/**
 * @file parser_yin.c
 * @author David Sedlák <xsedla1d@stud.fit.vutbr.cz>
 * @brief YIN parser.
 *
 * Copyright (c) 2015 - 2019 CESNET, z.s.p.o.
 *
 * This source code is licensed under BSD 3-Clause License (the "License").
 * You may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     https://opensource.org/licenses/BSD-3-Clause
 */
#include "common.h"

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

#include "context.h"
#include "dict.h"
#include "xml.h"
#include "tree.h"
#include "tree_schema.h"
#include "tree_schema_internal.h"
#include "parser_yin.h"

/**
 * @brief check if given string is URI of yin namespace.
 * @param ns Namespace URI to check.
 *
 * @return true if ns equals YIN_NS_URI false otherwise.
 */
#define IS_YIN_NS(ns) (strcmp(ns, YIN_NS_URI) == 0)

const char *const yin_attr_list[] = {
    [YIN_ARG_NAME] = "name",
    [YIN_ARG_TARGET_NODE] = "target-node",
    [YIN_ARG_MODULE] = "module",
    [YIN_ARG_VALUE] = "value",
    [YIN_ARG_TEXT] = "text",
    [YIN_ARG_CONDITION] = "condition",
    [YIN_ARG_URI] = "uri",
    [YIN_ARG_DATE] = "date",
    [YIN_ARG_TAG] = "tag",
    [YIN_ARG_XMLNS] = "xmlns",
};

enum yang_keyword
yin_match_keyword(const char *data, size_t len, size_t prefix_len)
{
    if (!data || len == 0) {
        return YANG_NONE;
    }

    const char *start = data;
    enum yang_keyword kw = lysp_match_kw(NULL, &data);


    if (prefix_len != 0) {
        return YANG_CUSTOM;
    }

    if (data - start == (long int)len) {
        return kw;
    } else {
        return YANG_NONE;
    }
}


enum YIN_ARGUMENT
match_argument_name(const char *name, size_t len)
{
    enum YIN_ARGUMENT arg = YIN_ARG_UNKNOWN;
    size_t already_read = 0;
    LY_CHECK_RET(len == 0, YIN_ARG_NONE);

#define IF_ARG(STR, LEN, STMT) if (!strncmp((name) + already_read, STR, LEN)) {already_read+=LEN;arg=STMT;}
#define IF_ARG_PREFIX(STR, LEN) if (!strncmp((name) + already_read, STR, LEN)) {already_read+=LEN;
#define IF_ARG_PREFIX_END }

    switch (*name) {
    case 'x':
        already_read += 1;
        IF_ARG("mlns", 4, YIN_ARG_XMLNS);
        break;
    case 'c':
        already_read += 1;
        IF_ARG("ondition", 8, YIN_ARG_CONDITION);
        break;

    case 'd':
        already_read += 1;
        IF_ARG("ate", 3, YIN_ARG_DATE);
        break;

    case 'm':
        already_read += 1;
        IF_ARG("odule", 5, YIN_ARG_MODULE);
        break;

    case 'n':
        already_read += 1;
        IF_ARG("ame", 3, YIN_ARG_NAME);
        break;

    case 't':
        already_read += 1;
        IF_ARG_PREFIX("a", 1)
            IF_ARG("g", 1, YIN_ARG_TAG)
            else IF_ARG("rget-node", 9, YIN_ARG_TARGET_NODE)
        IF_ARG_PREFIX_END
        else IF_ARG("ext", 3, YIN_ARG_TEXT)
        break;

    case 'u':
        already_read += 1;
        IF_ARG("ri", 2, YIN_ARG_URI)
        break;

    case 'v':
        already_read += 1;
        IF_ARG("alue", 4, YIN_ARG_VALUE);
        break;
    }

    /* whole argument must be matched */
    if (already_read != len) {
        arg = YIN_ARG_UNKNOWN;
    }

