rustfs_mcp/

s3_client.rs

// Copyright 2024 RustFS Team
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use anyhow::{Context, Result};
use aws_sdk_s3::config::{Credentials, Region};
use aws_sdk_s3::primitives::ByteStream;
use aws_sdk_s3::{Client, Config as S3Config};
use aws_smithy_http_client::Builder as SmithyHttpClientBuilder;
use serde::{Deserialize, Serialize};
use std::path::Path;
use tokio::io::AsyncWriteExt;
use tracing::{debug, info};

use crate::config::Config;

/// Basic S3 bucket information.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BucketInfo {
    pub name: String,
    pub creation_date: Option<String>,
}

/// Basic S3 object metadata.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ObjectInfo {
    pub key: String,
    pub size: Option<i64>,
    pub last_modified: Option<String>,
    pub etag: Option<String>,
    pub storage_class: Option<String>,
}

/// Options for `list_objects_v2`.
#[derive(Debug, Clone, Default)]
pub struct ListObjectsOptions {
    pub prefix: Option<String>,
    pub delimiter: Option<String>,
    pub max_keys: Option<i32>,
    pub continuation_token: Option<String>,
    pub start_after: Option<String>,
}

/// Result payload for `list_objects_v2`.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ListObjectsResult {
    pub objects: Vec<ObjectInfo>,
    pub common_prefixes: Vec<String>,
    pub is_truncated: bool,
    pub next_continuation_token: Option<String>,
    pub max_keys: Option<i32>,
    pub key_count: i32,
}

/// Options for uploading a local file to S3.
#[derive(Debug, Clone, Default)]
pub struct UploadFileOptions {
    pub content_type: Option<String>,
    pub metadata: Option<std::collections::HashMap<String, String>>,
    pub storage_class: Option<String>,
    pub server_side_encryption: Option<String>,
    pub cache_control: Option<String>,
    pub content_disposition: Option<String>,
    pub content_encoding: Option<String>,
    pub content_language: Option<String>,
}

/// Options for reading/downloading an object from S3.
#[derive(Debug, Clone, Default)]
pub struct GetObjectOptions {
    pub version_id: Option<String>,
    pub range: Option<String>,
    pub if_modified_since: Option<String>,
    pub if_unmodified_since: Option<String>,
    pub max_content_size: Option<usize>,
}

/// File type classification used by get-object operations.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum DetectedFileType {
    Text,
    NonText(String), // mime type for non-text files
}

/// Result payload for object retrieval.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct GetObjectResult {
    pub bucket: String,
    pub key: String,
    pub content_type: String,
    pub content_length: u64,
    pub last_modified: Option<String>,
    pub etag: Option<String>,
    pub version_id: Option<String>,
    pub detected_type: DetectedFileType,
    pub content: Option<Vec<u8>>,     // Raw content bytes
    pub text_content: Option<String>, // UTF-8 decoded content for text files
}

/// Result payload for file upload.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct UploadResult {
    pub bucket: String,
    pub key: String,
    pub etag: String,
    pub location: String,
    pub version_id: Option<String>,
    pub file_size: u64,
    pub content_type: String,
    pub upload_id: Option<String>,
}
#[derive(Debug, Clone)]
pub struct S3Client {
    client: Client,
}

impl S3Client {
    /// Create an S3 client from validated [`Config`].
    pub async fn new(config: &Config) -> Result<Self> {
        info!("Initializing S3 client from configuration");

        let access_key = config.access_key_id();
        let secret_key = config.secret_access_key();

        debug!("Using AWS region: {}", config.region);
        if let Some(ref endpoint) = config.endpoint_url {
            debug!("Using custom endpoint: {}", endpoint);
        }

        let credentials = Credentials::new(access_key, secret_key, None, None, "rustfs-mcp-server");

        let mut config_builder = S3Config::builder()
            .credentials_provider(credentials)
            .region(Region::new(config.region.clone()))
            .behavior_version(aws_sdk_s3::config::BehaviorVersion::latest());

        if config
            .endpoint_url
            .as_deref()
            .is_some_and(|endpoint| endpoint.starts_with("http://"))
        {
            config_builder =
                config_builder.http_client(SmithyHttpClientBuilder::new().build_http());
        }

