#include "JSVM.h"
#include "JSDebugger.h"

// forward declaratons

static void duk_trans_socket_init(void);
static void duk_trans_socket_waitconn(void);
static duk_size_t duk_trans_socket_read_cb(void *udata, char *buffer, duk_size_t length);
static duk_size_t duk_trans_socket_write_cb(void *udata, const char *buffer, duk_size_t length);
static duk_size_t duk_trans_socket_peek_cb(void *udata);
static void duk_trans_socket_read_flush_cb(void *udata);
static void duk_trans_socket_write_flush_cb(void *udata);
static void debugger_detached (duk_context* ctx, void *udata);

namespace Atomic
{

JSDebugger* JSDebugger::instance_ = NULL;

JSDebugger::JSDebugger(Context* context) : Object(context)
{
    instance_ = this;
}

JSDebugger::~JSDebugger()
{
    instance_ = NULL;
}

void JSDebugger::Shutdown() const
{
    instance_ = NULL;
}

void JSDebugger::Reconnect() const
{
    duk_trans_socket_init();
    duk_trans_socket_waitconn();

    JSVM* vm = JSVM::GetJSVM(0);

    if(!vm)
    {
        return;
    }

    duk_context *ctx_ = vm->GetJSContext();

    if(!ctx_)
    {
        return;
    }

    duk_debugger_attach(ctx_,
                        duk_trans_socket_read_cb,
                        duk_trans_socket_write_cb,
                        duk_trans_socket_peek_cb,
                        duk_trans_socket_read_flush_cb,
                        duk_trans_socket_write_flush_cb,
                        NULL, // duk_debug_request_function - no custom application specific request functions
                        debugger_detached,
                        NULL);
}

}

static void do_reconnect()
{
    if (Atomic::JSDebugger::GetInstance())
    {
        Atomic::JSDebugger::GetInstance()->Reconnect();
    }
}

#ifdef ATOMIC_PLATFORM_WINDOWS

/*
 *  Example debug transport using a Windows TCP socket
 *
 *  Provides a TCP server socket which a debug client can connect to.
 *  After that data is just passed through.
 *
 *  https://msdn.microsoft.com/en-us/library/windows/desktop/ms737593(v=vs.85).aspx
 *
 *  Compiling 'duk' with debugger support using MSVC (Visual Studio):
 *
 *    > python2 tools\configure.py \
 *          --output-directory prep
 *          -DDUK_USE_DEBUGGER_SUPPORT -DDUK_USE_INTERRUPT_COUNTER
 *    > cl /W3 /O2 /Feduk.exe \
 *          /DDUK_CMDLINE_DEBUGGER_SUPPORT
 *          /Iexamples\debug-trans-socket /Iprep
 *          examples\cmdline\duk_cmdline.c
 *          examples\debug-trans-socket\duk_trans_socket_windows.c
 *          prep\duktape.c
 *
 *  With MinGW:
 *
 *    $ python2 tools\configure.py \
 *          --output-directory prep
 *          -DDUK_USE_DEBUGGER_SUPPORT -DDUK_USE_INTERRUPT_COUNTER
 *    $ gcc -oduk.exe -Wall -O2 \
 *          -DDUK_CMDLINE_DEBUGGER_SUPPORT \
 *          -Iexamples/debug-trans-socket -Iprep \
 *          examples/cmdline/duk_cmdline.c \
 *          examples/debug-trans-socket/duk_trans_socket_windows.c \
 *          prep/duktape.c -lm -lws2_32
 */

#undef UNICODE
#if !defined(WIN32_LEAN_AND_MEAN)
#define WIN32_LEAN_AND_MEAN
#endif

/* MinGW workaround for missing getaddrinfo() etc:
 * http://programmingrants.blogspot.fi/2009/09/tips-on-undefined-reference-to.html
 */
#if defined(__MINGW32__) || defined(__MINGW64__)
#if !defined(_WIN32_WINNT)
#define _WIN32_WINNT 0x0501
#endif
#endif

#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdio.h>
#include <string.h>
#include <ThirdParty/Duktape/duktape.h>

