-- Mock util.time

local now = 0; -- wibbly-wobbly... timey-wimey... stuff

local function later(n)

	now = now + n; -- time passes at a different rate

end

package.loaded["util.time"] = {

	now = function() return now; end

}

local throttle = require "util.throttle";

describe("util.throttle", function()

	describe("#create()", function()

		it("should be created with correct values", function()

			now = 5;

			local a = throttle.create(3, 10);

			assert.same(a, { balance = 3, max = 3, rate = 0.3, t = 5 });

			local a = throttle.create(3, 5);

			assert.same(a, { balance = 3, max = 3, rate = 0.6, t = 5 });

			local a = throttle.create(1, 1);

			assert.same(a, { balance = 1, max = 1, rate = 1, t = 5 });

			local a = throttle.create(10, 10);

			assert.same(a, { balance = 10, max = 10, rate = 1, t = 5 });

			local a = throttle.create(10, 1);

			assert.same(a, { balance = 10, max = 10, rate = 10, t = 5 });

		end);

	end);

	describe("#update()", function()

		it("does nothing when no time has passed, even if balance is not full", function()

			now = 5;

			local a = throttle.create(10, 10);

			for i=1,5 do

				a:update();

				assert.same(a, { balance = 10, max = 10, rate = 1, t = 5 });

			end

			a.balance = 0;

			for i=1,5 do

				a:update();

				assert.same(a, { balance = 0, max = 10, rate = 1, t = 5 });

			end

		end);

		it("updates only time when time passes but balance is full", function()

			now = 5;

			local a = throttle.create(10, 10);

			for i=1,5 do

				later(5);

				a:update();

				assert.same(a, { balance = 10, max = 10, rate = 1, t = 5 + i*5 });

			end

		end);

		it("updates balance when balance has room to grow as time passes", function()

			now = 5;

			local a = throttle.create(10, 10);

			a.balance = 0;

			assert.same(a, { balance = 0, max = 10, rate = 1, t = 5 });

			later(1);

			a:update();

			assert.same(a, { balance = 1, max = 10, rate = 1, t = 6 });

			later(3);

			a:update();

			assert.same(a, { balance = 4, max = 10, rate = 1, t = 9 });

			later(10);

			a:update();

			assert.same(a, { balance = 10, max = 10, rate = 1, t = 19 });

		end);

		it("handles 10 x 0.1s updates the same as 1 x 1s update ", function()

			now = 5;

			local a = throttle.create(1, 1);

			a.balance = 0;

			later(1);

			a:update();

			assert.same(a, { balance = 1, max = 1, rate = 1, t = now });

			a.balance = 0;

			for i=1,10 do

				later(0.1);

				a:update();

			end

			assert(math.abs(a.balance - 1) < 0.0001); -- incremental updates cause rounding errors

		end);

	end);

	-- describe("po")

	describe("#poll()", function()

		it("should only allow successful polls until cost is hit", function()

			now = 5;

			local a = throttle.create(3, 10);

			assert.same(a, { balance = 3, max = 3, rate = 0.3, t = 5 });

			assert.is_true(a:poll(1));  -- 3 -> 2

			assert.same(a, { balance = 2, max = 3, rate = 0.3, t = 5 });

			assert.is_true(a:poll(2));  -- 2 -> 1

			assert.same(a, { balance = 0, max = 3, rate = 0.3, t = 5 });

			assert.is_false(a:poll(1)); -- MEEP, out of credits!

			assert.is_false(a:poll(1)); -- MEEP, out of credits!

			assert.same(a, { balance = 0, max = 3, rate = 0.3, t = 5 });

		end);

		it("should not allow polls more than the cost", function()

			now = 0;

			local a = throttle.create(10, 10);

			assert.same(a, { balance = 10, max = 10, rate = 1, t = 0 });

			assert.is_false(a:poll(11));

			assert.same(a, { balance = 10, max = 10, rate = 1, t = 0 });

			assert.is_true(a:poll(6));

			assert.same(a, { balance = 4, max = 10, rate = 1, t = 0 });

			assert.is_false(a:poll(5));

			assert.same(a, { balance = 4, max = 10, rate = 1, t = 0 });

			-- fractional

			assert.is_true(a:poll(3.5));

			assert.same(a, { balance = 0.5, max = 10, rate = 1, t = 0 });

			assert.is_true(a:poll(0.25));

			assert.same(a, { balance = 0.25, max = 10, rate = 1, t = 0 });

			assert.is_false(a:poll(0.3));

			assert.same(a, { balance = 0.25, max = 10, rate = 1, t = 0 });

			assert.is_true(a:poll(0.25));

			assert.same(a, { balance = 0, max = 10, rate = 1, t = 0 });

			assert.is_false(a:poll(0.1));

			assert.same(a, { balance = 0, max = 10, rate = 1, t = 0 });

			assert.is_true(a:poll(0));

			assert.same(a, { balance = 0, max = 10, rate = 1, t = 0 });

		end);

	end);

end);