// (c) 2019-2020, Ava Labs, Inc. All rights reserved.
// See the file LICENSE for licensing terms.

package cache

import (
	"testing"

	"github.com/ava-labs/gecko/ids"
)

func TestLRU(t *testing.T) {
	cache := LRU{Size: 1}

	id1 := ids.NewID([32]byte{1})
	if _, found := cache.Get(id1); found {
		t.Fatalf("Retrieved value when none exists")
	}

	expectedValue1 := 1
	cache.Put(id1, expectedValue1)
	if value, found := cache.Get(id1); !found {
		t.Fatalf("Failed to retrieve value when one exists")
	} else if value != expectedValue1 {
		t.Fatalf("Failed to retrieve correct value when one exists")
	}

	cache.Put(id1, expectedValue1)
	if value, found := cache.Get(id1); !found {
		t.Fatalf("Failed to retrieve value when one exists")
	} else if value != expectedValue1 {
		t.Fatalf("Failed to retrieve correct value when one exists")
	}

	cache.Put(id1, expectedValue1)
	if value, found := cache.Get(id1); !found {
		t.Fatalf("Failed to retrieve value when one exists")
	} else if value != expectedValue1 {
		t.Fatalf("Failed to retrieve correct value when one exists")
	}

	id2 := ids.NewID([32]byte{2})

	expectedValue2 := 2
	cache.Put(id2, expectedValue2)
	if _, found := cache.Get(id1); found {
		t.Fatalf("Retrieved value when none exists")
	}
	if value, found := cache.Get(id2); !found {
		t.Fatalf("Failed to retrieve value when one exists")
	} else if value != expectedValue2 {
		t.Fatalf("Failed to retrieve correct value when one exists")
	}
}

func TestLRUEviction(t *testing.T) {
	cache := LRU{Size: 2}

	id1 := ids.NewID([32]byte{1})
	id2 := ids.NewID([32]byte{2})
	id3 := ids.NewID([32]byte{3})

	cache.Put(id1, 1)
	cache.Put(id2, 2)

	if val, found := cache.Get(id1); !found {
		t.Fatalf("Failed to retrieve value when one exists")
	} else if val != 1 {
		t.Fatalf("Retrieved wrong value")
	} else if val, found := cache.Get(id2); !found {
		t.Fatalf("Failed to retrieve value when one exists")
	} else if val != 2 {
		t.Fatalf("Retrieved wrong value")
	} else if _, found := cache.Get(id3); found {
		t.Fatalf("Retrieve value when none exists")
	}

	cache.Put(id3, 3)

	if _, found := cache.Get(id1); found {
		t.Fatalf("Retrieve value when none exists")
	} else if val, found := cache.Get(id2); !found {
		t.Fatalf("Failed to retrieve value when one exists")
	} else if val != 2 {
		t.Fatalf("Retrieved wrong value")
	} else if val, found := cache.Get(id3); !found {
		t.Fatalf("Failed to retrieve value when one exists")
	} else if val != 3 {
		t.Fatalf("Retrieved wrong value")
	}

	cache.Get(id2)
	cache.Put(id1, 1)

	if val, found := cache.Get(id1); !found {
		t.Fatalf("Failed to retrieve value when one exists")
	} else if val != 1 {
		t.Fatalf("Retrieved wrong value")
	} else if val, found := cache.Get(id2); !found {
		t.Fatalf("Failed to retrieve value when one exists")
	} else if val != 2 {
		t.Fatalf("Retrieved wrong value")
	} else if _, found := cache.Get(id3); found {
		t.Fatalf("Retrieved value when none exists")
	}

	cache.Evict(id2)
	cache.Put(id3, 3)

	if val, found := cache.Get(id1); !found {
		t.Fatalf("Failed to retrieve value when one exists")
	} else if val != 1 {
		t.Fatalf("Retrieved wrong value")
	} else if _, found := cache.Get(id2); found {
		t.Fatalf("Retrieved value when none exists")
	} else if val, found := cache.Get(id3); !found {
		t.Fatalf("Failed to retrieve value when one exists")
	} else if val != 3 {
		t.Fatalf("Retrieved wrong value")
	}

	cache.Flush()

	if _, found := cache.Get(id1); found {
		t.Fatalf("Retrieved value when none exists")
	} else if _, found := cache.Get(id2); found {
		t.Fatalf("Retrieved value when none exists")
	} else if _, found := cache.Get(id3); found {
		t.Fatalf("Retrieved value when none exists")
	}
}

func TestLRUResize(t *testing.T) {
	cache := LRU{Size: 2}

	id1 := ids.NewID([32]byte{1})
	id2 := ids.NewID([32]byte{2})

	cache.Put(id1, 1)
	cache.Put(id2, 2)

	if val, found := cache.Get(id1); !found {
		t.Fatalf("Failed to retrieve value when one exists")
	} else if val != 1 {
		t.Fatalf("Retrieved wrong value")
	} else if val, found := cache.Get(id2); !found {
		t.Fatalf("Failed to retrieve value when one exists")
	} else if val != 2 {
		t.Fatalf("Retrieved wrong value")
	}

	cache.Size = 1

	if _, found := cache.Get(id1); found {
		t.Fatalf("Retrieve value when none exists")
	} else if val, found := cache.Get(id2); !found {
		t.Fatalf("Failed to retrieve value when one exists")
	} else if val != 2 {
		t.Fatalf("Retrieved wrong value")
	}

	cache.Size = 0

	if _, found := cache.Get(id1); found {
		t.Fatalf("Retrieve value when none exists")
	} else if val, found := cache.Get(id2); !found {
		t.Fatalf("Failed to retrieve value when one exists")
	} else if val != 2 {
		t.Fatalf("Retrieved wrong value")
	}
}