require "spec"
require "file_utils"
require "./db-ships.cr"

def fork_process(&)
	Process.new Crystal::System::Process.fork { yield }
end

describe "DODB::DataBase" do
	describe "basics" do
		it "store and get data" do
			db = DODB::SpecDataBase(Ship).new

			Ship.all_ships.each do |ship|
				db << ship
			end

			db.to_a.sort.should eq(Ship.all_ships.sort)
		end

		it "rewrite already stored data" do
			db = DODB::SpecDataBase(Ship).new
			ship = Ship.all_ships[0]

			key = db << ship

			db[key] = Ship.new "broken"
			db[key] = ship

			db[key].should eq(ship)
		end

		it "properly remove data" do
			db = DODB::SpecDataBase(Ship).new

			Ship.all_ships.each do |ship|
				db << ship
			end

			Ship.all_ships.each do |ship|
				db.pop
			end

			Ship.all_ships.each_with_index do |ship, i|
				# FIXME: Should it raise a particular exception?
				expect_raises DODB::MissingEntry do
					db[i]
				end

				db[i]?.should be_nil
			end
		end

		it "preserves data on reopening" do
			db1 = DODB::SpecDataBase(Ship).new
			db1 << Ship.kisaragi

			db1.to_a.size.should eq(1)

			db2 = DODB::SpecDataBase(Ship).new remove_previous_data: false
			db2 << Ship.mutsuki

			db1.to_a.size.should eq(2)
		end

		it "iterates in normal and reversed order" do
			db = DODB::SpecDataBase(Ship).new

			Ship.all_ships.each do |ship|
				db << ship
			end

			# The two #each test iteration.
			db.each_with_key do |item, index|
				item.should eq Ship.all_ships[index]
			end

			db.each_with_key(reversed: true) do |item, index|
				item.should eq Ship.all_ships[index]
			end

			# Actual reversal is tested here.
			db.to_a(reversed: true).should eq db.to_a.reverse
		end

		it "respects the provided offsets if any" do
			db = DODB::SpecDataBase(Ship).new

			Ship.all_ships.each do |ship|
				db << ship
			end

			db.to_a(offset: 0, limit: 1)[0]?.should eq Ship.mutsuki
			db.to_a(offset: 1, limit: 1)[0]?.should eq Ship.kisaragi
			db.to_a(offset: 2, limit: 1)[0]?.should eq Ship.yayoi

			db.to_a(offset: 0, limit: 3).should eq [
				Ship.mutsuki, Ship.kisaragi, Ship.yayoi
			]
		end
	end

	describe "indices" do
		it "do basic indexing" do
			db = DODB::SpecDataBase(Ship).new

			db_ships_by_name = db.new_index "name", &.name

			Ship.all_ships.each do |ship|
				db << ship
			end

			Ship.all_ships.each_with_index do |ship|
				db_ships_by_name.get?(ship.name).should eq(ship)
			end
		end

		it "raise on index overload" do
			db = DODB::SpecDataBase(Ship).new

			db_ships_by_name = db.new_index "name", &.name

			db << Ship.kisaragi

			# Should not be allowed to store an entry whose “name” field
			# already exists.
			expect_raises(DODB::IndexOverload) do
				db << Ship.kisaragi
			end
		end

		it "properly deindex" do
			db = DODB::SpecDataBase(Ship).new

			db_ships_by_name = db.new_index "name", &.name

			Ship.all_ships.each do |ship|
				db << ship
			end

			Ship.all_ships.each_with_index do |ship, i|
				db.delete i
			end

			Ship.all_ships.each do |ship|
				db_ships_by_name.get?(ship.name).should be_nil
			end
		end

		it "properly reindex" do
			db = DODB::SpecDataBase(Ship).new

			db_ships_by_name = db.new_index "name", &.name

			key = db << Ship.kisaragi

			# We give the old id to the new ship, to get it replaced in
			# the database.
			some_new_ship = Ship.all_ships[2].clone

			db[key] = some_new_ship

			db[key].should eq(some_new_ship)

			db_ships_by_name.get?(some_new_ship.name).should eq(some_new_ship)
		end

		it "properly updates" do
			db = DODB::SpecDataBase(Ship).new

			db_ships_by_name = db.new_index "name", &.name

			Ship.all_ships.each do |ship|
				db << ship
			end

			new_kisaragi = Ship.kisaragi.clone.tap do |s|
				s.name = "Kisaragi Kai" # Don’t think about it too much.
			end

