package cli_test

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

	"git.vakhrushev.me/av/convy/internal/check"
	"git.vakhrushev.me/av/convy/internal/cli"
	"git.vakhrushev.me/av/convy/internal/doc"
	"git.vakhrushev.me/av/convy/internal/manifest"
)

// addComponent puts one more component into the project manifest.
func addComponent(t *testing.T, root, name string, c manifest.Component) {
	t.Helper()
	m, err := manifest.LoadProject(root)
	if err != nil {
		t.Fatal(err)
	}
	m.Components[name] = c
	if err := m.Save(); err != nil {
		t.Fatal(err)
	}
}

// readingGuide stands in for what a suite puts next to its copies: the short
// account of the language, naming every word the version line names.
const readingGuide = `# Как читать конвенцию

Слова толкуются так, и только когда написаны заглавными.

| Слово | Значение |
|---|---|
| ДОЛЖЕН | требование |
| НЕ ДОЛЖЕН | запрет |
| СЛЕДУЕТ | рекомендация |
| НЕ СЛЕДУЕТ | рекомендация против |
| ДОПУСКАЕТСЯ | разрешение |
| ПОЧЕМУ | обоснование |
| ПРИМЕРЫ | иллюстрация |
| МЕХАНИЗИРОВАНО | чем проверяется |
| СНЯТО | заглушка снятого правила |
`

// subscribable is a suite a project can take from: the fixture of the retire
// tests plus the guide that travels next to the copies.
func subscribable(t *testing.T) string {
	t.Helper()
	root := retirable(t)
	appendRules(t, root, "conventions/lang/go/time.md", `
### GTIM-1. «Сейчас» берётся у слоя хранилища

**ДОЛЖЕН.** Текущее время приходит из `+"`store.Now()`"+`.

**ПОЧЕМУ.** Единая точка даёт гарантированный UTC и один формат.
`)

	// A topic whose only layer sits on an axis: a component of another stack
	// takes nothing of it at all. The canon has such topics, and a fixture
	// where every topic has a base layer would never exercise that.
	run(t, root, "", false, "suite", "add", "--topic", "web-ui", "--about", "веб-UI",
		"--prefix", "HTMX", "--stack", "htmx", "--title", "Веб-UI на htmx")
	appendRules(t, root, "conventions/stack/htmx/web-ui.md", `
### HTMX-1. Партиал отвечает фрагментом, а не страницей

**ДОЛЖЕН.** Обработчик свопа возвращает только заменяемый фрагмент.

**ПОЧЕМУ.** Страница целиком заставляет браузер выбросить состояние формы.
`)

	name := filepath.Join(root, "READING.md")
	if err := os.WriteFile(name, []byte(readingGuide), 0o644); err != nil {
		t.Fatal(err)
	}
	edit(t, root, func(m *manifest.Manifest) { m.Language.Reading = "READING.md" })
	checkClean(t, root)
	return root
}

// edit changes the suite manifest the way the tool does: through the struct,
// because the file is data and carries nothing else to preserve.
func edit(t *testing.T, root string, change func(*manifest.Manifest)) {
	t.Helper()
	m, err := manifest.Load(root)
	if err != nil {
		t.Fatal(err)
	}
	change(m)
	if err := m.Save(); err != nil {
		t.Fatal(err)
	}
}

// wired builds a project taking from that suite, and returns its root.
func wired(t *testing.T, suiteRoot string, args ...string) string {
	t.Helper()
	root := filepath.Join(t.TempDir(), "app")
	if err := os.MkdirAll(root, 0o755); err != nil {
		t.Fatal(err)
	}
	all := append([]string{"init", "--source", suiteRoot}, args...)
	if code, out := run(t, root, "", false, all...); code != cli.OK {
		t.Fatalf("convy init returned %d: %s", code, out)
	}
	return root
}

func TestInitAddAndPullBuildACopyOutOfTheLayers(t *testing.T) {
	suiteRoot := subscribable(t)
	root := wired(t, suiteRoot, "--component", "backend", "--dir", "docs/conventions", "--lang", "go")

	code, out := run(t, root, "", false, "add", "time")
	if code != cli.OK {
		t.Fatalf("convy add returned %d: %s", code, out)
	}
	if !strings.Contains(out, "docs/conventions/time.md") {
		t.Errorf("the assembled file is not named:\n%s", out)
	}

	body := read(t, root, "docs/conventions/time.md")
	for _, want := range []string{
		"origin: time",
		"### TIME-1.",
		"#### GTIM-1.",
		"<!-- conv:local -->",
	} {
		if !strings.Contains(body, want) {
			t.Errorf("the copy lacks %q:\n%s", want, body)
		}
	}
	if strings.Contains(body, "prefix: TIME") {
		t.Errorf("the front matter of a layer travelled into the copy:\n%s", body)
	}

