/*
Copyright 2014 Workiva, LLC

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,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package yfast

import (
	"testing"

	"github.com/stretchr/testify/assert"
)

func generateEntries(num int) Entries {
	entries := make(Entries, 0, num)
	for i := uint64(0); i < uint64(num); i++ {
		entries = append(entries, newMockEntry(i))
	}

	return entries
}

func TestTrieSimpleInsert(t *testing.T) {
	yfast := New(uint8(0))

	e1 := newMockEntry(3)
	e2 := newMockEntry(7)
	e3 := newMockEntry(8)

	yfast.Insert(e1, e2, e3)

	result := yfast.get(3)
	assert.Equal(t, e1, result)

	result = yfast.get(7)
	assert.Equal(t, e2, result)

	result = yfast.get(8)
	assert.Equal(t, e3, result)

	result = yfast.get(250)
	assert.Nil(t, result)

	assert.Equal(t, uint64(3), yfast.Len())
}

func TestTrieOverwriteInsert(t *testing.T) {
	yfast := New(uint8(0))

	e1 := newMockEntry(3)
	e2 := newMockEntry(3)
	yfast.Insert(e1)

	yfast.Insert(e2)
	assert.Equal(t, e2, yfast.Get(3))
	assert.Equal(t, uint64(1), yfast.Len())
}

func TestTrieDelete(t *testing.T) {
	yfast := New(uint8(0))

	e1 := newMockEntry(3)
	e2 := newMockEntry(7)
	e3 := newMockEntry(8)

	yfast.Insert(e1, e2, e3)

	result := yfast.Delete(3)
	assert.Equal(t, Entries{e1}, result)
	assert.Nil(t, yfast.Get(3))
	assert.Equal(t, uint64(2), yfast.Len())

	result = yfast.Delete(7)
	assert.Equal(t, Entries{e2}, result)
	assert.Nil(t, yfast.Get(7))
	assert.Equal(t, uint64(1), yfast.Len())

	result = yfast.Delete(8)
	assert.Equal(t, Entries{e3}, result)
	assert.Nil(t, yfast.Get(8))
	assert.Equal(t, uint64(0), yfast.Len())

	result = yfast.Delete(5)
	assert.Equal(t, Entries{nil}, result)
	assert.Equal(t, uint64(0), yfast.Len())
}

func TestTrieSuccessor(t *testing.T) {
	yfast := New(uint8(0))

	e3 := newMockEntry(13)
	yfast.Insert(e3)

	successor := yfast.Successor(0)
	assert.Equal(t, e3, successor)

	e1 := newMockEntry(3)
	e2 := newMockEntry(7)

	yfast.Insert(e1, e2)

	successor = yfast.Successor(0)
	assert.Equal(t, e1, successor)

	successor = yfast.Successor(3)
	assert.Equal(t, e1, successor)

	successor = yfast.Successor(4)
	assert.Equal(t, e2, successor)

	successor = yfast.Successor(8)
	assert.Equal(t, e3, successor)

	successor = yfast.Successor(14)
	assert.Nil(t, successor)

	successor = yfast.Successor(100)
	assert.Nil(t, successor)
}

func TestTriePredecessor(t *testing.T) {
	yfast := New(uint8(0))

	predecessor := yfast.Predecessor(5)
	assert.Nil(t, predecessor)

	e1 := newMockEntry(5)
	yfast.Insert(e1)

	predecessor = yfast.Predecessor(13)
	assert.Equal(t, e1, predecessor)

	e2 := newMockEntry(12)
	yfast.Insert(e2)

	predecessor = yfast.Predecessor(11)
	assert.Equal(t, e1, predecessor)

	predecessor = yfast.Predecessor(5)
	assert.Equal(t, e1, predecessor)

	predecessor = yfast.Predecessor(4)
	assert.Nil(t, predecessor)

	predecessor = yfast.Predecessor(100)
	assert.Equal(t, e2, predecessor)
}

func TestTrieIterator(t *testing.T) {
	yfast := New(uint8(0))

	iter := yfast.Iter(5)
	assert.Equal(t, Entries{}, iter.exhaust())

	e1 := newMockEntry(5)
	yfast.Insert(e1)

	iter = yfast.Iter(5)
	assert.Equal(t, Entries{e1}, iter.exhaust())

	e2 := newMockEntry(12)
	yfast.Insert(e2)

	iter = yfast.Iter(5)
	assert.Equal(t, Entries{e1, e2}, iter.exhaust())

	iter = yfast.Iter(6)
	assert.Equal(t, Entries{e2}, iter.exhaust())

	e3 := newMockEntry(6)
	yfast.Insert(e3)

	iter = yfast.Iter(7)
	assert.Equal(t, Entries{e2}, iter.exhaust())

	iter = yfast.Iter(0)
	assert.Equal(t, Entries{e1, e3, e2}, iter.exhaust())

	iter = yfast.Iter(13)
	assert.Equal(t, Entries{}, iter.exhaust())
}

func BenchmarkInsert(b *testing.B) {
	yfast := New(uint64(0))
	entries := generateEntries(b.N)

	b.ResetTimer()

	for i := 0; i < b.N; i++ {
		yfast.Insert(entries[i])
	}
}

func BenchmarkGet(b *testing.B) {
	numItems := 1000

	entries := generateEntries(numItems)

	yfast := New(uint32(0))
	yfast.Insert(entries...)

	b.ResetTimer()

	for i := 0; i < b.N; i++ {
		yfast.Get(uint64(numItems / 2))
	}
}

func BenchmarkDelete(b *testing.B) {
	entries := generateEntries(b.N)
	yfast := New(uint64(0))
	yfast.Insert(entries...)

	b.ResetTimer()

	for i := 0; i < b.N; i++ {
		yfast.Delete(uint64(i))
	}
}

func BenchmarkSuccessor(b *testing.B) {
	numItems := 100000

	entries := make(Entries, 0, numItems)
	for i := uint64(0); i < uint64(numItems); i++ {
		entries = append(entries, newMockEntry(i+uint64(b.N/2)))
	}

	yfast := New(uint64(0))
	yfast.Insert(entries...)

	b.ResetTimer()

	for i := 0; i < b.N; i++ {
		yfast.Successor(uint64(i))
	}
}

func BenchmarkPredecessor(b *testing.B) {
	numItems := 100000

	entries := make(Entries, 0, numItems)
	for i := uint64(0); i < uint64(numItems); i++ {
		entries = append(entries, newMockEntry(i+uint64(b.N/2)))
	}

	yfast := New(uint64(0))
	yfast.Insert(entries...)

	b.ResetTimer()

	for i := 0; i < b.N; i++ {
		yfast.Predecessor(uint64(i))
	}
}

func BenchmarkIterator(b *testing.B) {
	numItems := 1000
	entries := generateEntries(numItems)

	yfast := New(uint64(0))
	yfast.Insert(entries...)

	b.ResetTimer()

	for i := 0; i < b.N; i++ {
		for iter := yfast.Iter(0); iter.Next(); {
			iter.Value()
		}
	}
}