/*
 * git-imap-send - drops patches into an imap Drafts folder
 *                 derived from isync/mbsync - mailbox synchronizer
 *
 * Copyright (C) 2000-2002 Michael R. Elkins <me@mutt.org>
 * Copyright (C) 2002-2004 Oswald Buddenhagen <ossi@users.sf.net>
 * Copyright (C) 2004 Theodore Y. Ts'o <tytso@mit.edu>
 * Copyright (C) 2006 Mike McCormack
 *
 *  This program 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 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "cache.h"
#ifdef NO_OPENSSL
typedef void *SSL;
#endif

struct store_conf {
        char *name;
        const char *path; /* should this be here? its interpretation is driver-specific */
        char *map_inbox;
        char *trash;
        unsigned max_size; /* off_t is overkill */
        unsigned trash_remote_new:1, trash_only_new:1;
};

struct string_list {
        struct string_list *next;
        char string[1];
};

struct channel_conf {
        struct channel_conf *next;
        char *name;
        struct store_conf *master, *slave;
        char *master_name, *slave_name;
        char *sync_state;
        struct string_list *patterns;
        int mops, sops;
        unsigned max_messages; /* for slave only */
};

struct group_conf {
        struct group_conf *next;
        char *name;
        struct string_list *channels;
};

/* For message->status */
#define M_RECENT       (1<<0) /* unsyncable flag; maildir_* depend on this being 1<<0 */
#define M_DEAD         (1<<1) /* expunged */
#define M_FLAGS        (1<<2) /* flags fetched */

struct message {
        struct message *next;
        /* struct string_list *keywords; */
        size_t size; /* zero implies "not fetched" */
        int uid;
        unsigned char flags, status;
};

struct store {
        struct store_conf *conf; /* foreign */

        /* currently open mailbox */
        const char *name; /* foreign! maybe preset? */
        char *path; /* own */
        struct message *msgs; /* own */
        int uidvalidity;
        unsigned char opts; /* maybe preset? */
        /* note that the following do _not_ reflect stats from msgs, but mailbox totals */
        int count; /* # of messages */
        int recent; /* # of recent messages - don't trust this beyond the initial read */
};

struct msg_data {
        char *data;
        int len;
        unsigned char flags;
        unsigned int crlf:1;
};

#define DRV_OK          0
#define DRV_MSG_BAD     -1
#define DRV_BOX_BAD     -2
#define DRV_STORE_BAD   -3

static int Verbose, Quiet;

static void imap_info(const char *, ...);
static void imap_warn(const char *, ...);

static char *next_arg(char **);

static void free_generic_messages(struct message *);

static int nfsnprintf(char *buf, int blen, const char *fmt, ...);

static int nfvasprintf(char **strp, const char *fmt, va_list ap)
{
        int len;
        char tmp[8192];

        len = vsnprintf(tmp, sizeof(tmp), fmt, ap);
        if (len < 0)
                die("Fatal: Out of memory\n");
        if (len >= sizeof(tmp))
                die("imap command overflow !\n");
        *strp = xmemdupz(tmp, len);
        return len;
}

static void arc4_init(void);
static unsigned char arc4_getbyte(void);

struct imap_server_conf {
        char *name;
        char *tunnel;
        char *host;
        int port;
        char *user;
        char *pass;
        int use_ssl;
        int ssl_verify;
};

struct imap_store_conf {
        struct store_conf gen;
        struct imap_server_conf *server;
        unsigned use_namespace:1;
};

#define NIL     (void *)0x1
#define LIST    (void *)0x2

struct imap_list {
        struct imap_list *next, *child;
        char *val;
        int len;
};

struct imap_socket {
        int fd;
        SSL *ssl;
};

struct imap_buffer {
        struct imap_socket sock;
        int bytes;
        int offset;
        char buf[1024];
};

struct imap_cmd;

struct imap {
        int uidnext; /* from SELECT responses */
        struct imap_list *ns_personal, *ns_other, *ns_shared; /* NAMESPACE info */
        unsigned caps, rcaps; /* CAPABILITY results */
        /* command queue */
        int nexttag, num_in_progress, literal_pending;
        struct imap_cmd *in_progress, **in_progress_append;
        struct imap_buffer buf; /* this is BIG, so put it last */
};

struct imap_store {
        struct store gen;
        int uidvalidity;
        struct imap *imap;
        const char *prefix;
        unsigned /*currentnc:1,*/ trashnc:1;
};

struct imap_cmd_cb {
        int (*cont)(struct imap_store *ctx, struct imap_cmd *cmd, const char *prompt);
        void (*done)(struct imap_store *ctx, struct imap_cmd *cmd, int response);
        void *ctx;
        char *data;
        int dlen;
        int uid;
        unsigned create:1, trycreate:1;
};

struct imap_cmd {
        struct imap_cmd *next;
        struct imap_cmd_cb cb;
        char *cmd;
        int tag;
};

#define CAP(cap) (imap->caps & (1 << (cap)))

enum CAPABILITY {
        NOLOGIN = 0,
        UIDPLUS,
        LITERALPLUS,
        NAMESPACE,
        STARTTLS,
};

static const char *cap_list[] = {
        "LOGINDISABLED",
        "UIDPLUS",
        "LITERAL+",
        "NAMESPACE",
        "STARTTLS",
};

