/*
 * mail2nntp.c
 *
 * The mail2nntp program reads mail from stdin and posts it
 * to one or more newsgroups using NNTP. It delivers the mes-
 * sage immediately or fails.  If queuing is desired it can
 * operate as a LMTP server.
 *
 * The OSSP Project, Cable & Wireless Deutschland GmbH
 * Thomas Lotterer, <thomas.lotterer@cw.com>
 *
 */


#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <fcntl.h>

/* third party */
#include "str.h"
#include "argz.h"

/* own headers */
#include "lmtp.h"

#ifndef FALSE
#define FALSE (1 != 1)
#endif
#ifndef TRUE
#define TRUE (!FALSE)
#endif

#define ERR_EXECUTION -1
#define ERR_DELIVERY -2

#define MESSAGE_MAXLEN 8*1024*1024

extern void lmtp_debug_dumplmtp(lmtp_t *lmtp);

static ssize_t trace_read(int d, void *buf, size_t nbytes);
static ssize_t trace_write(int d, const void *buf, size_t nbytes);

static lmtp_rc_t lmtp_cb_lhlo   (lmtp_t *lmtp, lmtp_io_t *io, lmtp_req_t *req, void *ctx);
static lmtp_rc_t lmtp_cb_mail   (lmtp_t *lmtp, lmtp_io_t *io, lmtp_req_t *req, void *ctx);
static lmtp_rc_t lmtp_cb_rcpt   (lmtp_t *lmtp, lmtp_io_t *io, lmtp_req_t *req, void *ctx);
static lmtp_rc_t lmtp_cb_data   (lmtp_t *lmtp, lmtp_io_t *io, lmtp_req_t *req, void *ctx);
static lmtp_rc_t lmtp_cb_noop   (lmtp_t *lmtp, lmtp_io_t *io, lmtp_req_t *req, void *ctx);
static lmtp_rc_t lmtp_cb_rset   (lmtp_t *lmtp, lmtp_io_t *io, lmtp_req_t *req, void *ctx);
static lmtp_rc_t lmtp_cb_quit   (lmtp_t *lmtp, lmtp_io_t *io, lmtp_req_t *req, void *ctx);

typedef struct {
    int option_verbose;
    int option_tracing;
    int option_mode;
    char  *azNewsgroups;
    size_t asNewsgroups;
    char *rfc822message;
    int saw_lhlo;
    char  *azRcpt;
    size_t asRcpt;
} lmtp2nntp_t;

enum {
    MODE_ONCE,
    MODE_MANY
};

/*
 * tracing
 */
ssize_t trace_read(int d, void *buf, size_t nbytes)
{
    ssize_t rc;
    int tracefile;

    rc = read(d, buf, nbytes);
    if ((tracefile = open("/tmp/t", O_CREAT|O_WRONLY|O_APPEND, 0664)) != -1) {
        write(tracefile, buf, rc);
        close(tracefile);
    }
    return rc;
}

ssize_t trace_write(int d, const void *buf, size_t nbytes)
{
    ssize_t rc;
    int tracefile;

    rc = write(d, buf, nbytes);
    if ((tracefile = open("/tmp/t", O_CREAT|O_WRONLY|O_APPEND, 0664)) != -1) {
        write(tracefile, buf, rc);
        close(tracefile);
    }
    return rc;
}

/*
 * print usage information
 */
static void usage(char *command)
{
    fprintf(stderr, 
            "USAGE: %s [-p protocol] [-l logtarget] "
            "[-h host[:port]] [-m mode] [-t] [-v] newsgroup [newsgroup ...]\n",
            command);
    return;
}

int main(int argc, char **argv)
{
    int rc = 0;
    lmtp_t *lmtp;
    lmtp_io_t lmtp_io;
    lmtp2nntp_t *ctx;
    int i; /* general purpose scratch int, index ... */

    char *progname = argv[0];

    /* create application context */
    if ((ctx = (lmtp2nntp_t *)malloc(sizeof(lmtp2nntp_t))) == NULL)
        exit(ERR_EXECUTION);
    ctx->option_verbose = FALSE;
    ctx->option_tracing = FALSE;
    ctx->option_mode = MODE_MANY;
    ctx->azNewsgroups = NULL;
    ctx->asNewsgroups = 0;
    ctx->rfc822message = NULL;
    ctx->saw_lhlo = FALSE;
    ctx->azRcpt = NULL;
    ctx->asRcpt = 0;

