mapa={
    name=nil,
    w=128,
    h=128,
    surface=-1,

    new = function(w,h)
        mapa.name=nil
        mapa.w,mapa.h=w,h
        if mapa.surface~=-1 then surf.free(mapa.surface) end
        mapa.surface=surf.new(w,h)
        map.surf(mapa.surface)
        for y=0,127 do
            for x=0,127 do
                map.tile(x,y,0)
            end
        end
        mapa.front_layer=nil
    end,

    load = function(filename)
        file = io.open("data/"..filename, "r")
        if file then
            io.input(file)
            mapa.w = tonumber(io.read())
            mapa.h = tonumber(io.read())
            local num_layers=tonumber(io.read())

            mapa.new(mapa.w, mapa.h)
            mapa.name=filename
            for y=0,mapa.h-1 do
                local line = io.read()
                local x=0
                for m in string.gmatch(line, "%d+") do
                    map.tile(x,y,m)
                    x=x+1
                end
            end

            if num_layers==2 then
                mapa.front_layer=surf.new(mapa.w,mapa.h)
                map.surf(mapa.front_layer)

                for y=0,mapa.h-1 do
                    local line = io.read()
                    local x=0
                    for m in string.gmatch(line, "%d+") do
                        map.tile(x,y,m)
                        x=x+1
                    end
                end
            end
            map.surf(mapa.surface)
            io.close(file)
        end
    end,

    save = function(filename)
        mapa.name=filename
        file = io.open("data/"..filename, "w")
        if file then
            io.output(file)
            io.write(mapa.w.."\n")
            io.write(mapa.h.."\n")
            if mapa.front_layer then io.write("2\n") else io.write("1\n") end
            map.surf(mapa.surface)
            for y=0,mapa.h-1 do
                for x=0,mapa.w-1 do
                    io.write(map.tile(x,y)..",")
                end
                io.write("\n")
            end
            if mapa.front_layer then
                map.surf(mapa.front_layer)
                for y=0,mapa.h-1 do
                    for x=0,mapa.w-1 do
                        io.write(map.tile(x,y)..",")
                    end
                    io.write("\n")
                end
            end
            io.close(file)
        end
    end,

    check_collision=function(x,y)
        return map.tile(x,y) >= 32 or map.tile(x+1,y) >= 32
    end
}