/*
 *      Gem-graph client
 *
 *      Desc: Model parsing functions
 *
 *  Copyright (C) 2023 Jean Sirmai <jean@a-lec.org>
 *  Copyright (C) 2024 Adrien Bourmault <neox@a-lec.org>
 *
 *  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 <http://www.gnu.org/licenses/>.
 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdbool.h>
#include <assert.h>
#include <limits.h>
#include <libxml/tree.h>
#include <libxml/parser.h>
#include <libxml/xmlreader.h> // http://xmlsoft.org/examples/#parse1.c
                              // https://gnome.pages.gitlab.gnome.org/libxml2/devhelp/general.html

#include "base.h"

#define READ_SITE 1 << 0
#define READ_WEIGHT 1 << 1
#define READ_X 1 << 2
#define READ_Y 1 << 3
#define READ_Z 1 << 4
#define SUCCESSFUL_READ_ARROW_X (READ_SITE | READ_WEIGHT | READ_X)
#define SUCCESSFUL_READ_ARROW_XY (READ_SITE | READ_WEIGHT | READ_X | READ_Y)
#define SUCCESSFUL_READ_ARROW_XYZ (READ_SITE | READ_WEIGHT | READ_X | READ_Y | READ_Z)

static xmlDocPtr model;
static xmlHashTablePtr model_hashtable;

bool model_init(const char *content, size_t length, const char *basename)
{
    xmlNode *node;

    /*
     * this initialize the library and check potential ABI mismatches
     * between the version it was compiled for and the actual shared
     * library used.
     */
    LIBXML_TEST_VERSION

	model = xmlReadMemory(content, length, basename, NULL, 0);

	if (model == NULL ) {
		return false;
	}

	node = xmlDocGetRootElement(model);

	if (node == NULL) {
		g_printerr("Empty XML model !\n");
		xmlFreeDoc(model);
		return false;
	}

	if (xmlStrcmp(node->name, (xmlChar *) "gem-graph-model")) {
		g_printerr("document of the wrong type, root node != gem-graph-model\n");
		xmlFreeDoc(model);
		return false;
	}

    model_hashtable = xmlHashCreate(0);

    if (model_hashtable == NULL) {
		g_printerr("Can't create model hash table !\n");
		xmlFreeDoc(model);
		return false;
    }

    return true;
}

bool model_shutdown(void)
{
    xmlFreeDoc(model);
    xmlHashFree(model_hashtable, NULL);

    // Cleanup function for the XML library
    xmlCleanupParser();

    // This is to debug memory for regression tests
    xmlMemoryDump();

    return true;
}

/******************************************************************************/

static inline xmlNodePtr getNextChild(xmlNodePtr node, xmlChar *last)
{
    while (node != NULL && xmlStrcmp(node->name, last)) {
        // //printf("   <>--- line n°%lu   <%s>\n", xmlGetLineNo(node), node->name);
        node = node->next;
    }
    return node;
}

static inline xmlChar* splitStrAtSlash(xmlChar *toSplit)
{
    toSplit = (xmlChar *)xmlStrchr(toSplit, '/');
    toSplit = xmlStrsub (toSplit, 1, xmlStrlen(toSplit));
    return toSplit;
}

static inline xmlChar* getFirstTag(xmlChar *path)
{
    xmlChar *preop = path;
    path = (xmlChar *)xmlStrchr(path, '/');
    path = xmlStrsub (path, 1, xmlStrlen(path));

    //printf("%s = %s + / + %s\n", preop,\
    xmlStrsub (preop, 0, xmlStrlen(preop) - xmlStrlen(path) - 1), path);

    return  xmlStrsub (preop, 0, xmlStrlen(preop) - xmlStrlen(path) - 1);
}

static inline xmlChar* getLastTag(xmlChar *path)
{
    while ((ulong)xmlStrchr (path, '/'))
        path = splitStrAtSlash((xmlChar *)path);

    // //printf("last tag in the path = <%s>\n", path);
    return path; // which is no more the given path but only its last tag !
}

/******************************************************************************/

static xmlNodePtr model_get_node(xmlChar *path)
{
    xmlNodePtr node;
    xmlChar *extrait;
    xmlChar *reste, *last, *affich;

    // Lookup for node from path in hash table
    node = xmlHashLookup(model_hashtable, path);

    // Found a node in hash table
    if (node) {
        return node;

