/*
    MSP430 Emulator
    Copyright (C) 2020 Rudolf Geosits (rgeosits@live.esu.edu)

    "MSP430 Emulator" is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    "MSP430 Emulator" is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program. If not, see <https://www.gnu.org/licenses/>.
*/

#include "server.h"

struct lws *ws = NULL;
struct lws_context *context;
pid_t emulator_pids[1000] = {0};

void handle_sigchld(int sig)
{
    int saved_errno = errno;

    while (waitpid((pid_t)(-1), 0, WNOHANG) > 0) {}
    errno = saved_errno;
}

void signal_callback_handler(int signum)
{
    printf("Caught signal %d\n", signum);
    // Cleanup and close up stuff here
    int saved_errno = errno;

    while (waitpid((pid_t)(-1), 0, WNOHANG) > 0) {}
    errno = saved_errno;

    // Terminate program
    exit(signum);
}

void web_send (char *buf)
{
    int len;
    char *msg, *begin;

    // send message 
    len = strlen(buf);

    msg = (char *) malloc(len + LWS_SEND_BUFFER_PRE_PADDING
			+ LWS_SEND_BUFFER_POST_PADDING);

    begin = msg + LWS_SEND_BUFFER_PRE_PADDING;

    strncpy(begin, buf, len);
    int n = lws_write(ws, begin, len, LWS_WRITE_TEXT);
    printf("sent %d bytes of %d len\n", n, len);
    
    free(msg);
}


int callback_http (
		     struct lws *wsi,
		     enum lws_callback_reasons reason,
		     void *user, void *in, size_t len)
{
    ws = wsi;
    return 0;
}

int callback_emu ( struct lws *wsi,
		     enum lws_callback_reasons reason,
		     void *user, void *in, size_t len )
{
    static unsigned new_ws_port = 9001;
    char port_str[100] = {0};
    
    switch (reason) {
        case LWS_CALLBACK_PROTOCOL_INIT: {
            ws = wsi;
            break;
        };

        case LWS_CALLBACK_SERVER_WRITEABLE: {
            pid_t pid;
            sprintf(port_str, "%u", new_ws_port);
    
            // Child (pty)         
            if( !(pid = fork()) ) {         
                printf("Child: Got pid #%u\n", pid);

                char * const args[] = {
                    "nice", "-20", "./MSP430", port_str,
	    //"./MSP430", port_str,
	    //"gdb", "-ex", "run", "--args", "./MSP430", port_str,
                    NULL
                };

	setpgid(0, 0);         
	execvp(args[0], args);
	exit(1);                                
            }

            // Parent 
            printf("Parent: Got pid #%u\n", pid);
            usleep(1000);
        
            web_send(port_str);
            ++new_ws_port;

            lws_close_reason(wsi, 0, NULL, 0);

            break;
        };

        case LWS_CALLBACK_ESTABLISHED: {
            puts("connection established");

            lws_callback_on_writable(wsi);
            break;
        }

        default: {
            printf("Some other thing: %d\n", reason); 
            break;
            
            ws = wsi;
        }
    }
    
    return 0;
}

int main (int argc, char **argv)
{
    int port = 9000;

    struct lws_context_creation_info context_info =
    {
        .port = port,
        .iface = NULL,
        .protocols = protocols,
        .ssl_cert_filepath = NULL,
        .ssl_private_key_filepath = NULL,
        .ssl_ca_filepath = NULL,

        .gid = -1,
        .uid = -1,

        .max_http_header_pool = 1,
        .options = 0,
    };
    
    // create lws context representing this server
    context = lws_create_context(&context_info);
    
    if (context == NULL)
    {
        puts("lws init failed\n");
        return -1;
    }

    signal(SIGINT, signal_callback_handler);

    // Setup child reaping handler
    struct sigaction sa;
    sa.sa_handler = &handle_sigchld;
    sigemptyset(&sa.sa_mask);
    sa.sa_flags = SA_RESTART | SA_NOCLDSTOP;
    if (sigaction(SIGCHLD, &sa, 0) == -1)
    {
        perror(0);
        exit(1);
    }

    printf("starting server...\n");

    while (true)
    {
        lws_service(context, 10); // ms
        //lws_callback_on_writable_all_protocol(context, &protocols[1]);
        usleep(1000);
    }

    lws_context_destroy(context);    
    return 0;
}