//! Integration tests for the `portping` command.

use std::io::{BufRead, BufReader, Read, Write};
use std::net::{TcpListener, TcpStream};
use std::process::{Child, Command as StdCommand, Stdio};
use std::sync::mpsc;
use std::thread;
use std::time::{Duration, Instant};

use assert_cmd::Command;
use portping::{Target, parse_target};
use predicates::prelude::*;

fn cargo_command() -> Command {
    Command::cargo_bin("portping").expect("binary")
}

fn spawn_http_server() -> u16 {
    let listener = TcpListener::bind("127.0.0.1:0").expect("listener");
    let port = listener.local_addr().expect("address").port();

    thread::spawn(move || {
        if let Ok((mut stream, _)) = listener.accept() {
            let mut buffer = [0_u8; 1024];
            let _ = stream.read(&mut buffer);
            let response = b"HTTP/1.1 200 OK\r\nContent-Length: 2\r\nConnection: close\r\n\r\nok";
            let _ = stream.write_all(response);
        }
    });

    port
}

fn spawn_capturing_http_server(status_line: &'static str) -> (u16, mpsc::Receiver<String>) {
    let listener = TcpListener::bind("127.0.0.1:0").expect("listener");
    let port = listener.local_addr().expect("address").port();
    let (sender, receiver) = mpsc::channel();

    thread::spawn(move || {
        if let Ok((mut stream, _)) = listener.accept() {
            let mut buffer = [0_u8; 1024];
            let read = stream.read(&mut buffer).expect("read request");
            let request = String::from_utf8_lossy(&buffer[..read]).to_string();
            sender.send(request).expect("send request");
            let response =
                format!("{status_line}\r\nContent-Length: 0\r\nConnection: close\r\n\r\n");
            stream
                .write_all(response.as_bytes())
                .expect("write response");
        }
    });

    (port, receiver)
}

fn unused_local_port() -> u16 {
    let listener = TcpListener::bind("127.0.0.1:0").expect("listener");
    let port = listener.local_addr().expect("address").port();
    drop(listener);
    port
}

struct ChildGuard(Child);

impl Drop for ChildGuard {
    fn drop(&mut self) {
        let _ = self.0.kill();
        let _ = self.0.wait();
    }
}

fn spawn_passive_listener_child(port: u16) -> ChildGuard {
    let mut child = StdCommand::new("pwsh")
        .arg("-NoProfile")
        .arg("-Command")
        .arg(format!(
            "$listener = [System.Net.Sockets.TcpListener]::new([System.Net.IPAddress]::Loopback, {port}); \
             $listener.Start(); \
             Write-Output 'ready'; \
             try {{ Start-Sleep -Seconds 30 }} finally {{ $listener.Stop() }}"
        ))
        .stdout(Stdio::piped())
        .spawn()
        .expect("spawn passive listener child");
    let stdout = child.stdout.take().expect("passive listener stdout");
    let (sender, receiver) = mpsc::channel();
    thread::spawn(move || {
        let mut line = String::new();
        let _ = BufReader::new(stdout).read_line(&mut line);
        let _ = sender.send(line);
    });

    let ready_line = receiver
        .recv_timeout(Duration::from_secs(15))
        .expect("passive listener child did not report readiness");
    assert!(
        ready_line.trim() == "ready",
        "unexpected passive listener readiness line: {ready_line:?}"
    );

    ChildGuard(child)
}

fn wait_for_tcp_listener(port: u16) {
    let deadline = Instant::now() + Duration::from_secs(5);
    while Instant::now() < deadline {
        if TcpStream::connect(("127.0.0.1", port)).is_ok() {
            return;
        }
        thread::sleep(Duration::from_millis(25));
    }
    panic!("passive listener on port {port} did not become ready");
}

#[test]
fn parses_targets() {
    assert!(matches!(
        parse_target("tcp://127.0.0.1:9000").expect("tcp"),
        Target::Tcp { port, .. } if port == 9000
    ));
    assert!(matches!(
        parse_target("http://127.0.0.1:9000/health").expect("http"),
        Target::Http { port, .. } if port == 9000
    ));
}

