package builder

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

const aBundle = `{"module":"greeter","version":"1",
  "build":{"artifacts":[
    {"name":"code","kind":"bundle","language":"typescript","entrypoints":["dist/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" {
		made := filepath.Join(dir, "dist")
		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)
	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])
	}
}

// **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)
	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)})
	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)
	}
}