#undef IF_ARG
#undef IF_ARG_PREFIX
#undef IF_ARG_PREFIX_END

    return arg;
}

/**
 * @brief parse yin argument, arg_val is unchanged if argument arg_type wasn't found.
 *
 * @param[in] xml_ctx XML parser context.
 * @param[in,out] data Data to read from.
 * @param[in] arg_type Type of argument that is expected in parsed element (use YIN_ARG_NONE for elements without special arguments).
 * @param[out] arg_val Where value of argument should be stored. Can be NULL if arg_type is specified as YIN_ARG_NONE.
 *
 * @return LY_ERR values.
 */
static LY_ERR
yin_parse_attribute(struct lyxml_context *xml_ctx, const char **data, enum YIN_ARGUMENT arg_type, const char **arg_val)
{
    LY_ERR ret = LY_SUCCESS;
    enum YIN_ARGUMENT arg = YIN_ARG_UNKNOWN;
    struct yin_arg_record *argument_array = NULL, *argument_record = NULL, *iter = NULL;
    const struct lyxml_ns *ns = NULL;

    /* load all attributes first */
    while (xml_ctx->status == LYXML_ATTRIBUTE) {
        LY_ARRAY_NEW_GOTO(xml_ctx->ctx, argument_array, argument_record, ret, cleanup);
        ret = lyxml_get_attribute(xml_ctx, data, &argument_record->prefix, &argument_record->prefix_len,
                                  &argument_record->name, &argument_record->name_len);
        LY_CHECK_ERR_GOTO(ret != LY_SUCCESS, LOGMEM(xml_ctx->ctx), cleanup);

        if (xml_ctx->status == LYXML_ATTR_CONTENT) {
            argument_record->content = NULL;
            argument_record->content_len = 0;
            argument_record->dynamic_content = 0;
            ret = lyxml_get_string(xml_ctx, data, &argument_record->content, &argument_record->content_len,
                                   &argument_record->content, &argument_record->content_len, &argument_record->dynamic_content);
            LY_CHECK_ERR_GOTO(ret != LY_SUCCESS, LOGMEM(xml_ctx->ctx), cleanup);
        }
    }

    /* validation of attributes */
    LY_ARRAY_FOR(argument_array, struct yin_arg_record, iter) {
        ns = lyxml_ns_get(xml_ctx, iter->prefix, iter->prefix_len);
        if (ns && IS_YIN_NS(ns->uri)) {
            arg = match_argument_name(iter->name, iter->name_len);
            if (arg == YIN_ARG_NONE) {
                continue;
            } else if (arg == arg_type) {
                if (iter->dynamic_content) {
                    *arg_val = lydict_insert_zc(xml_ctx->ctx, iter->content);
                } else {
                    *arg_val = lydict_insert(xml_ctx->ctx, iter->content, iter->content_len);
                    LY_CHECK_ERR_GOTO(!(*arg_val), LOGMEM(xml_ctx->ctx); ret = LY_EMEM, cleanup);
                }
            } else {
                if (iter->dynamic_content) {
                    free(iter->content);
                }
                LOGERR(xml_ctx->ctx, LYVE_SYNTAX_YIN, "Unexpected attribute \"%.*s\".", iter->name_len, iter->name);
                ret = LY_EVALID;
                goto cleanup;
            }
        }
    }

cleanup:
    LY_ARRAY_FREE(argument_array);
    return ret;
}

/**
 * @brief Parse content of whole element as text.
 *
 * @param[in] xml_ctx Xml context.
 * @param[in,out] data Data to read from.
 * @param[out] value Where content of element should be stored.
 *
 * @return LY_ERR values.
 */
LY_ERR
parse_text_element(struct lyxml_context *xml_ctx, const char **data, const char **value)
{
    LY_ERR ret = LY_SUCCESS;
    char *buf = NULL, *out = NULL;
    const char *prefix = NULL, *name = NULL;
    size_t buf_len = 0, out_len = 0, prefix_len = 0, name_len = 0;
    int dynamic = 0;

    ret = yin_parse_attribute(xml_ctx, data, YIN_ARG_NONE, NULL);
    LY_CHECK_RET(ret);
    LY_CHECK_RET(xml_ctx->status != LYXML_ELEM_CONTENT, LY_EVALID);

    if (xml_ctx->status == LYXML_ELEM_CONTENT) {
        ret = lyxml_get_string(xml_ctx, data, &buf, &buf_len, &out, &out_len, &dynamic);
        LY_CHECK_RET(ret);
        if (dynamic) {
            *value = lydict_insert_zc(xml_ctx->ctx, buf);
        } else {
            *value = lydict_insert(xml_ctx->ctx, out, out_len);
            LY_CHECK_ERR_RET(!(*value), LOGMEM(xml_ctx->ctx), LY_EMEM);
        }
    }