#define RESP_OK    0
#define RESP_NO    1
#define RESP_BAD   2

static int get_cmd_result(struct imap_store *ctx, struct imap_cmd *tcmd);


static const char *Flags[] = {
        "Draft",
        "Flagged",
        "Answered",
        "Seen",
        "Deleted",
};

#ifndef NO_OPENSSL
static void ssl_socket_perror(const char *func)
{
        fprintf(stderr, "%s: %s\n", func, ERR_error_string(ERR_get_error(), 0));
}
#endif

static void socket_perror(const char *func, struct imap_socket *sock, int ret)
{
#ifndef NO_OPENSSL
        if (sock->ssl) {
                int sslerr = SSL_get_error(sock->ssl, ret);
                switch (sslerr) {
                case SSL_ERROR_NONE:
                        break;
                case SSL_ERROR_SYSCALL:
                        perror("SSL_connect");
                        break;
                default:
                        ssl_socket_perror("SSL_connect");
                        break;
                }
        } else
#endif
        {
                if (ret < 0)
                        perror(func);
                else
                        fprintf(stderr, "%s: unexpected EOF\n", func);
        }
}

static int ssl_socket_connect(struct imap_socket *sock, int use_tls_only, int verify)
{
#ifdef NO_OPENSSL
        fprintf(stderr, "SSL requested but SSL support not compiled in\n");
        return -1;
#else
        SSL_METHOD *meth;
        SSL_CTX *ctx;
        int ret;

        SSL_library_init();
        SSL_load_error_strings();

        if (use_tls_only)
                meth = TLSv1_method();
        else
                meth = SSLv23_method();

        if (!meth) {
                ssl_socket_perror("SSLv23_method");
                return -1;
        }

        ctx = SSL_CTX_new(meth);

        if (verify)
                SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER, NULL);

        if (!SSL_CTX_set_default_verify_paths(ctx)) {
                ssl_socket_perror("SSL_CTX_set_default_verify_paths");
                return -1;
        }
        sock->ssl = SSL_new(ctx);
        if (!sock->ssl) {
                ssl_socket_perror("SSL_new");
                return -1;
        }
        if (!SSL_set_fd(sock->ssl, sock->fd)) {
                ssl_socket_perror("SSL_set_fd");
                return -1;
        }

        ret = SSL_connect(sock->ssl);
        if (ret <= 0) {
                socket_perror("SSL_connect", sock, ret);
                return -1;
        }

        return 0;
#endif
}

static int socket_read(struct imap_socket *sock, char *buf, int len)
{
        ssize_t n;
#ifndef NO_OPENSSL
        if (sock->ssl)
                n = SSL_read(sock->ssl, buf, len);
        else
#endif
                n = xread(sock->fd, buf, len);
        if (n <= 0) {
                socket_perror("read", sock, n);
                close(sock->fd);
                sock->fd = -1;
        }
        return n;
}

static int socket_write(struct imap_socket *sock, const char *buf, int len)
{
        int n;
#ifndef NO_OPENSSL
        if (sock->ssl)
                n = SSL_write(sock->ssl, buf, len);
        else
#endif
                n = write_in_full(sock->fd, buf, len);
        if (n != len) {
                socket_perror("write", sock, n);
                close(sock->fd);
                sock->fd = -1;
        }
        return n;
}

static void socket_shutdown(struct imap_socket *sock)
{
#ifndef NO_OPENSSL
        if (sock->ssl) {
                SSL_shutdown(sock->ssl);
                SSL_free(sock->ssl);
        }
#endif
        close(sock->fd);
}

/* simple line buffering */
static int buffer_gets(struct imap_buffer *b, char **s)
{
        int n;
        int start = b->offset;

        *s = b->buf + start;

        for (;;) {
                /* make sure we have enough data to read the \r\n sequence */
                if (b->offset + 1 >= b->bytes) {
                        if (start) {
                                /* shift down used bytes */
                                *s = b->buf;

                                assert(start <= b->bytes);
                                n = b->bytes - start;

                                if (n)
                                        memmove(b->buf, b->buf + start, n);
                                b->offset -= start;
                                b->bytes = n;
                                start = 0;
                        }

                        n = socket_read(&b->sock, b->buf + b->bytes,
                                         sizeof(b->buf) - b->bytes);

                        if (n <= 0)
                                return -1;

                        b->bytes += n;
                }

                if (b->buf[b->offset] == '\r') {
                        assert(b->offset + 1 < b->bytes);
                        if (b->buf[b->offset + 1] == '\n') {
                                b->buf[b->offset] = 0;  /* terminate the string */
                                b->offset += 2; /* next line */
                                if (Verbose)
                                        puts(*s);
                                return 0;
                        }
                }

                b->offset++;
        }
        /* not reached */
}

static void imap_info(const char *msg, ...)
{
        va_list va;

        if (!Quiet) {
                va_start(va, msg);
                vprintf(msg, va);
                va_end(va);
                fflush(stdout);
        }
}

static void imap_warn(const char *msg, ...)
{
        va_list va;

        if (Quiet < 2) {
                va_start(va, msg);
                vfprintf(stderr, msg, va);
                va_end(va);
        }
}

static char *next_arg(char **s)
{
        char *ret;

