package mru_test

import (
	"strings"
	"testing"

	"github.com/Code-Hex/go-generics-cache/policy/mru"
)

func TestSet(t *testing.T) {
	cache := mru.NewCache[string, int](mru.WithCapacity(2))
	cache.Set("foo", 1)
	cache.Set("bar", 2)
	if got := cache.Len(); got != 2 {
		t.Fatalf("invalid length: %d", got)
	}
	if got, ok := cache.Get("foo"); got != 1 || !ok {
		t.Fatalf("invalid value got %d, cachehit %v", got, ok)
	}

	// if over the cap
	cache.Set("baz", 3)
	if got := cache.Len(); got != 2 {
		t.Fatalf("invalid length: %d", got)
	}
	baz, ok := cache.Get("baz")
	if baz != 3 || !ok {
		t.Fatalf("invalid value baz %d, cachehit %v", baz, ok)
	}

	// check eviction most recently used
	if _, ok := cache.Get("bar"); ok {
		t.Log(cache.Keys())
		t.Fatalf("invalid eviction the newest value for bar %v", ok)
	}

	// current state
	// - baz <- recently used
	// - foo

	// valid: if over the cap but specify the oldest key
	cache.Set("foo", 100)
	if got := cache.Len(); got != 2 {
		t.Fatalf("invalid length: %d", got)
	}
	foo, ok := cache.Get("foo")
	if foo != 100 || !ok {
		t.Fatalf("invalid replacing value foo %d, cachehit %v", foo, ok)
	}
}

func TestDelete(t *testing.T) {
	cache := mru.NewCache[string, int](mru.WithCapacity(1))
	cache.Set("foo", 1)
	if got := cache.Len(); got != 1 {
		t.Fatalf("invalid length: %d", got)
	}

	cache.Delete("foo2")
	if got := cache.Len(); got != 1 {
		t.Fatalf("invalid length after deleted does not exist key: %d", got)
	}

	cache.Delete("foo")
	if got := cache.Len(); got != 0 {
		t.Fatalf("invalid length after deleted: %d", got)
	}
	if _, ok := cache.Get("foo"); ok {
		t.Fatalf("invalid get after deleted %v", ok)
	}
}

func TestKeys(t *testing.T) {
	cache := mru.NewCache[string, int]()
	cache.Set("foo", 1)
	cache.Set("bar", 2)
	cache.Set("baz", 3)
	cache.Set("bar", 4) // again
	cache.Set("foo", 5) // again

	got := strings.Join(cache.Keys(), ",")
	want := strings.Join([]string{
		"foo",
		"bar",
		"baz",
	}, ",")
	if got != want {
		t.Errorf("want %q, but got %q", want, got)
	}
	if len(cache.Keys()) != cache.Len() {
		t.Errorf("want number of keys %d, but got %d", len(cache.Keys()), cache.Len())
	}
}