    ret = lyxml_get_element(xml_ctx, data, &prefix, &prefix_len, &name, &name_len);
    LY_CHECK_RET(ret);

    return LY_SUCCESS;
}

/**
 * @brief function to parse meta tags eg. elements with text element as child
 *
 * @param[in] xml_ctx Xml context.
 * @param[in,out] data Data to read from.
 * @param[out] value Where the content of meta tag should be stored.
 *
 * @return LY_ERR values.
 */
LY_ERR
yin_parse_meta_element(struct lyxml_context *xml_ctx, const char **data, const char **value)
{
    LY_ERR ret = LY_SUCCESS;
    char *buf = NULL, *out = NULL;
    const char *prefix = NULL, *name = NULL;
    size_t buf_len = 0, out_len = 0, prefix_len = 0, name_len = 0;
    int dynamic = 0;
    const struct lyxml_ns *ns = NULL;
    enum YIN_ARGUMENT arg = YANG_NONE;

    ret = yin_parse_attribute(xml_ctx, data, YIN_ARG_NONE, NULL);
    LY_CHECK_RET(ret);
    LY_CHECK_RET(xml_ctx->status != LYXML_ELEM_CONTENT, LY_EVALID);

    ret = lyxml_get_string(xml_ctx, data, &buf, &buf_len, &out, &out_len, &dynamic);
    LY_CHECK_ERR_RET(ret != LY_EINVAL, LOGVAL_YANG(xml_ctx, LYVE_SYNTAX_YIN, "Expected \"text\" element as child of meta element."), LY_EINVAL);

    /* loop over all child elements and parse them */
    while (xml_ctx->status == LYXML_ELEMENT) {
        ret = lyxml_get_element(xml_ctx, data, &prefix, &prefix_len, &name, &name_len);
        LY_CHECK_RET(ret);
        if (name) {
            ns = lyxml_ns_get(xml_ctx, prefix, prefix_len);
            /* check if child element is from yin namespace, elements from other namespaces are silently ignored */
            if (IS_YIN_NS(ns->uri)) {
                arg = match_argument_name(name, name_len);
                if (arg == YIN_ARG_TEXT) {
                    parse_text_element(xml_ctx, data, value);
                } else {
                    LOGERR(xml_ctx->ctx, LYVE_SYNTAX_YIN, "Unexpected child element \"%.*s\".", name_len, name);
                    return LY_EVALID;
                }
            }

        } else {
            /* end of meta element reached */
            break;
        }

    }

    return LY_SUCCESS;
}

/**
 * @brief Parse revision date.
 *
 * @param[in] xml_ctx Xml context.
 * @param[in,out] data Data to read from.
 * @param[in,out] rev Array to store the parsed value in.
 * @param[in,out] exts Extension instances to add to.
 *
 * @return LY_ERR values.
 */
static LY_ERR
yin_parse_revision_date(struct lyxml_context *xml_ctx, const char **data, char *rev, struct lysp_ext_instance **exts)
{
    LY_ERR ret = LY_SUCCESS;
    const char *temp_rev;

    if (rev[0]) {
        LOGVAL_YANG(xml_ctx, LY_VCODE_DUPSTMT, "revision-date");
        return LY_EVALID;
    }

    LY_CHECK_RET(yin_parse_attribute(xml_ctx, data, YIN_ARG_DATE, &temp_rev))
    LY_CHECK_RET(ret != LY_SUCCESS, ret);
    LY_CHECK_RET(lysp_check_date((struct lys_parser_ctx *)xml_ctx, temp_rev, strlen(temp_rev), "revision-date") != LY_SUCCESS, LY_EVALID);

    strcpy(rev, temp_rev);
    lydict_remove(xml_ctx->ctx, temp_rev);
    /* TODO extension */

    return ret;
}

LY_ERR
yin_parse_import(struct lyxml_context *xml_ctx, const char *module_prefix, const char **data, struct lysp_import **imports)
{
    LY_ERR ret = LY_SUCCESS;
    enum yang_keyword kw;
    struct lysp_import *imp;
    const char *prefix, *name;
    size_t prefix_len, name_len;

