package builder

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

const aBundle = `{"module":"greeter","version":"1",
  "build":{"artifacts":[
    {"name":"code","kind":"bundle","language":"typescript","entrypoints":["index.js"]}]},
  "resources":[
    {"id":"files","type":"archive","path":"/opt/greeter","artifact":"code"}]}`

// compiling is a runner that behaves like a toolchain: when asked to compile, it leaves output
// where the toolchain says output lands. Without this the pack step has nothing to pack, and the
// test would be asserting on a failure rather than on a build.
type compiling struct{ *recorded }

func (c compiling) run(ctx context.Context, dir, name string, args ...string) (string, error) {
	out, err := c.recorded.run(ctx, dir, name, args...)
	if name != "docker" || len(args) == 0 || args[0] != "run" {
		return out, err
	}
	// **Writes where it was TOLD to**, rather than to a fixed directory. A fake that always wrote
	// to one place would pass whether or not the builder gave each artifact its own — which is the
	// thing being tested.
	where := ""
	for i, a := range args {
		if a == "--outDir" && i+1 < len(args) {
			where = args[i+1]
		}
	}
	if where == "" {
		return out, err
	}
	made := filepath.Join(dir, where)
	if err := os.MkdirAll(made, 0o755); err != nil {
		return "", err
	}
	if err := os.WriteFile(filepath.Join(made, "index.js"), []byte("console.log(1)"), 0o644); err != nil {
		return "", err
	}
	return out, err
}

// **A module says what it is written in, and needs no Dockerfile.** This is the whole point of the
// bundle recipe: the same module previously needed a hand-written recipe repeating an incantation
// that is easy to get wrong in ways that fail somewhere else.
func TestABundleIsCompiledAndPackedWithNoDockerfile(t *testing.T) {
	r, workspace := aRepository(t, aBundle, map[string]string{"index.ts": "console.log(1)"})
	held := map[string]string{"mesh-tools/build": "registry.invalid/mesh-tools/build@sha256:" + strings.Repeat("b", 64)}

	got, err := Build(context.Background(), compiling{r}.run, r,
		"https://forge.invalid/greeter.git", "", "", workspace, held, Npmrc{}, GitCredential{}, nil)
	if err != nil {
		t.Fatalf("a module with a language and no Dockerfile did not build: %v", err)
	}

	// Compiled in the toolchain the mesh chose, not in one the module named.
	var compiled string
	for _, line := range r.ran {
		if strings.HasPrefix(line, "docker run") {
			compiled = line
		}
	}
	if compiled == "" {
		t.Fatalf("nothing was compiled:\n%s", strings.Join(r.ran, "\n"))
	}
	if !strings.Contains(compiled, "mesh-tools/build@sha256:") {
		t.Fatalf("the compile did not run in the mesh's own toolchain: %s", compiled)
	}
	if strings.Contains(strings.Join(r.ran, "\n"), "docker build") {
		t.Fatalf("a bundle invoked a Dockerfile build, which is the thing it exists to avoid:\n%s",
			strings.Join(r.ran, "\n"))
	}

	// And pinned by a digest of what came out, like any other artifact.
	digest, _ := got.Manifest.Resources[0]["digest"].(string)
	if !strings.HasPrefix(digest, "sha256:") {
		t.Fatalf("the bundle was not pinned: %v", got.Manifest.Resources[0])
	}

	// **One file per entrypoint and launcher, in the toolchain's bundler** (novox/hq ADR 0193). A
	// second run in the same toolchain image bundles each into the artifact's bundled output, the SDK
	// inlined, refusing by name in an image that predates the bundler; and the toolchain's
	// node_modules is no longer copied into a bundle that keeps nothing external.
	var bundling []string
	for _, line := range r.ran {
		if strings.HasPrefix(line, "docker run") && strings.Contains(line, "esbuild") {
			bundling = append(bundling, line)
		}
	}
	if len(bundling) != 2 {
		t.Fatalf("want one bundling run for the entrypoints and one for the launchers:\n%s", strings.Join(r.ran, "\n"))
	}
	for _, want := range []string{"mesh-tools/build@sha256:", "predates one-file bundles", "--bundle", "--format=esm",
		"--platform=node", "--outdir=" + Out("code") + ".bundled", Out("code") + "/index.js"} {
		if !strings.Contains(bundling[0], want) {
			t.Errorf("the entrypoints' bundling lacks %q: %s", want, bundling[0])
		}
	}
	if !strings.Contains(bundling[1], Out("code")+"/index.serve.mjs") || !strings.Contains(bundling[1], "--out-extension:.js=.mjs") {
		t.Errorf("the launcher is not bundled under its own name: %s", bundling[1])
	}
	if strings.Contains(strings.Join(r.ran, "\n"), "/app/runtime") {
		t.Errorf("the toolchain's node_modules was copied into a bundle that keeps nothing external:\n%s", strings.Join(r.ran, "\n"))
	}
	if strings.Index(strings.Join(r.ran, "\n"), "--outDir") > strings.Index(strings.Join(r.ran, "\n"), "esbuild") {
		t.Fatal("the bundler ran before the compile wrote its output")
	}
}

