package extension

import (
	"go/ast"
	"go/parser"
	"go/token"
	"os"
	"path/filepath"
	"sort"
	"strings"
	"testing"
)

func TestSurfaceSnapshot(t *testing.T) {
	fset := token.NewFileSet()
	pkgs, err := parser.ParseDir(fset, ".", func(info os.FileInfo) bool {
		return !strings.HasSuffix(info.Name(), "_test.go")
	}, 0)
	if err != nil {
		t.Fatal(err)
	}
	pkg := pkgs["extension"]
	if pkg == nil {
		t.Fatal("package extension not parsed")
	}
	var names []string
	for _, f := range pkg.Files {
		for _, d := range f.Decls {
			switch n := d.(type) {
			case *ast.FuncDecl:
				if n.Recv == nil && n.Name.IsExported() {
					names = append(names, n.Name.Name)
				}
			case *ast.GenDecl:
				for _, spec := range n.Specs {
					switch s := spec.(type) {
					case *ast.TypeSpec:
						if s.Name.IsExported() {
							names = append(names, s.Name.Name)
						}
					case *ast.ValueSpec:
						for _, name := range s.Names {
							if name.IsExported() {
								names = append(names, name.Name)
							}
						}
					}
				}
			}
		}
	}
	sort.Strings(names)
	got := strings.Join(names, "\n") + "\n"
	path := filepath.Join("surface.txt")
	want, err := os.ReadFile(path)
	if err != nil {
		t.Fatal(err)
	}
	if got != string(want) {
		t.Fatalf("public surface drifted; update surface.txt if the change is intentional\n got:\n%s\nwant:\n%s", got, want)
	}
}

func TestMainWithoutLink(t *testing.T) {
	SetRunner(nil)
	if err := Main(Options{}); err != ErrNotLinked {
		t.Fatalf("got %v", err)
	}
}