#![warn(rust_2018_idioms)]

use std::io::Write;
use std::marker::Unpin;
use std::process::Command;
use std::ptr;

use async_std::io;
use async_std::net::{TcpListener, TcpStream};
use async_std::prelude::*;
use cfg_if::cfg_if;
use env_logger;
use futures::join;
use futures::stream::StreamExt;
use futures::AsyncWrite;
use native_tls;
use native_tls::{Identity, TlsAcceptor};

macro_rules! t {
    ($e:expr) => {
        match $e {
            Ok(e) => e,
            Err(e) => panic!("{} failed with {:?}", stringify!($e), e),
        }
    };
}

#[allow(dead_code)]
struct Keys {
    cert_der: Vec<u8>,
    pkey_der: Vec<u8>,
    pkcs12_der: Vec<u8>,
}

#[allow(dead_code)]
fn openssl_keys() -> &'static Keys {
    static INIT: Once = Once::new();
    static mut KEYS: *mut Keys = ptr::null_mut();

    INIT.call_once(|| {
        let path = t!(env::current_exe());
        let path = path.parent().unwrap();
        let keyfile = path.join("test.key");
        let certfile = path.join("test.crt");
        let config = path.join("openssl.config");

        File::create(&config)
            .unwrap()
            .write_all(
                b"\
            [req]\n\
            distinguished_name=dn\n\
            [ dn ]\n\
            CN=localhost\n\
            [ ext ]\n\
            basicConstraints=CA:FALSE,pathlen:0\n\
            subjectAltName = @alt_names
            extendedKeyUsage=serverAuth,clientAuth
            [alt_names]
            DNS.1 = localhost
        ",
            )
            .unwrap();

        let subj = "/C=US/ST=Denial/L=Sprintfield/O=Dis/CN=localhost";
        let output = t!(Command::new("openssl")
            .arg("req")
            .arg("-nodes")
            .arg("-x509")
            .arg("-newkey")
            .arg("rsa:2048")
            .arg("-config")
            .arg(&config)
            .arg("-extensions")
            .arg("ext")
            .arg("-subj")
            .arg(subj)
            .arg("-keyout")
            .arg(&keyfile)
            .arg("-out")
            .arg(&certfile)
            .arg("-days")
            .arg("1")
            .output());
        assert!(output.status.success());

        let crtout = t!(Command::new("openssl")
            .arg("x509")
            .arg("-outform")
            .arg("der")
            .arg("-in")
            .arg(&certfile)
            .output());
        assert!(crtout.status.success());
        let keyout = t!(Command::new("openssl")
            .arg("rsa")
            .arg("-outform")
            .arg("der")
            .arg("-in")
            .arg(&keyfile)
            .output());
        assert!(keyout.status.success());

        let pkcs12out = t!(Command::new("openssl")
            .arg("pkcs12")
            .arg("-export")
            .arg("-nodes")
            .arg("-inkey")
            .arg(&keyfile)
            .arg("-in")
            .arg(&certfile)
            .arg("-password")
            .arg("pass:foobar")
            .output());
        assert!(pkcs12out.status.success());

        let keys = Box::new(Keys {
            cert_der: crtout.stdout,
            pkey_der: keyout.stdout,
            pkcs12_der: pkcs12out.stdout,
        });
        unsafe {
            KEYS = Box::into_raw(keys);
        }
    });
    unsafe { &*KEYS }
}

cfg_if! {
    if #[cfg(any(feature = "force-openssl",
                        all(not(target_os = "macos"),
                            not(target_os = "windows"),
                            not(target_os = "ios"))))] {
        use std::fs::File;
        use std::env;
        use std::sync::Once;
        use async_native_tls::TlsConnector;

        fn contexts() -> (async_native_tls::TlsAcceptor, async_native_tls::TlsConnector) {
            let keys = openssl_keys();

            let pkcs12 = t!(Identity::from_pkcs12(&keys.pkcs12_der, "foobar"));
            let srv = TlsAcceptor::builder(pkcs12);

            let cert = t!(native_tls::Certificate::from_der(&keys.cert_der));

            let client = TlsConnector::new();
            let client = client.add_root_certificate(cert);

