use axum::{
    Json,
    body::Body,
    extract::{Extension, Path, Query, State},
    http::{HeaderMap, StatusCode, header},
    response::IntoResponse,
};
use chrono::Utc;
use tokio_util::io::ReaderStream;
use uuid::Uuid;

use crate::auth::resolve_user_id;
use crate::dto::{
    AcknowledgeChangesRequest, ChangesResponse, ChunkUploadedResponse, ConflictResponse,
    CreateUploadSessionRequest, DeviceRegistrationResponse, DeviceResponse, GetChangesParams,
    RegisterDeviceRequest, ReportChangesRequest, ReportChangesResponse, ResolveConflictRequest,
    SyncChangeResponse, UpdateDeviceRequest, UploadSessionResponse,
};
use crate::error::{ApiError, ApiResult};
use crate::state::AppState;
use pinakes_core::config::ConflictResolution;
use pinakes_core::model::ContentHash;
use pinakes_core::sync::{
    DeviceId, DeviceType, SyncChangeType, SyncConflict, SyncDevice, SyncLogEntry, UploadSession,
    UploadStatus, generate_device_token, hash_device_token, update_device_cursor,
};
use std::path::Path as FilePath;

const DEFAULT_CHUNK_SIZE: u64 = 4 * 1024 * 1024; // 4MB
const DEFAULT_CHANGES_LIMIT: u64 = 100;

/// Register a new sync device
/// POST /api/sync/devices
pub async fn register_device(
    State(state): State<AppState>,
    Extension(username): Extension<String>,
    Json(req): Json<RegisterDeviceRequest>,
) -> ApiResult<Json<DeviceRegistrationResponse>> {
    let config = state.config.read().await;
    if !config.sync.enabled {
        return Err(ApiError::bad_request("Sync is not enabled"));
    }
    drop(config);

    let user_id = resolve_user_id(&state.storage, &username).await?;

    let device_type = req
        .device_type
        .parse::<DeviceType>()
        .map_err(|_| ApiError::bad_request("Invalid device type"))?;

    // Generate device token
    let device_token = generate_device_token();
    let token_hash = hash_device_token(&device_token);

    let now = Utc::now();
    let device = SyncDevice {
        id: DeviceId(Uuid::now_v7()),
        user_id,
        name: req.name,
        device_type,
        client_version: req.client_version,
        os_info: req.os_info,
        last_sync_at: None,
        last_seen_at: now,
        sync_cursor: Some(0),
        enabled: true,
        created_at: now,
        updated_at: now,
    };

    let registered = state
        .storage
        .register_device(&device, &token_hash)
        .await
        .map_err(|e| ApiError::internal(format!("Failed to register device: {}", e)))?;

    Ok(Json(DeviceRegistrationResponse {
        device: registered.into(),
        device_token,
    }))
}

/// List user's sync devices
/// GET /api/sync/devices
pub async fn list_devices(
    State(state): State<AppState>,
    Extension(username): Extension<String>,
) -> ApiResult<Json<Vec<DeviceResponse>>> {
    let user_id = resolve_user_id(&state.storage, &username).await?;
    let devices = state
        .storage
        .list_user_devices(user_id)
        .await
        .map_err(|e| ApiError::internal(format!("Failed to list devices: {}", e)))?;

    Ok(Json(devices.into_iter().map(Into::into).collect()))
}

/// Get device details
/// GET /api/sync/devices/{id}
pub async fn get_device(
    State(state): State<AppState>,
    Extension(username): Extension<String>,
    Path(id): Path<Uuid>,
) -> ApiResult<Json<DeviceResponse>> {
    let user_id = resolve_user_id(&state.storage, &username).await?;
    let device = state
        .storage
        .get_device(DeviceId(id))
        .await
        .map_err(|e| ApiError::not_found(format!("Device not found: {}", e)))?;

    // Verify ownership
    if device.user_id != user_id {
        return Err(ApiError::forbidden("Not authorized to access this device"));
    }

    Ok(Json(device.into()))
}

/// Update a device
/// PUT /api/sync/devices/{id}
pub async fn update_device(
    State(state): State<AppState>,
    Extension(username): Extension<String>,
    Path(id): Path<Uuid>,
    Json(req): Json<UpdateDeviceRequest>,
) -> ApiResult<Json<DeviceResponse>> {
    let user_id = resolve_user_id(&state.storage, &username).await?;
    let mut device = state
        .storage
        .get_device(DeviceId(id))
        .await
        .map_err(|e| ApiError::not_found(format!("Device not found: {}", e)))?;

