//! transport 模块（chunked 解码）的集成测试。
//! Integration tests for the transport module (chunked decoding).

use focus_transport::transport::decode_chunked;

#[test]
fn decodes_simple_chunked_body() {
    // 两个分块："Hello" 与 " World"，随后是终止分块。
    // Two chunks: "Hello" and " World", then terminating chunk.
    let body = b"5\r\nHello\r\n6\r\n World\r\n0\r\n\r\n";
    let decoded = decode_chunked(body).unwrap();
    assert_eq!(decoded, b"Hello World");
}

#[test]
fn decodes_chunk_with_extension() {
    let body = b"5;name=value\r\nHello\r\n0\r\n\r\n";
    let decoded = decode_chunked(body).unwrap();
    assert_eq!(decoded, b"Hello");
}

#[test]
fn decodes_single_chunk() {
    let body = b"3\r\nabc\r\n0\r\n\r\n";
    assert_eq!(decode_chunked(body).unwrap(), b"abc");
}

// ---- 增量 chunked 解码器 ----
// ---- incremental chunked decoder ------------------------------------------

use focus_transport::transport::ChunkedDecoder;

/// 把所有解码输出合并为一个字符串（测试辅助）。
/// Concatenate all decoded output into one string (test helper).
fn drain(dec: &mut ChunkedDecoder) -> String {
    let mut out = Vec::new();
    loop {
        match dec.take_decoded() {
            Some(mut chunk) => out.append(&mut chunk),
            None => {
                if dec.is_finished() {
                    break;
                }
                return String::from_utf8_lossy(&out).to_string();
            }
        }
    }
    String::from_utf8_lossy(&out).to_string()
}

#[test]
fn decodes_single_chunk_fed_at_once() {
    let mut dec = ChunkedDecoder::new();
    dec.feed(b"5\r\nhello\r\n0\r\n\r\n");
    assert_eq!(drain(&mut dec), "hello");
}

#[test]
fn decodes_chunk_split_across_feeds() {
    // 网络分块与 HTTP 分块不对齐：一次喂一半。
    // Network chunks misalign with HTTP chunks: feed half at a time.
    let mut dec = ChunkedDecoder::new();
    dec.feed(b"5\r\nhe");
    assert_eq!(drain(&mut dec), "he");
    dec.feed(b"llo\r\n0\r\n\r\n");
    assert_eq!(drain(&mut dec), "llo");
}

#[test]
fn decodes_multiple_chunks_and_extension() {
    let mut dec = ChunkedDecoder::new();
    dec.feed(b"5;name=value\r\nhello\r\n6\r\n world\r\n0\r\n\r\n");
    assert_eq!(drain(&mut dec), "hello world");
}

#[test]
fn yields_partial_data_before_terminator() {
    let mut dec = ChunkedDecoder::new();
    // 第一个分块完整、第二个分块只喂了部分，应先把已解码部分吐出。
    // First chunk complete, second partial: yield decoded bytes so far.
    dec.feed(b"3\r\nabc\r\n5\r\n12");
    assert_eq!(drain(&mut dec), "abc12");
    dec.feed(b"345\r\n0\r\n\r\n");
    assert_eq!(drain(&mut dec), "345");
}

#[test]
fn decodes_an_sse_stream_in_chunked_framing() {
    // 模拟完整 SSE 流（chunked 编码）经解码器逐块吐出。
    // Simulate a full SSE stream (chunked-encoded) drained through the decoder.
    let payload = "event: message_start\r\ndata: {\"type\":\"x\"}\r\n\r\n";
    let mut dec = ChunkedDecoder::new();
    dec.feed(format!("{:x}\r\n{}\r\n", payload.len(), payload).as_bytes());
    dec.feed(b"0\r\n\r\n");
    assert_eq!(drain(&mut dec), payload);
}