        if (!s || !*s)
                return NULL;
        while (isspace((unsigned char) **s))
                (*s)++;
        if (!**s) {
                *s = NULL;
                return NULL;
        }
        if (**s == '"') {
                ++*s;
                ret = *s;
                *s = strchr(*s, '"');
        } else {
                ret = *s;
                while (**s && !isspace((unsigned char) **s))
                        (*s)++;
        }
        if (*s) {
                if (**s)
                        *(*s)++ = 0;
                if (!**s)
                        *s = NULL;
        }
        return ret;
}

static void free_generic_messages(struct message *msgs)
{
        struct message *tmsg;

        for (; msgs; msgs = tmsg) {
                tmsg = msgs->next;
                free(msgs);
        }
}

static int nfsnprintf(char *buf, int blen, const char *fmt, ...)
{
        int ret;
        va_list va;

        va_start(va, fmt);
        if (blen <= 0 || (unsigned)(ret = vsnprintf(buf, blen, fmt, va)) >= (unsigned)blen)
                die("Fatal: buffer too small. Please report a bug.\n");
        va_end(va);
        return ret;
}

static struct {
        unsigned char i, j, s[256];
} rs;

static void arc4_init(void)
{
        int i, fd;
        unsigned char j, si, dat[128];

        if ((fd = open("/dev/urandom", O_RDONLY)) < 0 && (fd = open("/dev/random", O_RDONLY)) < 0) {
                fprintf(stderr, "Fatal: no random number source available.\n");
                exit(3);
        }
        if (read_in_full(fd, dat, 128) != 128) {
                fprintf(stderr, "Fatal: cannot read random number source.\n");
                exit(3);
        }
        close(fd);

        for (i = 0; i < 256; i++)
                rs.s[i] = i;
        for (i = j = 0; i < 256; i++) {
                si = rs.s[i];
                j += si + dat[i & 127];
                rs.s[i] = rs.s[j];
                rs.s[j] = si;
        }
        rs.i = rs.j = 0;

        for (i = 0; i < 256; i++)
                arc4_getbyte();
}

static unsigned char arc4_getbyte(void)
{
        unsigned char si, sj;

        rs.i++;
        si = rs.s[rs.i];
        rs.j += si;
        sj = rs.s[rs.j];
        rs.s[rs.i] = sj;
        rs.s[rs.j] = si;
        return rs.s[(si + sj) & 0xff];
}

static struct imap_cmd *v_issue_imap_cmd(struct imap_store *ctx,
                                         struct imap_cmd_cb *cb,
                                         const char *fmt, va_list ap)
{
        struct imap *imap = ctx->imap;
        struct imap_cmd *cmd;
        int n, bufl;
        char buf[1024];

        cmd = xmalloc(sizeof(struct imap_cmd));
        nfvasprintf(&cmd->cmd, fmt, ap);
        cmd->tag = ++imap->nexttag;

        if (cb)
                cmd->cb = *cb;
        else
                memset(&cmd->cb, 0, sizeof(cmd->cb));

        while (imap->literal_pending)
                get_cmd_result(ctx, NULL);

        bufl = nfsnprintf(buf, sizeof(buf), cmd->cb.data ? CAP(LITERALPLUS) ?
                           "%d %s{%d+}\r\n" : "%d %s{%d}\r\n" : "%d %s\r\n",
                           cmd->tag, cmd->cmd, cmd->cb.dlen);
        if (Verbose) {
                if (imap->num_in_progress)
                        printf("(%d in progress) ", imap->num_in_progress);
                if (memcmp(cmd->cmd, "LOGIN", 5))
                        printf(">>> %s", buf);
                else
                        printf(">>> %d LOGIN <user> <pass>\n", cmd->tag);
        }
        if (socket_write(&imap->buf.sock, buf, bufl) != bufl) {
                free(cmd->cmd);
                free(cmd);
                if (cb)
                        free(cb->data);
                return NULL;
        }
        if (cmd->cb.data) {
                if (CAP(LITERALPLUS)) {
                        n = socket_write(&imap->buf.sock, cmd->cb.data, cmd->cb.dlen);
                        free(cmd->cb.data);
                        if (n != cmd->cb.dlen ||
                            (n = socket_write(&imap->buf.sock, "\r\n", 2)) != 2) {
                                free(cmd->cmd);
                                free(cmd);
                                return NULL;
                        }
                        cmd->cb.data = NULL;
                } else
                        imap->literal_pending = 1;
        } else if (cmd->cb.cont)
                imap->literal_pending = 1;
        cmd->next = NULL;
        *imap->in_progress_append = cmd;
        imap->in_progress_append = &cmd->next;
        imap->num_in_progress++;
        return cmd;
}

static struct imap_cmd *issue_imap_cmd(struct imap_store *ctx,
                                       struct imap_cmd_cb *cb,
                                       const char *fmt, ...)
{
        struct imap_cmd *ret;
        va_list ap;

        va_start(ap, fmt);
        ret = v_issue_imap_cmd(ctx, cb, fmt, ap);
        va_end(ap);
        return ret;
}

static int imap_exec(struct imap_store *ctx, struct imap_cmd_cb *cb,
                     const char *fmt, ...)
{
        va_list ap;
        struct imap_cmd *cmdp;

        va_start(ap, fmt);
        cmdp = v_issue_imap_cmd(ctx, cb, fmt, ap);
        va_end(ap);
        if (!cmdp)
                return RESP_BAD;