	// The guide to reading a rule belongs to the suite and travels with the
	// copies; README.md in the same directory belongs to the repository.
	if guide := read(t, root, "docs/conventions/READING.md"); !strings.Contains(guide, "ДОПУСКАЕТСЯ") {
		t.Errorf("the reading guide did not travel:\n%s", guide)
	}

	if manifest := read(t, root, ".conventions.toml"); !strings.Contains(manifest, `topics = ["time"]`) {
		t.Errorf("the subscription was not written:\n%s", manifest)
	}

	if code, out := run(t, root, "", false, "check"); code != cli.OK {
		t.Fatalf("checking what the tool assembled returned %d: %s", code, out)
	}
}

// The whole point of the marker: what the repository wrote survives, what the
// suite wrote is replaced.
func TestPullKeepsTheLocalPartAndReplacesTheRest(t *testing.T) {
	suiteRoot := subscribable(t)
	root := wired(t, suiteRoot, "--component", "backend", "--dir", "docs/conventions", "--lang", "go")
	run(t, root, "", false, "add", "time")

	name := filepath.Join(root, "docs", "conventions", "time.md")
	body := read(t, root, "docs/conventions/time.md")
	body = strings.Replace(body, "**ДОЛЖЕН.** Момент времени", "**ДОЛЖЕН.** Правка выше маркера", 1)
	body += "\nTIME-1 — МЕХАНИЗИРОВАНО: `internal/archrules`.\n"
	if err := os.WriteFile(name, []byte(body), 0o644); err != nil {
		t.Fatal(err)
	}

	code, out := run(t, root, "", false, "pull")
	if code != cli.OK {
		t.Fatalf("convy pull returned %d: %s", code, out)
	}
	if !strings.Contains(out, "local part kept") {
		t.Errorf("the pull did not say the local part survived:\n%s", out)
	}

	body = read(t, root, "docs/conventions/time.md")
	if strings.Contains(body, "Правка выше маркера") {
		t.Errorf("an edit above the marker survived, and it is declared not to:\n%s", body)
	}
	if !strings.Contains(body, "МЕХАНИЗИРОВАНО: `internal/archrules`") {
		t.Errorf("the local part was lost:\n%s", body)
	}
}

// A layer travels when the axis it declares agrees with the component; the base
// layer travels always.
func TestAComponentTakesOnlyTheLayersThatFitIt(t *testing.T) {
	suiteRoot := subscribable(t)
	root := wired(t, suiteRoot, "--component", "web", "--dir", "web/docs/conventions", "--lang", "javascript")
	run(t, root, "", false, "add", "time")

	body := read(t, root, "web/docs/conventions/time.md")
	if !strings.Contains(body, "### TIME-1.") {
		t.Errorf("the base layer did not travel:\n%s", body)
	}
	if strings.Contains(body, "GTIM-1") {
		t.Errorf("a go layer travelled into a javascript component:\n%s", body)
	}
}

func TestProjectCommandsRefuseWhatTheyCannotDo(t *testing.T) {
	suiteRoot := subscribable(t)
	root := wired(t, suiteRoot, "--component", "backend", "--dir", "docs/conventions", "--lang", "go")
	run(t, root, "", false, "add", "time")

	cases := []struct {
		name string
		args []string
		want string
	}{{
		name: "a topic the suite does not declare",
		args: []string{"add", "billing"},
		want: "declares no topic",
	}, {
		name: "a topic taken twice",
		args: []string{"add", "time"},
		want: "subscribed to",
	}, {
		name: "a component that is not there",
		args: []string{"pull", "--for", "mobile"},
		want: "no component",
	}}

	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			code, out := run(t, root, "", false, tc.args...)
			if code == cli.OK {
				t.Fatalf("the command went through:\n%s", out)
			}
			if !strings.Contains(out, tc.want) {
				t.Errorf("the refusal does not say %q:\n%s", tc.want, out)
			}
		})
	}
}

