// Copyright 2019 TiKV Project Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.

package statistics

import (
	"time"

	. "github.com/pingcap/check"
)

var _ = Suite(&testAvgOverTimeSuite{})

type testAvgOverTimeSuite struct{}

func (t *testAvgOverTimeSuite) TestPulse(c *C) {
	aot := NewAvgOverTime(5 * time.Second)
	// warm up
	for i := 0; i < 5; i++ {
		aot.Add(1000, time.Second)
		aot.Add(0, time.Second)
	}
	for i := 0; i < 100; i++ {
		if i%2 == 0 {
			aot.Add(1000, time.Second)
		} else {
			aot.Add(0, time.Second)
		}
		c.Assert(aot.Get(), LessEqual, 600.)
		c.Assert(aot.Get(), GreaterEqual, 400.)
	}
}

func (t *testAvgOverTimeSuite) TestChange(c *C) {
	aot := NewAvgOverTime(5 * time.Second)

	// phase 1: 1000
	for i := 0; i < 20; i++ {
		aot.Add(1000, time.Second)
	}
	c.Assert(aot.Get(), LessEqual, 1010.)
	c.Assert(aot.Get(), GreaterEqual, 990.)

	//phase 2: 500
	for i := 0; i < 5; i++ {
		aot.Add(500, time.Second)
	}
	c.Assert(aot.Get(), LessEqual, 900.)
	c.Assert(aot.Get(), GreaterEqual, 495.)
	for i := 0; i < 15; i++ {
		aot.Add(500, time.Second)
	}

	//phase 3: 100
	for i := 0; i < 5; i++ {
		aot.Add(100, time.Second)
	}
	c.Assert(aot.Get(), LessEqual, 678.)
	c.Assert(aot.Get(), GreaterEqual, 99.)
}