local testCount = 0
local failCount = 0

local function test(msg, f)
	testCount = testCount + 1
	local success, error = xpcall(f, debug.traceback)
	if success then
		print(msg .. "\t\t[OK]")
	else
		failCount = failCount + 1
		print(msg .. "\t\t[FAIL]")
		print(error)
	end
end


local ecs = require 'ecs'


--===== EntityDb tests =====--

local EntityDb = ecs.EntityDb


test("EntityDb.createEntity() always returns a new id", function()
	local db = EntityDb()

	local ids = {}
	for i=1,100 do
		local id = db:createEntity()
		assert(ids[id] == nil, "id was already returned!")
		ids[id] = true
	end
end)


test("EntityDb.queryComponent() gets all entities with a given component", function()
	local db = EntityDb()

	local ids = {}
	for i=1,100 do
		local id = db:createEntity()
		if i%2==0 then
			ids[id] = 5*i
			db:addComponent(id, "number", 5*i)
		end
	end

	local query = db:queryComponent("number")
	local count = 0
	for id, number in pairs(query) do
		count = count + 1
		assert(number == ids[id])
	end
	assert(count == 50)
end)


test("EntityDb.queryEntity() gets all components associated with an entity", function()
	local db = EntityDb()

	local entity
	for i=1,100 do
		local id = db:createEntity()
		if i%2 == 0 then db:addComponent(id, "number", 2) end
		if i%3 == 0 then db:addComponent(id, "string", "hello") end
		if i%5 == 0 then db:addComponent(id, "number2", 4) end
		if i%7 == 0 then db:addComponent(id, "string2", "world") end
		if i == 30 then entity=id end
	end

	local query = db:queryEntity(entity)
	assert(query.number == 2)
	assert(query.string == "hello")
	assert(query.number2 == 4)
	assert(query.string2 == nil)
end)


test("EntityDb.removeComponent() removes components correctly", function()
	local db = EntityDb()

	local id = db:createEntity()
	db:addComponent(id, "number", 2)
	db:addComponent(id, "string", "hello")
	db:addComponent(id, "number2", 4)
	db:addComponent(id, "string2", "world")

	local query = db:queryEntity(id)
	assert(query.number == 2)
	assert(query.string == "hello")
	assert(query.number2 == 4)
	assert(query.string2 == "world")

	db:removeComponent(id, "string2")
	query = db:queryEntity(id)
	assert(query.number == 2)
	assert(query.string == "hello")
	assert(query.number2 == 4)
	assert(query.string2 == nil)

	db:removeComponent(id, "number2")
	query = db:queryEntity(id)
	assert(query.number == 2)
	assert(query.string == "hello")
	assert(query.number2 == nil)
	assert(query.string2 == nil)

	db:removeComponent(id, "string")
	query = db:queryEntity(id)
	assert(query.number == 2)
	assert(query.string == nil)
	assert(query.number2 == nil)
	assert(query.string2 == nil)

	db:removeComponent(id, "number")
	query = db:queryEntity(id)
	assert(query.number == nil)
	assert(query.string == nil)
	assert(query.number2 == nil)
	assert(query.string2 == nil)
end)


test("EntityDb.removeComponent() deletes component table when empty", function()
	local db = EntityDb()
	local id1 = db:createEntity()
	local id2 = db:createEntity()
	db:addComponent(id1, "number", 2)
	db:addComponent(id2, "number", 3)

	assert(db.components.number ~= nil)
	db:removeComponent(id1, "number")
	assert(db.components.number ~= nil)
	db:removeComponent(id2, "number")
	assert(db.components.number == nil)
end)


test("EntityDb.removeComponent() does nothing if the component is not present", function()
	local db = EntityDb()
	local id1 = db:createEntity()
	local id2 = db:createEntity()
	db:addComponent(id1, "number", 2)
	db:addComponent(id2, "number", 3)

	assert(db.components.number ~= nil)
	db:removeComponent(id1, "number")
	assert(db.components.number ~= nil)
	db:removeComponent(id1, "number")
	assert(db.components.number ~= nil)

