/*
ESP8266 web server - platform-dependent routines, FreeRTOS version
Thanks to my collague at Espressif for writing the foundations of this code.
*/

#include "httpd.h"
#include "httpd-platform.h"
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
#include <netinet/tcp.h>
#include <fcntl.h>
#include <errno.h>
#include "httpd-logging.h"
#include "httpd-types.h"

struct HttpdConnType {
  int fd;
  bool needWriteDoneNotif;
  bool needsClose;
  uint16_t port;
  httpd_ipaddr_t ip;
};

static HttpdConnType s_rconn[HTTPD_MAX_CONNECTIONS];
static uint8_t s_recv_buf[HTTPD_RECV_BUF_LEN];
static volatile bool s_shutdown_requested = false;

static int fd_is_valid(int fd)
{
    return fcntl(fd, F_GETFD) != -1 || errno != EBADF;
}

int httpdConnSendData(ConnTypePtr conn, const uint8_t *buff, size_t len)
{
    conn->needWriteDoneNotif = 1;
    if (!fd_is_valid(conn->fd)) {
        return 0;
    }
    return write(conn->fd, buff, len) == (int) len;
}

void httpdConnDisconnect(ConnTypePtr conn)
{
    conn->needsClose = 1;
    conn->needWriteDoneNotif = 1; //because the real close is done in the writable select code
}

void httpdServerTask(void *pvParameters)
{
    int32_t listenfd;
    int32_t len;
    int32_t ret;
    //char *precvbuf;
    fd_set readset, writeset;
    struct sockaddr_in server_addr;
    struct sockaddr_in remote_addr;
    uint16_t httpPort;

    s_shutdown_requested = false;

    const struct httpd_init_options *options = pvParameters;
    if (options == NULL) {
        httpPort = 80;
    } else {
        httpPort = options->port;
    }

    for (int i = 0; i < HTTPD_MAX_CONNECTIONS; i++) {
        s_rconn[i].fd = -1;
    }

    /* Construct local address structure */
    memset(&server_addr, 0, sizeof(server_addr)); /* Zero out structure */
    server_addr.sin_family = AF_INET;            /* Internet address family */
    server_addr.sin_addr.s_addr = INADDR_ANY;   /* Any incoming interface */
    server_addr.sin_port = htons(httpPort); /* Local port */

    /* Create socket for incoming connections */
    do {
        listenfd = socket(AF_INET, SOCK_STREAM, 0);
        if (listenfd == -1) {
            error("httpdServerTask: failed to create sock!");
            httpdPlatDelayMs(1000);
        }
    } while (listenfd == -1);

    /*
     * Allow taking over an old socket after the server was killed or crashed.
     * https://stackoverflow.com/questions/5592747/bind-error-while-recreating-socket
     */
    const int yes = 1;
    if (setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes)) == -1) {
        perror("setsockopt");
    }

    /* Bind to the local port */
    do {
        ret = bind(listenfd, (struct sockaddr *) &server_addr, sizeof(server_addr));
        if (ret != 0) {
            error("httpdServerTask: failed to bind!");
            httpdPlatDelayMs(1000);
        }
    } while (ret != 0);

    do {
        /* Listen to the local connection */
        ret = listen(listenfd, HTTPD_MAX_CONNECTIONS);
        if (ret != 0) {
            error("httpdServerTask: failed to listen!");
            httpdPlatDelayMs(1000);
        }
    } while (ret != 0);

    info("httpd: listening on http://0.0.0.0:%d/", httpPort);
    while (1) {
        if (s_shutdown_requested) {
            info("httpd: Shutting down");
            break;
        }

        //dbg("httpd: loop running");

        // clear fdset, and set the select function wait time
        int socketsFull = 1;
        int maxfdp = 0;
        FD_ZERO(&readset);
        FD_ZERO(&writeset);

        // shutdown flag polling timeout
        struct timeval timeout;
        timeout.tv_sec = 1;
        timeout.tv_usec = 0;

        for (int i = 0; i < HTTPD_MAX_CONNECTIONS; i++) {
            if (s_rconn[i].fd != -1) {
                FD_SET(s_rconn[i].fd, &readset);
                if (s_rconn[i].needWriteDoneNotif) {
                    FD_SET(s_rconn[i].fd, &writeset);
                }
                if (s_rconn[i].fd > maxfdp) {
                    maxfdp = s_rconn[i].fd;
                }
            } else {
                socketsFull = 0;
            }
        }

        if (!socketsFull) {
            FD_SET(listenfd, &readset);
            if (listenfd > maxfdp) {
                maxfdp = listenfd;
            }
        }