    // Verify ownership
    if device.user_id != user_id {
        return Err(ApiError::forbidden("Not authorized to update this device"));
    }

    if let Some(name) = req.name {
        device.name = name;
    }
    if let Some(enabled) = req.enabled {
        device.enabled = enabled;
    }

    state
        .storage
        .update_device(&device)
        .await
        .map_err(|e| ApiError::internal(format!("Failed to update device: {}", e)))?;

    Ok(Json(device.into()))
}

/// Delete a device
/// DELETE /api/sync/devices/{id}
pub async fn delete_device(
    State(state): State<AppState>,
    Extension(username): Extension<String>,
    Path(id): Path<Uuid>,
) -> ApiResult<StatusCode> {
    let user_id = resolve_user_id(&state.storage, &username).await?;
    let device = state
        .storage
        .get_device(DeviceId(id))
        .await
        .map_err(|e| ApiError::not_found(format!("Device not found: {}", e)))?;

    // Verify ownership
    if device.user_id != user_id {
        return Err(ApiError::forbidden("Not authorized to delete this device"));
    }

    state
        .storage
        .delete_device(DeviceId(id))
        .await
        .map_err(|e| ApiError::internal(format!("Failed to delete device: {}", e)))?;

    Ok(StatusCode::NO_CONTENT)
}

/// Regenerate device token
/// POST /api/sync/devices/{id}/token
pub async fn regenerate_token(
    State(state): State<AppState>,
    Extension(username): Extension<String>,
    Path(id): Path<Uuid>,
) -> ApiResult<Json<DeviceRegistrationResponse>> {
    let user_id = resolve_user_id(&state.storage, &username).await?;
    let device = state
        .storage
        .get_device(DeviceId(id))
        .await
        .map_err(|e| ApiError::not_found(format!("Device not found: {}", e)))?;

    // Verify ownership
    if device.user_id != user_id {
        return Err(ApiError::forbidden(
            "Not authorized to regenerate token for this device",
        ));
    }

    // Generate new token
    let new_token = generate_device_token();
    let token_hash = hash_device_token(&new_token);

    // Re-register with new token (this updates the token hash)
    let updated = state
        .storage
        .register_device(&device, &token_hash)
        .await
        .map_err(|e| ApiError::internal(format!("Failed to regenerate token: {}", e)))?;

    Ok(Json(DeviceRegistrationResponse {
        device: updated.into(),
        device_token: new_token,
    }))
}

/// Get changes since cursor
/// GET /api/sync/changes
pub async fn get_changes(
    State(state): State<AppState>,
    Query(params): Query<GetChangesParams>,
) -> ApiResult<Json<ChangesResponse>> {
    let config = state.config.read().await;
    if !config.sync.enabled {
        return Err(ApiError::bad_request("Sync is not enabled"));
    }
    drop(config);

    let cursor = params.cursor.unwrap_or(0);
    let limit = params.limit.unwrap_or(DEFAULT_CHANGES_LIMIT);

    let changes = state
        .storage
        .get_changes_since(cursor, limit + 1)
        .await
        .map_err(|e| ApiError::internal(format!("Failed to get changes: {}", e)))?;

    let has_more = changes.len() > limit as usize;
    let changes: Vec<SyncChangeResponse> = changes
        .into_iter()
        .take(limit as usize)
        .map(Into::into)
        .collect();

    let new_cursor = changes.last().map(|c| c.sequence).unwrap_or(cursor);

    Ok(Json(ChangesResponse {
        changes,
        cursor: new_cursor,
        has_more,
    }))
}

/// Report local changes from client
/// POST /api/sync/report
pub async fn report_changes(
    State(state): State<AppState>,
    Extension(_username): Extension<String>,
    Json(req): Json<ReportChangesRequest>,
) -> ApiResult<Json<ReportChangesResponse>> {
    let config = state.config.read().await;
    if !config.sync.enabled {
        return Err(ApiError::bad_request("Sync is not enabled"));
    }
    let conflict_resolution = config.sync.default_conflict_resolution.clone();
    drop(config);

    let mut accepted = Vec::new();
    let mut conflicts = Vec::new();
    let mut upload_required = Vec::new();

    for change in req.changes {
        // Check for conflicts
        if let Some(content_hash) = &change.content_hash {
            let server_state = state
                .storage
                .get_media_by_path(FilePath::new(&change.path))
                .await
                .ok()
                .flatten();