#[test]
fn probes_http_endpoint_as_json() {
    let port = spawn_http_server();
    let mut command = cargo_command();
    command
        .arg(format!("http://127.0.0.1:{port}/health"))
        .arg("--json")
        .assert()
        .success()
        .stdout(predicate::str::contains("\"status_code\":200"))
        .stdout(predicate::str::contains("\"ok\":true"));
}

#[test]
fn reports_closed_tcp_port() {
    let port = unused_local_port();

    let mut command = cargo_command();
    command
        .arg(format!("tcp://127.0.0.1:{port}"))
        .arg("--json")
        .assert()
        .code(1)
        .stdout(predicate::str::contains("\"ok\":false"))
        .stdout(predicate::str::contains("\"error\""));
}

#[test]
fn report_mode_keeps_diagnostic_sweeps_successful_when_probe_fails() {
    let port = unused_local_port();

    let mut command = cargo_command();
    command
        .arg(format!("tcp://127.0.0.1:{port}"))
        .arg("--report")
        .arg("--json")
        .assert()
        .success()
        .stdout(predicate::str::contains("\"ok\":false"))
        .stdout(predicate::str::contains("\"error_code\""));
}

#[test]
fn supports_powershell_pipeline() {
    let port = spawn_http_server();
    let binary = assert_cmd::cargo::cargo_bin("portping");
    let script = format!(
        "'http://127.0.0.1:{port}/health' | & '{}'",
        binary.display()
    );

    let mut command = Command::new("pwsh");
    command
        .arg("-NoProfile")
        .arg("-Command")
        .arg(script)
        .assert()
        .success()
        .stdout(predicate::str::contains("200"))
        .stdout(predicate::str::contains("ok"));
}

#[test]
fn supports_head_requests_and_expected_status_checks() {
    let (port, receiver) = spawn_capturing_http_server("HTTP/1.1 204 No Content");
    let mut command = cargo_command();
    command
        .arg(format!("http://127.0.0.1:{port}/health"))
        .arg("--method")
        .arg("HEAD")
        .arg("--expect-status")
        .arg("204")
        .arg("--json")
        .assert()
        .success()
        .stdout(predicate::str::contains("\"method\":\"HEAD\""))
        .stdout(predicate::str::contains("\"expected_status\":204"))
        .stdout(predicate::str::contains(
            "\"status_matches_expectation\":true",
        ))
        .stdout(predicate::str::contains("\"ok\":true"));

    let request = receiver.recv().expect("captured request");
    assert!(request.starts_with("HEAD /health HTTP/1.1\r\n"));
}

#[test]
fn probes_passive_loopback_listener_started_by_child_process() {
    let port = unused_local_port();
    let _listener = spawn_passive_listener_child(port);
    wait_for_tcp_listener(port);

    let mut command = cargo_command();
    command
        .arg(format!("tcp://127.0.0.1:{port}"))
        .arg("--json")
        .assert()
        .success()
        .stdout(predicate::str::contains("\"ok\":true"));
}

#[test]
fn marks_status_mismatches_as_failed_results() {
    let port = spawn_http_server();
    let mut command = cargo_command();
    command
        .arg(format!("http://127.0.0.1:{port}/health"))
        .arg("--expect-status")
        .arg("204")
        .arg("--json")
        .assert()
        .code(1)
        .stdout(predicate::str::contains("\"status_code\":200"))
        .stdout(predicate::str::contains(
            "\"status_matches_expectation\":false",
        ))
        .stdout(predicate::str::contains("\"ok\":false"));
}

#[test]
fn help_includes_health_check_examples() {
    let mut command = cargo_command();
    command
        .arg("--help")
        .assert()
        .success()
        .stdout(predicate::str::contains("--method"))
        .stdout(predicate::str::contains("--expect-status"))
        .stdout(predicate::str::contains("--report"))
        .stdout(predicate::str::contains("Exit code"))
        .stdout(predicate::str::contains("--toon"));
}