        return get_cmd_result(ctx, cmdp);
}

static int imap_exec_m(struct imap_store *ctx, struct imap_cmd_cb *cb,
                       const char *fmt, ...)
{
        va_list ap;
        struct imap_cmd *cmdp;

        va_start(ap, fmt);
        cmdp = v_issue_imap_cmd(ctx, cb, fmt, ap);
        va_end(ap);
        if (!cmdp)
                return DRV_STORE_BAD;

        switch (get_cmd_result(ctx, cmdp)) {
        case RESP_BAD: return DRV_STORE_BAD;
        case RESP_NO: return DRV_MSG_BAD;
        default: return DRV_OK;
        }
}

static int is_atom(struct imap_list *list)
{
        return list && list->val && list->val != NIL && list->val != LIST;
}

static int is_list(struct imap_list *list)
{
        return list && list->val == LIST;
}

static void free_list(struct imap_list *list)
{
        struct imap_list *tmp;

        for (; list; list = tmp) {
                tmp = list->next;
                if (is_list(list))
                        free_list(list->child);
                else if (is_atom(list))
                        free(list->val);
                free(list);
        }
}

static int parse_imap_list_l(struct imap *imap, char **sp, struct imap_list **curp, int level)
{
        struct imap_list *cur;
        char *s = *sp, *p;
        int n, bytes;

        for (;;) {
                while (isspace((unsigned char)*s))
                        s++;
                if (level && *s == ')') {
                        s++;
                        break;
                }
                *curp = cur = xmalloc(sizeof(*cur));
                curp = &cur->next;
                cur->val = NULL; /* for clean bail */
                if (*s == '(') {
                        /* sublist */
                        s++;
                        cur->val = LIST;
                        if (parse_imap_list_l(imap, &s, &cur->child, level + 1))
                                goto bail;
                } else if (imap && *s == '{') {
                        /* literal */
                        bytes = cur->len = strtol(s + 1, &s, 10);
                        if (*s != '}')
                                goto bail;

                        s = cur->val = xmalloc(cur->len);

                        /* dump whats left over in the input buffer */
                        n = imap->buf.bytes - imap->buf.offset;

                        if (n > bytes)
                                /* the entire message fit in the buffer */
                                n = bytes;

                        memcpy(s, imap->buf.buf + imap->buf.offset, n);
                        s += n;
                        bytes -= n;

                        /* mark that we used part of the buffer */
                        imap->buf.offset += n;

                        /* now read the rest of the message */
                        while (bytes > 0) {
                                if ((n = socket_read(&imap->buf.sock, s, bytes)) <= 0)
                                        goto bail;
                                s += n;
                                bytes -= n;
                        }

                        if (buffer_gets(&imap->buf, &s))
                                goto bail;
                } else if (*s == '"') {
                        /* quoted string */
                        s++;
                        p = s;
                        for (; *s != '"'; s++)
                                if (!*s)
                                        goto bail;
                        cur->len = s - p;
                        s++;
                        cur->val = xmemdupz(p, cur->len);
                } else {
                        /* atom */
                        p = s;
                        for (; *s && !isspace((unsigned char)*s); s++)
                                if (level && *s == ')')
                                        break;
                        cur->len = s - p;
                        if (cur->len == 3 && !memcmp("NIL", p, 3))
                                cur->val = NIL;
                        else
                                cur->val = xmemdupz(p, cur->len);
                }

                if (!level)
                        break;
                if (!*s)
                        goto bail;
        }
        *sp = s;
        *curp = NULL;
        return 0;

bail:
        *curp = NULL;
        return -1;
}

static struct imap_list *parse_imap_list(struct imap *imap, char **sp)
{
        struct imap_list *head;

        if (!parse_imap_list_l(imap, sp, &head, 0))
                return head;
        free_list(head);
        return NULL;
}

static struct imap_list *parse_list(char **sp)
{
        return parse_imap_list(NULL, sp);
}

static void parse_capability(struct imap *imap, char *cmd)
{
        char *arg;
        unsigned i;

        imap->caps = 0x80000000;
        while ((arg = next_arg(&cmd)))
                for (i = 0; i < ARRAY_SIZE(cap_list); i++)
                        if (!strcmp(cap_list[i], arg))
                                imap->caps |= 1 << i;
        imap->rcaps = imap->caps;
}

static int parse_response_code(struct imap_store *ctx, struct imap_cmd_cb *cb,
                               char *s)
{
        struct imap *imap = ctx->imap;
        char *arg, *p;