        // Set force path style if custom endpoint or explicitly requested
        let should_force_path_style = config.endpoint_url.is_some() || config.force_path_style;
        if should_force_path_style {
            config_builder = config_builder.force_path_style(true);
        }

        if let Some(endpoint) = &config.endpoint_url {
            config_builder = config_builder.endpoint_url(endpoint);
        }

        let s3_config = config_builder.build();
        let client = Client::from_conf(s3_config);

        info!("S3 client initialized successfully");

        Ok(Self { client })
    }

    /// Create a bucket.
    pub async fn create_bucket(&self, bucket_name: &str) -> Result<BucketInfo> {
        info!("Creating S3 bucket: {}", bucket_name);

        self.client
            .create_bucket()
            .bucket(bucket_name)
            .send()
            .await
            .context(format!("Failed to create S3 bucket: {bucket_name}"))?;

        info!("Bucket '{}' created successfully", bucket_name);
        Ok(BucketInfo {
            name: bucket_name.to_string(),
            creation_date: None, // Creation date not returned by create_bucket
        })
    }

    /// Delete a bucket.
    pub async fn delete_bucket(&self, bucket_name: &str) -> Result<()> {
        info!("Deleting S3 bucket: {}", bucket_name);
        self.client
            .delete_bucket()
            .bucket(bucket_name)
            .send()
            .await
            .context(format!("Failed to delete S3 bucket: {bucket_name}"))?;

        info!("Bucket '{}' deleted successfully", bucket_name);
        Ok(())
    }

    /// List all accessible buckets.
    pub async fn list_buckets(&self) -> Result<Vec<BucketInfo>> {
        debug!("Listing S3 buckets");

        let response = self
            .client
            .list_buckets()
            .send()
            .await
            .context("Failed to list S3 buckets")?;

        let buckets: Vec<BucketInfo> = response
            .buckets()
            .iter()
            .map(|bucket| {
                let name = bucket.name().unwrap_or("unknown").to_string();
                let creation_date = bucket.creation_date().map(|dt| {
                    dt.fmt(aws_sdk_s3::primitives::DateTimeFormat::DateTime)
                        .unwrap()
                });

                BucketInfo {
                    name,
                    creation_date,
                }
            })
            .collect();

        debug!("Found {} buckets", buckets.len());
        Ok(buckets)
    }

    /// List objects in a bucket with optional pagination/filtering.
    pub async fn list_objects_v2(
        &self,
        bucket_name: &str,
        options: ListObjectsOptions,
    ) -> Result<ListObjectsResult> {
        debug!(
            "Listing objects in bucket '{}' with options: {:?}",
            bucket_name, options
        );

        let mut request = self.client.list_objects_v2().bucket(bucket_name);

        if let Some(prefix) = options.prefix {
            request = request.prefix(prefix);
        }

        if let Some(delimiter) = options.delimiter {
            request = request.delimiter(delimiter);
        }

        if let Some(max_keys) = options.max_keys {
            request = request.max_keys(max_keys);
        }

        if let Some(continuation_token) = options.continuation_token {
            request = request.continuation_token(continuation_token);
        }

        if let Some(start_after) = options.start_after {
            request = request.start_after(start_after);
        }

        let response = request
            .send()
            .await
            .context(format!("Failed to list objects in bucket '{bucket_name}'"))?;

        let objects: Vec<ObjectInfo> = response
            .contents()
            .iter()
            .map(|obj| {
                let key = obj.key().unwrap_or("unknown").to_string();
                let size = obj.size();
                let last_modified = obj.last_modified().map(|dt| {
                    dt.fmt(aws_sdk_s3::primitives::DateTimeFormat::DateTime)
                        .unwrap()
                });
                let etag = obj.e_tag().map(|e| e.to_string());
                let storage_class = obj.storage_class().map(|sc| sc.as_str().to_string());

