//! End-to-end smoke test that actually boots `ccc serve` on the real
//! smarm/urus runtime and drives it over a raw TCP socket. This is the
//! regression test for the segfault-on-startup issue: if the runtime
//! still crashes on boot or on first request, this test hangs/fails
//! instead of the bug only showing up in production.

use std::io::{Read, Write};
use std::net::{TcpListener, TcpStream};
use std::path::PathBuf;
use std::process::{Child, Command, Stdio};
use std::time::{Duration, Instant};

fn bin() -> &'static str {
    env!("CARGO_BIN_EXE_CCC")
}

fn free_port() -> u16 {
    let listener = TcpListener::bind("127.0.0.1:0").expect("failed to bind ephemeral port");
    listener.local_addr().unwrap().port()
}

struct Server {
    child: Child,
    port: u16,
    db_path: PathBuf,
}

impl Server {
    fn start(tag: &str) -> Self {
        let db_path = std::env::temp_dir().join(format!(
            "ccc-server-test-{tag}-{}-{:?}.db",
            std::process::id(),
            std::time::SystemTime::now()
                .duration_since(std::time::UNIX_EPOCH)
                .unwrap()
                .as_nanos()
        ));
        let _ = std::fs::remove_file(&db_path);
        let port = free_port();

        let child = Command::new(bin())
            .args(["serve", "-p", &port.to_string()])
            .env("CCC_DB_PATH", &db_path)
            .stdout(Stdio::piped())
            .stderr(Stdio::piped())
            .spawn()
            .expect("failed to spawn ccc serve");

        let server = Server { child, port, db_path };
        server.wait_for_ready();
        server
    }

    fn wait_for_ready(&self) {
        let deadline = Instant::now() + Duration::from_secs(10);
        loop {
            if Instant::now() > deadline {
                panic!("server on port {} did not become ready in time (possible segfault/hang on boot)", self.port);
            }
            match TcpStream::connect(("127.0.0.1", self.port)) {
                Ok(_) => return,
                Err(_) => std::thread::sleep(Duration::from_millis(50)),
            }
        }
    }

    fn cli(&self, args: &[&str]) -> std::process::Output {
        Command::new(bin())
            .args(args)
            .env("CCC_DB_PATH", &self.db_path)
            .output()
            .expect("failed to run ccc CLI")
    }

    /// Sends a bare-bones HTTP/1.1 GET request and returns (status, headers-lowercased, body).
    fn get(&self, path: &str) -> (u16, Vec<(String, String)>, Vec<u8>) {
        let mut stream = TcpStream::connect(("127.0.0.1", self.port)).expect("connect failed");
        stream.set_read_timeout(Some(Duration::from_secs(5))).unwrap();
        let req = format!(
            "GET {path} HTTP/1.1\r\nHost: 127.0.0.1\r\nAccept-Encoding: identity\r\nConnection: close\r\n\r\n"
        );
        stream.write_all(req.as_bytes()).expect("write failed");

        let mut buf = Vec::new();
        stream.read_to_end(&mut buf).expect("read failed");
        parse_http_response(&buf)
    }

    /// Like `get`, but advertises gzip support so we can check the raw compressed path too.
    fn get_gzip(&self, path: &str) -> (u16, Vec<(String, String)>, Vec<u8>) {
        let mut stream = TcpStream::connect(("127.0.0.1", self.port)).expect("connect failed");
        stream.set_read_timeout(Some(Duration::from_secs(5))).unwrap();
        let req = format!(
            "GET {path} HTTP/1.1\r\nHost: 127.0.0.1\r\nAccept-Encoding: gzip\r\nConnection: close\r\n\r\n"
        );
        stream.write_all(req.as_bytes()).expect("write failed");

        let mut buf = Vec::new();
        stream.read_to_end(&mut buf).expect("read failed");
        parse_http_response(&buf)
    }
}

impl Drop for Server {
    fn drop(&mut self) {
        let _ = self.child.kill();
        let _ = self.child.wait();
        let _ = std::fs::remove_file(&self.db_path);
    }
}

fn parse_http_response(buf: &[u8]) -> (u16, Vec<(String, String)>, Vec<u8>) {
    let sep = b"\r\n\r\n";
    let split_at = buf
        .windows(sep.len())
        .position(|w| w == sep)
        .expect("response missing header/body separator");
    let head = std::str::from_utf8(&buf[..split_at]).expect("head not valid utf8");
    let body = buf[split_at + sep.len()..].to_vec();

    let mut lines = head.split("\r\n");
    let status_line = lines.next().expect("missing status line");
    let status: u16 = status_line
        .split_whitespace()
        .nth(1)
        .expect("malformed status line")
        .parse()
        .expect("status code not numeric");

    let headers = lines
        .filter_map(|l| l.split_once(':'))
        .map(|(k, v)| (k.trim().to_lowercase(), v.trim().to_string()))
        .collect();

