#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
#include <errno.h>

#include <glib/gstdio.h>
#include <jansson.h>

#include "searpc-utils.h"
#include "searpc-client.h"
#include "searpc-server.h"
#include "searpc-named-pipe-transport.h"

static void* named_pipe_listen(void *arg);
static void* named_pipe_client_handler(void *arg);
static char* searpc_named_pipe_send(void *arg, const gchar *fcall_str, size_t fcall_len, size_t *ret_len);

static char * request_to_json(const char *service, const char *fcall_str, size_t fcall_len);
static int request_from_json (const char *content, size_t len, char **service, char **fcall_str);
static void json_object_set_string_member (json_t *object, const char *key, const char *value);
static const char * json_object_get_string_member (json_t *object, const char *key);

typedef struct {
    SearpcNamedPipeClient* client;
    char *service;
} ClientTransportData;

SearpcClient*
searpc_client_with_named_pipe_transport(SearpcNamedPipeClient *pipe_client,
                                        const char *service)
{
    SearpcClient *client= searpc_client_new();
    client->send = searpc_named_pipe_send;

    ClientTransportData *data = g_malloc(sizeof(ClientTransportData));
    data->client = pipe_client;
    data->service = g_strdup(service);

    client->arg = data;
    return client;
}

SearpcNamedPipeClient* searpc_create_named_pipe_client(const char *path)
{
    SearpcNamedPipeClient *client = g_malloc0(sizeof(SearpcNamedPipeClient));
    memcpy(client->path, path, strlen(path) + 1);
    return client;
}

SearpcNamedPipeServer* searpc_create_named_pipe_server(const char *path)
{
    SearpcNamedPipeServer *server = g_malloc0(sizeof(SearpcNamedPipeServer));
    memcpy(server->path, path, strlen(path) + 1);
    return server;
}

int searpc_named_pipe_server_start(SearpcNamedPipeServer *server)
{
    int pipe_fd = socket (AF_UNIX, SOCK_STREAM, 0);
    const char *un_path = server->path;
    if (pipe_fd < 0) {
        g_warning ("Failed to create unix socket fd : %s\n",
                   strerror(errno));
        return -1;
    }

    struct sockaddr_un saddr;
    saddr.sun_family = AF_UNIX;

    if (strlen(server->path) > sizeof(saddr.sun_path)-1) {
        g_warning ("Unix socket path %s is too long."
                       "Please set or modify UNIX_SOCKET option in ccnet.conf.\n",
                       un_path);
        goto failed;
    }

    if (g_file_test (un_path, G_FILE_TEST_EXISTS)) {
        g_warning ("socket file exists, delete it anyway\n");
        if (g_unlink (un_path) < 0) {
            g_warning ("delete socket file failed : %s\n", strerror(errno));
            goto failed;
        }
    }

    g_strlcpy (saddr.sun_path, un_path, sizeof(saddr.sun_path));
    if (bind(pipe_fd, (struct sockaddr *)&saddr, sizeof(saddr)) < 0) {
        g_warning ("failed to bind unix socket fd to %s : %s\n",
                      un_path, strerror(errno));
        goto failed;
    }

    if (listen(pipe_fd, 3) < 0) {
        g_warning ("failed to listen to unix socket: %s\n", strerror(errno));
        goto failed;
    }

    if (chmod(un_path, 0700) < 0) {
        g_warning ("failed to set permisson for unix socket %s: %s\n",
                      un_path, strerror(errno));
        goto failed;
    }

    server->pipe_fd = pipe_fd;

    /* TODO: use glib thread pool */
    pthread_create(&server->listener_thread, NULL, named_pipe_listen, server);

    return 0;

failed:
    close(pipe_fd);

    return -1;
}

typedef struct {
    SearpcNamedPipeServer *server;
    int connfd;
} ServerHandlerData;

static void* named_pipe_listen(void *arg)
{
    SearpcNamedPipeServer *server = arg;
    while (1) {
        int connfd = accept (server->pipe_fd, NULL, 0);
        pthread_t *handler = g_malloc(sizeof(pthread_t));
        ServerHandlerData *data = g_malloc(sizeof(ServerHandlerData));
        data->server = server;
        data->connfd = connfd;
        // TODO(low priority): Instead of using a thread to handle each client,
        // use select(unix)/iocp(windows) to do it.
        pthread_create(handler, NULL, named_pipe_client_handler, data);
        server->handlers = g_list_append(server->handlers, handler);
    }
    return NULL;
}

static void* named_pipe_client_handler(void *arg)
{
    ServerHandlerData *data = arg;
    // SearpcNamedPipeServer *server = data->server;
    int connfd = data->connfd;