    /* allocate sized array for imports */
    LY_ARRAY_NEW_RET(xml_ctx->ctx, *imports, imp, LY_EVALID);

    /* parse import attributes  */
    LY_CHECK_RET(yin_parse_attribute(xml_ctx, data, YIN_ARG_MODULE, &imp->name));

    while ((ret = lyxml_get_element(xml_ctx, data, &prefix, &prefix_len, &name, &name_len) == LY_SUCCESS && name != NULL)) {
        kw = yin_match_keyword(name, name_len, prefix_len);
        switch (kw) {
        case YANG_PREFIX:
            LY_CHECK_ERR_RET(imp->prefix, LOGVAL_YANG(xml_ctx, LY_VCODE_DUPSTMT, "prefix"), LY_EVALID);
            LY_CHECK_RET(yin_parse_attribute(xml_ctx, data, YIN_ARG_VALUE, &imp->prefix));
            LY_CHECK_RET(lysp_check_prefix((struct lys_parser_ctx *)xml_ctx, *imports, module_prefix, &imp->prefix), LY_EVALID);
            break;
        case YANG_DESCRIPTION:
            LY_CHECK_ERR_RET(imp->dsc, LOGVAL_YANG(xml_ctx, LY_VCODE_DUPSTMT, "description"), LY_EVALID);
            yin_parse_meta_element(xml_ctx, data, &imp->dsc);
            break;
        case YANG_REFERENCE:
            LY_CHECK_ERR_RET(imp->ref, LOGVAL_YANG(xml_ctx, LY_VCODE_DUPSTMT, "reference"), LY_EVALID);
            yin_parse_meta_element(xml_ctx, data, &imp->ref);
            break;
        case YANG_REVISION_DATE:
            yin_parse_revision_date(xml_ctx, data, imp->rev, &imp->exts);
            break;
        case YANG_CUSTOM:
            /* TODO parse extension */
            break;
        default:
            LOGERR(xml_ctx->ctx, LY_VCODE_UNEXP_SUBELEM, name_len, name, "import");
            return LY_EVALID;
        }
    }

    LY_CHECK_ERR_RET(!imp->prefix, LOGVAL_YANG(xml_ctx, LY_VCODE_MISSATTR, "prefix", "import"), LY_EVALID);
    return ret;
}

/**
 * @brief Parse status statement.
 *
 * @param[in] xml_ctx Xml context.
 * @param[in,out] data Data to read from.
 * @param[in,out] flags Flags to add to.
 * @param[in,out] exts Extension instances to add to.
 *
 * @return LY_ERR values.
 */
LY_ERR
yin_parse_status(struct lyxml_context *xml_ctx, const char **data, uint16_t *flags, struct lysp_ext_instance **exts)
{
    LY_ERR ret = LY_SUCCESS;
    enum yang_keyword kw = YANG_NONE;
    const char *value = NULL, *prefix = NULL, *name = NULL;
    char *out;
    size_t prefix_len = 0, name_len = 0, out_len = 0;
    int dynamic = 0;

    if (*flags & LYS_STATUS_MASK) {
        LOGVAL_YANG(xml_ctx, LY_VCODE_DUPELEM, "status");
        return LY_EVALID;
    }

    LY_CHECK_RET(yin_parse_attribute(xml_ctx, data, YIN_ARG_VALUE, &value));
    /* TODO separate to function and check if dynamic was set to 1 in case of error */
    ret = lyxml_get_string(xml_ctx, data, &out, &out_len, &out, &out_len, &dynamic);
    LY_CHECK_ERR_RET(ret != LY_EINVAL, LOGVAL_YANG(xml_ctx, LYVE_SYNTAX_YIN, "Expected new element after status element."), LY_EINVAL);

    if (strcmp(value, "current") == 0) {
        *flags |= LYS_STATUS_CURR;
    } else if (strcmp(value, "deprecated") == 0) {
        *flags |= LYS_STATUS_DEPRC;
    } else if (strcmp(value, "obsolete") == 0) {
        *flags |= LYS_STATUS_OBSLT;
    } else {
        LOGVAL_YANG(xml_ctx, LY_VCODE_INVAL_YIN, value, "status");
        lydict_remove(xml_ctx->ctx, value);
        return LY_EVALID;
    }
    lydict_remove(xml_ctx->ctx, value);