			# We’re changing an indexed value on purpose.
			db_ships_by_name.update "Kisaragi", new_kisaragi

			db_ships_by_name.get?("Kisaragi").should be_nil
			db_ships_by_name.get?(new_kisaragi.name).should eq new_kisaragi
		end
	end

	describe "partitions" do
		it "do basic partitioning" do
			db = DODB::SpecDataBase(Ship).new

			db_ships_by_class = db.new_partition "class", &.klass

			Ship.all_ships.each do |ship|
				db << ship
			end

			Ship.all_ships.each do |ship|
				db_ships_by_class.get(ship.klass).should contain(ship)
			end

			# We extract the possible classes to do test on them.
			ship_classes = Ship.all_ships.map(&.klass).uniq
			ship_classes.each do |klass|
				partition = db_ships_by_class.get klass

				# A partition on “class” should contain entries that all
				# share the same value of “class”.
				partition.map(&.klass.==(klass)).reduce { |a, b|
					a && b
				}.should be_true
			end

			db_ships_by_class.get?("does-not-exist").should be_nil
		end

		it "removes select elements from partitions" do
			db = DODB::SpecDataBase(Ship).new

			db_ships_by_class = db.new_partition "class", &.klass

			Ship.all_ships.each do |ship|
				db << ship
			end

			db_ships_by_class.delete "Mutsuki", &.name.==("Kisaragi")

			Ship.all_ships.map(&.klass).uniq.each do |klass|
				partition = db_ships_by_class.get klass

				partition.any?(&.name.==("Kisaragi")).should be_false
			end
		end
	end

	describe "tags" do
		it "do basic tagging" do
			db = DODB::SpecDataBase(Ship).new

			db_ships_by_tags = db.new_tags "tags", &.tags

			Ship.all_ships.each do |ship|
				db << ship
			end

			db_ships_by_tags.get("flagship").should eq([Ship.flagship])

			# All returned entries should have the requested tag.
			db_ships_by_tags.get("name ship")
				.map(&.tags.includes?("name ship"))
				.reduce { |a, e| a && e }
				.should be_true

			# There shouldn’t be one in our data about WWII Japanese warships…
			db_ships_by_tags.get?("starship").should be_nil
		end

		it "properly removes tags" do
			db = DODB::SpecDataBase(Ship).new

			db_ships_by_tags = db.new_tags "tags", &.tags

			Ship.all_ships.each do |ship|
				db << ship
			end

			# Removing the “flagship” tag, brace for impact.
			flagship, index = db_ships_by_tags.get_with_indice("flagship")[0]
			flagship.tags = [] of String
			db[index] = flagship



#			ship, index = db_ships_by_tags.update(tag: "flagship") do |ship, index|
#				ship.tags = [] of String
#				db[index] = ship
#			end

			db_ships_by_tags.get("flagship").should eq([] of Ship)
		end

		it "gets items that have multiple tags" do
			db = DODB::SpecDataBase(Ship).new

			db_ships_by_tags = db.new_tags "tags", &.tags

			Ship.all_ships.each do |ship|
				db << ship
			end

			results = db_ships_by_tags.get(["flagship", "name ship"])
			results.should eq([Ship.yamato])

			results = db_ships_by_tags.get(["name ship", "flagship"])
			results.should eq([Ship.yamato])

			results = db_ships_by_tags.get(["flagship"])
			results.should eq([Ship.yamato])
		end
	end

	describe "atomic operations" do
		it "safe_get and safe_get?" do
			db = DODB::SpecDataBase(Ship).new