        if (*s != '[')
                return RESP_OK;         /* no response code */
        s++;
        if (!(p = strchr(s, ']'))) {
                fprintf(stderr, "IMAP error: malformed response code\n");
                return RESP_BAD;
        }
        *p++ = 0;
        arg = next_arg(&s);
        if (!strcmp("UIDVALIDITY", arg)) {
                if (!(arg = next_arg(&s)) || !(ctx->gen.uidvalidity = atoi(arg))) {
                        fprintf(stderr, "IMAP error: malformed UIDVALIDITY status\n");
                        return RESP_BAD;
                }
        } else if (!strcmp("UIDNEXT", arg)) {
                if (!(arg = next_arg(&s)) || !(imap->uidnext = atoi(arg))) {
                        fprintf(stderr, "IMAP error: malformed NEXTUID status\n");
                        return RESP_BAD;
                }
        } else if (!strcmp("CAPABILITY", arg)) {
                parse_capability(imap, s);
        } else if (!strcmp("ALERT", arg)) {
                /* RFC2060 says that these messages MUST be displayed
                 * to the user
                 */
                for (; isspace((unsigned char)*p); p++);
                fprintf(stderr, "*** IMAP ALERT *** %s\n", p);
        } else if (cb && cb->ctx && !strcmp("APPENDUID", arg)) {
                if (!(arg = next_arg(&s)) || !(ctx->gen.uidvalidity = atoi(arg)) ||
                    !(arg = next_arg(&s)) || !(*(int *)cb->ctx = atoi(arg))) {
                        fprintf(stderr, "IMAP error: malformed APPENDUID status\n");
                        return RESP_BAD;
                }
        }
        return RESP_OK;
}

static int get_cmd_result(struct imap_store *ctx, struct imap_cmd *tcmd)
{
        struct imap *imap = ctx->imap;
        struct imap_cmd *cmdp, **pcmdp, *ncmdp;
        char *cmd, *arg, *arg1, *p;
        int n, resp, resp2, tag;

        for (;;) {
                if (buffer_gets(&imap->buf, &cmd))
                        return RESP_BAD;

                arg = next_arg(&cmd);
                if (*arg == '*') {
                        arg = next_arg(&cmd);
                        if (!arg) {
                                fprintf(stderr, "IMAP error: unable to parse untagged response\n");
                                return RESP_BAD;
                        }

                        if (!strcmp("NAMESPACE", arg)) {
                                imap->ns_personal = parse_list(&cmd);
                                imap->ns_other = parse_list(&cmd);
                                imap->ns_shared = parse_list(&cmd);
                        } else if (!strcmp("OK", arg) || !strcmp("BAD", arg) ||
                                   !strcmp("NO", arg) || !strcmp("BYE", arg)) {
                                if ((resp = parse_response_code(ctx, NULL, cmd)) != RESP_OK)
                                        return resp;
                        } else if (!strcmp("CAPABILITY", arg))
                                parse_capability(imap, cmd);
                        else if ((arg1 = next_arg(&cmd))) {
                                if (!strcmp("EXISTS", arg1))
                                        ctx->gen.count = atoi(arg);
                                else if (!strcmp("RECENT", arg1))
                                        ctx->gen.recent = atoi(arg);
                        } else {
                                fprintf(stderr, "IMAP error: unable to parse untagged response\n");
                                return RESP_BAD;
                        }
                } else if (!imap->in_progress) {
                        fprintf(stderr, "IMAP error: unexpected reply: %s %s\n", arg, cmd ? cmd : "");
                        return RESP_BAD;
                } else if (*arg == '+') {
                        /* This can happen only with the last command underway, as
                           it enforces a round-trip. */
                        cmdp = (struct imap_cmd *)((char *)imap->in_progress_append -
                               offsetof(struct imap_cmd, next));
                        if (cmdp->cb.data) {
                                n = socket_write(&imap->buf.sock, cmdp->cb.data, cmdp->cb.dlen);
                                free(cmdp->cb.data);
                                cmdp->cb.data = NULL;
                                if (n != (int)cmdp->cb.dlen)
                                        return RESP_BAD;
                        } else if (cmdp->cb.cont) {
                                if (cmdp->cb.cont(ctx, cmdp, cmd))
                                        return RESP_BAD;
                        } else {
                                fprintf(stderr, "IMAP error: unexpected command continuation request\n");
                                return RESP_BAD;
                        }
                        if (socket_write(&imap->buf.sock, "\r\n", 2) != 2)
                                return RESP_BAD;
                        if (!cmdp->cb.cont)
                                imap->literal_pending = 0;
                        if (!tcmd)
                                return DRV_OK;
                } else {
                        tag = atoi(arg);
                        for (pcmdp = &imap->in_progress; (cmdp = *pcmdp); pcmdp = &cmdp->next)
                                if (cmdp->tag == tag)
                                        goto gottag;
                        fprintf(stderr, "IMAP error: unexpected tag %s\n", arg);
                        return RESP_BAD;
                gottag:
                        if (!(*pcmdp = cmdp->next))
                                imap->in_progress_append = pcmdp;
                        imap->num_in_progress--;
                        if (cmdp->cb.cont || cmdp->cb.data)
                                imap->literal_pending = 0;
                        arg = next_arg(&cmd);
                        if (!strcmp("OK", arg))
                                resp = DRV_OK;
                        else {
                                if (!strcmp("NO", arg)) {
                                        if (cmdp->cb.create && cmd && (cmdp->cb.trycreate || !memcmp(cmd, "[TRYCREATE]", 11))) { /* SELECT, APPEND or UID COPY */
                                                p = strchr(cmdp->cmd, '"');
                                                if (!issue_imap_cmd(ctx, NULL, "CREATE \"%.*s\"", strchr(p + 1, '"') - p + 1, p)) {
                                                        resp = RESP_BAD;
                                                        goto normal;
                                                }
                                                /* not waiting here violates the spec, but a server that does not
                                                   grok this nonetheless violates it too. */
                                                cmdp->cb.create = 0;
                                                if (!(ncmdp = issue_imap_cmd(ctx, &cmdp->cb, "%s", cmdp->cmd))) {
                                                        resp = RESP_BAD;
                                                        goto normal;
                                                }
                                                free(cmdp->cmd);
                                                free(cmdp);
                                                if (!tcmd)
                                                        return 0;       /* ignored */
                                                if (cmdp == tcmd)
                                                        tcmd = ncmdp;
                                                continue;
                                        }
                                        resp = RESP_NO;
                                } else /*if (!strcmp("BAD", arg))*/
                                        resp = RESP_BAD;
                                fprintf(stderr, "IMAP command '%s' returned response (%s) - %s\n",
                                         memcmp(cmdp->cmd, "LOGIN", 5) ?
                                                        cmdp->cmd : "LOGIN <user> <pass>",
                                                        arg, cmd ? cmd : "");
                        }
                        if ((resp2 = parse_response_code(ctx, &cmdp->cb, cmd)) > resp)
                                resp = resp2;
                normal:
                        if (cmdp->cb.done)
                                cmdp->cb.done(ctx, cmdp, resp);
                        free(cmdp->cb.data);
                        free(cmdp->cmd);
                        free(cmdp);
                        if (!tcmd || tcmd == cmdp)
                                return resp;
                }
        }
        /* not reached */
}

