package main

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

	"github.com/novox/mesh-controller/internal/catalogue"
	snapshot "github.com/novox/mesh-controller/internal/facts"
	"github.com/novox/mesh-controller/internal/inventory"
)

// A file's text kept as a template file in its module's repository (novox/hq ADR 0349 §2, design 57 package T1,
// issue 654): `module check` and the merge gate read it from the tree beside the manifest, so a change to a
// template alone is judged as a change to its module.

const templatedNotifier = `{"module":"notifier","version":"1",
  "build":{"artifacts":[{"name":"files","kind":"archive","from":"files"}]},
  "resources":[{"id":"conf","type":"file","path":"/etc/notifier/notifier.conf","mode":"0644","template":"files/notifier.conf"}]}`

// inlineNotifier is the same module as the mesh holds it: built, its text inline.
const inlineNotifier = `{"module":"notifier","version":"1",
  "resources":[{"id":"conf","type":"file","path":"/etc/notifier/notifier.conf","mode":"0644","content":"volume = 3\n"}]}`

// aTemplatedModule writes a module's directory: its manifest and its files/.
func aTemplatedModule(t *testing.T, dir, manifest string, files map[string]string) string {
	t.Helper()
	if err := os.MkdirAll(dir, 0o755); err != nil {
		t.Fatal(err)
	}
	path := filepath.Join(dir, "module.json")
	if err := os.WriteFile(path, []byte(manifest), 0o644); err != nil {
		t.Fatal(err)
	}
	for name, text := range files {
		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(text), 0o644); err != nil {
			t.Fatal(err)
		}
	}
	return path
}

func TestModuleCheckReadsTemplatesFromTheTreeBesideTheManifest(t *testing.T) {
	good := aTemplatedModule(t, t.TempDir(), templatedNotifier, map[string]string{"files/notifier.conf": "volume = 3\n"})
	var out bytes.Buffer
	if err := moduleCheck([]string{good}, &out); err != nil || !strings.Contains(out.String(), "notifier: ok") {
		t.Fatalf("a module with its text in files/ was refused: %v\n%s", err, out.String())
	}

	// A change to the template alone, to text the controller refuses inline, is refused the same.
	bad := aTemplatedModule(t, t.TempDir(), templatedNotifier,
		map[string]string{"files/notifier.conf": "volume = 3\nstore = ${dir:nowhere}\n"})
	out.Reset()
	if err := moduleCheck([]string{bad}, &out); err == nil || !strings.Contains(out.String(), "nowhere") {
		t.Fatalf("a template whose text is refused inline passed:\n%s", out.String())
	}

	// A symlink under files/ that no template names: the build's packing refuses it, so the check does too.
	linked := t.TempDir()
	aTemplatedModule(t, linked, templatedNotifier, map[string]string{"files/notifier.conf": "volume = 3\n"})
	if err := os.Symlink("/etc/hostname", filepath.Join(linked, "files", "elsewhere")); err != nil {
		t.Fatal(err)
	}
	out.Reset()
	if err := moduleCheck([]string{filepath.Join(linked, "module.json")}, &out); err == nil ||
		!strings.Contains(out.String(), "files/elsewhere is a symlink") {
		t.Fatalf("a symlink under files/ passed the check:\n%s", out.String())
	}

	// And a template the tree lacks, by name.
	missing := aTemplatedModule(t, t.TempDir(), templatedNotifier, nil)
	out.Reset()
	if err := moduleCheck([]string{missing}, &out); err == nil || !strings.Contains(out.String(), "files/notifier.conf") {
		t.Fatalf("a missing template was not refused by name:\n%s", out.String())
	}
}

// templatedMesh is catalogueMesh with the notifier on the laptop, registered as built: its text inline.
func templatedMesh(t *testing.T) (snapshot.Facts, map[string]string) {
	t.Helper()
	open := aMesh(t)
	ctx := t.Context()
	manifests := map[string]string{
		"lemurs": `{"module":"lemurs","version":"1","capabilities":["systemd"],
			"resources":[{"id":"service","type":"service","unit":"lemurs.service","state":"running","boot":"enabled"}]}`,
		"notifier": inlineNotifier,
	}
	for name, raw := range manifests {
		m, err := catalogue.ParseManifest([]byte(raw))
		if err != nil {
			t.Fatalf("%s: %v", name, err)
		}
		if err := open.inventory.RegisterModule(ctx, m, inventory.Source{Repository: "novox/mesh-catalog",
			Path: "modules/" + name, BuiltFrom: "c0ffee"}); err != nil {
			t.Fatal(err)
		}
		if _, err := assign(ctx, open, "laptop", name); err != nil {
			t.Fatalf("assign %s: %v", name, err)
		}
	}
	f, err := gatherFacts(ctx, open, "2.11.17")
	if err != nil {
		t.Fatal(err)
	}
	return f, manifests
}

