#!/bin/sh

set -e

# Backup docker volumes to S3
# This script lists all docker volumes, creates tar.gz backups,
# uploads them to S3, and deletes local archives one at a time
# to minimize disk space usage.

export AWS_PROFILE="volume-backup"

# Configuration
S3_BUCKET="homelab-volume-backups-v2"
HOSTNAME=$(hostname -s)
BACKUP_PREFIX="volumes/$HOSTNAME"
TEMP_DIR=$(mktemp -d)
TIMESTAMP=$(date +%Y_%m_%d)

# Logging functions
log_info() {
    echo "[INFO] $1"
}

log_warn() {
    echo "[WARN] $1"
}

log_error() {
    echo "[ERROR] $1"
}



# Validate configuration
validate_config() {
    # Test AWS credentials
    if ! aws s3 ls "s3://$S3_BUCKET" >/dev/null 2>&1; then
        log_error "Cannot access S3 bucket: $S3_BUCKET"
        log_error "Please check your AWS credentials and bucket permissions"
        exit 1
    fi
}

# Cleanup temporary directory
cleanup() {
    if [ -d "$TEMP_DIR" ]; then
        rm -rf "$TEMP_DIR"
        log_info "Cleaned up temporary directory"
    fi
}

# Backup a single volume
backup_volume() {
    local volume_name="$1"
    local archive_name="${volume_name}_${TIMESTAMP}.tar.gz"
    local archive_path="$TEMP_DIR/$archive_name"
    local s3_path="s3://$S3_BUCKET/$BACKUP_PREFIX/$archive_name"

    log_info "Starting backup of volume: $volume_name"

    # Create tar.gz archive of the volume
    # We use a temporary container to mount and backup the volume
    log_info "Creating archive: $archive_name"

    if docker run --rm \
        -v "$volume_name:/volume:ro" \
        -v "$TEMP_DIR:/backup" \
        alpine \
        tar czf "/backup/$archive_name" -C /volume . 2>/dev/null; then

        log_info "Archive created successfully"
    else
        log_error "Failed to create archive for volume: $volume_name"
        return 1
    fi

    # Get archive size for logging
    if [ -f "$archive_path" ]; then
        archive_size=$(du -h "$archive_path" | cut -f1)
        log_info "Archive size: $archive_size"

        # Upload to S3
        log_info "Uploading to S3: $s3_path"

        if aws s3 cp "$archive_path" "$s3_path"; then
            log_info "Successfully uploaded to S3"

            # Delete local archive
            rm -f "$archive_path"
            log_info "Deleted local archive"

            return 0
        else
            log_error "Failed to upload to S3"
            rm -f "$archive_path"
            return 1
        fi
    else
        log_error "Archive file not found: $archive_path"
        return 1
    fi
}

# Main backup process
main() {
    log_info "Docker Volume Backup Script"
    log_info "==========================="
    validate_config
    log_info "Fetching list of Docker volumes..."
    volumes=$(docker volume ls -q)

    if [ -z "$volumes" ]; then
        log_warn "No Docker volumes found"
        cleanup
        exit 0
    fi

    volume_count=$(echo "$volumes" | wc -l | tr -d ' ')
    log_info "Found $volume_count volume(s) to backup"

    successful=0
    failed=0
    current=0
    for volume in $volumes; do
        current=$((current + 1))
        log_info "Processing volume $current/$volume_count"

        if backup_volume "$volume"; then
            successful=$((successful + 1))
        else
            failed=$((failed + 1))
        fi

        echo ""
    done

    # Cleanup
    cleanup

    # Print summary
    log_info "==========================="
    log_info "Backup Summary"
    log_info "==========================="
    log_info "Total volumes: $volume_count"
    log_info "Successful: $successful"
    log_info "Failed: $failed"

    if [ "$failed" -gt 0 ]; then
        log_warn "Some backups failed. Please check the logs above."
        exit 1
    else
        log_info "All backups completed successfully!"
        exit 0
    fi
}

# Run main function
main