// SPDX-License-Identifier: MIT

package fsx

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

func TestWriteFileAtomicCreatesAndReplaces(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "nested", "file.json")

	if err := WriteFileAtomic(path, []byte("first"), 0o600); err != nil {
		t.Fatalf("WriteFileAtomic: %v", err)
	}
	got, err := os.ReadFile(path)
	if err != nil {
		t.Fatalf("ReadFile: %v", err)
	}
	if string(got) != "first" {
		t.Fatalf("content = %q, want %q", got, "first")
	}
	info, err := os.Stat(path)
	if err != nil {
		t.Fatalf("Stat: %v", err)
	}
	if info.Mode().Perm() != 0o600 {
		t.Fatalf("perm = %o, want 600", info.Mode().Perm())
	}

	if err := WriteFileAtomic(path, []byte("second"), 0o600); err != nil {
		t.Fatalf("second WriteFileAtomic: %v", err)
	}
	got, _ = os.ReadFile(path)
	if string(got) != "second" {
		t.Fatalf("content = %q, want %q", got, "second")
	}
}

func TestWriteFileAtomicLeavesNoTempFiles(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "state.json")
	if err := WriteFileAtomic(path, []byte("x"), 0o644); err != nil {
		t.Fatalf("WriteFileAtomic: %v", err)
	}
	entries, err := os.ReadDir(dir)
	if err != nil {
		t.Fatalf("ReadDir: %v", err)
	}
	if len(entries) != 1 || entries[0].Name() != "state.json" {
		t.Fatalf("unexpected directory contents: %v", entries)
	}
}