static void imap_close_server(struct imap_store *ictx)
{
        struct imap *imap = ictx->imap;

        if (imap->buf.sock.fd != -1) {
                imap_exec(ictx, NULL, "LOGOUT");
                socket_shutdown(&imap->buf.sock);
        }
        free_list(imap->ns_personal);
        free_list(imap->ns_other);
        free_list(imap->ns_shared);
        free(imap);
}

static void imap_close_store(struct store *ctx)
{
        imap_close_server((struct imap_store *)ctx);
        free_generic_messages(ctx->msgs);
        free(ctx);
}

static struct store *imap_open_store(struct imap_server_conf *srvc)
{
        struct imap_store *ctx;
        struct imap *imap;
        char *arg, *rsp;
        struct hostent *he;
        struct sockaddr_in addr;
        int s, a[2], preauth;
        pid_t pid;

        ctx = xcalloc(sizeof(*ctx), 1);

        ctx->imap = imap = xcalloc(sizeof(*imap), 1);
        imap->buf.sock.fd = -1;
        imap->in_progress_append = &imap->in_progress;

        /* open connection to IMAP server */

        if (srvc->tunnel) {
                imap_info("Starting tunnel '%s'... ", srvc->tunnel);

                if (socketpair(PF_UNIX, SOCK_STREAM, 0, a)) {
                        perror("socketpair");
                        exit(1);
                }

                pid = fork();
                if (pid < 0)
                        _exit(127);
                if (!pid) {
                        if (dup2(a[0], 0) == -1 || dup2(a[0], 1) == -1)
                                _exit(127);
                        close(a[0]);
                        close(a[1]);
                        execl("/bin/sh", "sh", "-c", srvc->tunnel, NULL);
                        _exit(127);
                }

                close(a[0]);

                imap->buf.sock.fd = a[1];

                imap_info("ok\n");
        } else {
                memset(&addr, 0, sizeof(addr));
                addr.sin_port = htons(srvc->port);
                addr.sin_family = AF_INET;

                imap_info("Resolving %s... ", srvc->host);
                he = gethostbyname(srvc->host);
                if (!he) {
                        perror("gethostbyname");
                        goto bail;
                }
                imap_info("ok\n");

                addr.sin_addr.s_addr = *((int *) he->h_addr_list[0]);

                s = socket(PF_INET, SOCK_STREAM, 0);

                imap_info("Connecting to %s:%hu... ", inet_ntoa(addr.sin_addr), ntohs(addr.sin_port));
                if (connect(s, (struct sockaddr *)&addr, sizeof(addr))) {
                        close(s);
                        perror("connect");
                        goto bail;
                }

                imap->buf.sock.fd = s;

                if (srvc->use_ssl &&
                    ssl_socket_connect(&imap->buf.sock, 0, srvc->ssl_verify)) {
                        close(s);
                        goto bail;
                }
                imap_info("ok\n");
        }

        /* read the greeting string */
        if (buffer_gets(&imap->buf, &rsp)) {
                fprintf(stderr, "IMAP error: no greeting response\n");
                goto bail;
        }
        arg = next_arg(&rsp);
        if (!arg || *arg != '*' || (arg = next_arg(&rsp)) == NULL) {
                fprintf(stderr, "IMAP error: invalid greeting response\n");
                goto bail;
        }
        preauth = 0;
        if (!strcmp("PREAUTH", arg))
                preauth = 1;
        else if (strcmp("OK", arg) != 0) {
                fprintf(stderr, "IMAP error: unknown greeting response\n");
                goto bail;
        }
        parse_response_code(ctx, NULL, rsp);
        if (!imap->caps && imap_exec(ctx, NULL, "CAPABILITY") != RESP_OK)
                goto bail;