			db_ships_by_name = db.new_index "name", &.name

			Ship.all_ships.each do |ship|
				db << ship
			end

			Ship.all_ships.each do |ship|
				db_ships_by_name.safe_get ship.name do |results|
					results.should eq(ship)
				end

				db_ships_by_name.safe_get? ship.name do |results|
					results.should eq(ship)
				end
			end
		end
	end

	describe "tools" do
		it "rebuilds indexes" do
			db = DODB::SpecDataBase(Ship).new

			db_ships_by_name  = db.new_index     "name", &.name
			db_ships_by_class = db.new_partition "class", &.klass
			db_ships_by_tags  = db.new_tags      "tags", &.tags

			Ship.all_ships.each do |ship|
				db << ship
			end

			db.reindex_everything!

			Ship.all_ships.each do |ship|
				db_ships_by_name.get?(ship.name).should eq(ship)
				db_ships_by_class.get(ship.klass).should contain(ship)
			end
		end

		it "migrates properly" do
			::FileUtils.rm_rf "test-storage-migration-origin"
			old_db = DODB::DataBase(PrimitiveShip).new "test-storage-migration-origin"

			old_ships_by_name  = old_db.new_index     "name", &.name
			old_ships_by_class = old_db.new_partition "class", &.class_name

			PrimitiveShip.all_ships.each do |ship|
				old_db << ship
			end

			# At this point, the “old” DB is filled. Now we need to convert
			# to the new DB.

			new_db = DODB::SpecDataBase(Ship).new "-migration-target"

			new_ships_by_name  = new_db.new_index     "name", &.name
			new_ships_by_class = new_db.new_partition "class", &.klass
			new_ships_by_tags  = new_db.new_tags      "tags", &.tags

			old_db.each_with_key do |ship, index|
				new_ship = Ship.new ship.name,
					klass: ship.class_name,
					id: ship.id,
					tags: Array(String).new.tap { |tags|
						tags << "name ship" if ship.name == ship.class_name
					}

				new_db[index] = new_ship
			end

			# At this point, the conversion is done, so… we’re making a few
			# arbitrary tests on the new data.

			old_db.each_with_key do |old_ship, old_index|
				ship = new_db[old_index]

				ship.id.should eq(old_ship.id)
				ship.klass.should eq(old_ship.class_name)

				ship.tags.any?(&.==("name ship")).should be_true if ship.name == ship.klass
			end
		end
	end

	describe "parallel support" do
		# Not sure how many forks would be safe in a test like that.
		fork_count = 25
		entries_per_fork = 100

		it "works for pushing values" do
			db = DODB::SpecDataBase(Ship).new

			processes = [] of Process

			fork_count.times do |fork_id|
				processes << fork_process do
					entries_per_fork.times do |entry_id|
						db << Ship.new("entry-#{fork_id}-#{entry_id}", "???")
					end
				end
			end

			processes.each &.wait

			dump = db.to_a

			dump.size.should eq fork_count * entries_per_fork
		end

		it "works for updating values" do
			db = DODB::SpecDataBase(Ship).new
			db_entries_by_name = db.new_index "name", &.name

			# First pass, creating data.
			processes = [] of Process
			fork_count.times do |fork_id|
				processes << fork_process do
					entries_per_fork.times do |entry_id|
						db << Ship.new("entry-#{fork_id}-#{entry_id}", "???")
					end
				end
			end
			processes.each &.wait

			# Second pass, updating data.
			processes = [] of Process
			fork_count.times do |fork_id|
				processes << fork_process do
					entries_per_fork.times do |entry_id|
						db_entries_by_name.update Ship.new("entry-#{fork_id}-#{entry_id}", "???", tags: ["updated"])
					end
				end
			end
			processes.each &.wait

			# Third pass, testing database content.
			dump = db.to_a

			fork_count.times do |fork_id|
				entries_per_fork.times do |entry_id|
					entry = db_entries_by_name.get "entry-#{fork_id}-#{entry_id}"

					entry.tags.should eq ["updated"]
				end
			end
		end

		it "does parallel-safe updates" do
			db = DODB::SpecDataBase(Ship).new
			db_entries_by_name = db.new_index "name", &.name