                ObjectInfo {
                    key,
                    size,
                    last_modified,
                    etag,
                    storage_class,
                }
            })
            .collect();

        let common_prefixes: Vec<String> = response
            .common_prefixes()
            .iter()
            .filter_map(|cp| cp.prefix())
            .map(|p| p.to_string())
            .collect();

        let result = ListObjectsResult {
            objects,
            common_prefixes,
            is_truncated: response.is_truncated().unwrap_or(false),
            next_continuation_token: response.next_continuation_token().map(|t| t.to_string()),
            max_keys: response.max_keys(),
            key_count: response.key_count().unwrap_or(0),
        };

        debug!(
            "Found {} objects and {} common prefixes in bucket '{}'",
            result.objects.len(),
            result.common_prefixes.len(),
            bucket_name
        );

        Ok(result)
    }

    /// Upload a local file to S3.
    pub async fn upload_file(
        &self,
        local_path: &str,
        bucket_name: &str,
        object_key: &str,
        options: UploadFileOptions,
    ) -> Result<UploadResult> {
        info!(
            "Starting file upload: '{}' -> s3://{}/{}",
            local_path, bucket_name, object_key
        );

        let path = Path::new(local_path);
        let canonical_path = path
            .canonicalize()
            .context(format!("Failed to resolve file path: {local_path}"))?;

        if !canonical_path.exists() {
            anyhow::bail!("File does not exist: {local_path}");
        }

        if !canonical_path.is_file() {
            anyhow::bail!("Path is not a file: {local_path}");
        }

        let metadata = tokio::fs::metadata(&canonical_path)
            .await
            .context(format!("Failed to read file metadata: {local_path}"))?;

        let file_size = metadata.len();
        debug!("File size: {file_size} bytes");

        let content_type = options.content_type.unwrap_or_else(|| {
            let detected = mime_guess::from_path(&canonical_path)
                .first_or_octet_stream()
                .to_string();
            debug!("Auto-detected content type: {detected}");
            detected
        });

        let file_content = tokio::fs::read(&canonical_path)
            .await
            .context(format!("Failed to read file content: {local_path}"))?;

        let byte_stream = ByteStream::from(file_content);

        let mut request = self
            .client
            .put_object()
            .bucket(bucket_name)
            .key(object_key)
            .body(byte_stream)
            .content_type(&content_type)
            .content_length(file_size as i64);

        if let Some(storage_class) = &options.storage_class {
            request = request.storage_class(storage_class.as_str().into());
        }

        if let Some(cache_control) = &options.cache_control {
            request = request.cache_control(cache_control);
        }

        if let Some(content_disposition) = &options.content_disposition {
            request = request.content_disposition(content_disposition);
        }

        if let Some(content_encoding) = &options.content_encoding {
            request = request.content_encoding(content_encoding);
        }

        if let Some(content_language) = &options.content_language {
            request = request.content_language(content_language);
        }

        if let Some(sse) = &options.server_side_encryption {
            request = request.server_side_encryption(sse.as_str().into());
        }

        if let Some(metadata_map) = &options.metadata {
            for (key, value) in metadata_map {
                request = request.metadata(key, value);
            }
        }

        debug!("Executing S3 put_object request");
        let response = request.send().await.context(format!(
            "Failed to upload file to s3://{bucket_name}/{object_key}"
        ))?;

        let etag = response.e_tag().unwrap_or("unknown").to_string();
        let version_id = response.version_id().map(|v| v.to_string());

        let location = format!("s3://{bucket_name}/{object_key}");

        let upload_result = UploadResult {
            bucket: bucket_name.to_string(),
            key: object_key.to_string(),
            etag,
            location,
            version_id,
            file_size,
            content_type,
            upload_id: None,
        };

        info!(
            "File upload completed successfully: {} bytes uploaded to s3://{}/{}",
            file_size, bucket_name, object_key
        );