            if let Some(server_item) = server_state {
                let client_hash = ContentHash(content_hash.clone());
                if server_item.content_hash != client_hash {
                    // Conflict detected
                    let conflict = SyncConflict {
                        id: Uuid::now_v7(),
                        device_id: DeviceId(Uuid::nil()), // Will be set by device context
                        path: change.path.clone(),
                        local_hash: content_hash.clone(),
                        local_mtime: change.local_mtime.unwrap_or(0),
                        server_hash: server_item.content_hash.to_string(),
                        server_mtime: server_item.updated_at.timestamp(),
                        detected_at: Utc::now(),
                        resolved_at: None,
                        resolution: None,
                    };

                    // Auto-resolve if configured
                    match conflict_resolution {
                        ConflictResolution::ServerWins => {
                            // Client should download server version
                            accepted.push(change.path);
                        }
                        ConflictResolution::ClientWins => {
                            // Client should upload
                            upload_required.push(change.path);
                        }
                        ConflictResolution::KeepBoth | ConflictResolution::Manual => {
                            conflicts.push(conflict.into());
                        }
                    }
                    continue;
                }
            }
        }

        // No conflict, check if upload is needed
        match change.change_type.as_str() {
            "created" | "modified" => {
                if change.content_hash.is_some() {
                    upload_required.push(change.path);
                } else {
                    accepted.push(change.path);
                }
            }
            "deleted" => {
                // Record deletion
                let entry = SyncLogEntry {
                    id: Uuid::now_v7(),
                    sequence: 0, // Will be assigned by storage
                    change_type: SyncChangeType::Deleted,
                    media_id: None,
                    path: change.path.clone(),
                    content_hash: None,
                    file_size: None,
                    metadata_json: None,
                    changed_by_device: None,
                    timestamp: Utc::now(),
                };

                if state.storage.record_sync_change(&entry).await.is_ok() {
                    accepted.push(change.path);
                }
            }
            _ => {
                accepted.push(change.path);
            }
        }
    }

    Ok(Json(ReportChangesResponse {
        accepted,
        conflicts,
        upload_required,
    }))
}

/// Acknowledge processed changes
/// POST /api/sync/ack
pub async fn acknowledge_changes(
    State(state): State<AppState>,
    Extension(_username): Extension<String>,
    headers: HeaderMap,
    Json(req): Json<AcknowledgeChangesRequest>,
) -> ApiResult<StatusCode> {
    // Get device from header or context
    let device_token = headers
        .get("X-Device-Token")
        .and_then(|v| v.to_str().ok())
        .ok_or_else(|| ApiError::bad_request("Missing X-Device-Token header"))?;

    let token_hash = hash_device_token(device_token);
    let device = state
        .storage
        .get_device_by_token(&token_hash)
        .await
        .map_err(|e| ApiError::internal(format!("Failed to get device: {}", e)))?
        .ok_or_else(|| ApiError::unauthorized("Invalid device token"))?;

    // Update device cursor
    update_device_cursor(&state.storage, device.id, req.cursor)
        .await
        .map_err(|e| ApiError::internal(format!("Failed to update cursor: {}", e)))?;

    Ok(StatusCode::OK)
}

/// List unresolved conflicts
/// GET /api/sync/conflicts
pub async fn list_conflicts(
    State(state): State<AppState>,
    Extension(_username): Extension<String>,
    headers: HeaderMap,
) -> ApiResult<Json<Vec<ConflictResponse>>> {
    let device_token = headers
        .get("X-Device-Token")
        .and_then(|v| v.to_str().ok())
        .ok_or_else(|| ApiError::bad_request("Missing X-Device-Token header"))?;

    let token_hash = hash_device_token(device_token);
    let device = state
        .storage
        .get_device_by_token(&token_hash)
        .await
        .map_err(|e| ApiError::internal(format!("Failed to get device: {}", e)))?
        .ok_or_else(|| ApiError::unauthorized("Invalid device token"))?;

    let conflicts = state
        .storage
        .get_unresolved_conflicts(device.id)
        .await
        .map_err(|e| ApiError::internal(format!("Failed to get conflicts: {}", e)))?;

