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


local ecs = require 'ecs'


--===== Component tests =====--

local Component = ecs.Component

test("factories work as expected", function()
	local factory = Component.newFactory("health", { percent=100 })
	local comp1 = factory()
	assert(comp1.__type == "health", "bad component type for comp1")
	assert(comp1.percent == 100, "bat percent for comp1")

	local comp2 = factory{ percent=50 }
	assert(comp2.__type == "health", "bad component type for comp2")
	assert(comp2.percent == 50, "bad percent for comp2")

	local success = pcall(function()
		comp2.dne = 5
	end)
	assert(not success, "incorrectly succeeded in setting comp2.dne")

	local success = pcall(function()
		local comp3 = factory{ percent = 44, something = 2 }
	end)
	assert(not success, "incorrectly succeeded in creating comp3")
end)


test("components serialize as expected", function()
	local position = Component.newFactory("position", { x=0, y=0, z=0 })
	local comp = position{x=10, y=15, z=10}
	local str = tostring(comp)
	local tbl = (loadstring("return " .. str))()
	assert(tbl.__type == "position", "bad type")
	assert(tbl.x == 10, "bad x")
	assert(tbl.y == 15, "bad y")
	assert(tbl.z == 10, "bad z")
end)


test("components serialize successfully with subcomponents", function()
	local position = Component.newFactory("position", { x=0, y=0, z=0 })
	local player = Component.newFactory("player", { name="", position={} })

	local p = player{ name="hannah", position=position{x=10, y=9, z=8} }
	local tbl = (loadstring("return " .. tostring(p)))()
	assert(tbl.__type == "player")
	assert(tbl.name == "hannah")
	assert(tbl.position.__type == "position")
	assert(tbl.position.x == 10)
	assert(tbl.position.y == 9)
	assert(tbl.position.z == 8)
end)


--===== 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)