			# We’ll be storing an integer in the "klass" field, and incrementing
			# it in forks in a second time.
			db << Ship.new("test", "0")

			processes = [] of Process
			fork_count.times do |fork_id|
				processes << fork_process do
					entries_per_fork.times do |entry_id|
						db_entries_by_name.safe_get "test" do |entry|
							entry.klass = (entry.klass.to_i + 1).to_s

							db_entries_by_name.update "test", entry
						end
					end
				end
			end
			processes.each &.wait

			db_entries_by_name.get("test").klass.should eq((fork_count * entries_per_fork).to_s)
		end
	end
end

# Basically the same thing as before, with some slight
# differences based on the fact that changing the on-disk data
# won't change the cached one.
describe "DODB::CachedDataBase" do
	describe "basics" do
		it "store and get data" do
			db = DODB::CachedSpecDataBase(Ship).new

			Ship.all_ships.each do |ship|
				db << ship
			end

			db.to_a.sort.should eq(Ship.all_ships.sort)

			db.rm_storage_dir
		end

		it "rewrite already stored data" do
			db = DODB::CachedSpecDataBase(Ship).new
			ship = Ship.all_ships[0]

			key = db << ship

			db[key] = Ship.new "broken"
			db[key] = ship

			db[key].should eq(ship)

			db.rm_storage_dir
		end

		it "properly remove data" do
			db = DODB::CachedSpecDataBase(Ship).new

			Ship.all_ships.each do |ship|
				db << ship
			end

			Ship.all_ships.each do |ship|
				db.pop
			end

			Ship.all_ships.each_with_index do |ship, i|
				# FIXME: Should it raise a particular exception?
				expect_raises DODB::MissingEntry do
					db[i]
				end

				db[i]?.should be_nil
			end

			db.rm_storage_dir
		end

		it "preserves data on reopening" do
			db1 = DODB::CachedSpecDataBase(Ship).new
			db1 << Ship.kisaragi

			db1.to_a.size.should eq(1)

			db2 = DODB::CachedSpecDataBase(Ship).new remove_previous_data: false
			db2 << Ship.mutsuki

			# Only difference with DODB::DataBase: concurrent DB cannot coexists.
			db2.to_a.size.should eq(2)

			db1.rm_storage_dir
			db2.rm_storage_dir
		end

		it "iterates in normal and reversed order" do
			db = DODB::CachedSpecDataBase(Ship).new

			Ship.all_ships.each do |ship|
				db << ship
			end

			# The two #each test iteration.
			db.each_with_key do |item, index|
				item.should eq Ship.all_ships[index]
			end

			db.each_with_key(reversed: true) do |item, index|
				item.should eq Ship.all_ships[index]
			end

			# Actual reversal is tested here.
			db.to_a(reversed: true).should eq db.to_a.reverse

			db.rm_storage_dir
		end

		it "respects the provided offsets if any" do
			db = DODB::CachedSpecDataBase(Ship).new

			Ship.all_ships.each do |ship|
				db << ship
			end

			db.to_a(offset: 0, limit: 1)[0]?.should eq Ship.mutsuki
			db.to_a(offset: 1, limit: 1)[0]?.should eq Ship.kisaragi
			db.to_a(offset: 2, limit: 1)[0]?.should eq Ship.yayoi

			db.to_a(offset: 0, limit: 3).should eq [
				Ship.mutsuki, Ship.kisaragi, Ship.yayoi
			]

			db.rm_storage_dir
		end
	end

	describe "indices" do
		it "do basic indexing" do
			db = DODB::CachedSpecDataBase(Ship).new

			db_ships_by_name = db.new_index "name", &.name

			Ship.all_ships.each do |ship|
				db << ship
			end

			Ship.all_ships.each_with_index do |ship|
				db_ships_by_name.get?(ship.name).should eq(ship)
			end