#if defined(_MSC_VER)
#pragma comment (lib, "Ws2_32.lib")
#endif

#if !defined(DUK_DEBUG_PORT)
#define DUK_DEBUG_PORT 9091
#endif
#if !defined(DUK_DEBUG_ADDRESS)
#define DUK_DEBUG_ADDRESS "0.0.0.0"
#endif
#define DUK__STRINGIFY_HELPER(x) #x
#define DUK__STRINGIFY(x) DUK__STRINGIFY_HELPER(x)

#if 0
#define DEBUG_PRINTS
#endif

static SOCKET server_sock = INVALID_SOCKET;
static SOCKET client_sock = INVALID_SOCKET;
static int wsa_inited = 0;

/*
 *  Transport init and finish
 */

void duk_trans_socket_init(void) {
    WSADATA wsa_data;
    struct addrinfo hints;
    struct addrinfo *result = NULL;
    int rc;

    memset((void *) &wsa_data, 0, sizeof(wsa_data));
    memset((void *) &hints, 0, sizeof(hints));

    rc = WSAStartup(MAKEWORD(2, 2), &wsa_data);
    if (rc != 0) {
        fprintf(stderr, "%s: WSAStartup() failed: %d\n", __FILE__, rc);
        fflush(stderr);
        goto fail;
    }
    wsa_inited = 1;

    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_protocol = IPPROTO_TCP;
    hints.ai_flags = AI_PASSIVE;

    rc = getaddrinfo(DUK_DEBUG_ADDRESS, DUK__STRINGIFY(DUK_DEBUG_PORT), &hints, &result);
    if (rc != 0) {
        fprintf(stderr, "%s: getaddrinfo() failed: %d\n", __FILE__, rc);
        fflush(stderr);
        goto fail;
    }

    server_sock = socket(result->ai_family, result->ai_socktype, result->ai_protocol);
    if (server_sock == INVALID_SOCKET) {
        fprintf(stderr, "%s: socket() failed with error: %ld\n",
                __FILE__, (long) WSAGetLastError());
        fflush(stderr);
        goto fail;
    }

    rc = bind(server_sock, result->ai_addr, (int) result->ai_addrlen);
    if (rc == SOCKET_ERROR) {
        fprintf(stderr, "%s: bind() failed with error: %ld\n",
                __FILE__, (long) WSAGetLastError());
        fflush(stderr);
        goto fail;
    }

    rc = listen(server_sock, SOMAXCONN);
    if (rc == SOCKET_ERROR) {
        fprintf(stderr, "%s: listen() failed with error: %ld\n",
                __FILE__, (long) WSAGetLastError());
        fflush(stderr);
        goto fail;
    }

    if (result != NULL) {
        freeaddrinfo(result);
        result = NULL;
    }
    return;

fail:
    if (result != NULL) {
        freeaddrinfo(result);
        result = NULL;
    }
    if (server_sock != INVALID_SOCKET) {
        (void) closesocket(server_sock);
        server_sock = INVALID_SOCKET;
    }
    if (wsa_inited) {
        WSACleanup();
        wsa_inited = 0;
    }
}

void duk_trans_socket_finish(void) {
    if (client_sock != INVALID_SOCKET) {
        (void) closesocket(client_sock);
        client_sock = INVALID_SOCKET;
    }
    if (server_sock != INVALID_SOCKET) {
        (void) closesocket(server_sock);
        server_sock = INVALID_SOCKET;
    }
    if (wsa_inited) {
        WSACleanup();
        wsa_inited = 0;
    }

    // auto-restart
    do_reconnect();

}

void duk_trans_socket_waitconn(void) {
    if (server_sock == INVALID_SOCKET) {
        fprintf(stderr, "%s: no server socket, skip waiting for connection\n",
                __FILE__);
        fflush(stderr);
        return;
    }
    if (client_sock != INVALID_SOCKET) {
        (void) closesocket(client_sock);
        client_sock = INVALID_SOCKET;
    }

    fprintf(stderr, "Waiting for debug connection on port %d\n", (int) DUK_DEBUG_PORT);
    fflush(stderr);

    client_sock = accept(server_sock, NULL, NULL);
    if (client_sock == INVALID_SOCKET) {
        fprintf(stderr, "%s: accept() failed with error %ld, skip waiting for connection\n",
                __FILE__, (long) WSAGetLastError());
        fflush(stderr);
        goto fail;
    }

    fprintf(stderr, "Debug connection established\n");
    fflush(stderr);