            (t!(srv.build()).into(), client.into())
        }
    } else if #[cfg(any(target_os = "macos", target_os = "ios"))] {
        use std::env;
        use std::fs::File;
        use std::sync::Once;

        fn contexts() -> (async_native_tls::TlsAcceptor, async_native_tls::TlsConnector) {
            let keys = openssl_keys();

            let pkcs12 = t!(Identity::from_pkcs12(&keys.pkcs12_der, "foobar"));
            let srv = TlsAcceptor::builder(pkcs12);

            let cert = native_tls::Certificate::from_der(&keys.cert_der).unwrap();
            let client = async_native_tls::TlsConnector::new().add_root_certificate(cert);

            (t!(srv.build()).into(), client.into())
        }
    } else {
        use schannel;
        use winapi;

        use std::env;
        use std::fs::File;
        use std::io;
        use std::mem;
        use std::sync::Once;

        use schannel::cert_context::CertContext;
        use schannel::cert_store::{CertStore, CertAdd, Memory};
        use winapi::shared::basetsd::*;
        use winapi::shared::lmcons::*;
        use winapi::shared::minwindef::*;
        use winapi::shared::ntdef::WCHAR;
        use winapi::um::minwinbase::*;
        use winapi::um::sysinfoapi::*;
        use winapi::um::timezoneapi::*;
        use winapi::um::wincrypt::*;

        const FRIENDLY_NAME: &'static str = "async-native-tls localhost testing cert";

        fn contexts() -> (async_native_tls::TlsAcceptor, async_native_tls::TlsConnector) {
            let cert = localhost_cert();
            let mut store = t!(Memory::new()).into_store();
            t!(store.add_cert(&cert, CertAdd::Always));
            let pkcs12_der = t!(store.export_pkcs12("foobar"));
            let pkcs12 = t!(Identity::from_pkcs12(&pkcs12_der, "foobar"));

            let srv = TlsAcceptor::builder(pkcs12);
            let client = TlsConnector::builder();
            (t!(srv.build()).into(), t!(client.build()).into())
        }

        // ====================================================================
        // Magic!
        //
        // Lots of magic is happening here to wrangle certificates for running
        // these tests on Windows. For more information see the test suite
        // in the schannel-rs crate as this is just coyping that.
        //
        // The general gist of this though is that the only way to add custom
        // trusted certificates is to add it to the system store of trust. To
        // do that we go through the whole rigamarole here to generate a new
        // self-signed certificate and then insert that into the system store.
        //
        // This generates some dialogs, so we print what we're doing sometimes,
        // and otherwise we just manage the ephemeral certificates. Because
        // they're in the system store we always ensure that they're only valid
        // for a small period of time (e.g. 1 day).

        fn localhost_cert() -> CertContext {
            static INIT: Once = Once::new();
            INIT.call_once(|| {
                for cert in local_root_store().certs() {
                    let name = match cert.friendly_name() {
                        Ok(name) => name,
                        Err(_) => continue,
                    };
                    if name != FRIENDLY_NAME {
                        continue
                    }
                    if !cert.is_time_valid().unwrap() {
                        io::stdout().write_all(br#"

The async-native-tls test suite is about to delete an old copy of one of its
certificates from your root trust store. This certificate was only valid for one
day and it is no longer needed. The host should be "localhost" and the
description should mention "async-native-tls".

        "#).unwrap();
                        cert.delete().unwrap();
                    } else {
                        return
                    }
                }

                install_certificate().unwrap();
            });

            for cert in local_root_store().certs() {
                let name = match cert.friendly_name() {
                    Ok(name) => name,
                    Err(_) => continue,
                };
                if name == FRIENDLY_NAME {
                    return cert
                }
            }

            panic!("couldn't find a cert");
        }

        fn local_root_store() -> CertStore {
            if env::var("CI").is_ok() {
                CertStore::open_local_machine("Root").unwrap()
            } else {
                CertStore::open_current_user("Root").unwrap()
            }
        }

        fn install_certificate() -> io::Result<CertContext> {
            unsafe {
                let mut provider = 0;
                let mut hkey = 0;

                let mut buffer = "async-native-tls test suite".encode_utf16()
                                                         .chain(Some(0))
                                                         .collect::<Vec<_>>();
                let res = CryptAcquireContextW(&mut provider,
                                               buffer.as_ptr(),
                                               ptr::null_mut(),
                                               PROV_RSA_FULL,
                                               CRYPT_MACHINE_KEYSET);
                if res != TRUE {
                    // create a new key container (since it does not exist)
                    let res = CryptAcquireContextW(&mut provider,
                                                   buffer.as_ptr(),
                                                   ptr::null_mut(),
                                                   PROV_RSA_FULL,
                                                   CRYPT_NEWKEYSET | CRYPT_MACHINE_KEYSET);
                    if res != TRUE {
                        return Err(Error::last_os_error())
                    }
                }