    /* read in the arguments */
    {
        char buf[1000];
        int bufused = 0;
        int tracefile;

        for (i=0; i<argc; i++)
            bufused+=sprintf(buf+bufused, "[%d]=\"%s\"\n", i, argv[i]);
        if ((tracefile = open("/tmp/t", O_CREAT|O_WRONLY|O_APPEND, 0664)) != -1) {
            write(tracefile, buf, bufused);
            close(tracefile);
        }
    }
    while ((i = getopt(argc, argv, "p:l:h:m:tvo:c:i:t:")) != -1) {
        switch (i) {
            case 'p': // -p protocol
                break;
            case 'l': // -l logtarget
                break;
            case 'o': // FIXME
                break;
            case 'c': // FIXME
                break;
            case 'i': // FIXME
                break;
            case 't': // FIXME
                break;
            case 'h': // -h host[:port]
                break;
            case 'm': // -m mode
                if (strcasecmp(argv[optind], "once") == 0)
                    ctx->option_mode = MODE_ONCE;
                else if (strcasecmp(argv[optind], "many") == 0)
                    ctx->option_mode = MODE_MANY;
                else {
                    fprintf(stderr, "%s:Error: Invalid mode \"%s\" to option -m\n", progname, argv[optind]);
                    exit(ERR_EXECUTION);
                }
                break;
            case 'd': // -t (tracing)
                ctx->option_tracing = TRUE;
                break;
            case 'v': // -v (verbose)
                ctx->option_verbose = TRUE;
                break;
            case '?':
            default:
                usage(progname);
                exit(ERR_EXECUTION);
        }
    }
    /* remaining arguments are newsgroup names */
    for (i = optind; i < argc; i++)
        argz_add(&ctx->azNewsgroups, &ctx->asNewsgroups, argv[i]);

    /* initialize LMTP context */
    lmtp_io.read  = trace_read;
    lmtp_io.write = trace_write;
    if ((lmtp = lmtp_create(STDIN_FILENO, STDOUT_FILENO, &lmtp_io)) == NULL) {
        fprintf(stderr, "%s:Error: Unable to initialize LMTP library\n", progname);
        exit(ERR_EXECUTION);
    }
    lmtp_register(lmtp, "LHLO", lmtp_cb_lhlo, ctx, NULL, NULL); 
    lmtp_register(lmtp, "MAIL", lmtp_cb_mail, ctx, NULL, NULL);
    lmtp_register(lmtp, "RCPT", lmtp_cb_rcpt, ctx, NULL, NULL);
    lmtp_register(lmtp, "DATA", lmtp_cb_data, ctx, NULL, NULL);
    lmtp_register(lmtp, "NOOP", lmtp_cb_noop, ctx, NULL, NULL);
    lmtp_register(lmtp, "RSET", lmtp_cb_rset, ctx, NULL, NULL);
    lmtp_register(lmtp, "QUIT", lmtp_cb_quit, ctx, NULL, NULL);
    
    /* loop for LMTP protocol */
    lmtp_loop(lmtp);

    return 0;
}

static lmtp_rc_t lmtp_cb_lhlo(lmtp_t *lmtp, lmtp_io_t *io, lmtp_req_t *req, void *_ctx)
{
    /*  
     *  RFC821 [excerpt] 4.1. SMTP COMMANDS
     *  4.1.1.  COMMAND SEMANTICS, HELO
     *  This command and an OK reply to it confirm that both the sender-SMTP
     *  and the receiver-SMTP are in the initial state, that is, there is no
     *  transaction in progress and all state tables and buffers are cleared.
     * 
     */
    lmtp_rc_t rc = LMTP_OK;
    lmtp_res_t res;
    lmtp2nntp_t *ctx = (lmtp2nntp_t *)_ctx;

    //FIXME use rset() not lmtp_cb_rset()
    ctx->saw_lhlo = TRUE;

    res.statuscode = "250";
    res.dsncode    = NULL; /* DSN not used for greeting */
    res.statusmsg  = "ENHANCEDSTATUSCODES\nDSN\nPIPELINING\n8BITMIME";
    res.statusmsg  = "ENHANCEDSTATUSCODES\nDSN\n8BITMIME";
        /*
         *  RFC2034 = EHANCEDSTATUSCODES
         *  RFC1894 = DSN
         *  RFC1854 = PIPELINING
         *  RFC1652 = 8BITMIME
         */
    lmtp_response(lmtp, &res);
    return rc;
}

static lmtp_rc_t lmtp_cb_mail(lmtp_t *lmtp, lmtp_io_t *io, lmtp_req_t *req, void *_ctx)
{
    lmtp_res_t res;
    lmtp_rc_t rc = LMTP_OK;
    lmtp2nntp_t *ctx = (lmtp2nntp_t *)_ctx;

