package buildstep

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

func filesUnder(t *testing.T, root string) []string {
	t.Helper()
	var out []string
	_ = filepath.Walk(root, func(p string, info os.FileInfo, err error) error {
		if err == nil && !info.IsDir() {
			rel, _ := filepath.Rel(root, p)
			out = append(out, filepath.ToSlash(rel))
		}
		return nil
	})
	sort.Strings(out)
	return out
}

// A build of an artifact that names its paths sees only those paths, its manifest and its lock files (novox/hq ADR 0499
// clause 4): Narrow removes everything else of the fetched tree but .git, package.json and go.mod among it, since
// neither is in the named tree nor among the lock files; with no paths it changes nothing.
func TestNarrowLeavesOnlyTheNamedPathsTheManifestAndTheLocks(t *testing.T) {
	tree := t.TempDir()
	for _, f := range []string{".git/HEAD", "module.json", "package.json", "package-lock.json", "go.sum", "src/index.ts",
		"src/deep/a.ts", "test/a.test.ts", "tsconfig.json", "go/delivery/x.go", "README.md", "other/module.json"} {
		writeTreeFile(t, tree, f, "x")
	}
	if err := Narrow(tree, FetchRequest{}); err != nil {
		t.Fatal(err)
	}
	if got := len(filesUnder(t, tree)); got != 12 {
		t.Fatalf("a request without paths changed the tree: %d files", got)
	}
	if err := Narrow(tree, FetchRequest{Dir: ".", Paths: []string{"src", "test", "tsconfig.json"}}); err != nil {
		t.Fatal(err)
	}
	want := ".git/HEAD,go.sum,module.json,package-lock.json,src/deep/a.ts,src/index.ts,test/a.test.ts,tsconfig.json"
	if got := strings.Join(filesUnder(t, tree), ","); got != want {
		t.Fatalf("the narrowed tree holds %s\nwant %s", got, want)
	}
}

func TestNarrowKeepsAModuleDirectorysPathsAndFailsOnAnAbsentOne(t *testing.T) {
	tree := t.TempDir()
	for _, f := range []string{".git/config", "modules/a/module.json", "modules/a/go.mod", "modules/a/src/x.ts",
		"modules/a/notes.md", "modules/b/module.json", "root.txt"} {
		writeTreeFile(t, tree, f, "x")
	}
	err := Narrow(tree, FetchRequest{Dir: "modules/a", Paths: []string{"src", "gone"}})
	if err == nil || !strings.Contains(err.Error(), `"gone"`) {
		t.Fatalf("an absent named path gave %v", err)
	}
	if len(filesUnder(t, tree)) != 7 {
		t.Fatal("a refused narrowing removed files")
	}
	if err := Narrow(tree, FetchRequest{Dir: "modules/a", Paths: []string{"src"}}); err != nil {
		t.Fatal(err)
	}
	if got := strings.Join(filesUnder(t, tree), ","); got != ".git/config,modules/a/module.json,modules/a/src/x.ts" {
		t.Fatalf("the narrowed tree holds %s", got)
	}
}

// A build that needs package.json or go.mod names it among its paths, and so keys on it (ADR 0499 clause 4).
func TestNarrowKeepsAManifestOfTheLanguageOnlyWhenNamed(t *testing.T) {
	tree := t.TempDir()
	for _, f := range []string{"module.json", "package.json", "go.mod", "src/a.ts"} {
		writeTreeFile(t, tree, f, "x")
	}
	if err := Narrow(tree, FetchRequest{Dir: ".", Paths: []string{"src", "package.json"}}); err != nil {
		t.Fatal(err)
	}
	if got := strings.Join(filesUnder(t, tree), ","); got != "module.json,package.json,src/a.ts" {
		t.Fatalf("the narrowed tree holds %s", got)
	}
}