    (status, headers, body)
}

fn header<'a>(headers: &'a [(String, String)], name: &str) -> Option<&'a str> {
    headers.iter().find(|(k, _)| k == name).map(|(_, v)| v.as_str())
}

fn write_temp_file(name: &str, contents: &[u8]) -> PathBuf {
    // Keep `name` (with its extension) as the trailing path component so
    // the CLI's mime-guessing logic sees the real file extension.
    let dir = std::env::temp_dir().join(format!(
        "ccc-server-src-{}-{:?}",
        std::process::id(),
        std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .unwrap()
            .as_nanos()
    ));
    std::fs::create_dir_all(&dir).unwrap();
    let path = dir.join(name);
    let mut f = std::fs::File::create(&path).unwrap();
    f.write_all(contents).unwrap();
    path
}

#[test]
fn server_boots_without_segfaulting_and_answers_health_ish_route() {
    let mut server = Server::start("boot");
    // If we got past Server::start() the process accepted a TCP connection,
    // i.e. it did not segfault/panic during startup.
    let (status, _headers, body) = server.get("/packages");
    assert_eq!(status, 200, "body: {}", String::from_utf8_lossy(&body));
    let text = String::from_utf8_lossy(&body);
    assert_eq!(text, "[]", "fresh DB should list no packages, got: {text}");

    // The child must still be alive (no crash-on-request) after serving it.
    match server.child.try_wait() {
        Ok(None) => {}
        Ok(Some(status)) => panic!("server process exited unexpectedly: {status}"),
        Err(e) => panic!("failed to poll child status: {e}"),
    }
}

#[test]
fn server_serves_added_asset_uncompressed_and_gzip() {
    let server = Server::start("asset");
    assert!(server.cli(&["create", "demo"]).status.success());
    let src = write_temp_file("app.js", b"console.log('hello from ccc');");
    let add = server.cli(&["add", "demo", src.to_str().unwrap(), "1.0.0"]);
    assert!(add.status.success(), "stderr: {}", String::from_utf8_lossy(&add.stderr));

    let (status, headers, body) = server.get("/assets/demo/1.0.0/app.js");
    assert_eq!(status, 200, "body: {}", String::from_utf8_lossy(&body));
    assert_eq!(header(&headers, "content-type"), Some("application/javascript"));
    assert_eq!(body, b"console.log('hello from ccc');");

    let (gz_status, gz_headers, gz_body) = server.get_gzip("/assets/demo/1.0.0/app.js");
    assert_eq!(gz_status, 200);
    assert_eq!(header(&gz_headers, "content-encoding"), Some("gzip"));
    // Decompress and confirm round-trip integrity through the actual HTTP path.
    use flate2::read::GzDecoder;
    let mut decoder = GzDecoder::new(&gz_body[..]);
    let mut decompressed = Vec::new();
    decoder.read_to_end(&mut decompressed).unwrap();
    assert_eq!(decompressed, b"console.log('hello from ccc');");

    let _ = std::fs::remove_file(&src);
}

#[test]
fn server_returns_404_for_unknown_asset() {
    let server = Server::start("404");
    let (status, _headers, body) = server.get("/assets/ghost/9.9.9/missing.js");
    assert_eq!(status, 404, "body: {}", String::from_utf8_lossy(&body));
}

#[test]
fn server_lists_packages_created_out_of_band_via_cli() {
    let server = Server::start("listing");
    assert!(server.cli(&["create", "alpha"]).status.success());
    assert!(server.cli(&["create", "beta"]).status.success());
    let src = write_temp_file("a.txt", b"x");
    assert!(server.cli(&["add", "alpha", src.to_str().unwrap(), "1.0.0"]).status.success());

    let (status, _headers, body) = server.get("/packages");
    assert_eq!(status, 200);
    let text = String::from_utf8_lossy(&body);
    assert!(text.contains("alpha"), "body: {text}");
    assert!(text.contains("beta"), "body: {text}");
    assert!(text.contains("1.0.0"), "body: {text}");

    let _ = std::fs::remove_file(&src);
}

#[test]
fn archived_package_is_hidden_from_listing() {
    let server = Server::start("archived-listing");
    assert!(server.cli(&["create", "demo"]).status.success());
    assert!(server.cli(&["archive", "demo"]).status.success());

    let (status, _headers, body) = server.get("/packages");
    assert_eq!(status, 200);
    let text = String::from_utf8_lossy(&body);
    assert!(!text.contains("demo"), "archived package leaked into listing: {text}");
}

#[test]
fn server_survives_multiple_sequential_requests() {
    // Repeated request/response cycles against the same long-lived process
    // are exactly the pattern that would surface a use-after-free / double
    // free in a bespoke runtime, hence several round trips here rather than
    // just one.
    let server = Server::start("multi");
    for _ in 0..10 {
        let (status, _headers, _body) = server.get("/packages");
        assert_eq!(status, 200);
    }
}