    Ok(Json(conflicts.into_iter().map(Into::into).collect()))
}

/// Resolve a sync conflict
/// POST /api/sync/conflicts/{id}/resolve
pub async fn resolve_conflict(
    State(state): State<AppState>,
    Extension(_username): Extension<String>,
    Path(id): Path<Uuid>,
    Json(req): Json<ResolveConflictRequest>,
) -> ApiResult<StatusCode> {
    let resolution = match req.resolution.as_str() {
        "server_wins" => ConflictResolution::ServerWins,
        "client_wins" => ConflictResolution::ClientWins,
        "keep_both" => ConflictResolution::KeepBoth,
        _ => return Err(ApiError::bad_request("Invalid resolution type")),
    };

    state
        .storage
        .resolve_conflict(id, resolution)
        .await
        .map_err(|e| ApiError::internal(format!("Failed to resolve conflict: {}", e)))?;

    Ok(StatusCode::OK)
}

/// Create an upload session for chunked upload
/// POST /api/sync/upload
pub async fn create_upload(
    State(state): State<AppState>,
    Extension(_username): Extension<String>,
    headers: HeaderMap,
    Json(req): Json<CreateUploadSessionRequest>,
) -> ApiResult<Json<UploadSessionResponse>> {
    let config = state.config.read().await;
    if !config.sync.enabled {
        return Err(ApiError::bad_request("Sync is not enabled"));
    }
    let upload_timeout_hours = config.sync.upload_timeout_hours;
    drop(config);

    let device_token = headers
        .get("X-Device-Token")
        .and_then(|v| v.to_str().ok())
        .ok_or_else(|| ApiError::bad_request("Missing X-Device-Token header"))?;

    let token_hash = hash_device_token(device_token);
    let device = state
        .storage
        .get_device_by_token(&token_hash)
        .await
        .map_err(|e| ApiError::internal(format!("Failed to get device: {}", e)))?
        .ok_or_else(|| ApiError::unauthorized("Invalid device token"))?;

    let chunk_size = req.chunk_size.unwrap_or(DEFAULT_CHUNK_SIZE);
    let chunk_count = (req.expected_size + chunk_size - 1) / chunk_size;
    let now = Utc::now();

    let session = UploadSession {
        id: Uuid::now_v7(),
        device_id: device.id,
        target_path: req.target_path,
        expected_hash: ContentHash(req.expected_hash),
        expected_size: req.expected_size,
        chunk_size,
        chunk_count,
        status: UploadStatus::Pending,
        created_at: now,
        expires_at: now + chrono::Duration::hours(upload_timeout_hours as i64),
        last_activity: now,
    };

    state
        .storage
        .create_upload_session(&session)
        .await
        .map_err(|e| ApiError::internal(format!("Failed to create upload session: {}", e)))?;

    // Create temp file for chunked upload if manager is available
    if let Some(ref manager) = state.chunked_upload_manager {
        manager
            .create_temp_file(&session)
            .await
            .map_err(|e| ApiError::internal(format!("Failed to create temp file: {}", e)))?;
    }

    Ok(Json(session.into()))
}

/// Upload a chunk
/// PUT /api/sync/upload/{id}/chunks/{index}
pub async fn upload_chunk(
    State(state): State<AppState>,
    Path((session_id, chunk_index)): Path<(Uuid, u64)>,
    _headers: HeaderMap,
    body: axum::body::Bytes,
) -> ApiResult<Json<ChunkUploadedResponse>> {
    let session = state
        .storage
        .get_upload_session(session_id)
        .await
        .map_err(|e| ApiError::not_found(format!("Upload session not found: {}", e)))?;

    if session.status == UploadStatus::Expired {
        return Err(ApiError::bad_request("Upload session has expired"));
    }

    if chunk_index >= session.chunk_count {
        return Err(ApiError::bad_request("Invalid chunk index"));
    }

    // Require chunked upload manager to be available
    let manager = state
        .chunked_upload_manager
        .as_ref()
        .ok_or_else(|| ApiError::internal("Chunked upload manager not available"))?;

    // Write chunk data to temp file
    let chunk = manager
        .write_chunk(&session, chunk_index, body.as_ref())
        .await
        .map_err(|e| ApiError::internal(format!("Failed to write chunk: {}", e)))?;

    // Record chunk metadata in database
    state
        .storage
        .record_chunk(session_id, &chunk)
        .await
        .map_err(|e| ApiError::internal(format!("Failed to record chunk: {}", e)))?;

    Ok(Json(ChunkUploadedResponse {
        chunk_index,
        received: true,
    }))
}