// A file that lost its origin key has become a document of the repository, and
// assembly has no business overwriting it.
func TestPullDoesNotOverwriteWhatIsNoLongerACopy(t *testing.T) {
	suiteRoot := subscribable(t)
	root := wired(t, suiteRoot, "--component", "backend", "--dir", "docs/conventions", "--lang", "go")
	run(t, root, "", false, "add", "time")

	name := filepath.Join(root, "docs", "conventions", "time.md")
	body := read(t, root, "docs/conventions/time.md")
	body = strings.Replace(body, "---\norigin: time\n---\n\n", "", 1)
	if err := os.WriteFile(name, []byte(body), 0o644); err != nil {
		t.Fatal(err)
	}

	code, out := run(t, root, "", false, "pull")
	if code == cli.OK {
		t.Fatalf("the pull overwrote a document of the repository:\n%s", out)
	}
	if !strings.Contains(out, "no origin key") {
		t.Errorf("the refusal does not say why:\n%s", out)
	}
	if got := read(t, root, "docs/conventions/time.md"); strings.Contains(got, "origin: time") {
		t.Errorf("the file was rewritten anyway:\n%s", got)
	}
}

// The context is read off the manifest lying next to you, and nothing is done
// at a guess.
func TestAProjectCommandInsideASuiteSaysWhereItIs(t *testing.T) {
	suiteRoot := subscribable(t)
	code, out := run(t, suiteRoot, "", false, "pull")
	if code == cli.OK {
		t.Fatalf("convy pull ran inside a suite:\n%s", out)
	}
	if !strings.Contains(out, "convy suite") {
		t.Errorf("the refusal does not point at the commands of a suite:\n%s", out)
	}
}

func TestListShowsWhatIsTakenAndWhatIsNot(t *testing.T) {
	suiteRoot := subscribable(t)
	root := wired(t, suiteRoot, "--component", "backend", "--dir", "docs/conventions", "--lang", "go")
	run(t, root, "", false, "add", "time")

	code, out := run(t, root, "", false, "list")
	if code != cli.OK {
		t.Fatalf("convy list returned %d: %s", code, out)
	}
	for _, want := range []string{"backend — docs/conventions", "lang=go", "time", "2 layers", "not taken", "logging"} {
		if !strings.Contains(out, want) {
			t.Errorf("the listing lacks %q:\n%s", want, out)
		}
	}
}

// The topic stands in front of the flags, and the flag package stops at the
// first argument that is not one — so "convy add time --for backend", the form
// the model writes, has to keep the component rather than drop it in silence.
func TestAddTakesTheTopicBeforeTheFlags(t *testing.T) {
	suiteRoot := subscribable(t)
	root := wired(t, suiteRoot, "--component", "backend", "--dir", "backend/docs", "--lang", "go")

	addComponent(t, root, "web", manifest.Component{Dir: "web/docs", Topics: []string{}})

	code, out := run(t, root, "", false, "add", "logging", "--for", "web")
	if code != cli.OK {
		t.Fatalf("convy add returned %d: %s", code, out)
	}
	if !strings.Contains(out, "web/docs/logging.md") {
		t.Errorf("the copy did not land in the named component:\n%s", out)
	}
	if manifest := read(t, root, ".conventions.toml"); !strings.Contains(manifest, `topics = ["logging"]`) {
		t.Errorf("the subscription went to the wrong component:\n%s", manifest)
	}
}

// Distinct directories are the only thing that tells two copies of one topic
// apart, so sharing one is an error of the manifest rather than a reason to
// rename files.
func TestTwoComponentsMayNotShareADirectory(t *testing.T) {
	suiteRoot := subscribable(t)
	root := wired(t, suiteRoot, "--component", "backend", "--dir", "docs/conventions", "--lang", "go")

	addComponent(t, root, "web", manifest.Component{Dir: "docs/conventions", Topics: []string{}})

	code, out := run(t, root, "", false, "pull")
	if code == cli.OK {
		t.Fatalf("two components wrote into one directory:\n%s", out)
	}
	if !strings.Contains(out, "share the directory") {
		t.Errorf("the refusal does not say what collides:\n%s", out)
	}
}

// Bare, a project command asks; that mode is for a person, and the one with
// flags is for agents and scripts.
func TestAddAsksWhichTopicWhenToldNothing(t *testing.T) {
	suiteRoot := subscribable(t)
	root := wired(t, suiteRoot, "--component", "backend", "--dir", "docs/conventions", "--lang", "go")

	code, out := run(t, root, "time\n", true, "add")
	if code != cli.OK {
		t.Fatalf("the dialogue returned %d: %s", code, out)
	}
	if !strings.Contains(out, "Topic") || !strings.Contains(out, "время") {
		t.Errorf("the question carries no hint about what is on offer:\n%s", out)
	}
	if !strings.Contains(out, "docs/conventions/time.md") {
		t.Errorf("the dialogue assembled nothing:\n%s", out)
	}

