package catalogue

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

// A file resource may name a template file in its module's repository (novox/hq ADR 0349 §2, design 57 package
// T1, issue 654): the build packs files/ into an archive, and resolving the build reads each template's text back
// into content, so the mesh holds, composes and sends exactly what it would for the same text inline.

// The two forms of one module: its text inline, and its text in files/.
const (
	inlineTwin = `{"module":"tidy","version":"1",
  "build":{"artifacts":[{"name":"files","kind":"archive","from":"files"}]},
  "resources":[
    {"id":"conf","type":"directory","path":"${dir:conf}"},
    {"id":"main","type":"file","path":"${dir:conf}/tidy.conf","mode":"0644","content":"` + mainText + `"},
    {"id":"extra","type":"file","path":"${dir:conf}/extra.conf","content":"` + extraText + `"}]}`
	templatedTwin = `{"module":"tidy","version":"1",
  "build":{"artifacts":[{"name":"files","kind":"archive","from":"files"}]},
  "resources":[
    {"id":"conf","type":"directory","path":"${dir:conf}"},
    {"id":"main","type":"file","path":"${dir:conf}/tidy.conf","mode":"0644","template":"files/tidy.conf"},
    {"id":"extra","type":"file","path":"${dir:conf}/extra.conf","template":"files/deeper/extra.conf"}]}`
	mainText  = `# tidy\nroot = ${dir:conf}\nquoted = \"yes\" é\n`
	extraText = `one\ntwo\n`
)

// templateTexts is what a build reads back from the packed files/ archive: by path inside it.
func templateTexts(t *testing.T) map[string]string {
	t.Helper()
	var m struct{ Main, Extra string }
	if err := json.Unmarshal([]byte(`{"Main":"`+mainText+`","Extra":"`+extraText+`"}`), &m); err != nil {
		t.Fatal(err)
	}
	return map[string]string{"tidy.conf": m.Main, "deeper/extra.conf": m.Extra, "unused.conf": "not named"}
}

func builtFiles(texts map[string]string) []Built {
	return []Built{{Name: "files", Kind: ArtifactArchive,
		Reference: ArtifactStoreScheme + "tidy/files/blobs/sha256:" + strings.Repeat("c", 64),
		Digest:    "sha256:" + strings.Repeat("c", 64), Texts: texts}}
}

// held is a manifest as registration holds it: resolved with what was built, then read again strictly.
func held(t *testing.T, raw string, built []Built) Manifest {
	t.Helper()
	m, err := ParseManifest([]byte(raw))
	if err != nil {
		t.Fatal(err)
	}
	resolved, err := m.Resolve(built)
	if err != nil {
		t.Fatal(err)
	}
	again, err := json.Marshal(resolved)
	if err != nil {
		t.Fatal(err)
	}
	out, err := ParseManifest(again)
	if err != nil {
		t.Fatal(err)
	}
	if problem := HeldTemplateProblem(out); problem != "" {
		t.Fatal(problem)
	}
	return out
}

func composed(t *testing.T, m Manifest) string {
	t.Helper()
	got, err := Resolve(shelf(m), []string{m.Module}, workstation(), World{})
	if err != nil {
		t.Fatal(err)
	}
	out, err := json.Marshal(mustDeclare(t, got))
	if err != nil {
		t.Fatal(err)
	}
	return string(out)
}

func TestATemplatedModuleComposesByteIdenticallyToItsInlineTwin(t *testing.T) {
	inline := composed(t, held(t, inlineTwin, builtFiles(nil)))
	templated := composed(t, held(t, templatedTwin, builtFiles(templateTexts(t))))
	if inline != templated {
		t.Fatalf("the two forms compose differently:\ninline:    %s\ntemplated: %s", inline, templated)
	}
	if !strings.Contains(templated, "quoted = \\\"yes\\\"") || strings.Contains(templated, `"template"`) {
		t.Fatalf("the composition does not carry the template's text as content: %s", templated)
	}
}

// What `module check`, the merge gate and `module add` judge: the text read from the tree beside the manifest.
func TestATemplatedModuleReadFromItsTreeComposesByteIdenticallyToItsInlineTwin(t *testing.T) {
	dir := t.TempDir()
	for name, text := range templateTexts(t) {
		full := filepath.Join(dir, "files", filepath.FromSlash(name))
		if err := os.MkdirAll(filepath.Dir(full), 0o755); err != nil {
			t.Fatal(err)
		}
		if err := os.WriteFile(full, []byte(text), 0o644); err != nil {
			t.Fatal(err)
		}
	}
	m, err := ParseManifest([]byte(templatedTwin))
	if err != nil {
		t.Fatal(err)
	}
	filled, err := WithTemplatesFrom(m, dir)
	if err != nil {
		t.Fatal(err)
	}
	if filled.Templated() {
		t.Fatal("a manifest read from its tree still names a template")
	}
	resolved, err := filled.Resolve(builtFiles(nil))
	if err != nil {
		t.Fatal(err)
	}
	if got, want := composed(t, resolved), composed(t, held(t, inlineTwin, builtFiles(nil))); got != want {
		t.Fatalf("read from the tree, the module composes differently:\ninline:    %s\ntemplated: %s", want, got)
	}
}

