package wal

import (
	"path/filepath"
	"testing"
)

func TestWALAppendLoad(t *testing.T) {
	path := filepath.Join(t.TempDir(), "wal.bin")
	w, err := Open(path)
	if err != nil {
		t.Fatalf("Open: %v", err)
	}
	defer w.Close()

	if err := w.Append(1, []byte("a")); err != nil {
		t.Fatalf("Append: %v", err)
	}
	if err := w.Append(2, []byte("bb")); err != nil {
		t.Fatalf("Append: %v", err)
	}

	recs, err := w.Load()
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	if len(recs) != 2 {
		t.Fatalf("len(recs)=%d, want 2", len(recs))
	}
	if recs[0].Seq != 1 || string(recs[0].Payload) != "a" {
		t.Fatalf("recs[0]=%+v", recs[0])
	}
	if recs[1].Seq != 2 || string(recs[1].Payload) != "bb" {
		t.Fatalf("recs[1]=%+v", recs[1])
	}
}

func TestWALTruncateBefore(t *testing.T) {
	path := filepath.Join(t.TempDir(), "wal.bin")
	w, err := Open(path)
	if err != nil {
		t.Fatalf("Open: %v", err)
	}
	defer w.Close()

	for i := int64(1); i <= 5; i++ {
		if err := w.Append(i, []byte{byte(i)}); err != nil {
			t.Fatalf("Append %d: %v", i, err)
		}
	}

	if err := w.TruncateBefore(3); err != nil {
		t.Fatalf("TruncateBefore: %v", err)
	}
	recs, err := w.Load()
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	if len(recs) != 3 {
		t.Fatalf("len(recs)=%d, want 3", len(recs))
	}
	for i, want := range []int64{3, 4, 5} {
		if recs[i].Seq != want {
			t.Fatalf("recs[%d].Seq=%d, want %d", i, recs[i].Seq, want)
		}
	}
}

func TestWALReopenPersists(t *testing.T) {
	path := filepath.Join(t.TempDir(), "wal.bin")
	w, err := Open(path)
	if err != nil {
		t.Fatalf("Open: %v", err)
	}
	if err := w.Append(7, []byte("persist")); err != nil {
		t.Fatalf("Append: %v", err)
	}
	if err := w.Close(); err != nil {
		t.Fatalf("Close: %v", err)
	}

	w2, err := Open(path)
	if err != nil {
		t.Fatalf("Reopen: %v", err)
	}
	defer w2.Close()
	recs, err := w2.Load()
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	if len(recs) != 1 || recs[0].Seq != 7 || string(recs[0].Payload) != "persist" {
		t.Fatalf("recs=%+v", recs)
	}
}