ] && [ -s "$DUMP_FILE" ] && [ ! -s "$ERR_FILE" ]; then
        echo "SUCCESS: $DB_NAME backed up successfully"
        echo "Dump size: $(du -h "$DUMP_FILE" | cut -f1)"
        rm -f "$ERR_FILE"
    else
        echo "ERROR: Backup failed for database: $DB_NAME"
        echo "Exit code: $EXIT_CODE"
        echo "Dump file:"
        ls -lh "$DUMP_FILE" 2>/dev/null || echo "  (not created)"
        echo "Error output:"
        [ -s "$ERR_FILE" ] && cat "$ERR_FILE" || echo "  (no stderr output)"
    fi

    # ======================================================
    # CLEANUP OLD BACKUPS
    # 1. Smaž zálohy starší než KEEP_DAYS dnů
    # 2. Z toho co zbyde, ponech jen posledních KEEP_COUNT
    # ======================================================
    echo "Cleaning up old backups for $DB_NAME..."
    find "$BASE_PATH/$UNRAID_NAME/$DB_NAME" \
        -mindepth 1 -maxdepth 1 -type d -mtime +$KEEP_DAYS \
        -exec rm -rf {} \;

    # Nech jen posledních KEEP_COUNT záloh
    ls -td "$BASE_PATH/$UNRAID_NAME/$DB_NAME"/*/ 2>/dev/null \
        | tail -n +$((KEEP_COUNT + 1)) \
        | xargs -r rm -rf

done

echo "------------------------------------------"
echo "All backup tasks completed at $(date)"
echo "Started at: $START_TS"
set +x