func TestAFileNamingBothATemplateAndContentIsRefused(t *testing.T) {
	raw := strings.Replace(templatedTwin, `"template":"files/tidy.conf"`,
		`"template":"files/tidy.conf","content":"x"`, 1)
	_, err := ParseManifest([]byte(raw))
	if err == nil || !strings.Contains(err.Error(), "main") || !strings.Contains(err.Error(), "never both") {
		t.Fatalf("a file with both a template and content was not refused by name: %v", err)
	}
}

func TestATemplateOutsideFilesIsRefusedByName(t *testing.T) {
	for _, bad := range []string{"../tidy.conf", "/etc/tidy.conf", "files", "files/", "files/../tidy.conf",
		"files/./tidy.conf", "other/tidy.conf", "tidy.conf", "files//tidy.conf", `files\\tidy.conf`} {
		raw := strings.Replace(templatedTwin, `"files/tidy.conf"`, `"`+bad+`"`, 1)
		_, err := ParseManifest([]byte(raw))
		if err == nil || !strings.Contains(err.Error(), "main") || !strings.Contains(err.Error(), "not a file under files/") {
			t.Errorf("the template %q was not refused by name: %v", bad, err)
		}
	}
}

func TestATemplateOnAResourceThatIsNotAFileIsRefused(t *testing.T) {
	raw := strings.Replace(templatedTwin, `{"id":"conf","type":"directory","path":"${dir:conf}"}`,
		`{"id":"conf","type":"directory","path":"${dir:conf}","template":"files/tidy.conf"}`, 1)
	_, err := ParseManifest([]byte(raw))
	if err == nil || !strings.Contains(err.Error(), "conf is a directory and names a template") {
		t.Fatalf("a directory naming a template was not refused: %v", err)
	}
}

func TestATemplatedModuleWhoseBuildPacksNoFilesIsRefused(t *testing.T) {
	for _, build := range []string{
		``,
		`"build":{"artifacts":[{"name":"look","kind":"archive","from":"theme"}]},`,
		`"build":{"artifacts":[{"name":"a","kind":"archive","from":"files"},{"name":"b","kind":"archive","from":"./files/"}]},`,
	} {
		raw := strings.Replace(templatedTwin,
			`"build":{"artifacts":[{"name":"files","kind":"archive","from":"files"}]},`, build, 1)
		_, err := ParseManifest([]byte(raw))
		if err == nil || !strings.Contains(err.Error(), "files/") {
			t.Errorf("a templated module with the build %q was not refused: %v", build, err)
		}
	}
}

func TestAMissingTemplateIsRefusedByName(t *testing.T) {
	m, err := ParseManifest([]byte(templatedTwin))
	if err != nil {
		t.Fatal(err)
	}
	// In the tree beside the manifest.
	dir := t.TempDir()
	if err := os.MkdirAll(filepath.Join(dir, "files"), 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(dir, "files", "tidy.conf"), []byte("x"), 0o644); err != nil {
		t.Fatal(err)
	}
	_, err = WithTemplatesFrom(m, dir)
	if err == nil || !strings.Contains(err.Error(), "extra") || !strings.Contains(err.Error(), "files/deeper/extra.conf") {
		t.Fatalf("a template missing from the tree was not refused by name: %v", err)
	}
	// And in what the build read back from its archive.
	texts := templateTexts(t)
	delete(texts, "deeper/extra.conf")
	_, err = m.Resolve(builtFiles(texts))
	if err == nil || !strings.Contains(err.Error(), "extra") || !strings.Contains(err.Error(), "files/deeper/extra.conf") {
		t.Fatalf("a template missing from the archive was not refused by name: %v", err)
	}
}

func TestATemplateThatIsASymlinkIsRefused(t *testing.T) {
	m, err := ParseManifest([]byte(templatedTwin))
	if err != nil {
		t.Fatal(err)
	}
	dir := t.TempDir()
	if err := os.MkdirAll(filepath.Join(dir, "files", "deeper"), 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(dir, "elsewhere"), []byte("x"), 0o644); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(dir, "files", "tidy.conf"), []byte("x"), 0o644); err != nil {
		t.Fatal(err)
	}
	if err := os.Symlink(filepath.Join(dir, "elsewhere"), filepath.Join(dir, "files", "deeper", "extra.conf")); err != nil {
		t.Fatal(err)
	}
	if _, err := WithTemplatesFrom(m, dir); err == nil || !strings.Contains(err.Error(), "not a plain file") {
		t.Fatalf("a template that is a symlink was not refused: %v", err)
	}
}

