//=-------------------------------------------------------------------------=//
//  XML management tools                                                     //
//                                                                           //
//  Copyright © 2021 The Gem-graph Project                                   //
//                                                                           //
//  This file is part of gem-graph.                                          //
//                                                                           //
//  This program is free software: you can redistribute it and/or modify     //
//  it under the terms of the GNU Affero General Public License as           //
//  published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.                      //
//                                                                           //
//  You should have received a copy of the GNU Affero General Public License //
//  along with this program.  If not, see <https://www.gnu.org/licenses/>.   //
//=-------------------------------------------------------------------------=//

#ifndef BASE_H
    #include "../include/base.h"
#endif

/* -------------------------------------------------------------------------- */

#include <string.h>
#include <stdlib.h>
#include <libxml2/libxml/xmlmemory.h>
#include <libxml2/libxml/parser.h>

/* -------------------------------------------------------------------------- */

static xmlDocPtr currentDocument = NULL;
static xmlNodePtr currentDocumentRoot = NULL;

/* -------------------------------------------------------------------------- */

// -------------------------------------------------------------------------- //
// Open and set a document as current document                                //
// -------------------------------------------------------------------------- //
static inline void XmlSetNewDocument(const char *filename)
{
    currentDocument = xmlParseFile(filename);

    if (currentDocument == NULL ) {
        printLog("%s not parsed successfully.\n", filename);
        xmlFreeDoc(currentDocument);
        currentDocument = NULL;
        return;
    }

    currentDocumentRoot = xmlDocGetRootElement(currentDocument);

    if (currentDocumentRoot == NULL ) {
        printLog("%s is invalid (no root)\n", filename);
        xmlFreeDoc(currentDocument);
        currentDocument = NULL;
        currentDocumentRoot = NULL;
        return;
    }
}

// -------------------------------------------------------------------------- //
// Close and unset current document                                           //
// -------------------------------------------------------------------------- //
static inline void XmlCloseCurrentDocument(void)
{
    xmlFreeDoc(currentDocument);
    currentDocumentRoot = NULL;
    currentDocument = NULL;
}

// -------------------------------------------------------------------------- //
// Reset current working root to document root                                //
// -------------------------------------------------------------------------- //
static inline void XmlResetWorkingRoot(void)
{
    currentDocumentRoot = xmlDocGetRootElement(currentDocument);
}

// -------------------------------------------------------------------------- //
// Parse content of a given XML tag                                           //
// -------------------------------------------------------------------------- //
static inline int XmlParseTag(const char* tagName, char *destination,
                              char destSize)
{
    char *curString;
    size_t cursor = 0;
    char res = 0;

    xmlNodePtr cur = currentDocumentRoot;

    //printLog("Asked for %s\n", tagName);

    // Enumerate all brothers in tree from current root
    while (cur != NULL) {
        //printLog("\tGot %s (res = %d)\n", cur->name, res);

        // Check if current tag is the asked tag
        if ((!xmlStrcmp(cur->name, (const xmlChar *)tagName))) {
            //printLog("\tFound %s\n", cur->name);
            curString = (char*)xmlNodeListGetString(currentDocument,
                                        cur->xmlChildrenNode, 1);
            //printLog("\t\tString : %s\n", curString);

            // Check there is text in that tag (and that is asked)
            if (destination && curString[0] != '\n') {
                cursor =
                    snprintf(
                        destination + cursor * sizeof(char),
                        destSize,
                        "%s\n",
                        curString);
                res++;
            }
            free(curString);
        }
            cur = cur->next;
    }
    return res;
}

// -------------------------------------------------------------------------- //
// Find a working root for a given tag                                        //
// -------------------------------------------------------------------------- //
static inline xmlNodePtr findWorkingRoot(const char *tagName,
                                         xmlNodePtr curRoot)
{
    xmlNodePtr cur = curRoot;
    xmlNodePtr recur;

    //printLog("Asked for %s\n", tagName);

    while (cur != NULL) {
        if ((!xmlStrcmp(cur->name, (const xmlChar *)tagName))){
            currentDocumentRoot = cur;
            return cur;
        }

        if (cur->xmlChildrenNode) {
            if ((recur =
                 findWorkingRoot(tagName,
                                 (xmlNodePtr)cur->xmlChildrenNode)) != NULL)
                return recur;
        }

        cur = cur->next;
    }

    return NULL;
}

// -------------------------------------------------------------------------- //
// Parse and validate an XML tree from given structural tree                  //
// and current document                                                       //
// -------------------------------------------------------------------------- //
static inline int XmlParseTree(ModelField_t *curTree)
{
    int currentOrSonCorrectlyParsed = 0;
    int curValueLen;

    while (curTree) {
        if (findWorkingRoot(
             curTree->tag,
             currentDocumentRoot->parent
                      ) == NULL) {
            printLog("Error : can't find a new root\n");
            return EBADF;
        }

        //printLog("Asked for %s\n", curTree->tag);

        // Try to parse current tag
        if (XmlParseTag(curTree->tag, curTree->destination,
                        curTree->size) != 0) {
            // There are values in that tag
            if (curTree->destination[0])
                if (!(curTree->destination[0] == '\0')) {
                    curValueLen = strlen(curTree->destination);

                    // Delete \n chars
                    for(int i = 0; i < curValueLen; i++) {
                        if(curTree->destination[i] == '\n') {
                            memmove(&curTree->destination[i],
                                    &curTree->destination[i+1],
                                    curValueLen - i);
                            curValueLen--;
                            i--;
                        }
                    }
                    printLog("Field %s: %s\n", curTree->tag, curTree->destination);
                }
        } else {
            // There aren't values in that tag
            if (curTree->mandatory) {
                // But it was mandatory
                printLog("Error : can't find %s\n", curTree->tag);
                return EBADF;
            }
        }

        if (curTree->son)
            currentOrSonCorrectlyParsed |= XmlParseTree(curTree->son);

        curTree = curTree->next;
    }
    return currentOrSonCorrectlyParsed;
}