-- SPDX-FileCopyrightText: © 2022—2026 Vladimir Zorin <vladimir@deviant.guru>
-- SPDX-License-Identifier: LicenseRef-OWL-1.0-or-later
-- Licensed under OWL v1.0+. See LICENSE.

local testimony = require("testimony")
local cache = require("lilgit.cache")

local testify = testimony.new("== lilgit.cache ==")

testify:that("get/set roundtrip, miss returns nil", function()
	local c = cache.new(4)
	testimony.assert_nil(c:get("a"))
	c:set("a", "va")
	testimony.assert_equal("va", c:get("a"))
	c:set("a", "va2")
	testimony.assert_equal("va2", c:get("a"))
end)

testify:that("entries survive one rotation via the stale generation", function()
	local c = cache.new(2)
	c:set("a", "va")
	c:set("b", "vb")
	-- Cap reached: a and b are now stale, fresh is empty.
	testimony.assert_equal("va", c:get("a"))
	testimony.assert_equal("vb", c:get("b"))
end)

testify:that("cold entries evict after two rotations", function()
	local c = cache.new(2)
	c:set("a", "va")
	c:set("b", "vb")
	-- First rotation done; fill the fresh generation without touching a.
	c:set("c", "vc")
	c:set("d", "vd")
	-- Second rotation: a and b are gone, c and d are stale.
	testimony.assert_nil(c:get("a"))
	testimony.assert_nil(c:get("b"))
	testimony.assert_equal("vc", c:get("c"))
	testimony.assert_equal("vd", c:get("d"))
end)

testify:that("a promoted hit outlives the generation it was born in", function()
	local c = cache.new(2)
	c:set("a", "va")
	c:set("b", "vb")
	-- Promote a into the fresh generation.
	testimony.assert_equal("va", c:get("a"))
	-- Fill and rotate again: b (never touched) dies, a survives.
	c:set("c", "vc")
	testimony.assert_nil(c:get("b"))
	testimony.assert_equal("va", c:get("a"))
end)

testify:that("live entries never exceed twice the cap", function()
	local c = cache.new(3)
	for i = 1, 100 do
		c:set("k" .. i, i)
	end
	local live = 0
	for _ in pairs(c.__state.fresh) do
		live = live + 1
	end
	for _ in pairs(c.__state.stale) do
		live = live + 1
	end
	testimony.assert_true(live <= 6, "live entries: " .. live)
end)

testify:conclude()