func TestAResolveWithoutTheArchivesTextIsRefused(t *testing.T) {
	m, err := ParseManifest([]byte(templatedTwin))
	if err != nil {
		t.Fatal(err)
	}
	if _, err := m.Resolve(builtFiles(nil)); err == nil || !strings.Contains(err.Error(), "files") {
		t.Fatalf("a templated module resolved with no text read back from its archive: %v", err)
	}
}

func TestATemplateThatIsNotUTF8IsRefused(t *testing.T) {
	m, err := ParseManifest([]byte(templatedTwin))
	if err != nil {
		t.Fatal(err)
	}
	texts := templateTexts(t)
	texts["tidy.conf"] = "\xff\xfe"
	if _, err := m.Resolve(builtFiles(texts)); err == nil || !strings.Contains(err.Error(), "UTF-8") {
		t.Fatalf("a template that is not UTF-8 was resolved: %v", err)
	}
}

// What registration refuses: a manifest to be held that still names a template — one resolved by a builder that
// predates templates would otherwise compose files with no text.
func TestAManifestStillNamingATemplateIsNotHeld(t *testing.T) {
	m, err := ParseManifest([]byte(templatedTwin))
	if err != nil {
		t.Fatal(err)
	}
	if problem := HeldTemplateProblem(m); !strings.Contains(problem, "main") || !strings.Contains(problem, "files/tidy.conf") {
		t.Fatalf("a manifest naming a template would be held: %q", problem)
	}
	if problem := HeldTemplateProblem(held(t, inlineTwin, builtFiles(nil))); problem != "" {
		t.Fatalf("an inline manifest is refused: %s", problem)
	}
}

// A symlinked files/, or a symlinked directory under it, would read a file outside the tree: refused by name,
// as is any symlink or special file under files/ that no template names, which the build's packing refuses.
func TestASymlinkAnywhereUnderFilesIsRefusedByName(t *testing.T) {
	m, err := ParseManifest([]byte(templatedTwin))
	if err != nil {
		t.Fatal(err)
	}
	outside := t.TempDir()
	if err := os.MkdirAll(filepath.Join(outside, "deeper"), 0o755); err != nil {
		t.Fatal(err)
	}
	for _, name := range []string{"tidy.conf", "deeper/extra.conf", "secret"} {
		if err := os.WriteFile(filepath.Join(outside, filepath.FromSlash(name)), []byte("outside"), 0o644); err != nil {
			t.Fatal(err)
		}
	}
	write := func(t *testing.T, dir, name string) {
		t.Helper()
		full := filepath.Join(dir, filepath.FromSlash(name))
		if err := os.MkdirAll(filepath.Dir(full), 0o755); err != nil {
			t.Fatal(err)
		}
		if err := os.WriteFile(full, []byte("inside"), 0o644); err != nil {
			t.Fatal(err)
		}
	}
	link := func(t *testing.T, target, at string) {
		t.Helper()
		if err := os.MkdirAll(filepath.Dir(at), 0o755); err != nil {
			t.Fatal(err)
		}
		if err := os.Symlink(target, at); err != nil {
			t.Fatal(err)
		}
	}
	for _, c := range []struct {
		name  string
		make  func(t *testing.T, dir string)
		names string
	}{
		{"files/ itself", func(t *testing.T, dir string) {
			link(t, outside, filepath.Join(dir, "files"))
		}, "files/ is a symlink"},
		{"a directory under files/", func(t *testing.T, dir string) {
			write(t, dir, "files/tidy.conf")
			link(t, filepath.Join(outside, "deeper"), filepath.Join(dir, "files", "deeper"))
		}, "files/deeper is a symlink"},
		{"a file no template names", func(t *testing.T, dir string) {
			write(t, dir, "files/tidy.conf")
			write(t, dir, "files/deeper/extra.conf")
			link(t, filepath.Join(outside, "secret"), filepath.Join(dir, "files", "unnamed"))
		}, "files/unnamed is a symlink"},
	} {
		dir := t.TempDir()
		c.make(t, dir)
		_, err := WithTemplatesFrom(m, dir)
		if err == nil || !strings.Contains(err.Error(), c.names) {
			t.Errorf("a symlinked %s was not refused by name: %v", c.name, err)
		}
		if err != nil && strings.Contains(err.Error(), "outside") {
			t.Errorf("a symlinked %s was read: %v", c.name, err)
		}
	}
}