/// Get upload session status
/// GET /api/sync/upload/{id}
pub async fn get_upload_status(
    State(state): State<AppState>,
    Path(id): Path<Uuid>,
) -> ApiResult<Json<UploadSessionResponse>> {
    let session = state
        .storage
        .get_upload_session(id)
        .await
        .map_err(|e| ApiError::not_found(format!("Upload session not found: {}", e)))?;

    Ok(Json(session.into()))
}

/// Complete an upload session
/// POST /api/sync/upload/{id}/complete
pub async fn complete_upload(
    State(state): State<AppState>,
    Path(id): Path<Uuid>,
) -> ApiResult<StatusCode> {
    let mut session = state
        .storage
        .get_upload_session(id)
        .await
        .map_err(|e| ApiError::not_found(format!("Upload session not found: {}", e)))?;

    // Verify all chunks received
    let chunks = state
        .storage
        .get_upload_chunks(id)
        .await
        .map_err(|e| ApiError::internal(format!("Failed to get chunks: {}", e)))?;

    if chunks.len() != session.chunk_count as usize {
        return Err(ApiError::bad_request(format!(
            "Missing chunks: expected {}, got {}",
            session.chunk_count,
            chunks.len()
        )));
    }

    // Require chunked upload manager to be available
    let manager = state
        .chunked_upload_manager
        .as_ref()
        .ok_or_else(|| ApiError::internal("Chunked upload manager not available"))?;

    // Verify and finalize the temp file
    let temp_path = manager
        .finalize(&session, &chunks)
        .await
        .map_err(|e| ApiError::internal(format!("Failed to finalize upload: {}", e)))?;

    // Validate and resolve target path securely
    let target_path = std::path::Path::new(&session.target_path);

    // Reject absolute paths from client
    if target_path.is_absolute() {
        return Err(ApiError::bad_request("Absolute paths are not allowed"));
    }

    // Reject empty paths
    if target_path.as_os_str().is_empty() {
        return Err(ApiError::bad_request("Empty target path not allowed"));
    }

    // Get root directory from config
    let config = state.config.read().await;
    let root = config
        .directories
        .roots
        .first()
        .cloned()
        .ok_or_else(|| ApiError::internal("No root directory configured"))?;
    drop(config);

    // Build candidate path
    let candidate = root.join(target_path);

    // Canonicalize root to resolve symlinks and get absolute path
    let root_canon = tokio::fs::canonicalize(&root)
        .await
        .map_err(|e| ApiError::internal(format!("Failed to canonicalize root: {}", e)))?;

    // Ensure parent directory exists before canonicalizing candidate
    if let Some(parent) = candidate.parent() {
        tokio::fs::create_dir_all(parent)
            .await
            .map_err(|e| ApiError::internal(format!("Failed to create directory: {}", e)))?;
    }

    // Try to canonicalize the candidate path (without the final file)
    // If it exists, canonicalize it; otherwise canonicalize parent and append filename
    let final_path = if let Ok(canon) = tokio::fs::canonicalize(&candidate).await {
        canon
    } else if let Some(parent) = candidate.parent() {
        let parent_canon = tokio::fs::canonicalize(parent)
            .await
            .map_err(|e| ApiError::internal(format!("Failed to canonicalize parent: {}", e)))?;

        if let Some(filename) = candidate.file_name() {
            parent_canon.join(filename)
        } else {
            return Err(ApiError::bad_request("Invalid target path"));
        }
    } else {
        return Err(ApiError::bad_request("Invalid target path"));
    };

    // Ensure resolved path is still under root (path traversal check)
    if !final_path.starts_with(&root_canon) {
        return Err(ApiError::bad_request("Path traversal not allowed"));
    }

    // Move temp file to final location (with cross-filesystem fallback)
    if let Err(e) = tokio::fs::rename(&temp_path, &final_path).await {
        // Check for cross-filesystem error
        if e.kind() == std::io::ErrorKind::CrossesDevices || e.raw_os_error() == Some(18)
        // EXDEV on Linux
        {
            // Fallback: copy then remove
            tokio::fs::copy(&temp_path, &final_path)
                .await
                .map_err(|e| ApiError::internal(format!("Failed to copy file: {}", e)))?;

            let _ = tokio::fs::remove_file(&temp_path).await;
        } else {
            return Err(ApiError::internal(format!("Failed to move file: {}", e)));
        }
    }

    tracing::info!(
        session_id = %id,
        target = %final_path.display(),
        "completed chunked upload"
    );

    // Mark session as completed
    session.status = UploadStatus::Completed;
    state
        .storage
        .update_upload_session(&session)
        .await
        .map_err(|e| ApiError::internal(format!("Failed to update session: {}", e)))?;

