/*
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"
)

// 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!")
}

// RingBuffer object used over testing funcs
var ringBuffer = RingBuffer{}

// 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) {
	ringBuffer.Make(10, 10)
	if len(ringBuffer.Memory) != 10 {
		t.Errorf("Len of buffer is wrong!")
	}
	if len(ringBuffer.Memory[0]) != 10 {
		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 ringBuffer.DoneWriting(1) == nil {
		noErrorFail(t)
	}
}

// Test call to done writing when there has been some 'writing'
func TestDoneWriting2(t *testing.T) {
	if _, err := ringBuffer.Get(); err != nil {
		falseErrorFail(t, err)
	}
	if err := ringBuffer.DoneWriting(1); err != nil {
		falseErrorFail(t, err)
	}
}

// Try to 'write' to the buffer when full. Set buffer size to arbitrary number of 3.
// We write over buffer size of 3 (write 4 times)
func TestWritingWhenFull(t *testing.T) {
	ringBuffer.Make(3, 10)
	var err error
	for i := 0; i < 4; i++ {
		_, err = ringBuffer.Get()
		ringBuffer.DoneWriting(1)
	}
	if err == nil {
		noErrorFail(t)
	}
}

// Test call to done reading when there hasn't been any reading
func TestDoneReading1(t *testing.T) {
	ringBuffer.Make(10, 10)
	if ringBuffer.DoneReading() == nil {
		noErrorFail(t)
	}
}

// Test read when there hasn't been anything written to buffer
func TestReadingWithoutWrite(t *testing.T) {
	ringBuffer.Make(10, 10)
	_, _, err := ringBuffer.Read()
	if err == nil {
		noErrorFail(t)
	}
}

// Try Writing twice without calling DoneWriting
func TestWritingTwice(t *testing.T) {
	ringBuffer.Make(10, 10)
	_, err := ringBuffer.Get()
	_, err = ringBuffer.Get()
	if err == nil {
		noErrorFail(t)
	}
}

// Test call to done reading when there has been some reading
func TestDoneReading2(t *testing.T) {
	ringBuffer.Make(10, 10)
	_, err := ringBuffer.Get()
	ringBuffer.DoneWriting(1)
	_, _, err = ringBuffer.Read()
	if err != nil {
		falseErrorFail(t, err)
	}
	ringBuffer.DoneReading()
}

// Testing writing then reading for single 'write' and single 'read' routines
func TestWritingAndReading1(t *testing.T) {
	ringBuffer.Make(10, 10)
	if _, err := ringBuffer.Get(); err != nil {
		falseErrorFail(t, err)
	}
	if err := ringBuffer.DoneWriting(1); err != nil {
		falseErrorFail(t, err)
	}
	if _, _, err := ringBuffer.Read(); err != nil {
		falseErrorFail(t, err)
	}
	if err := ringBuffer.DoneReading(); err != nil {
		falseErrorFail(t, err)
	}
}

// Testing two 'writes' and two 'reads'
func TestWritingAndReading2(t *testing.T) {
	ringBuffer.Make(10, 10)
	for i := 0; i < 2; i++ {
		if _, err := ringBuffer.Get(); err != nil {
			falseErrorFail(t, err)
		}
		if err := ringBuffer.DoneWriting(1); err != nil {
			falseErrorFail(t, err)
		}
	}
	for i := 0; i < 2; i++ {
		if _, _, err := ringBuffer.Read(); err != nil {
			falseErrorFail(t, err)
		}
		if err := ringBuffer.DoneReading(); err != nil {
			falseErrorFail(t, err)
		}
	}
}

// Testing one 'write' and two 'reads'
func TestWritingAndReading3(t *testing.T) {
	ringBuffer.Make(10, 10)
	if _, err := ringBuffer.Get(); err != nil {
		falseErrorFail(t, err)
	}
	if err := ringBuffer.DoneWriting(1); err != nil {
		falseErrorFail(t, err)
	}
	var err1 error
	var err2 error
	for i := 0; i < 2; i++ {
		_, _, err1 = ringBuffer.Read()
		err2 = ringBuffer.DoneReading()
	}
	if err1 == nil {
		noErrorFail(t)
	}
	if err2 == nil {
		noErrorFail(t)
	}
}