        if (!preauth) {
#ifndef NO_OPENSSL
                if (!srvc->use_ssl && CAP(STARTTLS)) {
                        if (imap_exec(ctx, 0, "STARTTLS") != RESP_OK)
                                goto bail;
                        if (ssl_socket_connect(&imap->buf.sock, 1,
                                               srvc->ssl_verify))
                                goto bail;
                        /* capabilities may have changed, so get the new capabilities */
                        if (imap_exec(ctx, 0, "CAPABILITY") != RESP_OK)
                                goto bail;
                }
#endif
                imap_info("Logging in...\n");
                if (!srvc->user) {
                        fprintf(stderr, "Skipping server %s, no user\n", srvc->host);
                        goto bail;
                }
                if (!srvc->pass) {
                        char prompt[80];
                        sprintf(prompt, "Password (%s@%s): ", srvc->user, srvc->host);
                        arg = getpass(prompt);
                        if (!arg) {
                                perror("getpass");
                                exit(1);
                        }
                        if (!*arg) {
                                fprintf(stderr, "Skipping account %s@%s, no password\n", srvc->user, srvc->host);
                                goto bail;
                        }
                        /*
                         * getpass() returns a pointer to a static buffer.  make a copy
                         * for long term storage.
                         */
                        srvc->pass = xstrdup(arg);
                }
                if (CAP(NOLOGIN)) {
                        fprintf(stderr, "Skipping account %s@%s, server forbids LOGIN\n", srvc->user, srvc->host);
                        goto bail;
                }
                if (!imap->buf.sock.ssl)
                        imap_warn("*** IMAP Warning *** Password is being "
                                  "sent in the clear\n");
                if (imap_exec(ctx, NULL, "LOGIN \"%s\" \"%s\"", srvc->user, srvc->pass) != RESP_OK) {
                        fprintf(stderr, "IMAP error: LOGIN failed\n");
                        goto bail;
                }
        } /* !preauth */

        ctx->prefix = "";
        ctx->trashnc = 1;
        return (struct store *)ctx;

bail:
        imap_close_store(&ctx->gen);
        return NULL;
}

static int imap_make_flags(int flags, char *buf)
{
        const char *s;
        unsigned i, d;

        for (i = d = 0; i < ARRAY_SIZE(Flags); i++)
                if (flags & (1 << i)) {
                        buf[d++] = ' ';
                        buf[d++] = '\\';
                        for (s = Flags[i]; *s; s++)
                                buf[d++] = *s;
                }
        buf[0] = '(';
        buf[d++] = ')';
        return d;
}

#define TUIDL 8

static int imap_store_msg(struct store *gctx, struct msg_data *data, int *uid)
{
        struct imap_store *ctx = (struct imap_store *)gctx;
        struct imap *imap = ctx->imap;
        struct imap_cmd_cb cb;
        char *fmap, *buf;
        const char *prefix, *box;
        int ret, i, j, d, len, extra, nocr;
        int start, sbreak = 0, ebreak = 0;
        char flagstr[128], tuid[TUIDL * 2 + 1];

        memset(&cb, 0, sizeof(cb));

        fmap = data->data;
        len = data->len;
        nocr = !data->crlf;
        extra = 0, i = 0;
        if (!CAP(UIDPLUS) && uid) {
        nloop:
                start = i;
                while (i < len)
                        if (fmap[i++] == '\n') {
                                extra += nocr;
                                if (i - 2 + nocr == start) {
                                        sbreak = ebreak = i - 2 + nocr;
                                        goto mktid;
                                }
                                if (!memcmp(fmap + start, "X-TUID: ", 8)) {
                                        extra -= (ebreak = i) - (sbreak = start) + nocr;
                                        goto mktid;
                                }
                                goto nloop;
                        }
                /* invalid message */
                free(fmap);
                return DRV_MSG_BAD;
        mktid:
                for (j = 0; j < TUIDL; j++)
                        sprintf(tuid + j * 2, "%02x", arc4_getbyte());
                extra += 8 + TUIDL * 2 + 2;
        }
        if (nocr)
                for (; i < len; i++)
                        if (fmap[i] == '\n')
                                extra++;

        cb.dlen = len + extra;
        buf = cb.data = xmalloc(cb.dlen);
        i = 0;
        if (!CAP(UIDPLUS) && uid) {
                if (nocr) {
                        for (; i < sbreak; i++)
                                if (fmap[i] == '\n') {
                                        *buf++ = '\r';
                                        *buf++ = '\n';
                                } else
                                        *buf++ = fmap[i];
                } else {
                        memcpy(buf, fmap, sbreak);
                        buf += sbreak;
                }
                memcpy(buf, "X-TUID: ", 8);
                buf += 8;
                memcpy(buf, tuid, TUIDL * 2);
                buf += TUIDL * 2;
                *buf++ = '\r';
                *buf++ = '\n';
                i = ebreak;
        }
        if (nocr) {
                for (; i < len; i++)
                        if (fmap[i] == '\n') {
                                *buf++ = '\r';
                                *buf++ = '\n';
                        } else
                                *buf++ = fmap[i];
        } else
                memcpy(buf, fmap + i, len - i);

        free(fmap);

        d = 0;
        if (data->flags) {
                d = imap_make_flags(data->flags, flagstr);
                flagstr[d++] = ' ';
        }
        flagstr[d] = 0;

