/**
 * @file parser_yin.c
 * @author David Sedlák <xsedla1d@stud.fit.vutbr.cz>
 * @brief YIN parser.
 *
 * Copyright (c) 2015 - 2018 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"

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_UNKNOWN);

#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
 *
 * @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 spedified as YIN_ARG_NONE.
 */
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;
    const char *prefix, *name;
    size_t prefix_len, name_len;

    char *buf = NULL, *out = NULL;
    size_t buf_len = 0, out_len = 0;
    int dynamic;
    enum YIN_ARGUMENT arg = YIN_ARG_UNKNOWN;

    while (xml_ctx->status == LYXML_ATTRIBUTE) {
        ret = lyxml_get_attribute(xml_ctx, data, &prefix, &prefix_len, &name, &name_len);
        LY_CHECK_ERR_RET(ret != LY_SUCCESS, LOGMEM(xml_ctx->ctx), LY_EMEM);

        arg = match_argument_name(name, name_len);

        if (arg == arg_type) {
            LY_CHECK_RET(ret);
            ret = lyxml_get_string(xml_ctx, data, &buf, &buf_len, &out, &out_len, &dynamic);
            LY_CHECK_RET(ret);
            *arg_val = lydict_insert(xml_ctx->ctx, out, out_len);
            LY_CHECK_ERR_RET(!(*arg_val), LOGMEM(xml_ctx->ctx), LY_EMEM);
        } else if (arg_type == YIN_ARG_NONE) {
            continue;
        } else {
            /* unrecognized or unexpected attribute */
            /* TODO add name of attribute to error message */
            if (name) {
                LOGERR(xml_ctx->ctx, LY_EDENIED, "Invalid attribute");
                return LY_EVALID;
            }
        }
    }

    return LY_SUCCESS;
}

/**
 * @brief Parse content of whole element as text.
 *
 * @param[in] xml_ctx Xml context.
 * @param[in] data Data to read from.
 * @param[out] value Where content of element should be stored.
 */
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;
    size_t buf_len = 0, out_len = 0;
    int dynamic;

    ret = yin_parse_attribute(xml_ctx, data, YIN_ARG_NONE, NULL);
    LY_CHECK_RET(ret != LY_SUCCESS, 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);
        *value = lydict_insert(xml_ctx->ctx, out, out_len);
        LY_CHECK_ERR_RET(!(*value), LOGMEM(xml_ctx->ctx), LY_EMEM);
    }

    return LY_SUCCESS;
}

LY_ERR
parse_namespace(struct lyxml_context *xml_ctx, const char **data, const char **namespace)
{
    LY_ERR ret = LY_SUCCESS;

    ret = yin_parse_attribute(xml_ctx, data, YIN_ARG_URI, namespace);
    LY_CHECK_RET(ret != LY_SUCCESS, ret);

    return ret;
}

/**
 * @brief Parse prefix statement.
 *
 * @param[in] xml_ctx Xml context.
 * @param[in, out] data Data to reda from.
 * @param[out] prefix Where to store prefix value.
 *
 * @return LY_ERR values.
 */
LY_ERR
parse_prefix(struct lyxml_context *xml_ctx, const char **data, const char **prefix)
{
    LY_ERR ret = LY_SUCCESS;

    /* parse attributes */
    ret = yin_parse_attribute(xml_ctx, data, YIN_ARG_VALUE, prefix);
    LY_CHECK_RET(ret != LY_SUCCESS, ret);

    return ret;
}

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;
    }

    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  */
    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 = 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);
            parse_prefix(xml_ctx, data, &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);
            parse_text_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);
            parse_text_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:
            /* TODO log error */
            return LY_EVALID;
        }
    }

    /* TODO add log macro and log error */
    LY_CHECK_RET(!imp->prefix);
    return ret;
}

/**
 * @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;
    enum YIN_ARGUMENT arg = YIN_ARG_UNKNOWN;

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

    /* parse module attributes */
    while (xml_ctx->status == LYXML_ATTRIBUTE) {
        ret = lyxml_get_attribute(xml_ctx, data, &prefix, &prefix_len, &name, &name_len);
        LY_CHECK_ERR_RET(ret != LY_SUCCESS, LOGMEM(xml_ctx->ctx), LY_EMEM);

        arg = match_argument_name(name, name_len);

        switch (arg) {
        case YIN_ARG_NAME:
            /* check for multiple definitions of name */
            LY_CHECK_ERR_RET((*mod)->mod->name, LOGVAL_YANG(xml_ctx, LYVE_SYNTAX_YIN, "Duplicit definition of module name \"%s\"",
                                                            (*mod)->mod->name), LY_EEXIST);

            /* read module name */
            if (xml_ctx->status != LYXML_ATTR_CONTENT) {
                LOGVAL(xml_ctx->ctx, LY_VLOG_LINE, &xml_ctx->line, LYVE_SYNTAX, "Missing value of argument \"name\".");
            }
            ret = lyxml_get_string(xml_ctx, data, &buf, &buf_len, &out, &out_len, &dynamic);
            LY_CHECK_ERR_RET(ret != LY_SUCCESS, LOGMEM(xml_ctx->ctx), LY_EMEM);
            (*mod)->mod->name = lydict_insert(xml_ctx->ctx, out, out_len);
            LY_CHECK_ERR_RET(!(*mod)->mod->name, LOGMEM(xml_ctx->ctx), LY_EMEM);
            break;

        default:
            /* unrecognized attribute */
            /* unrecognized or unexpected attribute */
            /* TODO probably still can be from extension */
            if (arg != YIN_ARG_UNKNOWN || name) {
                LOGERR(xml_ctx->ctx, LY_EDENIED, "Invalid argument in module element");
                return LY_EVALID;
            }

            break;
        }
    }

    LY_CHECK_ERR_RET(!(*mod)->mod->name, LOGVAL_YANG(xml_ctx, LYVE_SYNTAX_YIN, "Missing argument name of a module", (*mod)->mod->name), LY_ENOTFOUND);

    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) {
/* TODO ADD error log to macro */
#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

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

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

            /* module header */
            case YANG_NAMESPACE:
                LY_CHECK_RET(parse_namespace(xml_ctx, data, &(*mod)->mod->ns));
                break;
            case YANG_PREFIX:
                LY_CHECK_RET(parse_prefix(xml_ctx, data, &(*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(parse_text_element(xml_ctx, data, &(*mod)->mod->org));
                break;
            case YANG_CONTACT:
                LY_CHECK_RET(parse_text_element(xml_ctx, data, &(*mod)->mod->contact));
                break;
            case YANG_DESCRIPTION:
                LY_CHECK_RET(parse_text_element(xml_ctx, data, &(*mod)->mod->dsc));
                break;
            case YANG_REFERENCE:
                LY_CHECK_RET(parse_text_element(xml_ctx, data, &(*mod)->mod->ref));
                break;

            default:
                return LY_EVALID;
                break;
            }
        }
    }

    return ret;
}

/**
 * @brief Parse yin submodule.
 *
 * @param[in] ctx Context of YANG schemas.
 * @param[in] data Data to read from.
 * @param[out] submod Module to write to.
 *
 * @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 = 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 = 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;
}