use super::*;
use std::fs;
use std::os::unix::fs::PermissionsExt;
use std::sync::atomic::{AtomicU64, Ordering};

static FIXTURE_ID: AtomicU64 = AtomicU64::new(0);

struct Fixture(PathBuf);

impl Fixture {
    fn new() -> Self {
        let path = std::env::temp_dir().join(format!(
            "vamp-clipboard-{}-{}",
            std::process::id(),
            FIXTURE_ID.fetch_add(1, Ordering::Relaxed)
        ));
        fs::create_dir(&path).unwrap();
        Self(path)
    }

    fn command(&self, name: &str, body: &str) -> PathBuf {
        let path = self.0.join(name);
        fs::write(&path, format!("#!/bin/sh\n{body}\n")).unwrap();
        fs::set_permissions(&path, fs::Permissions::from_mode(0o700)).unwrap();
        path
    }

    fn clipboard(&self, text: &[u8]) -> SystemClipboard {
        let state = self.0.join("state");
        fs::write(&state, text).unwrap();
        let state = format!("'{}'", state.to_str().unwrap().replace('\'', "'\\''"));
        SystemClipboard::with_commands(
            self.command("read", &format!("exec /bin/cat {state}")),
            self.command("write", &format!("exec /bin/cat > {state}")),
        )
    }
}

impl Drop for Fixture {
    fn drop(&mut self) {
        fs::remove_dir_all(&self.0).unwrap();
    }
}

#[test]
fn construction_does_not_probe_or_spawn() {
    assert!(SystemClipboard::new().commands.is_none());
}

#[test]
fn round_trips_unicode_whitespace_and_large_pipes_exactly() {
    let fixture = Fixture::new();
    let mut clipboard = fixture.clipboard(b"");
    for text in ["", "  héllo\t世界🙂\r\n\n", &"é\n".repeat(300_000)] {
        clipboard.write(text).unwrap();
        assert_eq!(fs::read(fixture.0.join("state")).unwrap(), text.as_bytes());
        assert_eq!(clipboard.read().unwrap(), text);
    }
}

#[test]
fn rejects_oversize_and_invalid_utf8_without_leaking_contents() {
    let fixture = Fixture::new();
    let mut clipboard = fixture.clipboard(&[0xff, b'\n']);
    assert_eq!(
        clipboard.read().unwrap_err(),
        "System clipboard is not valid UTF-8"
    );
    let maximum = "é".repeat(MAX_CLIPBOARD_BYTES / 2);
    clipboard.write(&maximum).unwrap();
    assert_eq!(clipboard.read().unwrap(), maximum);
    let too_large = format!("{maximum}x");
    assert_eq!(
        clipboard.write(&too_large).unwrap_err(),
        "System clipboard text exceeds 4 MiB"
    );
    assert_eq!(
        fs::read(fixture.0.join("state")).unwrap(),
        maximum.as_bytes()
    );
    fs::write(fixture.0.join("state"), &too_large).unwrap();
    assert_eq!(
        clipboard.read().unwrap_err(),
        "System clipboard text exceeds 4 MiB"
    );
    let mut incomplete = vec![b'x'; MAX_CLIPBOARD_BYTES - 1];
    incomplete.push(0xc3);
    fs::write(fixture.0.join("state"), incomplete).unwrap();
    assert_eq!(
        clipboard.read().unwrap_err(),
        "System clipboard is not valid UTF-8"
    );
}

#[test]
fn command_failures_and_stderr_cannot_leak_clipboard_text() {
    let fixture = Fixture::new();
    let failed = fixture.command(
        "failed",
        "printf 'private clipboard payload' >&2\nprintf 'private clipboard payload'\nexit 23",
    );
    let mut clipboard = SystemClipboard::with_commands(failed.clone(), failed);
    let error = clipboard.read().unwrap_err();
    assert!(error.contains("failed"));
    assert!(!error.contains("private clipboard payload"));
    let error = clipboard.write("private clipboard payload").unwrap_err();
    assert!(!error.contains("private clipboard payload"));
    let missing = fixture.0.join("not-an-executable");
    let mut clipboard = SystemClipboard::with_commands(missing.clone(), missing);
    assert!(clipboard.read().unwrap_err().contains("Cannot start"));
    assert!(
        clipboard
            .write("secret")
            .unwrap_err()
            .contains("Cannot start")
    );
}

#[test]
fn ignored_stderr_does_not_block_large_writes() {
    let fixture = Fixture::new();
    let mut clipboard = fixture.clipboard(b"");
    let state = fixture.0.join("state");
    let state = format!("'{}'", state.to_str().unwrap().replace('\'', "'\\''"));
    clipboard
        .commands
        .as_mut()
        .unwrap()
        .as_mut()
        .unwrap()
        .writer
        .as_mut()
        .unwrap()
        .program = fixture.command(
        "noisy",
        &format!("/bin/dd if=/dev/zero bs=65536 count=8 >&2\nexec /bin/cat > {state}"),
    );
    let text = "λ\n".repeat(300_000);
    clipboard.write(&text).unwrap();
    assert_eq!(clipboard.read().unwrap(), text);
}

#[test]
fn failed_process_cleanup_kills_and_reaps_a_running_child() {
    use std::io::Read;
    use std::os::unix::process::CommandExt;
    use std::process::{Command, Stdio};

    unsafe extern "C" {
        fn waitpid(pid: i32, status: *mut i32, options: i32) -> i32;
    }

    let fixture = Fixture::new();
    let hung = fixture.command("running", "printf R\nwhile :; do :; done");
    let mut command = Command::new(hung);
    command
        .process_group(0)
        .stdout(Stdio::piped())
        .stderr(Stdio::null());
    let mut child = command.spawn().unwrap();
    let pid = child.id() as i32;
    let mut ready = [0];
    child
        .stdout
        .as_mut()
        .unwrap()
        .read_exact(&mut ready)
        .unwrap();
    assert_eq!(ready, [b'R']);
    drop(ClipboardProcess(Some(child)));
    let mut status = 0;
    // SAFETY: waitpid's output pointer is valid; WNOHANG cannot block this check.
    assert_eq!(unsafe { waitpid(pid, &mut status, 1) }, -1);
    assert_eq!(std::io::Error::last_os_error().raw_os_error(), Some(10));
}

#[test]
fn immediate_injected_timeout_terminates_nonterminating_commands() {
    let fixture = Fixture::new();
    let hung = fixture.command("hung", "while :; do :; done");
    let mut clipboard = SystemClipboard::with_commands(hung.clone(), hung);
    // No assertion depends on wall-clock speed or a deadline remaining in the future.
    clipboard.timeout = Duration::ZERO;
    assert_eq!(
        clipboard.read().unwrap_err(),
        "System clipboard command timed out"
    );
    assert_eq!(
        clipboard.write("text").unwrap_err(),
        "System clipboard command timed out"
    );
}