/*
NAME
  RingBuffer_test.go - a test suite adopting the golang testing library to test functionality of the
  RingBuffer structure

DESCRIPTION
  See Readme.md

AUTHOR
  Saxon Nelson-Milton <saxon.milton@gmail.com>

LICENSE
  RingBuffer_test.go is Copyright (C) 2017 the Australian Ocean Lab (AusOcean)

  It is free software: you can redistribute it and/or modify them
  under the terms of the GNU General Public License as published by the
  Free Software Foundation, either version 3 of the License, or (at your
  option) any later version.

  It is distributed in the hope that it will be useful, but WITHOUT
  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
 for more details.

  You should have received a copy of the GNU General Public License
  along with revid in gpl.txt.  If not, see [GNU licenses](http://www.gnu.org/licenses).
*/

package ringbuffer

import (
	"testing"
	"time"
)

const (
	testBufferSize            = 10
	testElementSize           = 1
	testOverFlowSize          = 5
	testDataSize              = 1
	testConcurrencyBufferSize = 1000
)

var rb *ringBuffer

// Call when we get an error we shouldn't have
func falseErrorFail(t *testing.T, err error) {
	t.Errorf("Should not have got error: %v", err)
}

// Call when we should have got an error but didnt
func noErrorFail(t *testing.T) {
	t.Errorf("Should have got error!")
}

// Test that the Make method correctly allocates memory for arbitrary buffer
// size of 10 and arbitrary element size of 10
func TestMake(t *testing.T) {
	rb = NewRingBuffer(testBufferSize, testElementSize)
	if len(rb.dataMemory) != testBufferSize {
		t.Errorf("Len of buffer is wrong!")
	}
	if len(rb.dataMemory[0]) != testElementSize {
		t.Errorf("Len of individual element is wrong!")
	}
}

// Test call to done writing when no writing has occured.
// We pass arbitrary clipSize.
func TestDoneWriting1(t *testing.T) {
	if rb.DoneWriting(testDataSize) == nil {
		noErrorFail(t)
	}
}

// Test call to done writing when there has been some 'writing'
func TestDoneWriting2(t *testing.T) {
	if _, err := rb.Get(); err != nil {
		falseErrorFail(t, err)
	}
	if err := rb.DoneWriting(testDataSize); err != nil {
		falseErrorFail(t, err)
	}
}

// Test call to done reading when there hasn't been any reading
func TestDoneReading1(t *testing.T) {
	rb = NewRingBuffer(testBufferSize, testElementSize)
	if rb.DoneReading() == nil {
		noErrorFail(t)
	}
}

// Test read when there hasn't been anything written to buffer
func TestReadingWithoutWrite(t *testing.T) {
	rb = NewRingBuffer(testBufferSize, testElementSize)
	_, err := rb.Read()
	if err == nil {
		noErrorFail(t)
	}
}

// Try Writing twice without calling DoneWriting
func TestWritingTwice(t *testing.T) {
	rb = NewRingBuffer(testBufferSize, testElementSize)
	_, err := rb.Get()
	_, err = rb.Get()
	if err == nil {
		noErrorFail(t)
	}
}

// Test call to done reading when there has been some reading
func TestDoneReading2(t *testing.T) {
	rb = NewRingBuffer(testBufferSize, testElementSize)
	_, err := rb.Get()
	rb.DoneWriting(testDataSize)
	_, err = rb.Read()
	if err != nil {
		falseErrorFail(t, err)
	}
	rb.DoneReading()
}

// Testing writing then reading for single 'write' and single 'read' routines
func TestWritingAndReading1(t *testing.T) {
	rb = NewRingBuffer(testBufferSize, testElementSize)
	if _, err := rb.Get(); err != nil {
		falseErrorFail(t, err)
	}
	if err := rb.DoneWriting(testDataSize); err != nil {
		falseErrorFail(t, err)
	}
	if _, err := rb.Read(); err != nil {
		falseErrorFail(t, err)
	}
	if err := rb.DoneReading(); err != nil {
		falseErrorFail(t, err)
	}
}

// Testing two 'writes' and two 'reads'
func TestWritingAndReading2(t *testing.T) {
	rb = NewRingBuffer(testBufferSize, testElementSize)
	for i := 0; i < 2; i++ {
		if _, err := rb.Get(); err != nil {
			falseErrorFail(t, err)
		}
		if err := rb.DoneWriting(testDataSize); err != nil {
			falseErrorFail(t, err)
		}
	}
	for i := 0; i < 2; i++ {
		if _, err := rb.Read(); err != nil {
			falseErrorFail(t, err)
		}
		if err := rb.DoneReading(); err != nil {
			falseErrorFail(t, err)
		}
	}
}

// Testing one 'write' and two 'reads'
func TestWritingAndReading3(t *testing.T) {
	rb = NewRingBuffer(testBufferSize, testElementSize)
	if _, err := rb.Get(); err != nil {
		falseErrorFail(t, err)
	}
	if err := rb.DoneWriting(testDataSize); err != nil {
		falseErrorFail(t, err)
	}
	var err1 error
	var err2 error
	for i := 0; i < 2; i++ {
		_, err1 = rb.Read()
		err2 = rb.DoneReading()
	}
	if err1 == nil {
		noErrorFail(t)
	}
	if err2 == nil {
		noErrorFail(t)
	}
}

