package storage

import (
	"context"
	"fmt"
	"io"
	"net/url"
	"path/filepath"
	"strings"
	"time"

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

type MinioConfig struct {
	Endpoint  string
	AccessKey string
	SecretKey string
	Bucket    string
	UseSSL    bool
	PublicURL string
}

type MinioStorage struct {
	client    *minio.Client
	bucket    string
	publicURL string
}

type UploadResult struct {
	Key       string `json:"key"`
	Bucket    string `json:"bucket"`
	Size      int64  `json:"size"`
	ETag      string `json:"etag"`
	PublicURL string `json:"publicUrl,omitempty"`
}

func NewMinioStorage(cfg MinioConfig) (*MinioStorage, error) {
	client, err := minio.New(cfg.Endpoint, &minio.Options{
		Creds:  credentials.NewStaticV4(cfg.AccessKey, cfg.SecretKey, ""),
		Secure: cfg.UseSSL,
	})
	if err != nil {
		return nil, fmt.Errorf("failed to create minio client: %w", err)
	}

	ctx := context.Background()
	exists, err := client.BucketExists(ctx, cfg.Bucket)
	if err != nil {
		return nil, fmt.Errorf("failed to check bucket: %w", err)
	}

	if !exists {
		if err := client.MakeBucket(ctx, cfg.Bucket, minio.MakeBucketOptions{}); err != nil {
			return nil, fmt.Errorf("failed to create bucket: %w", err)
		}
	}

	return &MinioStorage{
		client:    client,
		bucket:    cfg.Bucket,
		publicURL: strings.TrimRight(cfg.PublicURL, "/"),
	}, nil
}

func (s *MinioStorage) GetPublicURL(key string) string {
	if s.publicURL != "" {
		return s.publicURL + "/" + s.bucket + "/" + key
	}
	return ""
}

func (s *MinioStorage) Bucket() string {
	return s.bucket
}

func (s *MinioStorage) Upload(ctx context.Context, reader io.Reader, size int64, filename, contentType string) (*UploadResult, error) {
	ext := filepath.Ext(filename)
	key := generateStorageKey(ext)

	opts := minio.PutObjectOptions{
		ContentType: contentType,
	}

	info, err := s.client.PutObject(ctx, s.bucket, key, reader, size, opts)
	if err != nil {
		return nil, fmt.Errorf("failed to upload file: %w", err)
	}

	return &UploadResult{
		Key:    key,
		Bucket: s.bucket,
		Size:   info.Size,
		ETag:   info.ETag,
	}, nil
}

func (s *MinioStorage) UploadWithKey(ctx context.Context, key string, reader io.Reader, size int64, contentType string) (*UploadResult, error) {
	opts := minio.PutObjectOptions{
		ContentType:  contentType,
		CacheControl: "public, max-age=2592000",
	}

	info, err := s.client.PutObject(ctx, s.bucket, key, reader, size, opts)
	if err != nil {
		return nil, fmt.Errorf("failed to upload file: %w", err)
	}

	return &UploadResult{
		Key:    key,
		Bucket: s.bucket,
		Size:   info.Size,
		ETag:   info.ETag,
	}, nil
}

func (s *MinioStorage) UploadUserFile(ctx context.Context, userID string, reader io.Reader, size int64, filename, contentType string) (*UploadResult, error) {
	ext := filepath.Ext(filename)
	key := fmt.Sprintf("users/%s/%s%s", userID, uuid.New().String(), ext)

	opts := minio.PutObjectOptions{
		ContentType: contentType,
		UserMetadata: map[string]string{
			"original-name": filename,
			"user-id":       userID,
		},
	}

	info, err := s.client.PutObject(ctx, s.bucket, key, reader, size, opts)
	if err != nil {
		return nil, fmt.Errorf("failed to upload file: %w", err)
	}

	return &UploadResult{
		Key:    key,
		Bucket: s.bucket,
		Size:   info.Size,
		ETag:   info.ETag,
	}, nil
}

