// Package storage provides S3-compatible object storage using RustFS/MinIO
package storage

import (
	"context"
	"errors"
	"io"
	"log"
	"os"
	"sync"
	"time"

	"github.com/minio/minio-go/v7"
	"github.com/minio/minio-go/v7/pkg/credentials"
)

var (
	// Client is the S3 client for storage operations
	Client *minio.Client
	// BucketName is the default bucket for storing objects
	BucketName string
	once       sync.Once
)

// Init initializes the S3 storage client from environment variables
// Required environment variables:
//   - RUSTFS_ENDPOINT: S3 endpoint URL (e.g., "localhost:9000")
//   - RUSTFS_ACCESS_KEY: Access key ID
//   - RUSTFS_SECRET_KEY: Secret access key
//   - RUSTFS_BUCKET: Bucket name (optional, defaults to "rsmon")
//   - RUSTFS_REGION: Region (optional, defaults to "us-east-1")
//   - RUSTFS_USE_SSL: Use SSL (optional, defaults to "false")
func Init() error {
	var initErr error
	once.Do(func() {
		endpoint := os.Getenv("RUSTFS_ENDPOINT")
		if endpoint == "" {
			initErr = errors.New("RUSTFS_ENDPOINT not set")
			return
		}

		accessKey := os.Getenv("RUSTFS_ACCESS_KEY")
		if accessKey == "" {
			initErr = errors.New("RUSTFS_ACCESS_KEY not set")
			return
		}

		secretKey := os.Getenv("RUSTFS_SECRET_KEY")
		if secretKey == "" {
			initErr = errors.New("RUSTFS_SECRET_KEY not set")
			return
		}

		bucket := os.Getenv("RUSTFS_BUCKET")
		if bucket == "" {
			bucket = "rsmon"
		}
		BucketName = bucket

		region := os.Getenv("RUSTFS_REGION")
		if region == "" {
			region = "us-east-1"
		}

		useSSL := os.Getenv("RUSTFS_USE_SSL") == "true"

		// Initialize minio client
		client, err := minio.New(endpoint, &minio.Options{
			Creds:  credentials.NewStaticV4(accessKey, secretKey, ""),
			Secure: useSSL,
			Region: region,
		})
		if err != nil {
			initErr = err
			return
		}

		Client = client
		log.Printf("[storage] Initialized S3 client: endpoint=%s, bucket=%s, ssl=%v", endpoint, bucket, useSSL) //nolint:lll // accepted security trade-off

		// Create bucket if it doesn't exist
		ctx := context.Background()
		exists, err := client.BucketExists(ctx, bucket)
		if err != nil {
			initErr = err
			return
		}

		if !exists {
			err = client.MakeBucket(ctx, bucket, minio.MakeBucketOptions{Region: region})
			if err != nil {
				log.Printf("[storage] Warning: failed to create bucket: %v", err)
			} else {
				log.Printf("[storage] Created bucket: %s", bucket)
			}
		}
	})

	return initErr
}

// IsAvailable returns true if the storage client is initialized
func IsAvailable() bool {
	return Client != nil
}

// PutObject stores an object in S3
func PutObject(ctx context.Context, objectName string, reader io.Reader, size int64, opts minio.PutObjectOptions) (info minio.UploadInfo, err error) { //nolint:lll,gocritic // hugeParam: accepted for interface compatibility
	if Client == nil {
		return minio.UploadInfo{}, errors.New("storage client not initialized")
	}
	return Client.PutObject(ctx, BucketName, objectName, reader, size, opts)
}

// GetObject retrieves an object from S3
func GetObject(ctx context.Context, objectName string, opts minio.GetObjectOptions) (*minio.Object, error) { //nolint:gocritic,lll // hugeParam: accepted for interface compatibility
	if Client == nil {
		return nil, errors.New("storage client not initialized")
	}
	return Client.GetObject(ctx, BucketName, objectName, opts)
}

// RemoveObject removes an object from S3
func RemoveObject(ctx context.Context, objectName string, opts minio.RemoveObjectOptions) error { //nolint:gocritic,lll // hugeParam: accepted for interface compatibility
	if Client == nil {
		return errors.New("storage client not initialized")
	}
	return Client.RemoveObject(ctx, BucketName, objectName, opts)
}

// PresignedGetObject generates a presigned URL for getting an object
func PresignedGetObject(ctx context.Context, objectName string, expires time.Duration) (string, error) {
	if Client == nil {
		return "", errors.New("storage client not initialized")
	}
	presignedURL, err := Client.PresignedGetObject(ctx, BucketName, objectName, expires, nil)
	if err != nil {
		return "", err
	}
	return presignedURL.String(), nil
}