        Ok(upload_result)
    }

    /// Fetch object content and metadata from S3.
    pub async fn get_object(
        &self,
        bucket_name: &str,
        object_key: &str,
        options: GetObjectOptions,
    ) -> Result<GetObjectResult> {
        info!("Getting object: s3://{}/{}", bucket_name, object_key);

        let mut request = self.client.get_object().bucket(bucket_name).key(object_key);

        if let Some(version_id) = &options.version_id {
            request = request.version_id(version_id);
        }

        if let Some(range) = &options.range {
            request = request.range(range);
        }

        if let Some(if_modified_since) = &options.if_modified_since {
            request = request.if_modified_since(
                aws_sdk_s3::primitives::DateTime::from_str(
                    if_modified_since,
                    aws_sdk_s3::primitives::DateTimeFormat::DateTime,
                )
                .context("Failed to parse if_modified_since date")?,
            );
        }

        debug!("Executing S3 get_object request");
        let response = request.send().await.context(format!(
            "Failed to get object from s3://{bucket_name}/{object_key}"
        ))?;

        let content_type = response
            .content_type()
            .unwrap_or("application/octet-stream")
            .to_string();
        let content_length = response.content_length().unwrap_or(0) as u64;
        let last_modified = response.last_modified().map(|dt| {
            dt.fmt(aws_sdk_s3::primitives::DateTimeFormat::DateTime)
                .unwrap()
        });
        let etag = response.e_tag().map(|e| e.to_string());
        let version_id = response.version_id().map(|v| v.to_string());

        let max_size = options.max_content_size.unwrap_or(10 * 1024 * 1024);
        let mut content = Vec::new();
        let mut byte_stream = response.body;
        let mut total_read = 0;

        while let Some(bytes_result) = byte_stream
            .try_next()
            .await
            .context("Failed to read object content")?
        {
            if total_read + bytes_result.len() > max_size {
                anyhow::bail!("Object size exceeds maximum allowed size of {max_size} bytes");
            }
            content.extend_from_slice(&bytes_result);
            total_read += bytes_result.len();
        }

        debug!("Read {} bytes from object", content.len());

        let detected_type = Self::detect_file_type(Some(&content_type), &content);
        debug!("Detected file type: {detected_type:?}");

        let text_content = match &detected_type {
            DetectedFileType::Text => match std::str::from_utf8(&content) {
                Ok(text) => Some(text.to_string()),
                Err(_) => {
                    debug!("Failed to decode content as UTF-8, treating as binary");
                    None
                }
            },
            _ => None,
        };

        let result = GetObjectResult {
            bucket: bucket_name.to_string(),
            key: object_key.to_string(),
            content_type,
            content_length,
            last_modified,
            etag,
            version_id,
            detected_type,
            content: Some(content),
            text_content,
        };

        info!(
            "Object retrieved successfully: {} bytes from s3://{}/{}",
            result.content_length, bucket_name, object_key
        );

        Ok(result)
    }

    fn detect_file_type(content_type: Option<&str>, content_bytes: &[u8]) -> DetectedFileType {
        if let Some(ct) = content_type {
            let ct_lower = ct.to_lowercase();

            if ct_lower.starts_with("text/")
                || ct_lower == "application/json"
                || ct_lower == "application/xml"
                || ct_lower == "application/yaml"
                || ct_lower == "application/javascript"
                || ct_lower == "application/x-yaml"
                || ct_lower == "application/x-sh"
                || ct_lower == "application/x-shellscript"
                || ct_lower.contains("script")
                || ct_lower.contains("xml")
                || ct_lower.contains("json")
            {
                return DetectedFileType::Text;
            }