	// Without a terminal the same bare command refuses instead of blocking on
	// an answer nobody is there to give.
	code, out = run(t, root, "", false, "add")
	if code == cli.OK {
		t.Fatalf("a bare command went through with no terminal:\n%s", out)
	}
	if !strings.Contains(out, "no terminal") {
		t.Errorf("the refusal does not say why:\n%s", out)
	}
}

// The language is a level of its own, and a suite may keep its documents apart.
// Nothing else changes: the guide still travels next to the copies.
func TestTheLanguageMayLiveApartFromTheSuite(t *testing.T) {
	suiteRoot := subscribable(t)

	apart := filepath.Join(filepath.Dir(suiteRoot), "language")
	if err := os.MkdirAll(apart, 0o755); err != nil {
		t.Fatal(err)
	}
	if err := os.Rename(filepath.Join(suiteRoot, "READING.md"), filepath.Join(apart, "READING.md")); err != nil {
		t.Fatal(err)
	}
	edit(t, suiteRoot, func(m *manifest.Manifest) { m.Language.Source = "../language" })
	checkClean(t, suiteRoot)

	// A check that did not run says so: silence would read as a check passed.
	if _, out := run(t, suiteRoot, "", false, "suite", "check"); !strings.Contains(out, "went unchecked") {
		t.Errorf("the check did not say it left the language alone:\n%s", out)
	}

	root := wired(t, suiteRoot, "--component", "backend", "--dir", "docs/conventions", "--lang", "go")
	if code, out := run(t, root, "", false, "add", "time"); code != cli.OK {
		t.Fatalf("convy add returned %d: %s", code, out)
	}
	if guide := read(t, root, "docs/conventions/READING.md"); !strings.Contains(guide, "ДОПУСКАЕТСЯ") {
		t.Errorf("the guide did not come from the level it lives on:\n%s", guide)
	}
}

// The rules of the repository take a prefix on X and live below the marker. One
// standing above it would be wiped by the next pull, and saying so afterwards
// is too late.
func TestCheckCatchesALocalRuleAboveTheMarker(t *testing.T) {
	suiteRoot := subscribable(t)
	root := wired(t, suiteRoot, "--component", "backend", "--dir", "docs/conventions", "--lang", "go")
	run(t, root, "", false, "add", "time")

	name := filepath.Join(root, "docs", "conventions", "time.md")
	body := read(t, root, "docs/conventions/time.md")
	local := "\n### XTIM-1. Часы в тестах замораживаются\n\n" +
		"**ДОЛЖЕН.** Тест берёт время у подменённого `store.Now`.\n\n" +
		"**ПОЧЕМУ.** Плавающее время делает падение теста невоспроизводимым.\n"

	if err := os.WriteFile(name, []byte(body+local), 0o644); err != nil {
		t.Fatal(err)
	}
	if code, out := run(t, root, "", false, "check"); code != cli.OK {
		t.Fatalf("a local rule below the marker was turned down: %d\n%s", code, out)
	}

	above := strings.Replace(body, "<!-- conv:local -->", local+"\n<!-- conv:local -->", 1)
	if err := os.WriteFile(name, []byte(above), 0o644); err != nil {
		t.Fatal(err)
	}
	code, out := run(t, root, "", false, "check")
	if code == cli.OK {
		t.Fatalf("a rule of the repository above the marker went unnoticed:\n%s", out)
	}
	if !strings.Contains(out, "would wipe it") {
		t.Errorf("the finding does not say what is at stake:\n%s", out)
	}
}

// copyClean is the project half of the invariant worth the most: what the tool
// writes, the tool accepts — and accepts in silence, warnings included.
func copyClean(t *testing.T, root, dir string) {
	t.Helper()
	var docs []*doc.Document
	entries, err := os.ReadDir(filepath.Join(root, filepath.FromSlash(dir)))
	if err != nil {
		t.Fatal(err)
	}
	for _, e := range entries {
		if filepath.Ext(e.Name()) != ".md" {
			continue
		}
		rel := path.Join(dir, e.Name())
		d, err := doc.Load(rel, filepath.Join(root, filepath.FromSlash(rel)))
		if err != nil {
			t.Fatalf("loading %s: %v", rel, err)
		}
		if d.Front.Origin != "" {
			docs = append(docs, d)
		}
	}
	if len(docs) == 0 {
		t.Fatalf("no copy was assembled in %s", dir)
	}
	rep := check.Copies(docs)
	if len(rep.Findings()) == 0 {
		return
	}
	var b strings.Builder
	for _, f := range rep.Findings() {
		fmt.Fprintf(&b, "  %s: %s\n", f.Path, f.Msg)
	}
	t.Fatalf("the copies the tool assembled do not check clean:\n%s", b.String())
}

