// SPDX-FileCopyrightText: Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
// SPDX-License-Identifier: Apache-2.0
//
// Based on https://github.com/64bit/async-openai/ by Himanshu Neema
// Original Copyright (c) 2022 Himanshu Neema
// Licensed under MIT License (see ATTRIBUTIONS-Rust.md)
//
// Modifications Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES.
// Licensed under Apache 2.0

use std::path::Path;

use reqwest::Body;
use tokio::fs::File;
use tokio_util::codec::{BytesCodec, FramedRead};

use crate::error::OpenAIError;
use crate::types::InputSource;

pub(crate) async fn file_stream_body(source: InputSource) -> Result<Body, OpenAIError> {
    let body = match source {
        InputSource::Path { path } => {
            let file = File::open(path)
                .await
                .map_err(|e| OpenAIError::FileReadError(e.to_string()))?;
            let stream = FramedRead::new(file, BytesCodec::new());
            Body::wrap_stream(stream)
        }
        _ => {
            return Err(OpenAIError::FileReadError(
                "Cannot create stream from non-file source".to_string(),
            ));
        }
    };
    Ok(body)
}

/// Creates the part for the given file for multipart upload.
pub(crate) async fn create_file_part(
    source: InputSource,
) -> Result<reqwest::multipart::Part, OpenAIError> {
    let (stream, file_name) = match source {
        InputSource::Path { path } => {
            let file_name = path
                .file_name()
                .ok_or_else(|| {
                    OpenAIError::FileReadError(format!(
                        "cannot extract file name from {}",
                        path.display()
                    ))
                })?
                .to_str()
                .unwrap()
                .to_string();

            (
                file_stream_body(InputSource::Path { path }).await?,
                file_name,
            )
        }
        InputSource::Bytes { filename, bytes } => (Body::from(bytes), filename),
        InputSource::VecU8 { filename, vec } => (Body::from(vec), filename),
    };

    let file_part = reqwest::multipart::Part::stream(stream).file_name(file_name);

    Ok(file_part)
}

pub(crate) fn create_all_dir<P: AsRef<Path>>(dir: P) -> Result<(), OpenAIError> {
    let exists = match Path::try_exists(dir.as_ref()) {
        Ok(exists) => exists,
        Err(e) => return Err(OpenAIError::FileSaveError(e.to_string())),
    };

    if !exists {
        std::fs::create_dir_all(dir.as_ref())
            .map_err(|e| OpenAIError::FileSaveError(e.to_string()))?;
    }

    Ok(())
}