            return DetectedFileType::NonText(ct.to_string());
        }

        if content_bytes.len() >= 4 {
            match &content_bytes[0..4] {
                // PNG: 89 50 4E 47
                [0x89, 0x50, 0x4E, 0x47] => {
                    return DetectedFileType::NonText("image/png".to_string());
                }
                // JPEG: FF D8 FF
                [0xFF, 0xD8, 0xFF, _] => {
                    return DetectedFileType::NonText("image/jpeg".to_string());
                }
                // GIF: 47 49 46 38
                [0x47, 0x49, 0x46, 0x38] => {
                    return DetectedFileType::NonText("image/gif".to_string());
                }
                // BMP: 42 4D
                [0x42, 0x4D, _, _] => return DetectedFileType::NonText("image/bmp".to_string()),
                // RIFF container (WebP/WAV)
                [0x52, 0x49, 0x46, 0x46] if content_bytes.len() >= 12 => {
                    if &content_bytes[8..12] == b"WEBP" {
                        return DetectedFileType::NonText("image/webp".to_string());
                    } else if &content_bytes[8..12] == b"WAVE" {
                        return DetectedFileType::NonText("audio/wav".to_string());
                    }
                    return DetectedFileType::NonText("application/octet-stream".to_string());
                }
                _ => {}
            }
        }

        // 3. Check if content is valid UTF-8 text as fallback
        if std::str::from_utf8(content_bytes).is_ok() {
            // Additional heuristics for text detection
            let non_printable_count = content_bytes
                .iter()
                .filter(|&&b| b < 0x20 && b != 0x09 && b != 0x0A && b != 0x0D) // Control chars except tab, LF, CR
                .count();
            let total_chars = content_bytes.len();

            // If less than 5% are non-printable control characters, consider it text
            if total_chars > 0 && (non_printable_count as f64 / total_chars as f64) < 0.05 {
                return DetectedFileType::Text;
            }
        }

        // Default to non-text binary
        DetectedFileType::NonText("application/octet-stream".to_string())
    }

    /// Download an S3 object directly to a local file path.
    pub async fn download_object_to_file(
        &self,
        bucket_name: &str,
        object_key: &str,
        local_path: &str,
        options: GetObjectOptions,
    ) -> Result<(u64, String)> {
        info!(
            "Downloading object: s3://{}/{} -> {}",
            bucket_name, object_key, local_path
        );

        let mut request = self.client.get_object().bucket(bucket_name).key(object_key);

        if let Some(version_id) = &options.version_id {
            request = request.version_id(version_id);
        }

        if let Some(range) = &options.range {
            request = request.range(range);
        }

        if let Some(if_modified_since) = &options.if_modified_since {
            request = request.if_modified_since(
                aws_sdk_s3::primitives::DateTime::from_str(
                    if_modified_since,
                    aws_sdk_s3::primitives::DateTimeFormat::DateTime,
                )
                .context("Failed to parse if_modified_since date")?,
            );
        }

        debug!("Executing S3 get_object request for download");
        let response = request.send().await.context(format!(
            "Failed to get object from s3://{bucket_name}/{object_key}"
        ))?;

        let local_file_path = Path::new(local_path);

        if let Some(parent) = local_file_path.parent() {
            tokio::fs::create_dir_all(parent).await.context(format!(
                "Failed to create parent directories for {local_path}"
            ))?;
        }

        let mut file = tokio::fs::File::create(local_file_path)
            .await
            .context(format!("Failed to create local file: {local_path}"))?;

        let mut byte_stream = response.body;
        let mut total_bytes = 0u64;

        while let Some(bytes_result) = byte_stream
            .try_next()
            .await
            .context("Failed to read object content")?
        {
            file.write_all(&bytes_result)
                .await
                .context(format!("Failed to write to local file: {local_path}"))?;
            total_bytes += bytes_result.len() as u64;
        }

        file.flush().await.context("Failed to flush file to disk")?;

        let absolute_path = local_file_path
            .canonicalize()
            .unwrap_or_else(|_| local_file_path.to_path_buf())
            .to_string_lossy()
            .to_string();

        info!(
            "Object downloaded successfully: {} bytes from s3://{}/{} to {}",
            total_bytes, bucket_name, object_key, absolute_path
        );