    // no node found in hash table
    } else {
        reste = path;
        affich = reste;
        last = getLastTag(reste);
        node = xmlDocGetRootElement(model);

        while (xmlStrchr (reste, '/')) {
            extrait = getFirstTag(reste);
            reste = splitStrAtSlash((xmlChar *)reste);
            node = node->xmlChildrenNode;
            node = getNextChild(node, extrait);
        }

        if(node && xmlStrcmp(node->name, last)) {
            node = node->xmlChildrenNode;

            while (node && xmlStrcmp(node->name, last)) {
                node = node->next;
            }
            xmlHashAddEntry (model_hashtable, path, node);
        }

        return node;

    }

    return NULL;
}

/******************************************************************************/

static inline long model_get_node_long_attrib(xmlNodePtr node, char *id)
{
    xmlAttr *attribute;
    xmlChar* value;
    long ret_value;

    if (node && node->properties) {
        attribute = node->properties;
        while(attribute && attribute->name && attribute->children) {
            if (!xmlStrcmp(attribute->name, (const xmlChar *)id)) {
                value = xmlNodeListGetString(node->doc, attribute->children, 1);
                ret_value = strtol((char *)value, NULL, 0);
                xmlFree(value);
                return ret_value;
            }
            attribute = attribute->next;
        }
    }
    return 0;
}

static inline bool model_get_node_str_attrib(xmlNodePtr node,
                                             char *id,
                                             char *dest)
{
    xmlAttr *attribute;
    xmlChar* value;

    if (node && node->properties) {
        attribute = node->properties;
        while(attribute && attribute->name && attribute->children) {
            if (!xmlStrcmp(attribute->name, (const xmlChar *)id)) {
                value = xmlNodeListGetString(node->doc, attribute->children, 1);
                strcpy(dest, value);
                xmlFree(value);
                return true;
            }
            attribute = attribute->next;
        }
    }
    return false;
}

/******************************************************************************/

char model_get_dim(void)
{
    xmlAttr *attribute;
    xmlChar* value;
    xmlNodePtr node = model_get_node(
                        (xmlChar *)"parameters/space-param/dimension");

    if (xmlHasProp (node, (xmlChar *) "z")) return 3;
    if (xmlHasProp (node, (xmlChar *) "y")) return 2;
    if (xmlHasProp (node, (xmlChar *) "x")) return 1;
    return 0;
}

long model_get_dim_value(const char *axis)
{
    xmlAttr *attribute;
    xmlChar *value;
    long ret_value;
    xmlNodePtr node = model_get_node(
                        (xmlChar *)"parameters/space-param/dimension");

    return model_get_node_long_attrib(node, axis);
}

char model_get_multiplicity(void)
{
    xmlAttr *attribute;
    xmlChar* value;
    xmlNodePtr node = model_get_node(
                        (xmlChar *)"parameters/space-param/site_multiplicity");

    if (node->children)
        if (node->children->content)
            return (char)strtol((char *)node->children->content, NULL, 0);

    return 0;
}

bool model_get_next_state(char *new_state_id)
{
    static xmlNodePtr cur_node = NULL;
    xmlAttr *attribute;
    xmlChar *value;

    if (cur_node == NULL) {
        // Get first state
        cur_node = model_get_node((xmlChar *)"savedstates/state");

    } else {
        // Get next state
        if (cur_node->next)
            cur_node = cur_node->next;
        else
            return false;
    }

    // Lookup in properties
    if (model_get_node_str_attrib(cur_node, "id", new_state_id))
        return true;

    cur_node = NULL;
    return false;
}

long model_get_state_arrows_count(const char *state_id)
{
    xmlNodePtr cur_node = NULL;
    xmlAttr *attribute;
    long value = 0;
    bool found = false;
    char temp_char[25];
    uint check = 0; // bit field checker

    //printf("NEW CALL : cur_node = %p\n", cur_node);

    assert(state_id);

    // Get first state node
    cur_node = model_get_node((xmlChar *)"savedstates/state");

    // Lookup in properties
    while (cur_node && cur_node->properties) {
        attribute = cur_node->properties;

        // Look for the id attribute
        if (model_get_node_str_attrib(cur_node, "id", &temp_char)) {
            if (!xmlStrcmp(temp_char, (const xmlChar *)state_id)) {
                found = true;
                break;
            }
        }
        cur_node = cur_node->next;
    }

    // Check if the state has been found
    if (!found) {
        cur_node = NULL;
        return -1;
    }