    while (xml_ctx->status == LYXML_ELEMENT) {
        LY_CHECK_RET(lyxml_get_element(xml_ctx, data, &prefix, &prefix_len, &name, &name_len));
        if (!name) {
            break;
        }

        kw = yin_match_keyword(name, name_len, prefix_len);
        switch (kw) {
            case YANG_CUSTOM:
                /* TODO parse extension instance */
                break;
            default:
                LOGVAL_YANG(xml_ctx, LY_VCODE_INCHILDSTMT_YIN, name_len, name, 6, "status");
        }
    }

    return ret;
}

/**
 * @brief Parse the extension statement.
 *
 * @param[in] xml_ctx Xml context.
 * @param[in,out] data Data to read from.
 * @param[in,out] extensions Extensions to add to.
 *
 * @return LY_ERR values.
 */
LY_ERR
yin_parse_extension(struct lyxml_context *xml_ctx, const char **data, struct lysp_ext **extensions)
{
    LY_ERR ret = LY_SUCCESS;
    struct lysp_ext *ex;
    const char *prefix = NULL, *name = NULL;
    char *out = NULL;
    size_t out_len = 0, prefix_len = 0, name_len = 0;
    int dynamic = 0;
    enum yang_keyword kw = YANG_NONE;

    LY_ARRAY_NEW_RET(xml_ctx->ctx, *extensions, ex, LY_EMEM);
    yin_parse_attribute(xml_ctx, data, YIN_ARG_NAME, &ex->name);
    ret = lyxml_get_string(xml_ctx, data, &out, &out_len, &out, &out_len, &dynamic);
    LY_CHECK_ERR_RET(ret != LY_EINVAL, LOGVAL_YANG(xml_ctx, LYVE_SYNTAX_YIN, "Expected new element after extension element."), LY_EINVAL);

    while (xml_ctx->status == LYXML_ELEMENT) {
        ret = lyxml_get_element(xml_ctx, data, &prefix, &prefix_len, &name, &name_len);
        LY_CHECK_RET(ret);
        if (!name) {
            break;
        }

        kw = yin_match_keyword(name, name_len, prefix_len);
        switch (kw) {
            case YANG_ARGUMENT:
                break;
            case YANG_DESCRIPTION:
                LY_CHECK_RET(yin_parse_meta_element(xml_ctx, data, &ex->dsc));
                break;
            case YANG_REFERENCE:
                LY_CHECK_RET(yin_parse_meta_element(xml_ctx, data, &ex->ref));
                break;
            case YANG_STATUS:
                LY_CHECK_RET(yin_parse_status(xml_ctx, data, &ex->flags, &ex->exts));
                break;
            case YANG_CUSTOM:
                /* TODO parse extension instance */
                break;
            default:
                LOGVAL_YANG(xml_ctx, LY_VCODE_INCHILDSTMT_YIN, name_len, name, 9, "extension");
                return LY_EVALID;
        }
    }

    return ret;
}

/**
 * @brief Parse extension instance.
 *
 * @param[in]
 */
LY_ERR
yin_parse_extension_instane(struct lyxml_context *xml_ctx, const char *data)
{

    return LY_SUCCESS;
}

/**
 * @brief Parse module substatements.
 *
 * @param[in] xml_ctx Xml context.
 * @param[in,out] data Data to read from.
 * @param[out] mod Parsed module structure.
 *
 * @return LY_ERR values.
 */
LY_ERR
parse_mod(struct lyxml_context *xml_ctx, const char **data, struct lysp_module **mod)
{
    LY_ERR ret = LY_SUCCESS;
    enum yang_keyword kw = YANG_NONE;
    const char *prefix, *name;
    size_t prefix_len, name_len;
    enum yang_module_stmt mod_stmt = Y_MOD_MODULE_HEADER;

    char *buf = NULL, *out = NULL;
    size_t buf_len = 0, out_len = 0;
    int dynamic = 0;

    yin_parse_attribute(xml_ctx, data, YIN_ARG_NAME, &(*mod)->mod->name);