    if (ctx->saw_lhlo == TRUE) {
        res.statuscode = "250";
        res.dsncode    = "2.1.0";
        res.statusmsg  = "Sender ok FIXME";
        lmtp_response(lmtp, &res);
    } else {
        res.statuscode = "553";
        res.dsncode    = "5.1.8";
        res.statusmsg  = "friendly people say LHLO to open a transmission channel";
        lmtp_response(lmtp, &res);
    }
    return rc;
}

static lmtp_rc_t lmtp_cb_rcpt(lmtp_t *lmtp, lmtp_io_t *io, lmtp_req_t *req, void *_ctx)
{
    lmtp_rc_t rc = LMTP_OK;
    lmtp_res_t res;
    lmtp2nntp_t *ctx = (lmtp2nntp_t *)_ctx;

    argz_add(&ctx->azRcpt, &ctx->asRcpt, req->msg);
    res.statuscode = "250";
    res.dsncode    = "2.1.5";
    res.statusmsg  = "Recipient ok FIXME";
    lmtp_response(lmtp, &res);

    return rc;
}


static lmtp_rc_t lmtp_cb_data(lmtp_t *lmtp, lmtp_io_t *io, lmtp_req_t *req, void *_ctx)
{
    lmtp_res_t res;
    lmtp_rc_t rc = LMTP_OK;
    lmtp2nntp_t *ctx = (lmtp2nntp_t *)_ctx;
    char *buf;
    char errorstring[128];
    char *rcpt;

    res.statuscode = "354";
    res.dsncode    = NULL; /* DSN not used for data */
    res.statusmsg  = "Enter mail, end with \".\" on a line by itself";
    lmtp_response(lmtp, &res);
    rc = lmtp_readmsg(lmtp, &buf, MESSAGE_MAXLEN);

    rcpt = NULL;
    while ((rcpt = argz_next(ctx->azRcpt, ctx->asRcpt, rcpt)) != NULL)
    {
        if(rc == LMTP_OK) {
            res.statuscode = "250";
            res.dsncode    = "2.0.0";
            // res.statusmsg  = "Message accepted for delivery";
            str_format(errorstring, sizeof(errorstring),
                       "Message accepted for delivery to %s", rcpt);
            res.statusmsg  = errorstring;
        } else if (rc == LMTP_ERR_OVERFLOW) {
            res.statuscode = "500";
            res.dsncode    = "5.0.0";
            res.statusmsg  = "Message accepted for delivery";
        } else if (rc == LMTP_ERR_SYSTEM) {
            res.statuscode = "500";
            res.dsncode    = "5.0.0";
            str_format(errorstring, sizeof(errorstring),
                       "Message accepted for delivery %s", strerror(errno));
            res.statusmsg  = errorstring;
        }
        lmtp_response(lmtp, &res);
    }
    return rc;
}

static lmtp_rc_t lmtp_cb_noop(lmtp_t *lmtp, lmtp_io_t *io, lmtp_req_t *req, void *ctx)
{
    lmtp_res_t res;
    lmtp_rc_t rc = LMTP_OK;
    res.statuscode = "250";
    res.dsncode    = "2.0.0";
    res.statusmsg  = "OK";
    lmtp_response(lmtp, &res);
    return rc;
}
static lmtp_rc_t lmtp_cb_rset(lmtp_t *lmtp, lmtp_io_t *io, lmtp_req_t *req, void *_ctx)
{
    lmtp2nntp_t *ctx = (lmtp2nntp_t *)_ctx;
    lmtp_res_t res;
    lmtp_rc_t rc = LMTP_OK;

    if (ctx->azRcpt != NULL) {
        free(ctx->azRcpt);
        ctx->azRcpt = NULL;
        ctx->asRcpt = 0;
    }
    res.statuscode = "250";
    res.dsncode    = "2.0.0";
    res.statusmsg  = "Reset state.";
    lmtp_response(lmtp, &res);
    return rc;
}
static lmtp_rc_t lmtp_cb_quit(lmtp_t *lmtp, lmtp_io_t *io, lmtp_req_t *req, void *ctx)
{
    lmtp_res_t res;
    lmtp_rc_t rc = LMTP_EOF;
    res.statuscode = "221";
    res.dsncode    = "2.0.0";
    res.statusmsg  = "Closing connection.";
    lmtp_response(lmtp, &res);
    return rc;
}