    /* XXX: For now, close the listen socket because we won't accept new
     * connections anyway.  A better implementation would allow multiple
     * debug attaches.
     */

    if (server_sock != INVALID_SOCKET) {
        (void) closesocket(server_sock);
        server_sock = INVALID_SOCKET;
    }
    return;

fail:
    if (client_sock != INVALID_SOCKET) {
        (void) closesocket(client_sock);
        client_sock = INVALID_SOCKET;
    }
}

/*
 *  Duktape callbacks
 */

/* Duktape debug transport callback: (possibly partial) read. */
duk_size_t duk_trans_socket_read_cb(void *udata, char *buffer, duk_size_t length) {
    int ret;

    (void) udata;  /* not needed by the example */

#if defined(DEBUG_PRINTS)
    fprintf(stderr, "%s: udata=%p, buffer=%p, length=%ld\n",
            __FUNCTION__, (void *) udata, (void *) buffer, (long) length);
    fflush(stderr);
#endif

    if (client_sock == INVALID_SOCKET) {
        return 0;
    }

    if (length == 0) {
        /* This shouldn't happen. */
        fprintf(stderr, "%s: read request length == 0, closing connection\n",
                __FILE__);
        fflush(stderr);
        goto fail;
    }

    if (buffer == NULL) {
        /* This shouldn't happen. */
        fprintf(stderr, "%s: read request buffer == NULL, closing connection\n",
                __FILE__);
        fflush(stderr);
        goto fail;
    }

    /* In a production quality implementation there would be a sanity
     * timeout here to recover from "black hole" disconnects.
     */

    ret = recv(client_sock, buffer, (int) length, 0);
    if (ret < 0) {
        fprintf(stderr, "%s: debug read failed, error %d, closing connection\n",
                __FILE__, ret);
        fflush(stderr);
        goto fail;
    } else if (ret == 0) {
        fprintf(stderr, "%s: debug read failed, ret == 0 (EOF), closing connection\n",
                __FILE__);
        fflush(stderr);
        goto fail;
    } else if (ret > (int) length) {
        fprintf(stderr, "%s: debug read failed, ret too large (%ld > %ld), closing connection\n",
                __FILE__, (long) ret, (long) length);
        fflush(stderr);
        goto fail;
    }

    return (duk_size_t) ret;

fail:
    if (client_sock != INVALID_SOCKET) {
        (void) closesocket(client_sock);
        client_sock = INVALID_SOCKET;
    }
    return 0;
}

/* Duktape debug transport callback: (possibly partial) write. */
duk_size_t duk_trans_socket_write_cb(void *udata, const char *buffer, duk_size_t length) {
    int ret;

    (void) udata;  /* not needed by the example */

#if defined(DEBUG_PRINTS)
    fprintf(stderr, "%s: udata=%p, buffer=%p, length=%ld\n",
            __FUNCTION__, (void *) udata, (const void *) buffer, (long) length);
    fflush(stderr);
#endif

    if (client_sock == INVALID_SOCKET) {
        return 0;
    }

    if (length == 0) {
        /* This shouldn't happen. */
        fprintf(stderr, "%s: write request length == 0, closing connection\n",
                __FILE__);
        fflush(stderr);
        goto fail;
    }

    if (buffer == NULL) {
        /* This shouldn't happen. */
        fprintf(stderr, "%s: write request buffer == NULL, closing connection\n",
                __FILE__);
        fflush(stderr);
        goto fail;
    }

    /* In a production quality implementation there would be a sanity
     * timeout here to recover from "black hole" disconnects.
     */

    ret = send(client_sock, buffer, (int) length, 0);
    if (ret <= 0 || ret > (int) length) {
        fprintf(stderr, "%s: debug write failed, ret %d, closing connection\n",
                __FILE__, ret);
        fflush(stderr);
        goto fail;
    }

    return (duk_size_t) ret;

fail:
    if (client_sock != INVALID_SOCKET) {
        (void) closesocket(INVALID_SOCKET);
        client_sock = INVALID_SOCKET;
    }
    return 0;
}

duk_size_t duk_trans_socket_peek_cb(void *udata) {
    u_long avail;
    int rc;