// Test two 'writes' and one 'read'
func TestWritingAndReading4(t *testing.T) {
	rb = NewRingBuffer(testBufferSize, testElementSize)
	for i := 0; i < 2; i++ {
		if _, err := rb.Get(); err != nil {
			falseErrorFail(t, err)
		}
		if err := rb.DoneWriting(testDataSize); err != nil {
			falseErrorFail(t, err)
		}
	}
	if _, err := rb.Read(); err != nil {
		falseErrorFail(t, err)
	}
	if err := rb.DoneReading(); err != nil {
		falseErrorFail(t, err)
	}
}

// Test writing past capacity
func TestWritingAndReading5(t *testing.T) {
	rb = NewRingBuffer(testOverFlowSize, testElementSize)
	var err1 error
	var err2 error
	for i := 0; i < testOverFlowSize+1; i++ {
		_, err1 = rb.Get()
		err2 = rb.DoneWriting(testDataSize)
	}
	if err1 == nil {
		noErrorFail(t)
	}
	if err2 == nil {
		noErrorFail(t)
	}
}

// Test writing to size, then read some, then 'write' to test that we go back
// to start of buffer
func TestWritingAndReading6(t *testing.T) {
	rb = NewRingBuffer(testOverFlowSize, testElementSize)
	var err1 error
	var err2 error
	for i := 0; i < testOverFlowSize; i++ {
		_, err1 = rb.Get()
		err2 = rb.DoneWriting(testDataSize)
	}
	if err1 != nil {
		falseErrorFail(t, err1)
	}
	if err2 != nil {
		falseErrorFail(t, err2)
	}
	for i := 0; i < 2; i++ {
		_, err1 = rb.Read()
		err2 = rb.DoneReading()
	}
	if err1 != nil {
		falseErrorFail(t, err1)
	}
	if err2 != nil {
		falseErrorFail(t, err2)
	}
	_, err1 = rb.Get()
	err2 = rb.DoneWriting(testDataSize)
	if err1 != nil {
		falseErrorFail(t, err1)
	}
	if err2 != nil {
		falseErrorFail(t, err2)
	}
}

// Now let's do the previous test again, but this time we will try to write
// past capacity
func TestWritingAndReading7(t *testing.T) {
	rb = NewRingBuffer(testOverFlowSize, testElementSize)
	var err1 error
	var err2 error
	for i := 0; i < testOverFlowSize; i++ {
		_, err1 = rb.Get()
		err2 = rb.DoneWriting(testDataSize)
	}
	if err1 != nil {
		falseErrorFail(t, err1)
	}
	if err2 != nil {
		falseErrorFail(t, err2)
	}
	for i := 0; i < 2; i++ {
		_, err1 = rb.Read()
		err2 = rb.DoneReading()
	}
	if err1 != nil {
		falseErrorFail(t, err1)
	}
	if err2 != nil {
		falseErrorFail(t, err2)
	}
	for i := 0; i < testOverFlowSize; i++ {
		_, err1 = rb.Get()
		err2 = rb.DoneWriting(testDataSize)
	}
	if err1 == nil {
		noErrorFail(t)
	}
	if err2 == nil {
		noErrorFail(t)
	}
}

// Test reading twice without call to DoneReading
func TestWritingAndReading8(t *testing.T) {
	rb = NewRingBuffer(testBufferSize, 10)
	var err1 error
	var err2 error
	for i := 0; i < 2; i++ {
		_, err1 = rb.Get()
		err2 = rb.DoneWriting(testDataSize)
	}
	if err1 != nil {
		falseErrorFail(t, err1)
	}
	if err2 != nil {
		falseErrorFail(t, err2)
	}
	for i := 0; i < 2; i++ {
		_, err1 = rb.Read()
	}
	if err1 == nil {
		noErrorFail(t)
	}
}

// Let's see if we can do concurrency. (tip: run as: go test -race) to see
// any data race issues. We will continously write and read at concurrently
// time for a second
func TestConcurrency1(t *testing.T) {
	rb = NewRingBuffer(testConcurrencyBufferSize, testElementSize)
	go func() {
		for i := 0; i < 100; i++ {
			if data, err1 := rb.Read(); data != nil {
				err2 := rb.DoneReading()
				if err1 != nil {
					falseErrorFail(t, err1)
				}
				if err2 != nil {
					falseErrorFail(t, err2)
				}
			}
		}
	}()
	go func() {
		for i := 0; i < 100; i++ {
			_, err1 := rb.Get()
			err2 := rb.DoneWriting(testDataSize)
			if err1 != nil {
				falseErrorFail(t, err1)
			}
			if err2 != nil {
				falseErrorFail(t, err2)
			}
		}
	}()
	time.Sleep(1000 * time.Millisecond)
}