			db.rm_storage_dir
		end

		it "raise on index overload" do
			db = DODB::CachedSpecDataBase(Ship).new

			db_ships_by_name = db.new_index "name", &.name

			db << Ship.kisaragi

			# Should not be allowed to store an entry whose “name” field
			# already exists.
			expect_raises(DODB::IndexOverload) do
				db << Ship.kisaragi
			end

			db.rm_storage_dir
		end

		it "properly deindex" do
			db = DODB::CachedSpecDataBase(Ship).new

			db_ships_by_name = db.new_index "name", &.name

			Ship.all_ships.each do |ship|
				db << ship
			end

			Ship.all_ships.each_with_index do |ship, i|
				db.delete i
			end

			Ship.all_ships.each do |ship|
				db_ships_by_name.get?(ship.name).should be_nil
			end

			db.rm_storage_dir
		end

		it "properly reindex" do
			db = DODB::CachedSpecDataBase(Ship).new

			db_ships_by_name = db.new_index "name", &.name

			key = db << Ship.kisaragi

			# We give the old id to the new ship, to get it replaced in
			# the database.
			some_new_ship = Ship.all_ships[2].clone

			db[key] = some_new_ship

			db[key].should eq(some_new_ship)

			db_ships_by_name.get?(some_new_ship.name).should eq(some_new_ship)

			db.rm_storage_dir
		end

		it "properly updates" do
			db = DODB::CachedSpecDataBase(Ship).new

			db_ships_by_name = db.new_index "name", &.name

			Ship.all_ships.each do |ship|
				db << ship
			end

			new_kisaragi = Ship.kisaragi.clone.tap do |s|
				s.name = "Kisaragi Kai" # Don’t think about it too much.
			end

			# We’re changing an indexed value on purpose.
			db_ships_by_name.update "Kisaragi", new_kisaragi

			db_ships_by_name.get?("Kisaragi").should be_nil
			db_ships_by_name.get?(new_kisaragi.name).should eq new_kisaragi

			db.rm_storage_dir
		end
	end

	describe "partitions" do
		it "do basic partitioning" do
			db = DODB::CachedSpecDataBase(Ship).new

			db_ships_by_class = db.new_partition "class", &.klass

			Ship.all_ships.each do |ship|
				db << ship
			end

			Ship.all_ships.each do |ship|
				db_ships_by_class.get(ship.klass).should contain(ship)
			end

			# We extract the possible classes to do test on them.
			ship_classes = Ship.all_ships.map(&.klass).uniq
			ship_classes.each do |klass|
				partition = db_ships_by_class.get klass

				# A partition on “class” should contain entries that all
				# share the same value of “class”.
				partition.map(&.klass.==(klass)).reduce { |a, b|
					a && b
				}.should be_true
			end

			db_ships_by_class.get?("does-not-exist").should be_nil

			db.rm_storage_dir
		end

		it "removes select elements from partitions" do
			db = DODB::CachedSpecDataBase(Ship).new

			db_ships_by_class = db.new_partition "class", &.klass

			Ship.all_ships.each do |ship|
				db << ship
			end

			db_ships_by_class.delete "Mutsuki", &.name.==("Kisaragi")

			Ship.all_ships.map(&.klass).uniq.each do |klass|
				partition = db_ships_by_class.get klass

				partition.any?(&.name.==("Kisaragi")).should be_false
			end

			db.rm_storage_dir
		end
	end

	describe "tags" do
		it "do basic tagging" do
			db = DODB::CachedSpecDataBase(Ship).new

			db_ships_by_tags = db.new_tags "tags", &.tags

			Ship.all_ships.each do |ship|
				db << ship
			end

			db_ships_by_tags.get("flagship").should eq([Ship.flagship])

			# All returned entries should have the requested tag.
			db_ships_by_tags.get("name ship")
				.map(&.tags.includes?("name ship"))
				.reduce { |a, e| a && e }
				.should be_true