// A bundle naming packages it keeps external is bundled with them as imports, and carries the
// toolchain's node_modules for them — the one case it still does.
func TestABundleKeepingAPackageExternalCarriesTheToolchainsModules(t *testing.T) {
	manifest := strings.Replace(aBundle, `"entrypoints":["index.js"]`, `"entrypoints":["index.js"],"external":["sharp"]`, 1)
	r, workspace := aRepository(t, manifest, map[string]string{"index.ts": "console.log(1)"})
	held := map[string]string{"mesh-tools/build": "registry.invalid/mesh-tools/build@sha256:" + strings.Repeat("b", 64)}
	if _, err := Build(context.Background(), compiling{r}.run, r,
		"https://forge.invalid/greeter.git", "", "", workspace, held, Npmrc{}, GitCredential{}, nil); err != nil {
		t.Fatal(err)
	}
	all := strings.Join(r.ran, "\n")
	if !strings.Contains(all, "--external:sharp") || !strings.Contains(all, "/app/runtime") {
		t.Errorf("an external package was not kept as an import with the toolchain's modules beside it:\n%s", all)
	}
}

// A language whose bundle carries its own dependencies copies nothing in: a Go binary is static.
func TestOnlyALanguageWithARuntimeDirectoryCopiesDependenciesIn(t *testing.T) {
	ts, _ := ToolchainFor("typescript")
	if ts.Dependencies != "/app/runtime" {
		t.Fatalf("typescript bundles run with %q", ts.Dependencies)
	}
	for _, language := range []string{"go", "python"} {
		chain, _ := ToolchainFor(language)
		if chain.Dependencies != "" {
			t.Fatalf("%s copies %q into every bundle, and its bundles carry their own", language, chain.Dependencies)
		}
	}
}

// **Refused before anything is built, naming what to build first.** A base the mesh has not built
// is not a compile that fails on its first line — it is a question somebody can answer, and saying
// it early is the difference between a fixable message and one about a missing image.
func TestABundleWhoseToolchainIsNotHeldIsRefusedFirst(t *testing.T) {
	r, workspace := aRepository(t, aBundle, map[string]string{"index.ts": "console.log(1)"})

	_, err := Build(context.Background(), compiling{r}.run, r,
		"https://forge.invalid/greeter.git", "", "", workspace, nil, Npmrc{}, GitCredential{}, nil)
	if err == nil {
		t.Fatal("a bundle was built with no toolchain to compile it in")
	}
	if !strings.Contains(err.Error(), "mesh-tools") {
		t.Fatalf("the refusal does not name what has to be built first: %v", err)
	}
	for _, line := range r.ran {
		if strings.HasPrefix(line, "docker run") {
			t.Fatalf("a compile was attempted before the refusal: %s", line)
		}
	}
}

// A language the mesh does not build is refused the same way, and names what it can build.
func TestABundleInAnUnknownLanguageIsRefused(t *testing.T) {
	manifest := strings.Replace(aBundle, `"language":"typescript"`, `"language":"cobol"`, 1)
	r, workspace := aRepository(t, manifest, map[string]string{"index.ts": "x"})

	_, err := Build(context.Background(), compiling{r}.run, r,
		"https://forge.invalid/greeter.git", "", "", workspace,
		map[string]string{"mesh-tools/build": "registry.invalid/x@sha256:" + strings.Repeat("c", 64)}, Npmrc{}, GitCredential{}, nil)
	if err == nil {
		t.Fatal("a language nothing can compile was accepted")
	}
	if !strings.Contains(err.Error(), "typescript") {
		t.Fatalf("the refusal does not say what would have worked: %v", err)
	}
}

// **One module, two bundles, and neither packs the other.**
//
// The case that matters for real modules: a module is one piece of software and may still carry a
// daemon in one language and tools in another (ADR 0040). An earlier version of this compiled
// every bundle into the toolchain's single output directory, so two of them would overwrite each
// other and then be packed together — one artifact containing both, twice.
func TestTwoBundlesInOneModuleArePackedSeparately(t *testing.T) {
	const two = `{"module":"greeter","version":"1",
	  "build":{"artifacts":[
	    {"name":"daemon","kind":"bundle","language":"typescript","entrypoints":["index.js"]},
	    {"name":"tools","kind":"bundle","language":"typescript","entrypoints":["index.js"]}]},
	  "resources":[
	    {"id":"a","type":"archive","path":"/opt/greeter/daemon","artifact":"daemon"},
	    {"id":"b","type":"archive","path":"/opt/greeter/tools","artifact":"tools"}]}`

	r, workspace := aRepository(t, two, map[string]string{"index.ts": "console.log(1)"})
	held := map[string]string{"mesh-tools/build": "registry.invalid/mesh-tools/build@sha256:" + strings.Repeat("b", 64)}

	got, err := Build(context.Background(), compiling{r}.run, r,
		"https://forge.invalid/greeter.git", "", "", workspace, held, Npmrc{}, GitCredential{}, nil)
	if err != nil {
		t.Fatalf("a module with two bundles did not build: %v", err)
	}

	// Compiled into two different places. Only the compile lines: the copy of each bundle's
	// dependencies names the same directory again, deliberately.
	var outputs []string
	for _, line := range r.ran {
		if !strings.Contains(line, "--outDir") {
			continue
		}
		for _, part := range strings.Fields(line) {
			if strings.HasPrefix(part, ".mesh-build/") {
				outputs = append(outputs, part)
			}
		}
	}
	if len(outputs) != 2 || outputs[0] == outputs[1] {
		t.Fatalf("two bundles did not get their own output directories: %v", outputs)
	}

	// And published as two artifacts, each with its own digest.
	if len(r.archives) != 2 {
		t.Fatalf("expected two archives published, got %v", r.archives)
	}
	first, _ := got.Manifest.Resources[0]["digest"].(string)
	second, _ := got.Manifest.Resources[1]["digest"].(string)
	if first == "" || second == "" {
		t.Fatalf("a bundle was not pinned: %v", got.Manifest.Resources)
	}
}