        if (!uid) {
                box = gctx->conf->trash;
                prefix = ctx->prefix;
                cb.create = 1;
                if (ctx->trashnc)
                        imap->caps = imap->rcaps & ~(1 << LITERALPLUS);
        } else {
                box = gctx->name;
                prefix = !strcmp(box, "INBOX") ? "" : ctx->prefix;
                cb.create = 0;
        }
        cb.ctx = uid;
        ret = imap_exec_m(ctx, &cb, "APPEND \"%s%s\" %s", prefix, box, flagstr);
        imap->caps = imap->rcaps;
        if (ret != DRV_OK)
                return ret;
        if (!uid)
                ctx->trashnc = 0;
        else
                gctx->count++;

        return DRV_OK;
}

#define CHUNKSIZE 0x1000

static int read_message(FILE *f, struct msg_data *msg)
{
        struct strbuf buf;

        memset(msg, 0, sizeof(*msg));
        strbuf_init(&buf, 0);

        do {
                if (strbuf_fread(&buf, CHUNKSIZE, f) <= 0)
                        break;
        } while (!feof(f));

        msg->len  = buf.len;
        msg->data = strbuf_detach(&buf, NULL);
        return msg->len;
}

static int count_messages(struct msg_data *msg)
{
        int count = 0;
        char *p = msg->data;

        while (1) {
                if (!prefixcmp(p, "From ")) {
                        count++;
                        p += 5;
                }
                p = strstr(p+5, "\nFrom ");
                if (!p)
                        break;
                p++;
        }
        return count;
}

static int split_msg(struct msg_data *all_msgs, struct msg_data *msg, int *ofs)
{
        char *p, *data;

        memset(msg, 0, sizeof *msg);
        if (*ofs >= all_msgs->len)
                return 0;

        data = &all_msgs->data[*ofs];
        msg->len = all_msgs->len - *ofs;

        if (msg->len < 5 || prefixcmp(data, "From "))
                return 0;

        p = strchr(data, '\n');
        if (p) {
                p = &p[1];
                msg->len -= p-data;
                *ofs += p-data;
                data = p;
        }

        p = strstr(data, "\nFrom ");
        if (p)
                msg->len = &p[1] - data;

        msg->data = xmemdupz(data, msg->len);
        *ofs += msg->len;
        return 1;
}

static struct imap_server_conf server = {
        NULL,   /* name */
        NULL,   /* tunnel */
        NULL,   /* host */
        0,      /* port */
        NULL,   /* user */
        NULL,   /* pass */
        0,      /* use_ssl */
        1,      /* ssl_verify */
};

static char *imap_folder;

static int git_imap_config(const char *key, const char *val, void *cb)
{
        char imap_key[] = "imap.";

        if (strncmp(key, imap_key, sizeof imap_key - 1))
                return 0;

        if (!val)
                return config_error_nonbool(key);

        key += sizeof imap_key - 1;

        if (!strcmp("folder", key)) {
                imap_folder = xstrdup(val);
        } else if (!strcmp("host", key)) {
                if (!prefixcmp(val, "imap:"))
                        val += 5;
                else if (!prefixcmp(val, "imaps:")) {
                        val += 6;
                        server.use_ssl = 1;
                }
                if (!prefixcmp(val, "//"))
                        val += 2;
                server.host = xstrdup(val);
        } else if (!strcmp("user", key))
                server.user = xstrdup(val);
        else if (!strcmp("pass", key))
                server.pass = xstrdup(val);
        else if (!strcmp("port", key))
                server.port = git_config_int(key, val);
        else if (!strcmp("tunnel", key))
                server.tunnel = xstrdup(val);
        else if (!strcmp("sslverify", key))
                server.ssl_verify = git_config_bool(key, val);
        return 0;
}

int main(int argc, char **argv)
{
        struct msg_data all_msgs, msg;
        struct store *ctx = NULL;
        int uid = 0;
        int ofs = 0;
        int r;
        int total, n = 0;
        int nongit_ok;

        /* init the random number generator */
        arc4_init();

        setup_git_directory_gently(&nongit_ok);
        git_config(git_imap_config, NULL);

        if (!server.port)
                server.port = server.use_ssl ? 993 : 143;

        if (!imap_folder) {
                fprintf(stderr, "no imap store specified\n");
                return 1;
        }
        if (!server.host) {
                if (!server.tunnel) {
                        fprintf(stderr, "no imap host specified\n");
                        return 1;
                }
                server.host = "tunnel";
        }

        /* read the messages */
        if (!read_message(stdin, &all_msgs)) {
                fprintf(stderr, "nothing to send\n");
                return 1;
        }

        total = count_messages(&all_msgs);
        if (!total) {
                fprintf(stderr, "no messages to send\n");
                return 1;
        }

        /* write it to the imap server */
        ctx = imap_open_store(&server);
        if (!ctx) {
                fprintf(stderr, "failed to open store\n");
                return 1;
        }

        fprintf(stderr, "sending %d message%s\n", total, (total != 1) ? "s" : "");
        ctx->name = imap_folder;
        while (1) {
                unsigned percent = n * 100 / total;
                fprintf(stderr, "%4u%% (%d/%d) done\r", percent, n, total);
                if (!split_msg(&all_msgs, &msg, &ofs))
                        break;
                r = imap_store_msg(ctx, &msg, &uid);
                if (r != DRV_OK)
                        break;
                n++;
        }
        fprintf(stderr, "\n");

        imap_close_store(ctx);

        return 0;
}