// vim: set ft=c:

#define IMAP_ROUTINE(name) \
name: { \
    return imap_routine_##name(cmd, node, ssl, state); \
}
#define IMAP_ROUTINE_BAD_TAG \
    imap_write(node, ssl, "%s BAD\n", cmd.tag);
#define IMAP_ROUTINE_BAD \
    imap_write(node, ssl, "* BAD\n");
#define IMAP_CHECK_ARGS(x) \
    if (cmd.p_count != x) { \
        IMAP_ROUTINE_BAD_TAG \
        return IMAP_FAIL; \
    }
#define IMAP_ROUTINE_END imap_flush(node, ssl);
#define IMAP_ROUTINE_OK(routine) \
    imap_write(node, ssl, "%s OK " #routine " completed\n", cmd.tag);
#define IMAP_ROUTINE_NO(routine) \
    imap_write(node, ssl, "%s NO " #routine " completed\n", cmd.tag);
#define IMAP_STRING(fmt, ...) \
    imap_write(node, ssl, fmt, ##__VA_ARGS__);
#define IMAP_NLINE imap_write(node, ssl, "\n");
#define IMAP_CHECK_STATE(s) \
    if (state != IMAP_STATE_##s) { \
        IMAP_ROUTINE_BAD \
        return IMAP_FAIL; \
    }

static inline uint8_t imap_routine_capability(imap_cmd cmd, client_list *node, uint8_t ssl, uint8_t state)
{
    char *cap;
    IMAP_STRING("* CAPABILITY")
    if (!ssl) {
        for (int i=0; (cap = imap_capabilities[i]); i++) {
            IMAP_STRING(" %s", cap)
        }
    } else {
        for (int i=0; (cap = imaps_capabilities[i]); i++) {
            IMAP_STRING(" %s", cap)
        }
    }
    IMAP_NLINE;
    IMAP_ROUTINE_OK(CAPABILITY)
    IMAP_ROUTINE_END

    return IMAP_SUCCESS;
}

static inline uint8_t imap_routine_noop(imap_cmd cmd, client_list *node, uint8_t ssl, uint8_t state)
{
    IMAP_ROUTINE_OK(NOOP)
    IMAP_ROUTINE_END
    
    return IMAP_SUCCESS;
}

static inline uint8_t imap_routine_logout(imap_cmd cmd, client_list *node, uint8_t ssl, uint8_t state)
{
    IMAP_STRING("* BYE IMAP4rev1 Server logging out\n")
    IMAP_ROUTINE_OK(LOGOUT)
    IMAP_ROUTINE_END
    return IMAP_LOGOUT;
}

static inline uint8_t imap_routine_starttls(imap_cmd cmd, client_list *node, uint8_t ssl, uint8_t state)
{
    IMAP_CHECK_STATE(NO_AUTH)

    IMAP_STRING("%s OK Begin TLS negotiation now\n", cmd.tag)
    IMAP_ROUTINE_END
    return IMAP_STARTTLS;
}

static inline uint8_t imap_routine_auth(imap_cmd cmd, client_list *node, uint8_t ssl, uint8_t state)
{
    IMAP_CHECK_STATE(NO_AUTH)
    IMAP_CHECK_ARGS(1)

    int bytes;

    if (strcmp(cmd.params[0], "plain") == 0) {
        IMAP_STRING("+\n");
        if ((bytes = imap_read(node, buf, CMD_MAX_SIZE, ssl)) < 0) {
            perror("recv");
            syslog(LOG_ERR, "Failed to receive data.");
        } else if (bytes == 0) {
            return IMAP_LOGOUT;
        } else {
            buf[bytes] = '\0';
            printf("%s\n", buf);
        }
    } else {
        IMAP_ROUTINE_BAD_TAG
    }

    IMAP_ROUTINE_END
    return IMAP_SUCCESS;
}

static inline uint8_t imap_routine_login(imap_cmd cmd, client_list *node, uint8_t ssl, uint8_t state)
{
    IMAP_CHECK_STATE(NO_AUTH)
    IMAP_CHECK_ARGS(2)
    size_t users = sizeof(imap_users)/sizeof(struct user);
    uint8_t found = 0;

    for (size_t i=0; i < users; i++) {
        if (strcmp(cmd.params[0], imap_users[i].username) == 0) {
            char hash[65];
            auth_sha256(cmd.params[1], hash);
            if (strcmp(hash, imap_users[i].password) == 0) {
                IMAP_ROUTINE_OK(LOGIN)
                found = 1;
            }
        }
    }
    
    if (!found) {
        IMAP_ROUTINE_NO(LOGIN)
    }
    
    IMAP_ROUTINE_END
    return IMAP_SUCCESS;
}