/*
 *  Support for custom units
 *  Copyright (C) 2009-2009  The Mana World Development Team
 *  Copyright (C) 2009-2010  The Mana Developers
 *
 *  This file is part of The Mana Client.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "units.h"

#include "log.h"

#include "utils/stringutils.h"
#include "utils/xml.h"

#include <cmath>
#include <climits>
#include <vector>

struct UnitLevel {
    std::string symbol;
    int count;
    int round;
};

struct UnitDescription {
    std::vector<struct UnitLevel> levels;
    double conversion;
    bool mix;
};

enum UnitType {
    UNIT_WEIGHT = 0,
    UNIT_CURRENCY = 1,
    UNIT_END
};

struct UnitDescription units[UNIT_END];

void Units::loadUnits()
{
    { // Setup default weight
        struct UnitDescription ud;

        ud.conversion = 1.0;
        ud.mix = false;

        struct UnitLevel bu;
        bu.symbol = "g";
        bu.count = 1;
        bu.round = 0;

        ud.levels.push_back(bu);

        struct UnitLevel ul;
        ul.symbol = "kg";
        ul.count = 1000;
        ul.round = 2;

        ud.levels.push_back(ul);

        units[UNIT_WEIGHT] = ud;
    }

    { // Setup default currency
        struct UnitDescription ud;

        ud.conversion = 1.0;
        ud.mix = false;

        struct UnitLevel bu;
        bu.symbol = "¤";
        bu.count = 1;
        bu.round = 0;

        ud.levels.push_back(bu);

        units[UNIT_CURRENCY] = ud;
    }

    XML::Document doc("units.xml");
    xmlNodePtr root = doc.rootNode();

    if (!root || !xmlStrEqual(root->name, BAD_CAST "units"))
    {
        logger->log("Error loading unit definition file: units.xml");
        return;
    }

    for_each_xml_child_node(node, root)
    {
        if (xmlStrEqual(node->name, BAD_CAST "unit"))
        {
            struct UnitDescription ud;
            int level = 1;
            const std::string type = XML::getProperty(node, "type", "");
            ud.conversion = XML::getProperty(node, "conversion", 1);
            ud.mix = XML::getProperty(node, "mix", "no") == "yes";

            struct UnitLevel bu;
            bu.symbol = XML::getProperty(node, "base", "¤");
            bu.count = 1;
            bu.round = XML::getProperty(node, "round", 2);

            ud.levels.push_back(bu);

            for_each_xml_child_node(uLevel, node)
            {
                if (xmlStrEqual(uLevel->name, BAD_CAST "level"))
                {
                    struct UnitLevel ul;
                    ul.symbol = XML::getProperty(uLevel, "symbol",
                                                    strprintf("¤%d",level));
                    ul.count = XML::getProperty(uLevel, "count", -1);
                    ul.round = XML::getProperty(uLevel, "round", bu.round);

                    if (ul.count > 0)
                    {
                        ud.levels.push_back(ul);
                        level++;
                    }
                    else
                    {
                        logger->log("Error bad unit count: %d for %s in %s",
                                        ul.count, ul.symbol.c_str(), bu.symbol.c_str());
                    }
                }
            }

            // Add one more level for saftey
            struct UnitLevel ll;
            ll.symbol = "";
            ll.count = INT_MAX;
            ll.round = 0;

            ud.levels.push_back(ll);

            if (type == "weight")
                units[UNIT_WEIGHT] = ud;
            else if (type == "currency")
                units[UNIT_CURRENCY] = ud;
            else
                logger->log("Error unknown unit type: %s", type.c_str());
        }
    }
}

std::string formatUnit(int value, int type)
{
    struct UnitDescription ud = units[type];
    struct UnitLevel ul;

    // Shortcut for 0; do the same for values less than 0  (for now)
    if (value <= 0)
    {
        ul = ud.levels[0];
        return strprintf("0%s", ul.symbol.c_str());
    }
    else
    {
        double amount = ud.conversion * value;

        // If only the first level is needed, act like mix if false
        if (ud.mix && ud.levels.size() > 0 && ud.levels[1].count < amount)
        {
            std::string output;
            struct UnitLevel pl = ud.levels[0];
            ul = ud.levels[1];
            int levelAmount = (int) amount;
            int nextAmount;

            levelAmount /= ul.count;

            amount -= levelAmount * ul.count;

            if (amount > 0)
            {
                output = strprintf("%.*f%s", pl.round, amount,
                                    pl.symbol.c_str());
            }

            for (unsigned int i = 2; i < ud.levels.size(); i++)
            {
                pl = ul;
                ul = ud.levels[i];

                nextAmount = levelAmount / ul.count;
                levelAmount %= ul.count;

                if (levelAmount > 0) output = strprintf("%d%s",
                    levelAmount, pl.symbol.c_str()) + output;

                if (!nextAmount) break;
                levelAmount = nextAmount;
            }

            return output;
        }
        else
        {
            for (unsigned int i = 0; i < ud.levels.size(); i++)
            {
                ul = ud.levels[i];
                if (amount < ul.count && ul.count > 0)
                {
                    ul = ud.levels[i - 1];
                    break;
                }
                amount /= ul.count;
            }

            return strprintf("%.*f%s", ul.round, amount, ul.symbol.c_str());
        }
    }
}

std::string Units::formatCurrency(int value)
{
    return formatUnit(value, UNIT_CURRENCY);
}

std::string Units::formatWeight(int value)
{
    return formatUnit(value, UNIT_WEIGHT);
}