			# There shouldn’t be one in our data about WWII Japanese warships…
			db_ships_by_tags.get?("starship").should be_nil

			db.rm_storage_dir
		end

		it "properly removes tags" do
			db = DODB::CachedSpecDataBase(Ship).new

			db_ships_by_tags = db.new_tags "tags", &.tags

			Ship.all_ships.each do |ship|
				db << ship
			end

			# Removing the “flagship” tag, brace for impact.
			flagship, index = db_ships_by_tags.get_with_indice("flagship")[0]
			flagship = flagship.clone
			flagship.tags = [] of String
			db[index] = flagship



#			ship, index = db_ships_by_tags.update(tag: "flagship") do |ship, index|
#				ship.tags = [] of String
#				db[index] = ship
#			end

			db_ships_by_tags.get("flagship").should eq([] of Ship)

			db.rm_storage_dir
		end

		it "gets items that have multiple tags" do
			db = DODB::CachedSpecDataBase(Ship).new

			db_ships_by_tags = db.new_tags "tags", &.tags

			Ship.all_ships.each do |ship|
				db << ship
			end

			results = db_ships_by_tags.get(["flagship", "name ship"])
			results.should eq([Ship.yamato])

			results = db_ships_by_tags.get(["name ship", "flagship"])
			results.should eq([Ship.yamato])

			results = db_ships_by_tags.get(["flagship"])
			results.should eq([Ship.yamato])

			db.rm_storage_dir
		end
	end

	describe "atomic operations" do
		it "safe_get and safe_get?" do
			db = DODB::CachedSpecDataBase(Ship).new

			db_ships_by_name = db.new_index "name", &.name

			Ship.all_ships.each do |ship|
				db << ship
			end

			Ship.all_ships.each do |ship|
				db_ships_by_name.safe_get ship.name do |results|
					results.should eq(ship)
				end

				db_ships_by_name.safe_get? ship.name do |results|
					results.should eq(ship)
				end
			end

			db.rm_storage_dir
		end
	end

	describe "tools" do
		it "rebuilds indexes" do
			db = DODB::CachedSpecDataBase(Ship).new

			db_ships_by_name  = db.new_index     "name", &.name
			db_ships_by_class = db.new_partition "class", &.klass
			db_ships_by_tags  = db.new_tags      "tags", &.tags

			Ship.all_ships.each do |ship|
				db << ship
			end

			db.reindex_everything!

			Ship.all_ships.each do |ship|
				db_ships_by_name.get?(ship.name).should eq(ship)
				db_ships_by_class.get(ship.klass).should contain(ship)
			end

			db.rm_storage_dir
		end

		it "migrates properly" do
			old_db = DODB::CachedSpecDataBase(PrimitiveShip).new "-migration-origin"

			old_ships_by_name  = old_db.new_index     "name", &.name
			old_ships_by_class = old_db.new_partition "class", &.class_name

			PrimitiveShip.all_ships.each do |ship|
				old_db << ship
			end

			# At this point, the “old” DB is filled. Now we need to convert
			# to the new DB.

			new_db = DODB::CachedSpecDataBase(Ship).new "-migration-target"

			new_ships_by_name  = new_db.new_index     "name", &.name
			new_ships_by_class = new_db.new_partition "class", &.klass
			new_ships_by_tags  = new_db.new_tags      "tags", &.tags

			old_db.each_with_key do |ship, index|
				new_ship = Ship.new ship.name,
					klass: ship.class_name,
					id: ship.id,
					tags: Array(String).new.tap { |tags|
						tags << "name ship" if ship.name == ship.class_name
					}

				new_db[index] = new_ship
			end

			# At this point, the conversion is done, so… we’re making a few
			# arbitrary tests on the new data.

			old_db.each_with_key do |old_ship, old_index|
				ship = new_db[old_index]

				ship.id.should eq(old_ship.id)
				ship.klass.should eq(old_ship.class_name)

				ship.tags.any?(&.==("name ship")).should be_true if ship.name == ship.klass
			end

			old_db.rm_storage_dir
			new_db.rm_storage_dir
		end
	end
end