        //polling all exist client handle,wait until readable/writable
        ret = select(maxfdp + 1, &readset, &writeset, NULL, &timeout);
        if (ret > 0) {
            //See if we need to accept a new connection
            if (FD_ISSET(listenfd, &readset)) {
                len = sizeof(struct sockaddr_in);
                const int remotefd = accept(listenfd, (struct sockaddr *) &remote_addr, (socklen_t *) &len);
                if (remotefd < 0) {
                    warn("httpdServerTask: Huh? Accept failed.");
                    continue;
                }

                // Find a free slot
                int socknum;
                for (socknum = 0; socknum < HTTPD_MAX_CONNECTIONS; socknum++) {
                    if (s_rconn[socknum].fd == -1) {
                        break;
                    }
                }
                if (socknum >= HTTPD_MAX_CONNECTIONS) {
                    warn("httpdServerTask: Huh? Got accept with all slots full.");
                    continue;
                }

                const int keepAlive = 1; //enable keepalive
                const int keepIdle = 60; //60s
                const int keepInterval = 5; //5s
                const int keepCount = 3; //retry times

                setsockopt(remotefd, SOL_SOCKET, SO_KEEPALIVE, (void *) &keepAlive, sizeof(keepAlive));
                setsockopt(remotefd, IPPROTO_TCP, TCP_KEEPIDLE, (void *) &keepIdle, sizeof(keepIdle));
                setsockopt(remotefd, IPPROTO_TCP, TCP_KEEPINTVL, (void *) &keepInterval, sizeof(keepInterval));
                setsockopt(remotefd, IPPROTO_TCP, TCP_KEEPCNT, (void *) &keepCount, sizeof(keepCount));

                s_rconn[socknum].fd = remotefd;
                s_rconn[socknum].needWriteDoneNotif = 0;
                s_rconn[socknum].needsClose = 0;

                struct sockaddr name;
                len = sizeof(name);
                getpeername(remotefd, &name, (socklen_t *) &len);
                struct sockaddr_in *piname = (struct sockaddr_in *) &name;

                s_rconn[socknum].port = piname->sin_port;
                memcpy(&s_rconn[socknum].ip, &piname->sin_addr.s_addr, sizeof(s_rconn[socknum].ip));

                httpdConnectCb(&s_rconn[socknum], s_rconn[socknum].ip, s_rconn[socknum].port);
            }

            //See if anything happened on the existing connections.
            for (int i = 0; i < HTTPD_MAX_CONNECTIONS; i++) {
                //Skip empty slots
                if (s_rconn[i].fd == -1) { continue; }

                //Check for write availability first: the read routines may write needWriteDoneNotif while
                //the select didn't check for that.
                if (s_rconn[i].needWriteDoneNotif && FD_ISSET(s_rconn[i].fd, &writeset)) {
                    s_rconn[i].needWriteDoneNotif = 0; //Do this first, httpdSentCb may write something making this 1 again.
                    if (s_rconn[i].needsClose) {
                        //Do callback and close fd.
                        httpdDisconCb(&s_rconn[i], s_rconn[i].ip, s_rconn[i].port);
                        close(s_rconn[i].fd);
                        s_rconn[i].fd = -1;
                    } else {
                        httpdSentCb(&s_rconn[i], s_rconn[i].ip, s_rconn[i].port);
                    }
                }

                if (FD_ISSET(s_rconn[i].fd, &readset)) {
                    ret = (int) recv(s_rconn[i].fd, s_recv_buf, HTTPD_RECV_BUF_LEN, 0);
                    if (ret > 0) {
                        //Data received. Pass to httpd.
                        httpdRecvCb(&s_rconn[i], s_rconn[i].ip, s_rconn[i].port, s_recv_buf, (size_t) ret);
                    } else {
                        //recv error,connection close
                        httpdDisconCb(&s_rconn[i], s_rconn[i].ip, s_rconn[i].port);
                        httpdConnRelease(&s_rconn[i]);
                    }
                }
            }
        }
    }

    httpdInternalCloseAllSockets();

    /*release listen socket*/
    close(listenfd);

    httpdPlatTaskEnd();
}

void httpdConnRelease(ConnTypePtr conn)
{
    if (conn && conn->fd >= 0) {
        close(conn->fd);
        conn->fd = -1;
    }

    // Don't free it - it's a pointer into the static struct!
}

void httpdShutdown(httpd_thread_handle_t *handle)
{
    s_shutdown_requested = true;
    httpdJoin(handle);
}