    // Count arrows
    if (cur_node->children) {
        cur_node = cur_node->children;
        while (cur_node) {
            if (!xmlStrcmp(cur_node->name, (const xmlChar *)"arrow"))
                value++;
            cur_node = cur_node->next;
        }
    } else {
        return -1;
    }
    return value;
}

bool model_get_next_arrow(struct arrow_t *new_arrow,
                          const char *state_id,
                          char dimension)
{
    static xmlNodePtr cur_node = NULL;
    xmlAttr *attribute;
    xmlChar *value;
    bool found = false;
    char temp_char[25];
    uint check = 0; // bit field checker

    //printf("NEW CALL : cur_node = %p\n", cur_node);

    assert(new_arrow);
    assert(state_id);

    if (cur_node == NULL) {
        // Get first state node
        cur_node = model_get_node((xmlChar *)"savedstates/state");

        // Lookup in properties
        while (cur_node && cur_node->properties) {
            attribute = cur_node->properties;

            // Look for the id attribute
            if (model_get_node_str_attrib(cur_node, "id", &temp_char)) {
                if (!xmlStrcmp(temp_char, (const xmlChar *)state_id)) {
                    found = true;
                    break;
                }
            }
            cur_node = cur_node->next;
        }

        // Check if the state has been found
        if (!found) {
            cur_node = NULL;
            return false;
        }

        // Get first arrow
        if (cur_node->children) {
            cur_node = cur_node->children;

            found = false;
            while (cur_node && cur_node->name) {
                if (!xmlStrcmp(cur_node->name, (const xmlChar *)"arrow")) {
                    found = true;
                    break;
                }
                cur_node = cur_node->next;
            }
        }

        // Check if the state has been found
        if (!found) {
            cur_node = NULL;
            return false;
        }

    } else {
        // Get next arrow
        found = false;
        while (cur_node->next) {
            cur_node = cur_node->next;
            if (!xmlStrcmp(cur_node->name, (const xmlChar *)"arrow")) {
                found = true;
                break;
            }
        }

        // Check if the state has been found
        if (!found) {
            cur_node = NULL;
            return false;
        }
    }

    //printf("DURING CALL : cur_node = %p\n", cur_node);
    //printf("DURING CALL : cur_node->name = %s\n", cur_node->name);

    // Lookup in properties
    if (cur_node && cur_node->properties) {
        attribute = cur_node->properties;

        while(attribute && attribute->name && attribute->children) {
            //printf("attr name : %s\n", attribute->name);
            if (!xmlStrcmp(attribute->name, (const xmlChar *)"site")) {
                value = xmlNodeListGetString(cur_node->doc, attribute->children, 1);
                new_arrow->site = strtol((char *)value, NULL, 0);
                xmlFree(value);
                check |= READ_SITE;
            }
            if (!xmlStrcmp(attribute->name, (const xmlChar *)"weight")) {
                value = xmlNodeListGetString(cur_node->doc, attribute->children, 1);
                new_arrow->load = strtol((char *)value, NULL, 0);
                xmlFree(value);
                check |= READ_WEIGHT;
            }
            if (!xmlStrcmp(attribute->name, (const xmlChar *)"x")) {
                value = xmlNodeListGetString(cur_node->doc, attribute->children, 1);
                new_arrow->x = strtol((char *)value, NULL, 0);
                xmlFree(value);
                check |= READ_X;
            }
            if (!xmlStrcmp(attribute->name, (const xmlChar *)"y")) {
                value = xmlNodeListGetString(cur_node->doc, attribute->children, 1);
                new_arrow->y = strtol((char *)value, NULL, 0);
                xmlFree(value);
                check |= READ_Y;
            }
            if (!xmlStrcmp(attribute->name, (const xmlChar *)"z")) {
                value = xmlNodeListGetString(cur_node->doc, attribute->children, 1);
                new_arrow->z = strtol((char *)value, NULL, 0);
                xmlFree(value);
                check |= READ_Z;
            }
            attribute = attribute->next;
        }

        switch(dimension) {
        case 3:
            return (bool)(check & SUCCESSFUL_READ_ARROW_XYZ);
        case 2:
            return (bool)(check & SUCCESSFUL_READ_ARROW_XY);
        case 1:
            return (bool)(check & SUCCESSFUL_READ_ARROW_X);
        }
    }
    cur_node = NULL;
    return false;
}