    (void) udata;  /* not needed by the example */

#if defined(DEBUG_PRINTS)
    fprintf(stderr, "%s: udata=%p\n", __FUNCTION__, (void *) udata);
    fflush(stderr);
#endif

    if (client_sock == INVALID_SOCKET) {
        return 0;
    }

    avail = 0;
    rc = ioctlsocket(client_sock, FIONREAD, &avail);
    if (rc != 0) {
        fprintf(stderr, "%s: ioctlsocket() returned %d, closing connection\n",
                __FILE__, rc);
        fflush(stderr);
        goto fail;  /* also returns 0, which is correct */
    } else {
        if (avail == 0) {
            return 0;  /* nothing to read */
        } else {
            return 1;  /* something to read */
        }
    }
    /* never here */

fail:
    if (client_sock != INVALID_SOCKET) {
        (void) closesocket(client_sock);
        client_sock = INVALID_SOCKET;
    }
    return 0;
}

void duk_trans_socket_read_flush_cb(void *udata) {
    (void) udata;  /* not needed by the example */

#if defined(DEBUG_PRINTS)
    fprintf(stderr, "%s: udata=%p\n", __FUNCTION__, (void *) udata);
    fflush(stderr);
#endif

    /* Read flush: Duktape may not be making any more read calls at this
     * time.  If the transport maintains a receive window, it can use a
     * read flush as a signal to update the window status to the remote
     * peer.  A read flush is guaranteed to occur before Duktape stops
     * reading for a while; it may occur in other situations as well so
     * it's not a 100% reliable indication.
     */

    /* This TCP transport requires no read flush handling so ignore.
     * You can also pass a NULL to duk_debugger_attach() and not
     * implement this callback at all.
     */
}

void duk_trans_socket_write_flush_cb(void *udata) {
    (void) udata;  /* not needed by the example */

#if defined(DEBUG_PRINTS)
    fprintf(stderr, "%s: udata=%p\n", __FUNCTION__, (void *) udata);
    fflush(stderr);
#endif

    /* Write flush.  If the transport combines multiple writes
     * before actually sending, a write flush is an indication
     * to write out any pending bytes: Duktape may not be doing
     * any more writes on this occasion.
     */

    /* This TCP transport requires no write flush handling so ignore.
     * You can also pass a NULL to duk_debugger_attach() and not
     * implement this callback at all.
     */
    return;
}

#undef DUK__STRINGIFY_HELPER
#undef DUK__STRINGIFY


#else  // OSX ad LINUX

/*
     *  Example debug transport using a Linux/Unix TCP socket
     *
     *  Provides a TCP server socket which a debug client can connect to.
     *  After that data is just passed through.
     */

#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
#include <poll.h>
#include <errno.h>
#include <ThirdParty/Duktape/duktape.h>

#if !defined(DUK_DEBUG_PORT)
#define DUK_DEBUG_PORT 9091
#endif

#if 0
#define DEBUG_PRINTS
#endif


static int server_sock = -1;
static int client_sock = -1;

/*
     *  Transport init and finish
     */

void duk_trans_socket_init(void) {
    struct sockaddr_in addr;
    int on;

    server_sock = socket(AF_INET, SOCK_STREAM, 0);
    if (server_sock < 0) {
        fprintf(stderr, "%s: failed to create server socket: %s\n",
                __FILE__, strerror(errno));
        fflush(stderr);
        goto fail;
    }

    on = 1;
    if (setsockopt(server_sock, SOL_SOCKET, SO_REUSEADDR, (const char *) &on, sizeof(on)) < 0) {
        fprintf(stderr, "%s: failed to set SO_REUSEADDR for server socket: %s\n",
                __FILE__, strerror(errno));
        fflush(stderr);
        goto fail;
    }

    memset((void *) &addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_addr.s_addr = INADDR_ANY;
    addr.sin_port = htons(DUK_DEBUG_PORT);

