require "spec"
require "../src/lru.cr"

describe "LRU" do
	it "add and remove values" do
		lru = LRU(Int32).new 3 # Only 3 allowed entries.
		(lru << 1).should be_nil # there is still room in the lru
		(lru << 2).should be_nil # there is still room in the lru
		(lru << 3).should be_nil # last entry without exceeding the allowed size
		(lru << 4).should eq 1   # -> 1 (least recently used data)
		(lru << 4).should be_nil # -> nil (already in the lru)
		(lru << 2).should be_nil # -> nil (already in the lru)
		(lru << 5).should eq 3   # -> 3 (least recently used data)
		lru.data.should eq([5, 2, 4] of Int32)

		lru.delete 2
		lru.data.should eq([5, 4] of Int32)
	end
end

describe "EfficientLRU" do
	it "add and remove values" do
		lru = EfficientLRU(Int32).new 3 # Only 3 allowed entries.
		(lru << 1).should be_nil # there is still room in the lru
		(lru << 2).should be_nil # there is still room in the lru
		(lru << 3).should be_nil # last entry without exceeding the allowed size
		(lru << 4).should eq 1   # -> 1 (least recently used data)
		(lru << 4).should be_nil # -> nil (already in the lru)
		(lru << 2).should be_nil # -> nil (already in the lru)
		(lru << 5).should eq 3   # -> 3 (least recently used data)
		lru.list.to_s.should eq "[ 5, 2, 4 ]"

		lru.delete 2
		lru.list.to_s.should eq "[ 5, 4 ]"

		(lru << 4).should be_nil # -> nil (just a re-order)
		lru.list.to_s.should eq "[ 4, 5 ]"

		lru.delete 5
		(lru << 0).should be_nil
		lru.list.to_s.should eq "[ 0, 4 ]"

		(lru << 1).should be_nil
		lru.list.to_s.should eq "[ 1, 0, 4 ]"

		lru.delete 4
		lru.list.to_s.should eq "[ 1, 0 ]"

		lru.delete 4
		lru.list.to_s.should eq "[ 1, 0 ]"
		lru.list.size.should eq 2
		lru.hash.size.should eq 2
	end
end