#include <string.h>
#include <stdio.h>
#include "dwt.h"
#include "server.h"
#include "libtelnet.h"
#include "socket.h"
#include "w5500.h"
#include "tick.h"
#include "config.h"
#include "cmd.h"

struct server {
	telnet_t          *telnet;

	zcHandle           console;

	SOCKET             tcp;
	int                port;

	volatile uint8_t  *rx_buffer;
	uint16_t           rx_buffer_size;
	volatile uint16_t  rx_head, rx_tail;
};

static volatile uint8_t __server0_rx_buffer[TARGET_SERVER_RXBUF_SZ] __attribute__((section(".txbuf.server,\"aw\",%nobits@")));
static struct server server0;

static void rx_buffer_put(struct server *srv, uint8_t data)
{
	srv->rx_buffer[srv->rx_tail % srv->rx_buffer_size] = data;
	srv->rx_tail++;
}

static int rx_buffer_empty(struct server *srv)
{
	return srv->rx_head == srv->rx_tail;
}

static uint8_t rx_buffer_get(struct server *srv)
{
	uint8_t data = srv->rx_buffer[srv->rx_head % srv->rx_buffer_size];
	srv->rx_head++;
	return data;
}

static void __delay_us(void *param, unsigned int us)
{
	dwt_wait_us(us);
}

static void __send_char(void *param, int _ch)
{
	char ch = _ch;
	struct server *srv = param;

	if (srv->telnet)
		telnet_send(srv->telnet, &ch, 1);
}

static int __get_char(void *param, char *ch)
{
	struct server *srv = param;
	if (!rx_buffer_empty(srv)) {
		*ch = rx_buffer_get(srv);
		return 1;
	}
	return 0;
}

static void tcp_output(struct server *srv, const void *buf, int len)
{
	int n;
	if (getSn_SR(srv->tcp) != SOCK_ESTABLISHED) { /* drop packets */
		return;
	}
	n = send(srv->tcp, buf, len, 0);
	if (n != len) {
		printf("drop packet: %d -> %d\r\n", len, n);
	}
	//delay(5);
	//fwrite(buf, 1, len, stdout);
}

static void event_handler(telnet_t *telnet, telnet_event_t *ev, void *user_data)
{
	int i;
	struct server *srv = user_data;

	switch (ev->type) {
		case TELNET_EV_DATA:
			for (i = 0; i < ev->data.size; ++i) {
				rx_buffer_put(srv, ev->data.buffer[i]);
			}
			break;
		case TELNET_EV_SEND:
			tcp_output(srv, ev->data.buffer, ev->data.size);
			break;
		case TELNET_EV_IAC:
			if (ev->iac.cmd == TELNET_SUSP || ev->iac.cmd == TELNET_ABORT) {
				rx_buffer_put(srv, 26); /* put CTRL-Z */
			}
			break;
		case TELNET_EV_DO:
			if (ev->neg.telopt == TELNET_TELOPT_ECHO) {
				if (srv->console)
					consoleSetEchoMode(srv->console, 1);
			}
			break;
		case TELNET_EV_DONT:
			if (ev->neg.telopt == TELNET_TELOPT_ECHO) {
				if (srv->console)
					consoleSetEchoMode(srv->console, 0);
			}
			break;
		case TELNET_EV_WILL:
			if (ev->neg.telopt == TELNET_TELOPT_ECHO) {
				if (srv->console)
					consoleSetEchoMode(srv->console, 0);
			}
			break;
		case TELNET_EV_WONT:
			if (ev->neg.telopt == TELNET_TELOPT_ECHO) {
				if (srv->console)
					consoleSetEchoMode(srv->console, 1);
			}
			break;
		case TELNET_EV_SUBNEGOTIATION:
			printf("opt: %d (%d)\r\n", ev->sub.telopt, ev->sub.size);
			break;
		default:
			break;
	}
}

int telnet_proto_init(SOCKET socket, int port)
{
	ConsoleCfg cfg;
	static const telnet_telopt_t my_telopts[] = {
		{ TELNET_TELOPT_ECHO,     TELNET_WONT, TELNET_DO },  /* I will, you don't */
		{ TELNET_TELOPT_BINARY,   TELNET_WILL, TELNET_DO },    /* I will, you do */
		{ TELNET_TELOPT_SGA,      TELNET_WILL, TELNET_DO },    /* I will, you do */
		{ TELNET_TELOPT_LINEMODE, TELNET_WONT, TELNET_DONT },    /* I will, you do */
		{ TELNET_TELOPT_TTYPE,    TELNET_WILL, TELNET_DO }, 
		{ -1, 0, 0 } 
	};
	memset(&server0, 0, sizeof server0);

	server0.rx_buffer      = __server0_rx_buffer;
	server0.rx_buffer_size = TARGET_SERVER_RXBUF_SZ;

	memset(&cfg, 0, sizeof cfg);
	cfg.delayUs = __delay_us;
	cfg.getc    = __get_char;
	cfg.putc    = __send_char;
	cfg.param   = &server0;
	cfg.prompt  = "A10> ";
	server0.console = consoleNew(&cfg);
	if (server0.console)
		consoleSetEchoMode(server0.console, 0);
	server0.telnet = telnet_init(my_telopts, event_handler, TELNET_FLAG_TRANSMIT_BINARY | TELNET_FLAG_RECEIVE_BINARY, &server0);
	if (server0.telnet == NULL) {
		return -1;
	}
	server0.tcp = socket;
	server0.port = port;
	return 0;
}

static int tcp_input(struct server *srv, int tcp)
{
	uint8 buf[64];
	int len = getSn_RX_RSR(tcp);

	if (len <= 0)
		return 0;
	
	if (len > sizeof buf)
		len = sizeof buf;
	len = recv(tcp, buf, len);
	if (srv->telnet)
		telnet_recv(srv->telnet, (const char *)buf, len);
	return len;
}

static void process_tcp(struct server *srv)
{
	int s = srv->tcp;
	int state = getSn_SR(s);

	switch (state) {
		case SOCK_CLOSED:
			if(socket(s, (Sn_MR_ND | Sn_MR_TCP),srv->port, 0x00) == 0) {
				printf("%d : Fail to create socket.\r\n", s);
			}
			break;
		case SOCK_INIT:   /* if a socket is initiated */
			listen(s);
			printf("%x :LISTEN socket %d\r\n",getSn_SR(s), s);
			break;
		case SOCK_ESTABLISHED:
			tcp_input(srv, s);
			break;
		case SOCK_CLOSE_WAIT: /* If the client request to close */
			disconnect(s);
			printf("%d : CLOSE_WAIT\r\n", s);
			break;
		default:
			break;
	}
}

zcHandle telnet_get_console()
{
	return server0.console;
}

void telnet_proto_loop()
{
	if (server0.telnet) {
		process_tcp(&server0);
	}
	if (server0.console)
		consoleProcess(server0.console);
}