package fileutil

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

func TestWriteFileAtomicCreatesParentDirectory(t *testing.T) {
	path := filepath.Join(t.TempDir(), "nested", "artifact.txt")

	if err := WriteFileAtomic(path, []byte("artifact")); err != nil {
		t.Fatalf("WriteFileAtomic() error = %v", err)
	}

	data, err := os.ReadFile(path)
	if err != nil {
		t.Fatalf("ReadFile() error = %v", err)
	}
	if string(data) != "artifact" {
		t.Fatalf("data = %q, want artifact", data)
	}
}

func TestWriteFileAtomicOverwritesTarget(t *testing.T) {
	path := filepath.Join(t.TempDir(), "artifact.txt")
	if err := WriteFileAtomic(path, []byte("old")); err != nil {
		t.Fatalf("WriteFileAtomic() initial error = %v", err)
	}

	if err := WriteFileAtomic(path, []byte("new")); err != nil {
		t.Fatalf("WriteFileAtomic() overwrite error = %v", err)
	}

	data, err := os.ReadFile(path)
	if err != nil {
		t.Fatalf("ReadFile() error = %v", err)
	}
	if string(data) != "new" {
		t.Fatalf("data = %q, want new", data)
	}
}

func TestWriteFileAtomicCleansTemporaryFileAfterRenameError(t *testing.T) {
	dir := t.TempDir()
	target := filepath.Join(dir, "target")
	if err := os.Mkdir(target, 0o755); err != nil {
		t.Fatalf("Mkdir() error = %v", err)
	}

	err := WriteFileAtomic(target, []byte("data"))
	if err == nil {
		t.Fatal("WriteFileAtomic() error = nil, want rename error")
	}
	if !strings.Contains(err.Error(), "save") {
		t.Fatalf("error = %q, want save context", err.Error())
	}
	matches, err := filepath.Glob(filepath.Join(dir, ".target.*.tmp"))
	if err != nil {
		t.Fatalf("Glob() error = %v", err)
	}
	if len(matches) != 0 {
		t.Fatalf("temporary files = %v, want none", matches)
	}
}

func TestWriteJSONAtomic(t *testing.T) {
	path := filepath.Join(t.TempDir(), "artifact.json")

	if err := WriteJSONAtomic(path, map[string]string{"status": "ok"}); err != nil {
		t.Fatalf("WriteJSONAtomic() error = %v", err)
	}

	data, err := os.ReadFile(path)
	if err != nil {
		t.Fatalf("ReadFile() error = %v", err)
	}
	if string(data) != "{\n  \"status\": \"ok\"\n}" {
		t.Fatalf("json = %q, want indented object", data)
	}
}

func TestCopyFileAtomic(t *testing.T) {
	dir := t.TempDir()
	source := filepath.Join(dir, "source.txt")
	target := filepath.Join(dir, "nested", "target.txt")
	if err := os.WriteFile(source, []byte("copied"), 0o600); err != nil {
		t.Fatalf("WriteFile() error = %v", err)
	}

	if err := CopyFileAtomic(source, target); err != nil {
		t.Fatalf("CopyFileAtomic() error = %v", err)
	}

	data, err := os.ReadFile(target)
	if err != nil {
		t.Fatalf("ReadFile() error = %v", err)
	}
	if string(data) != "copied" {
		t.Fatalf("data = %q, want copied", data)
	}
}