    size_t len;
    size_t bufsize = 4096;
    char *buf = g_malloc(bufsize);

    g_warning ("start to serve on pipe client\n");

    while (1) {
        if (pipe_read_n(connfd, &len, sizeof(uint32_t)) < 0) {
            g_warning("failed to read rpc request size: %s", strerror(errno));
            break;
        }

        while (bufsize < len) {
            bufsize *= 2;
            buf = realloc(buf, bufsize);
        }

        if (pipe_read_n(connfd, buf, len) < 0) {
            g_warning("failed to read rpc request: %s", strerror(errno));
            g_free (buf);
            break;
        }

        char *service, *body;
        if (request_from_json (buf, len, &service, &body) < 0) {
            break;
        }

        size_t ret_len;
        char *ret_str = searpc_server_call_function (service, body, strlen(body), &ret_len);
        g_free (service);
        g_free (body);

        if (pipe_write_n(connfd, &ret_len, sizeof(uint32_t)) < 0) {
            g_warning("failed to send rpc resopnse: %s", strerror(errno));
            g_free (ret_str);
            break;
        }

        if (pipe_write_n(connfd, ret_str, ret_len) < 0) {
            g_warning("failed to send rpc resopnse: %s", strerror(errno));
            g_free (ret_str);
            break;
        }
    }

    return NULL;
}


int searpc_named_pipe_client_connect(SearpcNamedPipeClient *client)
{
    client->pipe_fd = socket(AF_UNIX, SOCK_STREAM, 0);
    struct sockaddr_un servaddr;
    servaddr.sun_family = AF_UNIX;

    g_strlcpy (servaddr.sun_path, client->path, sizeof(servaddr.sun_path));
    if (connect(client->pipe_fd, (struct sockaddr *)&servaddr, (socklen_t)sizeof(servaddr)) < 0) {
        g_warning ("pipe client failed to connect to server\n");
        return -1;
    }
    g_warning ("pipe client connectd to server\n");
    return 0;
}

char *searpc_named_pipe_send(void *arg, const gchar *fcall_str,
                             size_t fcall_len, size_t *ret_len)
{
    g_warning ("searpc_named_pipe_send is called\n");
    ClientTransportData *data = arg;
    SearpcNamedPipeClient *client = data->client;

    char *json_str = request_to_json(data->service, fcall_str, fcall_len);
    size_t json_len = strlen(json_str);

    uint32_t len = json_len;
    if (pipe_write_n(client->pipe_fd, &len, sizeof(uint32_t)) < 0) {
        g_warning("failed to send rpc call: %s", strerror(errno));
        return NULL;
    }

    if (pipe_write_n(client->pipe_fd, json_str, json_len) < 0) {
        g_warning("failed to send rpc call: %s", strerror(errno));
        return NULL;
    }

    if (pipe_read_n(client->pipe_fd, &len, sizeof(uint32_t)) < 0) {
        g_warning("failed to read rpc response: %s", strerror(errno));
        return NULL;
    }

    char *buf = g_malloc(len);

    if (pipe_read_n(client->pipe_fd, buf, len) < 0) {
        g_warning("failed to read rpc response: %s", strerror(errno));
        g_free (buf);
        return NULL;
    }

    *ret_len = len;
    return buf;
}

static char *
request_to_json (const char *service, const char *fcall_str, size_t fcall_len)
{
    json_t *object = json_object ();

    char *temp_request = g_malloc0(fcall_len + 1);
    memcpy(temp_request, fcall_str, fcall_len);

    json_object_set_string_member (object, "service", service);
    json_object_set_string_member (object, "request", temp_request);

    g_free (temp_request);

    return json_dumps (object, 0);
}

static int
request_from_json (const char *content, size_t len, char **service, char **fcall_str)
{
    json_error_t jerror;
    json_t *object = json_loadb(content, len, 0, &jerror);
    if (!object) {
        g_warning ("Failed to parse request body: %s.\n", strlen(jerror.text) > 0 ? jerror.text : "");
        return -1;
    }

    *service = g_strdup(json_object_get_string_member (object, "service"));
    *fcall_str = g_strdup(json_object_get_string_member(object, "request"));

    json_decref (object);

    if (!*service || !*fcall_str) {
        g_free (*service);
        g_free (*fcall_str);
        return -1;
    }

    return 0;
}

static void json_object_set_string_member (json_t *object, const char *key, const char *value)
{
    json_object_set_new (object, key, json_string (value));
}

static const char *
json_object_get_string_member (json_t *object, const char *key)
{
    json_t *string = json_object_get (object, key);
    if (!string)
        return NULL;
    return json_string_value (string);
}