// Test two 'writes' and one 'read'
func TestWritingAndReading4(t *testing.T) {
	ringBuffer.Make(10, 10)
	for i := 0; i < 2; i++ {
		if _, err := ringBuffer.Get(); err != nil {
			falseErrorFail(t, err)
		}
		if err := ringBuffer.DoneWriting(1); err != nil {
			falseErrorFail(t, err)
		}
	}
	if _, _, err := ringBuffer.Read(); err != nil {
		falseErrorFail(t, err)
	}
	if err := ringBuffer.DoneReading(); err != nil {
		falseErrorFail(t, err)
	}
}

// Test writing past capacity
func TestWritingAndReading5(t *testing.T) {
	ringBuffer.Make(4, 10)
	var err1 error
	var err2 error
	for i := 0; i < 5; i++ {
		_, err1 = ringBuffer.Get()
		err2 = ringBuffer.DoneWriting(1)
	}
	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) {
	ringBuffer.Make(4, 10)
	var err1 error
	var err2 error
	for i := 0; i < 4; i++ {
		_, err1 = ringBuffer.Get()
		err2 = ringBuffer.DoneWriting(1)
	}
	if err1 != nil {
		falseErrorFail(t, err1)
	}
	if err2 != nil {
		falseErrorFail(t, err2)
	}
	for i := 0; i < 2; i++ {
		_, _, err1 = ringBuffer.Read()
		err2 = ringBuffer.DoneReading()
	}
	if err1 != nil {
		falseErrorFail(t, err1)
	}
	if err2 != nil {
		falseErrorFail(t, err2)
	}
	_, err1 = ringBuffer.Get()
	err2 = ringBuffer.DoneWriting(1)
	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) {
	ringBuffer.Make(4, 10)
	var err1 error
	var err2 error
	for i := 0; i < 4; i++ {
		_, err1 = ringBuffer.Get()
		err2 = ringBuffer.DoneWriting(1)
	}
	if err1 != nil {
		falseErrorFail(t, err1)
	}
	if err2 != nil {
		falseErrorFail(t, err2)
	}
	for i := 0; i < 2; i++ {
		_, _, err1 = ringBuffer.Read()
		err2 = ringBuffer.DoneReading()
	}
	if err1 != nil {
		falseErrorFail(t, err1)
	}
	if err2 != nil {
		falseErrorFail(t, err2)
	}
	for i := 0; i < 3; i++ {
		_, err1 = ringBuffer.Get()
		err2 = ringBuffer.DoneWriting(1)
	}
	if err1 == nil {
		noErrorFail(t)
	}
	if err2 == nil {
		noErrorFail(t)
	}
}

// Test reading twice without call to DoneReading
func TestWritingAndReading8(t *testing.T) {
	ringBuffer.Make(4, 10)
	var err1 error
	var err2 error
	for i := 0; i < 4; i++ {
		_, err1 = ringBuffer.Get()
		err2 = ringBuffer.DoneWriting(1)
	}
	if err1 != nil {
		falseErrorFail(t, err1)
	}
	if err2 != nil {
		falseErrorFail(t, err2)
	}
	for i := 0; i < 2; i++ {
		_, _, err1 = ringBuffer.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) {
	ringBuffer.Make(1000, 10)
	go func() {
		for i := 0; i < 100; i++ {
			if data, _, err1 := ringBuffer.Read(); data != nil {
				err2 := ringBuffer.DoneReading()
				if err1 != nil {
					falseErrorFail(t, err1)
				}
				if err2 != nil {
					falseErrorFail(t, err2)
				}
			}
		}
	}()
	go func() {
		for i := 0; i < 100; i++ {
			_, err1 := ringBuffer.Get()
			err2 := ringBuffer.DoneWriting(1)
			if err1 != nil {
				falseErrorFail(t, err1)
			}
			if err2 != nil {
				falseErrorFail(t, err2)
			}
		}
	}()
	time.Sleep(1000 * time.Millisecond)
}