        Ok((total_bytes, absolute_path))
    }

    /// Verify S3 connectivity by performing a lightweight list-buckets call.
    pub async fn health_check(&self) -> Result<()> {
        debug!("Performing S3 health check");

        self.client
            .list_buckets()
            .send()
            .await
            .context("S3 health check failed")?;

        debug!("S3 health check passed");
        Ok(())
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[tokio::test]
    #[ignore] // Requires AWS credentials
    async fn test_s3_client_creation() {
        let config = Config {
            access_key_id: Some("test_key".to_string()),
            secret_access_key: Some("test_secret".to_string()),
            region: "us-east-1".to_string(),
            ..Config::default()
        };

        let result = S3Client::new(&config).await;
        assert!(result.is_ok());
    }

    #[test]
    fn test_bucket_info_serialization() {
        let bucket = BucketInfo {
            name: "test-bucket".to_string(),
            creation_date: Some("2024-01-01T00:00:00Z".to_string()),
        };

        let json = serde_json::to_string(&bucket).unwrap();
        let deserialized: BucketInfo = serde_json::from_str(&json).unwrap();

        assert_eq!(bucket.name, deserialized.name);
        assert_eq!(bucket.creation_date, deserialized.creation_date);
    }

    #[test]
    fn test_detect_file_type_text_content_type() {
        let test_cases = vec![
            ("text/plain", "Hello world"),
            ("text/html", "<html></html>"),
            ("application/json", r#"{"key": "value"}"#),
            ("application/xml", "<xml></xml>"),
            ("application/yaml", "key: value"),
            ("application/javascript", "console.log('hello');"),
        ];

        for (content_type, content) in test_cases {
            let result = S3Client::detect_file_type(Some(content_type), content.as_bytes());
            match result {
                DetectedFileType::Text => {}
                _ => panic!("Expected Text for content type {content_type}"),
            }
        }
    }

    #[test]
    fn test_detect_file_type_non_text_content_type() {
        // Test various non-text content types
        let test_cases = vec![
            ("image/png", "image/png"),
            ("image/jpeg", "image/jpeg"),
            ("audio/mp3", "audio/mp3"),
            ("video/mp4", "video/mp4"),
            ("application/pdf", "application/pdf"),
        ];

        for (content_type, expected_mime) in test_cases {
            let result = S3Client::detect_file_type(Some(content_type), b"some content");
            match result {
                DetectedFileType::NonText(mime_type) => {
                    assert_eq!(mime_type, expected_mime);
                }
                _ => panic!("Expected NonText for content type {content_type}"),
            }
        }
    }

    #[test]
    fn test_detect_file_type_magic_bytes_simplified() {
        // Test magic bytes detection (now all return NonText)
        let test_cases = vec![
            // PNG magic bytes: 89 50 4E 47
            (
                vec![0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A],
                "image/png",
            ),
            // JPEG magic bytes: FF D8 FF
            (vec![0xFF, 0xD8, 0xFF, 0xE0], "image/jpeg"),
            // GIF magic bytes: 47 49 46 38
            (vec![0x47, 0x49, 0x46, 0x38, 0x37, 0x61], "image/gif"),
        ];

        for (content, expected_mime) in test_cases {
            let result = S3Client::detect_file_type(None, &content);
            match result {
                DetectedFileType::NonText(mime_type) => {
                    assert_eq!(mime_type, expected_mime);
                }
                _ => panic!("Expected NonText for magic bytes: {content:?}"),
            }
        }
    }