    LY_CHECK_ERR_RET(!(*mod)->mod->name, LOGVAL_YANG(xml_ctx, LYVE_SYNTAX_YIN, "Missing argument name of a module"), LY_EVALID);
    ret = lyxml_get_string(xml_ctx, data, &buf, &buf_len, &out, &out_len, &dynamic);
    LY_CHECK_ERR_RET(ret != LY_EINVAL, LOGVAL_YANG(xml_ctx, LYVE_SYNTAX_YIN, "Expected new xml element after module element."), LY_EINVAL);

    /* loop over all elements and parse them */
    while (xml_ctx->status != LYXML_END) {
#define CHECK_ORDER(SECTION) \
        if (mod_stmt > SECTION) {return LY_EVALID;}mod_stmt = SECTION

        switch (kw) {
        /* module header */
        case YANG_NAMESPACE:
        case YANG_PREFIX:
            CHECK_ORDER(Y_MOD_MODULE_HEADER);
            break;
        case YANG_YANG_VERSION:
            CHECK_ORDER(Y_MOD_MODULE_HEADER);
            break;
        /* linkage */
        case YANG_INCLUDE:
        case YANG_IMPORT:
            CHECK_ORDER(Y_MOD_LINKAGE);
            break;
        /* meta */
        case YANG_ORGANIZATION:
        case YANG_CONTACT:
        case YANG_DESCRIPTION:
        case YANG_REFERENCE:
            CHECK_ORDER(Y_MOD_META);
            break;

        /* revision */
        case YANG_REVISION:
            CHECK_ORDER(Y_MOD_REVISION);
            break;
        /* body */
        case YANG_ANYDATA:
        case YANG_ANYXML:
        case YANG_AUGMENT:
        case YANG_CHOICE:
        case YANG_CONTAINER:
        case YANG_DEVIATION:
        case YANG_EXTENSION:
        case YANG_FEATURE:
        case YANG_GROUPING:
        case YANG_IDENTITY:
        case YANG_LEAF:
        case YANG_LEAF_LIST:
        case YANG_LIST:
        case YANG_NOTIFICATION:
        case YANG_RPC:
        case YANG_TYPEDEF:
        case YANG_USES:
        case YANG_CUSTOM:
            mod_stmt = Y_MOD_BODY;
            break;
        default:
            /* error will be handled in the next switch */
            break;
        }
#undef CHECK_ORDER

        LY_CHECK_RET(lyxml_get_element(xml_ctx, data, &prefix, &prefix_len, &name, &name_len));

        if (name) {
            kw = yin_match_keyword(name, name_len, prefix_len);
            switch (kw) {

            /* module header */
            case YANG_NAMESPACE:
                LY_CHECK_RET(yin_parse_attribute(xml_ctx, data, YIN_ARG_URI, &(*mod)->mod->ns));
                break;
            case YANG_PREFIX:
                LY_CHECK_RET(yin_parse_attribute(xml_ctx, data, YIN_ARG_VALUE, &(*mod)->mod->prefix));
                break;

            /* linkage */
            case YANG_IMPORT:
                yin_parse_import(xml_ctx, (*mod)->mod->prefix, data, &(*mod)->imports);
                break;

            /* meta */
            case YANG_ORGANIZATION:
                LY_CHECK_RET(yin_parse_meta_element(xml_ctx, data, &(*mod)->mod->org));
                break;
            case YANG_CONTACT:
                LY_CHECK_RET(yin_parse_meta_element(xml_ctx, data, &(*mod)->mod->contact));
                break;
            case YANG_DESCRIPTION:
                LY_CHECK_RET(yin_parse_meta_element(xml_ctx, data, &(*mod)->mod->dsc));
                break;
            case YANG_REFERENCE:
                LY_CHECK_RET(yin_parse_meta_element(xml_ctx, data, &(*mod)->mod->ref));
                break;
            /* revision */