                // create a new keypair (RSA-2048)
                let res = CryptGenKey(provider,
                                      AT_SIGNATURE,
                                      0x0800<<16 | CRYPT_EXPORTABLE,
                                      &mut hkey);
                if res != TRUE {
                    return Err(Error::last_os_error());
                }

                // start creating the certificate
                let name = "CN=localhost,O=async-native-tls,OU=async-native-tls,\
                            G=async-native_tls".encode_utf16()
                                          .chain(Some(0))
                                          .collect::<Vec<_>>();
                let mut cname_buffer: [WCHAR; UNLEN as usize + 1] = mem::zeroed();
                let mut cname_len = cname_buffer.len() as DWORD;
                let res = CertStrToNameW(X509_ASN_ENCODING,
                                         name.as_ptr(),
                                         CERT_X500_NAME_STR,
                                         ptr::null_mut(),
                                         cname_buffer.as_mut_ptr() as *mut u8,
                                         &mut cname_len,
                                         ptr::null_mut());
                if res != TRUE {
                    return Err(Error::last_os_error());
                }

                let mut subject_issuer = CERT_NAME_BLOB {
                    cbData: cname_len,
                    pbData: cname_buffer.as_ptr() as *mut u8,
                };
                let mut key_provider = CRYPT_KEY_PROV_INFO {
                    pwszContainerName: buffer.as_mut_ptr(),
                    pwszProvName: ptr::null_mut(),
                    dwProvType: PROV_RSA_FULL,
                    dwFlags: CRYPT_MACHINE_KEYSET,
                    cProvParam: 0,
                    rgProvParam: ptr::null_mut(),
                    dwKeySpec: AT_SIGNATURE,
                };
                let mut sig_algorithm = CRYPT_ALGORITHM_IDENTIFIER {
                    pszObjId: szOID_RSA_SHA256RSA.as_ptr() as *mut _,
                    Parameters: mem::zeroed(),
                };
                let mut expiration_date: SYSTEMTIME = mem::zeroed();
                GetSystemTime(&mut expiration_date);
                let mut file_time: FILETIME = mem::zeroed();
                let res = SystemTimeToFileTime(&mut expiration_date,
                                               &mut file_time);
                if res != TRUE {
                    return Err(Error::last_os_error());
                }
                let mut timestamp: u64 = file_time.dwLowDateTime as u64 |
                                         (file_time.dwHighDateTime as u64) << 32;
                // one day, timestamp unit is in 100 nanosecond intervals
                timestamp += (1E9 as u64) / 100 * (60 * 60 * 24);
                file_time.dwLowDateTime = timestamp as u32;
                file_time.dwHighDateTime = (timestamp >> 32) as u32;
                let res = FileTimeToSystemTime(&file_time,
                                               &mut expiration_date);
                if res != TRUE {
                    return Err(Error::last_os_error());
                }

                // create a self signed certificate
                let cert_context = CertCreateSelfSignCertificate(
                        0 as ULONG_PTR,
                        &mut subject_issuer,
                        0,
                        &mut key_provider,
                        &mut sig_algorithm,
                        ptr::null_mut(),
                        &mut expiration_date,
                        ptr::null_mut());
                if cert_context.is_null() {
                    return Err(Error::last_os_error());
                }

                // TODO: this is.. a terrible hack. Right now `schannel`
                //       doesn't provide a public method to go from a raw
                //       cert context pointer to the `CertContext` structure it
                //       has, so we just fake it here with a transmute. This'll
                //       probably break at some point, but hopefully by then
                //       it'll have a method to do this!
                struct MyCertContext<T>(T);
                impl<T> Drop for MyCertContext<T> {
                    fn drop(&mut self) {}
                }

                let cert_context = MyCertContext(cert_context);
                let cert_context: CertContext = mem::transmute(cert_context);

                cert_context.set_friendly_name(FRIENDLY_NAME)?;

                // install the certificate to the machine's local store
                io::stdout().write_all(br#"

The async-native-tls test suite is about to add a certificate to your set of root
and trusted certificates. This certificate should be for the domain "localhost"
with the description related to "async-native-tls". This certificate is only valid
for one day and will be automatically deleted if you re-run the async-native-tls
test suite later.