    #[test]
    fn test_detect_file_type_webp_magic_bytes() {
        // WebP has more complex magic bytes: RIFF....WEBP
        let mut webp_content = vec![0x52, 0x49, 0x46, 0x46]; // RIFF
        webp_content.extend_from_slice(&[0x00, 0x00, 0x00, 0x00]); // Size (4 bytes)
        webp_content.extend_from_slice(b"WEBP"); // WEBP signature

        let result = S3Client::detect_file_type(None, &webp_content);
        match result {
            DetectedFileType::NonText(mime_type) => {
                assert_eq!(mime_type, "image/webp");
            }
            _ => panic!("Expected WebP NonText detection"),
        }
    }

    #[test]
    fn test_detect_file_type_wav_magic_bytes() {
        // WAV has magic bytes: RIFF....WAVE
        let mut wav_content = vec![0x52, 0x49, 0x46, 0x46]; // RIFF
        wav_content.extend_from_slice(&[0x00, 0x00, 0x00, 0x00]); // Size (4 bytes)
        wav_content.extend_from_slice(b"WAVE"); // WAVE signature

        let result = S3Client::detect_file_type(None, &wav_content);
        match result {
            DetectedFileType::NonText(mime_type) => {
                assert_eq!(mime_type, "audio/wav");
            }
            _ => panic!("Expected WAV NonText detection"),
        }
    }

    #[test]
    fn test_detect_file_type_utf8_text() {
        // Test UTF-8 text detection
        let utf8_content = "Hello, World! 🌍".as_bytes();
        let result = S3Client::detect_file_type(None, utf8_content);
        match result {
            DetectedFileType::Text => {}
            _ => panic!("Expected Text for UTF-8 content"),
        }

        // Test ASCII text
        let ascii_content = b"Hello, world! This is ASCII text.";
        let result = S3Client::detect_file_type(None, ascii_content);
        match result {
            DetectedFileType::Text => {}
            _ => panic!("Expected Text for ASCII content"),
        }
    }

    #[test]
    fn test_detect_file_type_binary() {
        // Test binary content that should not be detected as text
        let binary_content = vec![0x00, 0x01, 0x02, 0x03, 0xFF, 0xFE, 0xFD, 0xFC];
        let result = S3Client::detect_file_type(None, &binary_content);
        match result {
            DetectedFileType::NonText(mime_type) => {
                assert_eq!(mime_type, "application/octet-stream");
            }
            _ => panic!("Expected NonText for binary content"),
        }
    }

    #[test]
    fn test_detect_file_type_priority() {
        // Content-Type should take priority over magic bytes
        let png_magic_bytes = vec![0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A];

        // Even with PNG magic bytes, text content-type should win
        let result = S3Client::detect_file_type(Some("text/plain"), &png_magic_bytes);
        match result {
            DetectedFileType::Text => {}
            _ => panic!("Expected Text due to content-type priority"),
        }
    }

    #[test]
    fn test_get_object_options_default() {
        let options = GetObjectOptions::default();
        assert!(options.version_id.is_none());
        assert!(options.range.is_none());
        assert!(options.if_modified_since.is_none());
        assert!(options.if_unmodified_since.is_none());
        assert!(options.max_content_size.is_none());
    }

    #[test]
    fn test_detected_file_type_serialization() {
        let test_cases = vec![
            DetectedFileType::Text,
            DetectedFileType::NonText("image/png".to_string()),
            DetectedFileType::NonText("audio/mpeg".to_string()),
            DetectedFileType::NonText("application/octet-stream".to_string()),
        ];

        for file_type in test_cases {
            let json = serde_json::to_string(&file_type).unwrap();
            let deserialized: DetectedFileType = serde_json::from_str(&json).unwrap();

            match (&file_type, &deserialized) {
                (DetectedFileType::Text, DetectedFileType::Text) => {}
                (DetectedFileType::NonText(a), DetectedFileType::NonText(b)) => assert_eq!(a, b),
                _ => panic!("Serialization/deserialization mismatch"),
            }
        }
    }
}