            /*body */
            case YANG_EXTENSION:
                LY_CHECK_RET(yin_parse_extension(xml_ctx, data, &(*mod)->extensions));
                break;

            default:
                return LY_EVALID;
                break;
            }
        }
    }

    return LY_SUCCESS;
}

/**
 * @brief Parse yin submodule.
 *
 * @param[in] ctx Context of YANG schemas.
 * @param[in,out] data Data to read from.
 * @param[out] submod Parsed submodule structure.
 *
 * @return LY_ERR values.
 */
LY_ERR
yin_parse_submodule(struct ly_ctx *ctx, const char *data, struct lysp_submodule **submod)
{
    LY_ERR ret = LY_SUCCESS;
    enum yang_keyword kw = YANG_NONE;
    struct lyxml_context xml_ctx;
    struct lysp_submodule *mod_p = NULL;
    const char *prefix, *name;
    size_t prefix_len, name_len;

    /* initialize xml context */
    memset(&xml_ctx, 0, sizeof xml_ctx);
    xml_ctx.ctx = ctx;
    xml_ctx.line = 1;

    /* check submodule */
    ret = lyxml_get_element(&xml_ctx, &data, &prefix, &prefix_len, &name, &name_len);
    LY_CHECK_GOTO(ret != LY_SUCCESS, cleanup);
    kw = yin_match_keyword(name, name_len, prefix_len);
    if (kw == YANG_MODULE) {
        LOGERR(ctx, LY_EDENIED, "Input data contains module in situation when a submodule is expected.");
        ret = LY_EINVAL;
        goto cleanup;
    } else if (kw != YANG_SUBMODULE) {
        LOGVAL_YANG(&xml_ctx, LYVE_SYNTAX, "Invalid keyword \"%s\", expected \"module\" or \"submodule\".",
               ly_stmt2str(kw));
        ret = LY_EVALID;
        goto cleanup;
    }

    /* allocate module */
    mod_p = calloc(1, sizeof *mod_p);
    LY_CHECK_ERR_GOTO(!mod_p, LOGMEM(ctx), cleanup);
    mod_p->parsing = 1;

    /* parser submodule substatements */
    /* ret = parse_submod(&xml_ctx, &data, mod_p); */
    LY_CHECK_GOTO(ret, cleanup);

    mod_p->parsing = 0;
    *submod = mod_p;

cleanup:
    if (ret) {
        lysp_submodule_free(ctx, mod_p);
    }

    lyxml_context_clear(&xml_ctx);
    return ret;
}

LY_ERR
yin_parse_module(struct ly_ctx *ctx, const char *data, struct lys_module *mod)
{
    LY_ERR ret = LY_SUCCESS;
    enum yang_keyword kw = YANG_NONE;
    struct lys_parser_ctx parser_ctx;
    struct lyxml_context *xml_ctx = (struct lyxml_context *)&parser_ctx;
    struct lysp_module *mod_p = NULL;
    const char *prefix, *name;
    size_t prefix_len, name_len;

    /* initialize xml context */
    memset(&parser_ctx, 0, sizeof parser_ctx);
    xml_ctx->ctx = ctx;
    xml_ctx->line = 1;

    /* check submodule */
    ret = lyxml_get_element(xml_ctx, &data, &prefix, &prefix_len, &name, &name_len);
    LY_CHECK_GOTO(ret != LY_SUCCESS, cleanup);
    kw = yin_match_keyword(name, name_len, prefix_len);
    if (kw == YANG_SUBMODULE) {
        LOGERR(ctx, LY_EDENIED, "Input data contains submodule which cannot be parsed directly without its main module.");
        ret = LY_EINVAL;
        goto cleanup;
    } else if (kw != YANG_MODULE) {
        LOGVAL_YANG(xml_ctx, LYVE_SYNTAX, "Invalid keyword \"%s\", expected \"module\" or \"submodule\".",
                    ly_stmt2str(kw));
        ret = LY_EVALID;
        goto cleanup;
    }

    /* allocate module */
    mod_p = calloc(1, sizeof *mod_p);
    LY_CHECK_ERR_GOTO(!mod_p, LOGMEM(ctx), cleanup);
    mod_p->mod = mod;
    mod_p->parsing = 1;

    /* parser module substatements */
    ret = parse_mod(xml_ctx, &data, &mod_p);
    LY_CHECK_GOTO(ret, cleanup);

    mod_p->parsing = 0;
    mod->parsed = mod_p;

cleanup:
    if (ret) {
        lysp_module_free(mod_p);
    }

    lyxml_context_clear(xml_ctx);
    return ret;
}