"use strict";

const StairsBuilder = (function(){

    const StairsBuilder = function(hollow_bond){

        const is_volume_free = (occupied, xf, yf, zf, xt, yt, zt) => {
            for(let x = xf; x < xt; x ++)
                for(let y = yf; y < yt; y ++)
                    for(let z = zf; z < zt; z ++)
                        if(occupied.has(`${x}_${y}_${z}`))
                            return false;
            return true;
        };

        const reserve_volume = (occupied, xf, yf, zf, xt, yt, zt) => {
            for(let x = xf; x < xt; x ++)
                for(let y = yf; y < yt; y ++)
                    for(let z = zf; z < zt; z ++)
                        occupied.add(`${x}_${y}_${z}`);
        };

        this.generate = hole => {
            if(hole.height < hollow_bond.stairs_height)
                return hole.stairs;

            const occupied = new Set();

            for(let py = hole.yf; py <= hole.yt - hollow_bond.stairs_height; py++){

                if(hollow_bond.hash.stairs(hole.xf, py, hole.zf, hole.xt, py + hollow_bond.stairs_height, hole.zt, 0) > hollow_bond.stairs_probability)
                    continue;

                const wall_i = Math.floor(hollow_bond.hash.stairs(hole.xf, py, hole.zf, hole.xt, py + hollow_bond.stairs_height, hole.zt, 1) * 4);
                let stairs_xf, stairs_zf, stairs_xt, stairs_zt, wall_name;

                if(wall_i === 0 && hole.width >= hollow_bond.stairs_length){ // Pared Norte (Z = zf)
                    wall_name = "north";
                    stairs_xf = hole.xf + Math.floor(hollow_bond.hash.stairs(hole.xf, py, hole.zf, hole.xt, py + hollow_bond.stairs_height, hole.zt, 2) * (hole.width - hollow_bond.stairs_length + 1));
                    stairs_xt = stairs_xf + hollow_bond.stairs_length;
                    stairs_zf = hole.zf;
                    stairs_zt = stairs_zf + 1;
                }else if(wall_i === 1 && hole.width >= hollow_bond.stairs_length){ // Pared Sur (Z = zt - 1)
                    wall_name = "south";
                    stairs_xf = hole.xf + Math.floor(hollow_bond.hash.stairs(hole.xf, py, hole.zf, hole.xt, py + hollow_bond.stairs_height, hole.zt, 2) * (hole.width - hollow_bond.stairs_length + 1));
                    stairs_xt = stairs_xf + hollow_bond.stairs_length;
                    stairs_zt = hole.zt;
                    stairs_zf = stairs_zt - 1;
                }else if(wall_i === 2 && hole.depth >= hollow_bond.stairs_length){ // Pared Oeste (X = xf)
                    wall_name = "west";
                    stairs_zf = hole.zf + Math.floor(hollow_bond.hash.stairs(hole.xf, py, hole.zf, hole.xt, py + hollow_bond.stairs_height, hole.zt, 2) * (hole.depth - hollow_bond.stairs_length + 1));
                    stairs_zt = stairs_zf + hollow_bond.stairs_length;
                    stairs_xf = hole.xf;
                    stairs_xt = stairs_xf + 1;
                }else if(wall_i === 3 && hole.depth >= hollow_bond.stairs_length){ // Pared Este (X = xt - 1)
                    wall_name = "east";
                    stairs_zf = hole.zf + Math.floor(hollow_bond.hash.stairs(hole.xf, py, hole.zf, hole.xt, py + hollow_bond.stairs_height, hole.zt, 2) * (hole.depth - hollow_bond.stairs_length + 1));
                    stairs_zt = stairs_zf + hollow_bond.stairs_length;
                    stairs_xt = hole.xt;
                    stairs_xf = stairs_xt - 1;
                }else 
                    continue;

                const clearance_yt = Math.min(hole.yt, py + hollow_bond.stairs_height + 1);

                if(!is_volume_free(occupied, stairs_xf, py, stairs_zf, stairs_xt, clearance_yt, stairs_zt))
                    continue; // Hay conflicto vertical con otra escalera o descansillo

                reserve_volume(occupied, stairs_xf, py, stairs_zf, stairs_xt, clearance_yt, stairs_zt);

                hole.stairs.push(new StairsModel(hollow_bond, {
                    hole_id   : hole.id, 
                    xf        : stairs_xf, 
                    yf        : py, 
                    zf        : stairs_zf, 
                    xt        : stairs_xt, 
                    yt        : py + hollow_bond.stairs_height, 
                    zt        : stairs_zt, 
                    wall      : wall_name, 
                    direction : hollow_bond.hash.stairs(hole.xf, py, hole.zf, hole.xt, py + hollow_bond.stairs_height, hole.zt, 3) < 0.5 ? -1 : 1
                }));

            };

            return hole.stairs;
        };

    };

    return StairsBuilder;
})();