use std::{
    net::{Ipv4Addr, SocketAddr},
    path::Path,
};

use axum::{
    body::Body,
    http::{Method, Request, StatusCode, header},
};
use http_body_util::BodyExt;
use serde_json::json;
use tempfile::TempDir;
use tower::ServiceExt;
use upl::{
    app::{AppConfig, build_router},
    model::{CHUNK_SIZE, CreateUploadResponse, UploadProgressResponse},
};

#[tokio::test]
async fn stores_chunks_and_reports_progress() -> Result<(), Box<dyn std::error::Error>> {
    let temp_dir = TempDir::new()?;
    let app = test_app(temp_dir.path());
    let upload = create_upload(&app, temp_dir.path(), CHUNK_SIZE + 3).await?;

    let final_chunk = vec![b'z'; 3];
    let response = app
        .clone()
        .oneshot(chunk_request(&upload.upload_id, 1, final_chunk)?)
        .await?;
    assert_eq!(response.status(), StatusCode::NO_CONTENT);

    let progress = get_progress(&app, &upload.upload_id).await?;
    assert_eq!(progress.completed_chunks, vec![1]);

    let first_chunk = vec![b'a'; usize::try_from(CHUNK_SIZE)?];
    let response = app
        .clone()
        .oneshot(chunk_request(&upload.upload_id, 0, first_chunk)?)
        .await?;
    assert_eq!(response.status(), StatusCode::NO_CONTENT);

    let progress = get_progress(&app, &upload.upload_id).await?;
    assert_eq!(progress.completed_chunks, vec![0, 1]);

    let chunk_path = temp_dir
        .path()
        .join("staging")
        .join(&upload.upload_id)
        .join("chunks")
        .join("000000.part");
    assert_eq!(tokio::fs::metadata(chunk_path).await?.len(), CHUNK_SIZE);

    Ok(())
}

#[tokio::test]
async fn rejects_wrong_size_non_final_chunk() -> Result<(), Box<dyn std::error::Error>> {
    let temp_dir = TempDir::new()?;
    let app = test_app(temp_dir.path());
    let upload = create_upload(&app, temp_dir.path(), CHUNK_SIZE + 1).await?;

    let response = app
        .oneshot(chunk_request(&upload.upload_id, 0, b"too short".to_vec())?)
        .await?;

    assert_eq!(response.status(), StatusCode::BAD_REQUEST);

    Ok(())
}

#[tokio::test]
async fn accepts_duplicate_chunk_when_existing_length_matches()
-> Result<(), Box<dyn std::error::Error>> {
    let temp_dir = TempDir::new()?;
    let app = test_app(temp_dir.path());
    let upload = create_upload(&app, temp_dir.path(), 4).await?;

    let first = app
        .clone()
        .oneshot(chunk_request(&upload.upload_id, 0, b"data".to_vec())?)
        .await?;
    let second = app
        .oneshot(chunk_request(&upload.upload_id, 0, b"data".to_vec())?)
        .await?;

    assert_eq!(first.status(), StatusCode::NO_CONTENT);
    assert_eq!(second.status(), StatusCode::NO_CONTENT);

    Ok(())
}

#[tokio::test]
async fn rejects_unknown_upload_id() -> Result<(), Box<dyn std::error::Error>> {
    let temp_dir = TempDir::new()?;
    let app = test_app(temp_dir.path());

    let response = app
        .oneshot(chunk_request("missing", 0, b"data".to_vec())?)
        .await?;

    assert_eq!(response.status(), StatusCode::NOT_FOUND);

    Ok(())
}

async fn create_upload(
    app: &axum::Router,
    data_dir: &Path,
    size: u64,
) -> Result<CreateUploadResponse, Box<dyn std::error::Error>> {
    let response = app
        .clone()
        .oneshot(json_request(
            Method::POST,
            "/api/uploads",
            &json!({
                "name": "chunked.bin",
                "size": size,
                "last_modified": 1_760_000_000_000_i64
            }),
        )?)
        .await?;

    assert_eq!(response.status(), StatusCode::OK);
    assert!(data_dir.join("staging").is_dir());

    decode_body(response).await
}

async fn get_progress(
    app: &axum::Router,
    upload_id: &str,
) -> Result<UploadProgressResponse, Box<dyn std::error::Error>> {
    let response = app
        .clone()
        .oneshot(
            Request::builder()
                .method(Method::GET)
                .uri(format!("/api/uploads/{upload_id}"))
                .body(Body::empty())?,
        )
        .await?;

    assert_eq!(response.status(), StatusCode::OK);

    decode_body(response).await
}

fn test_app(data_dir: &Path) -> axum::Router {
    build_router(&AppConfig::new(
        SocketAddr::from((Ipv4Addr::LOCALHOST, 0)),
        concat!(env!("CARGO_MANIFEST_DIR"), "/static"),
        data_dir,
    ))
}

fn json_request(
    method: Method,
    uri: &str,
    body: &serde_json::Value,
) -> Result<Request<Body>, Box<dyn std::error::Error>> {
    Ok(Request::builder()
        .method(method)
        .uri(uri)
        .header(header::CONTENT_TYPE, "application/json")
        .body(Body::from(serde_json::to_vec(body)?))?)
}

fn chunk_request(
    upload_id: &str,
    index: u64,
    body: Vec<u8>,
) -> Result<Request<Body>, Box<dyn std::error::Error>> {
    Ok(Request::builder()
        .method(Method::PUT)
        .uri(format!("/api/uploads/{upload_id}/chunks/{index}"))
        .header(header::CONTENT_TYPE, "application/octet-stream")
        .body(Body::from(body))?)
}

async fn decode_body<T>(response: axum::response::Response) -> Result<T, Box<dyn std::error::Error>>
where
    T: serde::de::DeserializeOwned,
{
    let body = response.into_body().collect().await?.to_bytes();
    Ok(serde_json::from_slice(&body)?)
}