// vfs/cache/cache_test.go
package cache

import (
	"errors"
	"io"
	"testing"

	"s1d3sw1ped/SteamCache2/vfs"
	"s1d3sw1ped/SteamCache2/vfs/cachestate"
	"s1d3sw1ped/SteamCache2/vfs/memory"
	"s1d3sw1ped/SteamCache2/vfs/vfserror"
)

func testMemory() vfs.VFS {
	return memory.New(1024)
}

func TestNew(t *testing.T) {
	fast := testMemory()
	slow := testMemory()

	cache := New(nil)
	cache.SetFast(fast)
	cache.SetSlow(slow)
	if cache == nil {
		t.Fatal("expected cache to be non-nil")
	}
}

func TestNewPanics(t *testing.T) {
	defer func() {
		if r := recover(); r == nil {
			t.Fatal("expected panic but did not get one")
		}
	}()

	cache := New(nil)
	cache.SetFast(nil)
	cache.SetSlow(nil)
}

func TestCreateAndOpen(t *testing.T) {
	fast := testMemory()
	slow := testMemory()
	cache := New(nil)
	cache.SetFast(fast)
	cache.SetSlow(slow)

	key := "test"
	value := []byte("value")

	w, err := cache.Create(key, int64(len(value)))
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	w.Write(value)
	w.Close()

	rc, err := cache.Open(key)
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	got, _ := io.ReadAll(rc)
	rc.Close()

	if string(got) != string(value) {
		t.Fatalf("expected %s, got %s", value, got)
	}
}

func TestCreateAndOpenNoFast(t *testing.T) {
	slow := testMemory()
	cache := New(nil)
	cache.SetSlow(slow)

	key := "test"
	value := []byte("value")

	w, err := cache.Create(key, int64(len(value)))
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	w.Write(value)
	w.Close()

	rc, err := cache.Open(key)
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	got, _ := io.ReadAll(rc)
	rc.Close()

	if string(got) != string(value) {
		t.Fatalf("expected %s, got %s", value, got)
	}
}

func TestCachingPromotion(t *testing.T) {
	fast := testMemory()
	slow := testMemory()
	cache := New(func(fi *vfs.FileInfo, cs cachestate.CacheState) bool {
		return true
	})
	cache.SetFast(fast)
	cache.SetSlow(slow)

	key := "test"
	value := []byte("value")

	ws, _ := slow.Create(key, int64(len(value)))
	ws.Write(value)
	ws.Close()

	rc, err := cache.Open(key)
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	got, _ := io.ReadAll(rc)
	rc.Close()

	if string(got) != string(value) {
		t.Fatalf("expected %s, got %s", value, got)
	}

	// Check if promoted to fast
	_, err = fast.Open(key)
	if err != nil {
		t.Error("Expected promotion to fast cache")
	}
}

func TestOpenNotFound(t *testing.T) {
	fast := testMemory()
	slow := testMemory()
	cache := New(nil)
	cache.SetFast(fast)
	cache.SetSlow(slow)

	_, err := cache.Open("nonexistent")
	if !errors.Is(err, vfserror.ErrNotFound) {
		t.Fatalf("expected %v, got %v", vfserror.ErrNotFound, err)
	}
}

func TestDelete(t *testing.T) {
	fast := testMemory()
	slow := testMemory()
	cache := New(nil)
	cache.SetFast(fast)
	cache.SetSlow(slow)

	key := "test"
	value := []byte("value")

	w, err := cache.Create(key, int64(len(value)))
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	w.Write(value)
	w.Close()

	if err := cache.Delete(key); err != nil {
		t.Fatalf("unexpected error: %v", err)
	}

	_, err = cache.Open(key)
	if !errors.Is(err, vfserror.ErrNotFound) {
		t.Fatalf("expected %v, got %v", vfserror.ErrNotFound, err)
	}
}

func TestStat(t *testing.T) {
	fast := testMemory()
	slow := testMemory()
	cache := New(nil)
	cache.SetFast(fast)
	cache.SetSlow(slow)

	key := "test"
	value := []byte("value")

	w, err := cache.Create(key, int64(len(value)))
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	w.Write(value)
	w.Close()

	info, err := cache.Stat(key)
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}

	if info == nil {
		t.Fatal("expected file info to be non-nil")
	}
	if info.Size() != int64(len(value)) {
		t.Errorf("expected size %d, got %d", len(value), info.Size())
	}
}