package spool

import (
	"bytes"
	"errors"
	"os"
	"path/filepath"
	"testing"
)

func TestRoundTrip(t *testing.T) {
	dir := filepath.Join(t.TempDir(), "spool")
	s, err := Open(dir, 0)
	if err != nil {
		t.Fatal(err)
	}
	if fi, err := os.Stat(dir); err != nil || fi.Mode().Perm() != 0o700 {
		t.Fatalf("spool dir perms: %v %v", fi, err)
	}
	if _, _, err := s.Oldest(); !errors.Is(err, ErrEmpty) {
		t.Fatalf("expected ErrEmpty, got %v", err)
	}
	a := []byte("batch-a")
	b := []byte("batch-b-longer")
	na, _ := s.Write(a)
	nb, _ := s.Write(b)
	if na >= nb {
		t.Fatalf("names must sort chronologically: %s %s", na, nb)
	}
	n, size := s.Stats()
	if n != 2 || size != int64(len(a)+len(b)) {
		t.Fatalf("stats = %d %d", n, size)
	}
	name, data, err := s.Oldest()
	if err != nil || name != na || !bytes.Equal(data, a) {
		t.Fatalf("oldest = %s %q %v", name, data, err)
	}
	if err := s.Remove(name); err != nil {
		t.Fatal(err)
	}
	name, data, _ = s.Oldest()
	if name != nb || !bytes.Equal(data, b) {
		t.Fatalf("second oldest = %s %q", name, data)
	}
	s.Remove(name)
	if _, _, err := s.Oldest(); !errors.Is(err, ErrEmpty) {
		t.Fatal("spool should be empty")
	}
	if err := s.Remove("does-not-exist.json.gz"); err != nil {
		t.Fatalf("removing a missing file must be a no-op: %v", err)
	}
}

func TestCapDropsOldest(t *testing.T) {
	s, err := Open(t.TempDir(), 1000)
	if err != nil {
		t.Fatal(err)
	}
	chunk := bytes.Repeat([]byte("x"), 300)
	var names []string
	for i := 0; i < 5; i++ { // 1500 bytes > cap 1000 → the two oldest must go
		n, err := s.Write(chunk)
		if err != nil {
			t.Fatal(err)
		}
		names = append(names, n)
	}
	count, size := s.Stats()
	if count != 3 || size != 900 {
		t.Fatalf("after cap: %d files, %d bytes", count, size)
	}
	oldest, _, _ := s.Oldest()
	if oldest != names[2] {
		t.Fatalf("oldest kept should be %s, got %s", names[2], oldest)
	}
}

func TestIgnoresForeignFilesAndTmp(t *testing.T) {
	dir := t.TempDir()
	s, _ := Open(dir, 0)
	os.WriteFile(filepath.Join(dir, "notes.txt"), []byte("x"), 0o600)
	os.WriteFile(filepath.Join(dir, "1.json.gz.tmp"), []byte("x"), 0o600)
	if n, _ := s.Stats(); n != 0 {
		t.Fatalf("foreign files counted: %d", n)
	}
	s.Write([]byte("ok"))
	if _, err := os.Stat(filepath.Join(dir, "1.json.gz.tmp")); !errors.Is(err, os.ErrNotExist) {
		t.Fatal("stale tmp file should be cleaned on write")
	}
}