func (s *MinioStorage) Download(ctx context.Context, key string) (io.ReadCloser, *minio.ObjectInfo, error) {
	obj, err := s.client.GetObject(ctx, s.bucket, key, minio.GetObjectOptions{})
	if err != nil {
		return nil, nil, fmt.Errorf("failed to get object: %w", err)
	}

	info, err := obj.Stat()
	if err != nil {
		obj.Close()
		return nil, nil, fmt.Errorf("failed to stat object: %w", err)
	}

	return obj, &info, nil
}

func (s *MinioStorage) Delete(ctx context.Context, key string) error {
	return s.client.RemoveObject(ctx, s.bucket, key, minio.RemoveObjectOptions{})
}

func (s *MinioStorage) DeleteUserFiles(ctx context.Context, userID string) error {
	prefix := fmt.Sprintf("users/%s/", userID)

	objectsCh := s.client.ListObjects(ctx, s.bucket, minio.ListObjectsOptions{
		Prefix:    prefix,
		Recursive: true,
	})

	for obj := range objectsCh {
		if obj.Err != nil {
			return obj.Err
		}
		if err := s.client.RemoveObject(ctx, s.bucket, obj.Key, minio.RemoveObjectOptions{}); err != nil {
			return err
		}
	}

	return nil
}

func (s *MinioStorage) GetPresignedURL(ctx context.Context, key string, expiry time.Duration) (string, error) {
	presignedURL, err := s.client.PresignedGetObject(ctx, s.bucket, key, expiry, url.Values{})
	if err != nil {
		return "", fmt.Errorf("failed to generate presigned URL: %w", err)
	}
	return presignedURL.String(), nil
}

func (s *MinioStorage) GetPresignedUploadURL(ctx context.Context, key string, expiry time.Duration) (string, error) {
	presignedURL, err := s.client.PresignedPutObject(ctx, s.bucket, key, expiry)
	if err != nil {
		return "", fmt.Errorf("failed to generate presigned upload URL: %w", err)
	}
	return presignedURL.String(), nil
}

func (s *MinioStorage) ListUserFiles(ctx context.Context, userID string) ([]minio.ObjectInfo, error) {
	prefix := fmt.Sprintf("users/%s/", userID)

	var files []minio.ObjectInfo
	objectsCh := s.client.ListObjects(ctx, s.bucket, minio.ListObjectsOptions{
		Prefix:    prefix,
		Recursive: true,
	})

	for obj := range objectsCh {
		if obj.Err != nil {
			return nil, obj.Err
		}
		files = append(files, obj)
	}

	return files, nil
}

func (s *MinioStorage) GetUserStorageUsage(ctx context.Context, userID string) (int64, error) {
	files, err := s.ListUserFiles(ctx, userID)
	if err != nil {
		return 0, err
	}

	var total int64
	for _, f := range files {
		total += f.Size
	}

	return total, nil
}

func (s *MinioStorage) CopyObject(ctx context.Context, srcKey, dstKey string) error {
	_, err := s.client.CopyObject(ctx,
		minio.CopyDestOptions{Bucket: s.bucket, Object: dstKey},
		minio.CopySrcOptions{Bucket: s.bucket, Object: srcKey},
	)
	return err
}

func (s *MinioStorage) ObjectExists(ctx context.Context, key string) (bool, error) {
	_, err := s.client.StatObject(ctx, s.bucket, key, minio.StatObjectOptions{})
	if err != nil {
		errResp := minio.ToErrorResponse(err)
		if errResp.Code == "NoSuchKey" {
			return false, nil
		}
		return false, err
	}
	return true, nil
}

func generateStorageKey(ext string) string {
	now := time.Now()
	return fmt.Sprintf("%d/%02d/%02d/%s%s",
		now.Year(),
		now.Month(),
		now.Day(),
		uuid.New().String(),
		strings.ToLower(ext),
	)
}