        "#).unwrap();
                local_root_store().add_cert(&cert_context,
                                                 CertAdd::ReplaceExisting)?;
                Ok(cert_context)
            }
        }
    }
}

const AMT: usize = 128 * 1024;

async fn copy_data<W: AsyncWrite + Unpin>(mut w: W) -> Result<usize, io::Error> {
    let mut data = vec![9; AMT as usize];
    let mut amt = 0;
    while !data.is_empty() {
        let written = w.write(&data).await?;
        if written <= data.len() {
            amt += written;
            data.resize(data.len() - written, 0);
        } else {
            w.write_all(&data).await?;
            amt += data.len();
            break;
        }

        println!("remaining: {}", data.len());
    }
    Ok(amt)
}

#[async_std::test]
async fn client_to_server() {
    drop(env_logger::try_init());

    // Create a server listening on a port, then figure out what that port is
    let srv = t!(TcpListener::bind("127.0.0.1:0").await);
    let addr = t!(srv.local_addr());

    let (server_cx, client_cx) = contexts();

    // Create a future to accept one socket, connect the ssl stream, and then
    // read all the data from it.
    let server = async move {
        let mut incoming = srv.incoming();
        let socket = t!(incoming.next().await.unwrap());
        let mut socket = t!(server_cx.accept(socket).await);
        let mut data = Vec::new();
        t!(socket.read_to_end(&mut data).await);
        data
    };

    // Create a future to connect to our server, connect the ssl stream, and
    // then write a bunch of data to it.
    let client = async move {
        let socket = t!(TcpStream::connect(&addr).await);
        let socket = t!(client_cx.connect("localhost", socket).await);
        copy_data(socket).await
    };

    // Finally, run everything!
    let (data, _) = join!(server, client);
    // assert_eq!(amt, AMT);
    assert!(data == vec![9; AMT]);
}

#[async_std::test]
async fn server_to_client() {
    drop(env_logger::try_init());

    // Create a server listening on a port, then figure out what that port is
    let srv = t!(TcpListener::bind("127.0.0.1:0").await);
    let addr = t!(srv.local_addr());

    let (server_cx, client_cx) = contexts();

    let server = async move {
        let mut incoming = srv.incoming();
        let socket = t!(incoming.next().await.unwrap());
        let socket = t!(server_cx.accept(socket).await);
        copy_data(socket).await
    };

    let client = async move {
        let socket = t!(TcpStream::connect(&addr).await);
        let mut socket = t!(client_cx.connect("localhost", socket).await);
        let mut data = Vec::new();
        t!(socket.read_to_end(&mut data).await);
        data
    };

    // Finally, run everything!
    let (_, data) = join!(server, client);
    // assert_eq!(amt, AMT);
    assert!(data == vec![9; AMT]);
}

#[async_std::test]
async fn one_byte_at_a_time() {
    const AMT: usize = 1024;
    drop(env_logger::try_init());

    let srv = t!(TcpListener::bind("127.0.0.1:0").await);
    let addr = t!(srv.local_addr());

    let (server_cx, client_cx) = contexts();

    let server = async move {
        let mut incoming = srv.incoming();
        let socket = t!(incoming.next().await.unwrap());
        let mut socket = t!(server_cx.accept(socket).await);
        let mut amt = 0;
        for b in std::iter::repeat(9).take(AMT) {
            let data = [b as u8];
            t!(socket.write_all(&data).await);
            amt += 1;
        }
        amt
    };

    let client = async move {
        let socket = t!(TcpStream::connect(&addr).await);
        let mut socket = t!(client_cx.connect("localhost", socket).await);
        let mut data = Vec::new();
        loop {
            let mut buf = [0; 1];
            match socket.read_exact(&mut buf).await {
                Ok(_) => data.extend_from_slice(&buf),
                Err(ref err) if err.kind() == std::io::ErrorKind::UnexpectedEof => break,
                Err(err) => panic!("{}", err),
            }
        }
        data
    };

    let (amt, data) = join!(server, client);
    assert_eq!(amt, AMT);
    assert!(data == vec![9; AMT as usize]);
}