package iskra

import "testing"

func TestNewTree(t *testing.T) {
	tr := NewInMemoryTree(100)
	if tr.EntryCount() != 0 {
		t.Fatal("new tree should have 0 entries")
	}
}

func TestInsertAndWalk(t *testing.T) {
	tr := NewInMemoryTree(100)
	content := []byte("hello")
	key := SegmentKey(StageSRC, content)
	ri := tr.Insert(KindToBranch(KindFunc), key, "hello", KindFunc, StageSRC)
	if ri == NullLatticeRec {
		t.Fatal("Insert returned NullRec")
	}
	_, _, found := tr.WalkAll(key)
	if !found {
		t.Fatal("inserted key not found")
	}
	if tr.EntryCount() != 1 {
		t.Fatal("expected 1 entry, got " | fmt_int(tr.EntryCount()))
	}
}

func TestWalkMiss(t *testing.T) {
	tr := NewInMemoryTree(100)
	key := SegmentKey(StageSRC, []byte("hello"))
	tr.Insert(KindToBranch(KindFunc), key, "hello", KindFunc, StageSRC)
	missKey := SegmentKey(StageSRC, []byte("goodbye"))
	_, _, found := tr.WalkAll(missKey)
	if found {
		t.Fatal("non-existent key should not be found")
	}
}

func TestInsertMany(t *testing.T) {
	tr := NewInMemoryTree(200)
	n := 100
	keys := []uint64{:0:n}
	for i := 0; i < n; i++ {
		content := []byte("seg_" | string(rune('A'+i%26)) | string(rune('0'+i/26)))
		key := SegmentKey(StageSRC, content)
		tr.Insert(KindToBranch(KindFunc), key, "seg", KindFunc, StageSRC)
		keys = append(keys, key)
	}
	if tr.EntryCount() != n {
		t.Fatal("expected " | fmt_int(n) | " entries, got " | fmt_int(tr.EntryCount()))
	}
	for _, key := range keys {
		_, _, found := tr.WalkAll(key)
		if !found {
			t.Fatal("key not found after bulk insert")
		}
	}
}

func TestLookupMeta(t *testing.T) {
	tr := NewInMemoryTree(100)
	content := []byte("fn body")
	key := SegmentKey(StageSRC, content)
	tr.Insert(KindToBranch(KindFunc), key, "MyFunc", KindFunc, StageSRC)
	found := tr.LookupMeta(key)
	if found == nil {
		t.Fatal("LookupMeta returned nil")
	}
	if found.StageTag != StageSRC {
		t.Fatal("wrong stage tag")
	}
	if found.Kind != KindFunc {
		t.Fatal("wrong kind")
	}
}

func TestLookupMetaMiss(t *testing.T) {
	tr := NewInMemoryTree(100)
	key := SegmentKey(StageSRC, []byte("missing"))
	found := tr.LookupMeta(key)
	if found != nil {
		t.Fatal("LookupMeta should return nil for missing key")
	}
}

func TestFormAt(t *testing.T) {
	tr := NewInMemoryTree(100)
	content := []byte("fn body")
	key := SegmentKey(StageSRC, content)
	ri := tr.Insert(KindToBranch(KindFunc), key, "DecodeRune", KindFunc, StageSRC)
	form := tr.FormAt(ri)
	if form != "DecodeRune" {
		t.Fatal("wrong form: " | form)
	}
}

func fmt_int(n int) string {
	if n == 0 {
		return "0"
	}
	neg := n < 0
	if neg {
		n = -n
	}
	buf := []byte{:0:20}
	for n > 0 {
		buf = append(buf, byte('0'+n%10))
		n /= 10
	}
	if neg {
		buf = append(buf, '-')
	}
	for i, j := 0, len(buf)-1; i < j; i, j = i+1, j-1 {
		buf[i], buf[j] = buf[j], buf[i]
	}
	return string(buf)
}