    if (bind(server_sock, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
        fprintf(stderr, "%s: failed to bind server socket: %s\n",
                __FILE__, strerror(errno));
        fflush(stderr);
        goto fail;
    }

    listen(server_sock, 1 /*backlog*/);
    return;

fail:
    if (server_sock >= 0) {
        (void) close(server_sock);
        server_sock = -1;
    }
}

void duk_trans_socket_waitconn(void) {
    struct sockaddr_in addr;
    socklen_t sz;

    if (server_sock < 0) {
        fprintf(stderr, "%s: no server socket, skip waiting for connection\n",
                __FILE__);
        fflush(stderr);
        return;
    }
    if (client_sock >= 0) {
        (void) close(client_sock);
        client_sock = -1;
    }

    fprintf(stderr, "Waiting for debug connection on port %d\n", (int) DUK_DEBUG_PORT);
    fflush(stderr);

    sz = (socklen_t) sizeof(addr);
    client_sock = accept(server_sock, (struct sockaddr *) &addr, &sz);
    if (client_sock < 0) {
        fprintf(stderr, "%s: accept() failed, skip waiting for connection: %s\n",
                __FILE__, strerror(errno));
        fflush(stderr);
        goto fail;
    }

    fprintf(stderr, "Debug connection established\n");
    fflush(stderr);

    /* XXX: For now, close the listen socket because we won't accept new
         * connections anyway.  A better implementation would allow multiple
         * debug attaches.
         */

    if (server_sock >= 0) {
        (void) close(server_sock);
        server_sock = -1;
    }
    return;

fail:
    if (client_sock >= 0) {
        (void) close(client_sock);
        client_sock = -1;
    }
}

void duk_trans_socket_finish(void) {
    if (client_sock >= 0) {
        (void) close(client_sock);
        client_sock = -1;
    }
    if (server_sock >= 0) {
        (void) close(server_sock);
        server_sock = -1;
    }

    //
    // auto-restart
    do_reconnect();
}


/*
     *  Duktape callbacks
     */

/* Duktape debug transport callback: (possibly partial) read. */
duk_size_t duk_trans_socket_read_cb(void *udata, char *buffer, duk_size_t length) {
    ssize_t ret;

    (void) udata;  /* not needed by the example */

#if defined(DEBUG_PRINTS)
    fprintf(stderr, "%s: udata=%p, buffer=%p, length=%ld\n",
            __func__, (void *) udata, (void *) buffer, (long) length);
    fflush(stderr);
#endif

    if (client_sock < 0) {
        return 0;
    }

    if (length == 0) {
        /* This shouldn't happen. */
        fprintf(stderr, "%s: read request length == 0, closing connection\n",
                __FILE__);
        fflush(stderr);
        goto fail;
    }

    if (buffer == NULL) {
        /* This shouldn't happen. */
        fprintf(stderr, "%s: read request buffer == NULL, closing connection\n",
                __FILE__);
        fflush(stderr);
        goto fail;
    }

    /* In a production quality implementation there would be a sanity
         * timeout here to recover from "black hole" disconnects.
         */

    ret = read(client_sock, (void *) buffer, (size_t) length);
    if (ret < 0) {
        fprintf(stderr, "%s: debug read failed, closing connection: %s\n",
                __FILE__, strerror(errno));
        fflush(stderr);
        goto fail;
    } else if (ret == 0) {
        fprintf(stderr, "%s: debug read failed, ret == 0 (EOF), closing connection\n",
                __FILE__);
        fflush(stderr);
        goto fail;
    } else if (ret > (ssize_t) length) {
        fprintf(stderr, "%s: debug read failed, ret too large (%ld > %ld), closing connection\n",
                __FILE__, (long) ret, (long) length);
        fflush(stderr);
        goto fail;
    }

    return (duk_size_t) ret;

fail:
    if (client_sock >= 0) {
        (void) close(client_sock);
        client_sock = -1;
    }
    return 0;
}

/* Duktape debug transport callback: (possibly partial) write. */
duk_size_t duk_trans_socket_write_cb(void *udata, const char *buffer, duk_size_t length) {
    ssize_t ret;