    // Record the sync change
    let entry = SyncLogEntry {
        id: Uuid::now_v7(),
        sequence: 0,
        change_type: SyncChangeType::Created,
        media_id: None,
        path: session.target_path.clone(),
        content_hash: Some(session.expected_hash.clone()),
        file_size: Some(session.expected_size),
        metadata_json: None,
        changed_by_device: Some(session.device_id),
        timestamp: Utc::now(),
    };

    state
        .storage
        .record_sync_change(&entry)
        .await
        .map_err(|e| ApiError::internal(format!("Failed to record change: {}", e)))?;

    Ok(StatusCode::OK)
}

/// Cancel an upload session
/// DELETE /api/sync/upload/{id}
pub async fn cancel_upload(
    State(state): State<AppState>,
    Path(id): Path<Uuid>,
) -> ApiResult<StatusCode> {
    let mut session = state
        .storage
        .get_upload_session(id)
        .await
        .map_err(|e| ApiError::not_found(format!("Upload session not found: {}", e)))?;

    // Clean up temp file if manager is available
    if let Some(ref manager) = state.chunked_upload_manager {
        if let Err(e) = manager.cancel(id).await {
            tracing::warn!(session_id = %id, error = %e, "failed to clean up temp file");
        }
    }

    session.status = UploadStatus::Cancelled;
    state
        .storage
        .update_upload_session(&session)
        .await
        .map_err(|e| ApiError::internal(format!("Failed to cancel session: {}", e)))?;

    Ok(StatusCode::NO_CONTENT)
}

/// Download a file for sync (supports Range header)
/// GET /api/sync/download/{*path}
pub async fn download_file(
    State(state): State<AppState>,
    Path(path): Path<String>,
    headers: HeaderMap,
) -> ApiResult<impl IntoResponse> {
    let item = state
        .storage
        .get_media_by_path(FilePath::new(&path))
        .await
        .map_err(|e| ApiError::internal(format!("Failed to get media: {}", e)))?
        .ok_or_else(|| ApiError::not_found("File not found"))?;

    let file = tokio::fs::File::open(&item.path)
        .await
        .map_err(|e| ApiError::not_found(format!("File not found: {}", e)))?;

    let metadata = file
        .metadata()
        .await
        .map_err(|e| ApiError::internal(format!("Failed to get metadata: {}", e)))?;

    let file_size = metadata.len();

    // Check for Range header
    if let Some(range_header) = headers.get(header::RANGE) {
        if let Ok(range_str) = range_header.to_str() {
            if let Some(range) = parse_range_header(range_str, file_size) {
                // Partial content response
                let (start, end) = range;
                let length = end - start + 1;

                let file = tokio::fs::File::open(&item.path)
                    .await
                    .map_err(|e| ApiError::internal(format!("Failed to reopen file: {}", e)))?;

                let stream = ReaderStream::new(file);
                let body = Body::from_stream(stream);

                return Ok((
                    StatusCode::PARTIAL_CONTENT,
                    [
                        (header::CONTENT_TYPE, item.media_type.mime_type()),
                        (header::CONTENT_LENGTH, length.to_string()),
                        (
                            header::CONTENT_RANGE,
                            format!("bytes {}-{}/{}", start, end, file_size),
                        ),
                        (header::ACCEPT_RANGES, "bytes".to_string()),
                    ],
                    body,
                )
                    .into_response());
            }
        }
    }

    // Full content response
    let stream = ReaderStream::new(file);
    let body = Body::from_stream(stream);

    Ok((
        StatusCode::OK,
        [
            (header::CONTENT_TYPE, item.media_type.mime_type()),
            (header::CONTENT_LENGTH, file_size.to_string()),
            (header::ACCEPT_RANGES, "bytes".to_string()),
        ],
        body,
    )
        .into_response())
}

/// Parse HTTP Range header
fn parse_range_header(range: &str, file_size: u64) -> Option<(u64, u64)> {
    let range = range.strip_prefix("bytes=")?;
    let parts: Vec<&str> = range.split('-').collect();
    if parts.len() != 2 {
        return None;
    }

    let start: u64 = parts[0].parse().ok()?;
    let end: u64 = if parts[1].is_empty() {
        file_size - 1
    } else {
        parts[1].parse().ok()?
    };

    if start > end || end >= file_size {
        return None;
    }

    Some((start, end))
}