// aTemplatedTree is the catalogue's checkout with the notifier's text in files/.
func aTemplatedTree(t *testing.T, manifests map[string]string, text string, has bool) string {
	t.Helper()
	tree := aTree(t, withEdit(manifests, "notifier", ""))
	files := map[string]string{}
	if has {
		files["files/notifier.conf"] = text
	}
	aTemplatedModule(t, filepath.Join(tree, "modules", "notifier"), templatedNotifier, files)
	return tree
}

const notifierTemplate = "modules/notifier/files/notifier.conf"

func TestTheMergeGateJudgesAChangeToATemplateAlone(t *testing.T) {
	f, manifests := templatedMesh(t)

	// The module moved to its template, the same text: nothing changes on any machine.
	v := gateJudged(t, f, aTemplatedTree(t, manifests, "volume = 3\n", true), "modules/notifier/module.json",
		notifierTemplate)
	if v.Verdict == "fail" || v.Modules["notifier"] != "" {
		t.Fatalf("the module moved to its template with the same text reads as a change (%v):\n%s", v.Modules, v.Report())
	}

	// The template alone changed: its module changed, and composes.
	v = gateJudged(t, f, aTemplatedTree(t, manifests, "volume = 4\n", true), notifierTemplate)
	if v.Verdict == "fail" || v.Modules["notifier"] != "changed" {
		t.Fatalf("a change to the template alone is not a change to its module (%v):\n%s", v.Modules, v.Report())
	}
	if v.Width == nil || strings.Join(v.Width.Modules, ",") != "notifier" {
		t.Fatalf("a change to the template rebuilds %+v, not its module", v.Width)
	}

	// The template alone changed to text the controller refuses: the pull request fails, naming the module.
	v = gateJudged(t, f, aTemplatedTree(t, manifests, "store = ${dir:nowhere}\n", true), notifierTemplate)
	if v.Verdict != "fail" || !strings.Contains(v.Report(), "notifier") {
		t.Fatalf("a template the controller refuses passed the gate:\n%s", v.Report())
	}

	// A symlinked files/ fails: nothing is read from outside the tree.
	tree := aTree(t, withEdit(manifests, "notifier", ""))
	elsewhere := t.TempDir()
	if err := os.WriteFile(filepath.Join(elsewhere, "notifier.conf"), []byte("volume = 3\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	aTemplatedModule(t, filepath.Join(tree, "modules", "notifier"), templatedNotifier, nil)
	if err := os.Symlink(elsewhere, filepath.Join(tree, "modules", "notifier", "files")); err != nil {
		t.Fatal(err)
	}
	v = gateJudged(t, f, tree, notifierTemplate)
	if v.Verdict != "fail" || !strings.Contains(v.Report(), "files/ is a symlink") {
		t.Fatalf("a symlinked files/ passed the gate:\n%s", v.Report())
	}

	// And the template removed from the tree fails, naming it.
	v = gateJudged(t, f, aTemplatedTree(t, manifests, "", false), notifierTemplate)
	if v.Verdict != "fail" || !strings.Contains(v.Report(), "files/notifier.conf") {
		t.Fatalf("a missing template passed the gate:\n%s", v.Report())
	}
}

// What the gate composes for the module in its template form is what the mesh composes for it inline.
func TestTheMergeGateResolvesATemplatedModuleToItsInlineTwin(t *testing.T) {
	dir := t.TempDir()
	path := aTemplatedModule(t, dir, templatedNotifier, map[string]string{"files/notifier.conf": "volume = 3\n"})
	raw, err := os.ReadFile(path)
	if err != nil {
		t.Fatal(err)
	}
	m, err := catalogue.ParseManifest(raw)
	if err != nil {
		t.Fatal(err)
	}
	texts, err := catalogue.ReadTemplates(m, dir)
	if err != nil {
		t.Fatal(err)
	}
	resolved, err := standInBuild(m, texts)
	if err != nil {
		t.Fatal(err)
	}
	inline, err := catalogue.ParseManifest([]byte(inlineNotifier))
	if err != nil {
		t.Fatal(err)
	}
	if builtAlike(resolved) != builtAlike(inline) {
		got, _ := json.Marshal(resolved)
		t.Fatalf("the templated module resolves to %s, not its inline twin", got)
	}
}

