CellularAutomata = {
    map_w = 0,
    map_h = 0,
    iterations = 0,
}

function CellularAutomata.get_neighbors(map, x, y)
    local min_x = math.max(0, x-1)
    local min_y = math.max(0, y-1)
    local max_x = math.min(x+1, map:get_width()-1)
    local max_y = math.min(y+1, map:get_height()-1)
    local result = {}
    for mx = min_x, max_x do
        for my = min_y, max_y do
            table.insert(result, {x = mx, y = my})
        end
    end
    return result
end

function CellularAutomata:initialize(w, h)
    self.map_w = w
    self.map_h = h
    self.iterations = 3
    math.randomseed()
    for mx = 0, w-1 do
        for my = 0, h-1 do
            local is_wall = math.random(0, 1) == 1
            if is_wall then
                visualizer.map:draw_wall(mx, my)
            else
                visualizer.map:draw_floor(mx, my)
            end
        end
    end
end

function CellularAutomata:update()
    if self.iterations <= 0 then
        return true
    end

    local old_map = visualizer.map
    local new_map = old_map:clone()

    for mx = 0, self.map_w - 1 do
        for my = 0, self.map_h - 1 do
            local neighbors = self.get_neighbors(old_map, mx, my)
            local expected_neighbors = 9
            local walls = expected_neighbors - #neighbors
            local required_walls = 5
            --print(old_map:is_wall(mx, my))
            --print(new_map:is_wall(mx, my))
            for k,v in ipairs(neighbors) do
                if old_map:is_wall(v.x, v.y) then
                    walls = walls + 1
                end
            end
            if walls >= required_walls then
                new_map:draw_wall(mx, my)
            else
                new_map:draw_floor(mx, my)
            end
            --print(old_map:is_wall(mx, my))
            --print(new_map:is_wall(mx, my))
        end
    end

    -- Now draw the new map onto the existing one
    for mx = 0, self.map_w - 1 do
        for my = 0, self.map_h - 1 do
            if new_map:is_wall(mx, my) then
                old_map:draw_wall(mx, my)
            else
                old_map:draw_floor(mx, my)
            end
        end
    end

    self.iterations = self.iterations - 1
    return false
end

visualizer.algorithm_manager:register_algorithm("Cellular Automata", function (w, h) CellularAutomata:initialize(w, h) end, function () return CellularAutomata:update() end, 1)