    (void) udata;  /* not needed by the example */

#if defined(DEBUG_PRINTS)
    fprintf(stderr, "%s: udata=%p, buffer=%p, length=%ld\n",
            __func__, (void *) udata, (const void *) buffer, (long) length);
    fflush(stderr);
#endif

    if (client_sock < 0) {
        return 0;
    }

    if (length == 0) {
        /* This shouldn't happen. */
        fprintf(stderr, "%s: write request length == 0, closing connection\n",
                __FILE__);
        fflush(stderr);
        goto fail;
    }

    if (buffer == NULL) {
        /* This shouldn't happen. */
        fprintf(stderr, "%s: write request buffer == NULL, closing connection\n",
                __FILE__);
        fflush(stderr);
        goto fail;
    }

    /* In a production quality implementation there would be a sanity
         * timeout here to recover from "black hole" disconnects.
         */

    ret = write(client_sock, (const void *) buffer, (size_t) length);
    if (ret <= 0 || ret > (ssize_t) length) {
        fprintf(stderr, "%s: debug write failed, closing connection: %s\n",
                __FILE__, strerror(errno));
        fflush(stderr);
        goto fail;
    }

    return (duk_size_t) ret;

fail:
    if (client_sock >= 0) {
        (void) close(client_sock);
        client_sock = -1;
    }
    return 0;
}

duk_size_t duk_trans_socket_peek_cb(void *udata) {
    struct pollfd fds[1];
    int poll_rc;

    (void) udata;  /* not needed by the example */

#if defined(DEBUG_PRINTS)
    fprintf(stderr, "%s: udata=%p\n", __func__, (void *) udata);
    fflush(stderr);
#endif

    if (client_sock < 0) {
        return 0;
    }

    fds[0].fd = client_sock;
    fds[0].events = POLLIN;
    fds[0].revents = 0;

    poll_rc = poll(fds, 1, 0);
    if (poll_rc < 0) {
        fprintf(stderr, "%s: poll returned < 0, closing connection: %s\n",
                __FILE__, strerror(errno));
        fflush(stderr);
        goto fail;  /* also returns 0, which is correct */
    } else if (poll_rc > 1) {
        fprintf(stderr, "%s: poll returned > 1, treating like 1\n",
                __FILE__);
        fflush(stderr);
        return 1;  /* should never happen */
    } else if (poll_rc == 0) {
        return 0;  /* nothing to read */
    } else {
        return 1;  /* something to read */
    }

fail:
    if (client_sock >= 0) {
        (void) close(client_sock);
        client_sock = -1;
    }
    return 0;
}

void duk_trans_socket_read_flush_cb(void *udata) {
    (void) udata;  /* not needed by the example */

#if defined(DEBUG_PRINTS)
    fprintf(stderr, "%s: udata=%p\n", __func__, (void *) udata);
    fflush(stderr);
#endif

    /* Read flush: Duktape may not be making any more read calls at this
         * time.  If the transport maintains a receive window, it can use a
         * read flush as a signal to update the window status to the remote
         * peer.  A read flush is guaranteed to occur before Duktape stops
         * reading for a while; it may occur in other situations as well so
         * it's not a 100% reliable indication.
         */

    /* This TCP transport requires no read flush handling so ignore.
         * You can also pass a NULL to duk_debugger_attach() and not
         * implement this callback at all.
         */
}

void duk_trans_socket_write_flush_cb(void *udata) {
    (void) udata;  /* not needed by the example */

#if defined(DEBUG_PRINTS)
    fprintf(stderr, "%s: udata=%p\n", __func__, (void *) udata);
    fflush(stderr);
#endif

    /* Write flush.  If the transport combines multiple writes
         * before actually sending, a write flush is an indication
         * to write out any pending bytes: Duktape may not be doing
         * any more writes on this occasion.
         */

    /* This TCP transport requires no write flush handling so ignore.
         * You can also pass a NULL to duk_debugger_attach() and not
         * implement this callback at all.
         */
    return;
}
#endif // OSX ad LINUX

void debugger_detached (duk_context* ctx, void *udata) {

    fflush(stderr);

    /* Ensure socket is closed even when detach is initiated by Duktape
         * rather than debug client.
         */
    duk_trans_socket_finish();

}