func TestWhatTheToolAssemblesTheToolAccepts(t *testing.T) {
	suiteRoot := subscribable(t)
	root := wired(t, suiteRoot, "--component", "backend", "--dir", "docs/conventions", "--lang", "go")
	run(t, root, "", false, "add", "time")
	run(t, root, "", false, "add", "logging")
	copyClean(t, root, "docs/conventions")
}

// The flag package stops at the first argument that is not a flag, so a stray
// one hides every flag written after it and the command quietly does something
// else than what was asked.
func TestProjectCommandsTurnDownAStrayArgument(t *testing.T) {
	suiteRoot := subscribable(t)
	root := wired(t, suiteRoot, "--component", "backend", "--dir", "docs/conventions", "--lang", "go")

	for _, args := range [][]string{
		{"pull", "backend"},
		{"list", "backend"},
		{"check", "backend"},
		{"init", "somewhere"},
	} {
		t.Run(args[0], func(t *testing.T) {
			code, out := run(t, root, "", false, args...)
			if code == cli.OK {
				t.Fatalf("the stray argument went through:\n%s", out)
			}
			if !strings.Contains(out, "takes no argument") {
				t.Errorf("the refusal does not say what is wrong:\n%s", out)
			}
		})
	}
}

// The marker is always left by the assembler, so a copy without one was edited
// by hand — and everything in it would count as suite text to be replaced.
func TestPullRefusesACopyWhoseMarkerIsGone(t *testing.T) {
	suiteRoot := subscribable(t)
	root := wired(t, suiteRoot, "--component", "backend", "--dir", "docs/conventions", "--lang", "go")
	run(t, root, "", false, "add", "time")

	name := filepath.Join(root, "docs", "conventions", "time.md")
	body := read(t, root, "docs/conventions/time.md")
	body = strings.Replace(body, "<!-- conv:local -->", "Заметка, написанная руками.", 1)
	if err := os.WriteFile(name, []byte(body), 0o644); err != nil {
		t.Fatal(err)
	}

	code, out := run(t, root, "", false, "pull")
	if code == cli.OK {
		t.Fatalf("the pull went ahead over a hand-edited copy:\n%s", out)
	}
	if !strings.Contains(out, "carries no <!-- conv:local --> marker") {
		t.Errorf("the refusal does not say why:\n%s", out)
	}
	if got := read(t, root, "docs/conventions/time.md"); !strings.Contains(got, "Заметка, написанная руками") {
		t.Errorf("the hand-written text was destroyed anyway:\n%s", got)
	}
}

// Whatever the tool writes into the manifest it has to read back, and a
// backslash is the ordinary way that fails.
func TestInitWritesAManifestItCanRead(t *testing.T) {
	suiteRoot := subscribable(t)
	root := wired(t, suiteRoot, "--component", "backend", "--dir", `docs\conventions`)

	code, out := run(t, root, "", false, "list")
	if code != cli.OK {
		t.Fatalf("the manifest the tool wrote does not parse: %d\n%s", code, out)
	}
	if !strings.Contains(out, `docs\conventions`) {
		t.Errorf("the directory came back changed:\n%s", out)
	}
}

// A typo in a key costs a whole component, and the parser knows about it — so
// every command that reads the manifest has to pass that on.
func TestCheckSaysWhatItDidNotUnderstand(t *testing.T) {
	suiteRoot := subscribable(t)
	root := wired(t, suiteRoot, "--component", "backend", "--dir", "docs/conventions", "--lang", "go")

	body := read(t, root, ".conventions.toml")
	body = strings.Replace(body, `dir = "docs/conventions"`, `dyr = "docs/conventions"`, 1)
	if err := os.WriteFile(filepath.Join(root, ".conventions.toml"), []byte(body), 0o644); err != nil {
		t.Fatal(err)
	}

	code, out := run(t, root, "", false, "check")
	if !strings.Contains(out, "dyr") {
		t.Errorf("the typo in the manifest went unmentioned:\n%s", out)
	}
	if code == cli.OK {
		t.Errorf("a component with no dir was checked anyway:\n%s", out)
	}
}