	db:removeComponent(id2, "number")
	assert(db.components.number == nil)

end)


test("EntityDb.deleteEntity() correctly removes an entity", function()
	local db = EntityDb()
	local id1 = db:createEntity()
	local id2 = db:createEntity()
	db:addComponent(id1, "number", 2)
	db:addComponent(id2, "number", 3)

	local query = db:queryComponent("number")
	assert(query[id1] and query[id2])
	db:deleteEntity(id1)
	query = db:queryComponent("number")
	assert(query[id1] == nil)
	assert(query[id2] ~= nil)

	assert(false == pcall(function()
		local query = db:queryEntity(id1)
	end))
end)


--===== SystemDb tests =====--

local SystemDb = ecs.SystemDb

test("addSystems() correctly sorts systems", function()
	local sdb = SystemDb(nil)
	local str = ""

	local c = ecs.System("c", function(db, dt, params)
		str = str .. "c"
	end)

	local a = ecs.System("a", function(db, dt, params)
		str = str .. "a"
	end)

	local b = ecs.System("b", function(db, dt, params)
		str = str .. "b"
	end)

	b:addDependency(a)
	c:addDependency(b)

	sdb:addSystems({c, a, b}, nil)

	sdb:update(0)
	assert(str == "abc")
end)


test("addSystems() fails on dependency loop", function()
	local a = ecs.System("a", nil)
	local b = ecs.System("b", nil)
	local c = ecs.System("c", nil)

	a:addDependency(c)
	b:addDependency(a)
	c:addDependency(b)

	sdb = SystemDb(nil)
	local success = pcall(sdb,addSystems, sdb, {c, a, b}, nil)
	assert(success == false)
end)


test("addSystems() correctly inserts additional systems", function()
	local str = ""
	local sdb = SystemDb(nil)

	local c = ecs.System("c", function(db, dt, params)
		str = str .. "c"
	end)
	local a = ecs.System("a", function(db, dt, params)
		str = str .. "a"
	end)
	local b = ecs.System("b", function(db, dt, params)
		str = str .. "b"
	end)

	b:addDependency(a)
	c:addDependency(b)

	sdb:addSystems({c, a, b}, nil)

	local d = ecs.System("d", function(db, dt, params)
		str = str .. "d"
	end)
	local e = ecs.System("e", function(db, dt, params)
		str = str .. "e"
	end)

	d:addDependency(c)
	e:addDependency(d)

	sdb:addSystems({e, d}, nil)
	sdb:update(0)
	assert(str == "abcde")
end)


test("addSystems() correctly handles dangling dependencies", function()
	local str = ""
	local sdb = SystemDb(nil)

	local c = ecs.System("c", function(db, dt, params)
		str = str .. "c"
	end)
	local a = ecs.System("a", function(db, dt, params)
		str = str .. "a"
	end)
	local b = ecs.System("b", function(db, dt, params)
		str = str .. "b"
	end)

	b:addDependency(a)
	c:addDependency(b)

	local d = ecs.System("d", function(db, dt, params)
		str = str .. "d"
	end)
	local e = ecs.System("e", function(db, dt, params)
		str = str .. "e"
	end)

	d:addDependency(c)
	e:addDependency(d)

	sdb:addSystems({e, d}, nil)

	local success = pcall(sdb.update, sdb, nil)
	assert(success == false)

	sdb:addSystems({c, a, b}, nil)

	sdb:update(0)
	assert(str == "abcde")
end)




test("removeSystem() correctly handles things", function()
	local sdb = SystemDb(nil)
	local num = 1


	local two = ecs.System("x2", function(db, dt, p) num = num*2 end)	
	local three = ecs.System("x3", function(db, dt, p) num = num*3 end)	
	local five = ecs.System("x5", function(db, dt, p) num = num*5 end)	

	sdb:addSystems({two, three, five}, nil)

	sdb:update(0)
	assert(num == 30)

	num = 1

	sdb:removeSystems({three})
	sdb:update(1)
	assert(num == 10)
end)


print(string.format("ran %d tests, %d failed", testCount, failCount))