// A module whose files/ is unpacked onto the machine names its own templates directory (issue 731): `module check`
// reads its templates from there and says of it exactly what it says of the same module with its text inline.
func TestModuleCheckReadsTemplatesFromTheTemplatesDirectoryTheManifestNames(t *testing.T) {
	const inline = `{"module":"notifier","version":"1",
  "build":{"artifacts":[{"name":"scripts","kind":"archive","from":"files"}]},
  "resources":[{"id":"scripts","type":"archive","path":"/usr/local/lib/notifier","artifact":"scripts"},
    {"id":"conf","type":"file","path":"/etc/notifier/notifier.conf","mode":"0644","content":"volume = 3\n"}]}`
	const templated = `{"module":"notifier","version":"1","templates":"templates",
  "build":{"artifacts":[{"name":"scripts","kind":"archive","from":"files"},
    {"name":"templates","kind":"archive","from":"templates"}]},
  "resources":[{"id":"scripts","type":"archive","path":"/usr/local/lib/notifier","artifact":"scripts"},
    {"id":"conf","type":"file","path":"/etc/notifier/notifier.conf","mode":"0644","template":"templates/notifier.conf"}]}`
	scripts := map[string]string{"files/bin/notify": "#!/bin/sh\n"}
	var want bytes.Buffer
	if err := moduleCheck([]string{aTemplatedModule(t, t.TempDir(), inline, scripts)}, &want); err != nil {
		t.Fatalf("the inline module was refused: %v\n%s", err, want.String())
	}
	with := map[string]string{"files/bin/notify": "#!/bin/sh\n", "templates/notifier.conf": "volume = 3\n"}
	var got bytes.Buffer
	if err := moduleCheck([]string{aTemplatedModule(t, t.TempDir(), templated, with)}, &got); err != nil {
		t.Fatalf("a module with its text in templates/ was refused: %v\n%s", err, got.String())
	}
	if got.String() != want.String() {
		t.Fatalf("module check says otherwise of the templated module:\ninline:    %s\ntemplated: %s", want.String(),
			got.String())
	}

	// Its text in files/ instead, where the machine unpacks it, is not where its manifest says its templates are.
	misplaced := strings.Replace(templated, `"templates/notifier.conf"`, `"files/notifier.conf"`, 1)
	got.Reset()
	if err := moduleCheck([]string{aTemplatedModule(t, t.TempDir(), misplaced,
		map[string]string{"files/notifier.conf": "volume = 3\n"})}, &got); err == nil ||
		!strings.Contains(got.String(), "files/notifier.conf") {
		t.Fatalf("a template outside the templates directory the manifest names passed:\n%s", got.String())
	}
}

// Issue 876: the gate judges a moved module that names its templates as registration reads it after a real build,
// handed its templates; it refused every such module as "marked moved and names no template". This calls the gate's
// own shelf (shelfWithChange), which needs no database.
func TestReplay876(t *testing.T) {
	moved := strings.Replace(templatedNotifier, `"version":"1",`, `"version":"1","moved":true,`, 1)
	judge := func(manifest string, files map[string]string) (map[string]catalogue.Manifest, []string) {
		tree := t.TempDir()
		aTemplatedModule(t, filepath.Join(tree, "modules", "notifier"), manifest, files)
		out, failures, err := shelfWithChange(map[string]catalogue.Manifest{}, nil, snapshot.Facts{},
			"novox/mesh-catalog", tree, map[string]string{}, nil)
		if err != nil {
			t.Fatal(err)
		}
		return out, failures
	}
	out, failures := judge(moved, map[string]string{"files/notifier.conf": "volume = 3\n"})
	if len(failures) > 0 {
		t.Fatalf("a moved module naming its templates was refused: %v", failures)
	}
	if h := out["notifier"].Handed; h == nil || h.Templates["conf"] != "notifier.conf" {
		t.Fatalf("the gate did not hand the moved module its templates: %+v", h)
	}

	// A moved module naming no template is still refused.
	none := strings.Replace(strings.Replace(moved, `"template":"files/notifier.conf"`,
		`"content":"volume = 3\n"`, 1), `"build":{"artifacts":[{"name":"files","kind":"archive","from":"files"}]},`, "", 1)
	if _, failures := judge(none, nil); len(failures) != 1 || !strings.Contains(failures[0], "names no template") {
		t.Fatalf("a moved module naming no template was not refused: %v", failures)
	}
}