package builder

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

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

// A module's files kept as template files in its repository (novox/hq ADR 0349 §2, design 57 package T1, issue
// 654): the build packs files/ into the module's templates archive and reads each template's text back from the
// packed bytes into the file's content, so the manifest the mesh holds is the one it would hold for the text inline.

const templatedModule = `{"module":"meshboard","version":"1",
  "build":{"artifacts":[
    {"name":"server","kind":"image","from":"Dockerfile"},
    {"name":"files","kind":"archive","from":"files"}]},
  "resources":[
    {"id":"svc","type":"container","name":"meshboard","artifact":"server"},
    {"id":"conf","type":"file","path":"/etc/meshboard/meshboard.conf","template":"files/meshboard.conf"},
    {"id":"deeper","type":"file","path":"/etc/meshboard/deeper.conf","template":"files/a/deeper.conf"}]}`

var templatedFiles = map[string]string{
	"Dockerfile": "FROM scratch", "files/meshboard.conf": "listen = 8080\n\"quoted\" é\n",
	"files/a/deeper.conf": "deeper\n", "files/unused.conf": "packed, named by nothing",
}

func contentOf(t *testing.T, m catalogue.Manifest, id string) string {
	t.Helper()
	for _, r := range m.Resources {
		if r["id"] == id {
			if _, has := r[catalogue.TemplateField]; has {
				t.Fatalf("%s still names its template in the built manifest: %v", id, r)
			}
			text, ok := r["content"].(string)
			if !ok {
				t.Fatalf("%s carries no content: %v", id, r)
			}
			return text
		}
	}
	t.Fatalf("no resource %s in %v", id, m.Resources)
	return ""
}

func TestABuildReadsEachTemplateBackFromItsArchive(t *testing.T) {
	r, workspace := aRepository(t, templatedModule, templatedFiles)
	got, err := Build(context.Background(), r.run, r, "https://forge.invalid/meshboard.git", "", "", workspace, nil,
		Npmrc{}, GitCredential{}, nil)
	if err != nil {
		t.Fatal(err)
	}
	if text := contentOf(t, got.Manifest, "conf"); text != templatedFiles["files/meshboard.conf"] {
		t.Fatalf("the template's text is %q, not the file's", text)
	}
	if text := contentOf(t, got.Manifest, "deeper"); text != templatedFiles["files/a/deeper.conf"] {
		t.Fatalf("the template's text is %q, not the file's", text)
	}
	if r.archives["meshboard/files"] == "" {
		t.Fatalf("the templates archive was not published: %v", r.archives)
	}
	if problem := catalogue.HeldTemplateProblem(got.Manifest); problem != "" {
		t.Fatal(problem)
	}
}

func TestABuildWhoseTemplateIsMissingFailsNamingIt(t *testing.T) {
	files := map[string]string{}
	for k, v := range templatedFiles {
		files[k] = v
	}
	delete(files, "files/a/deeper.conf")
	r, workspace := aRepository(t, templatedModule, files)
	_, err := Build(context.Background(), r.run, r, "https://forge.invalid/meshboard.git", "", "", workspace, nil,
		Npmrc{}, GitCredential{}, nil)
	if err == nil || !strings.Contains(err.Error(), "files/a/deeper.conf") {
		t.Fatalf("a build whose template is missing did not fail naming it: %v", err)
	}
}

// A walk that takes its check's build copies the archive by digest and builds nothing: the templates are read back
// from the tree packed again, which is the archive only when it packs to the digest taken.
func TestAWalkTakingAChecksBuildReadsTheTemplatesBackToo(t *testing.T) {
	withVersion(t, "builder-1")
	contents := map[string]string{"mod/" + ManifestName: templatedModule}
	for k, v := range templatedFiles {
		contents["mod/"+k] = v
	}
	scratch := newScratch()
	r, run, workspace := aModuleWith(t, "tree-one", contents)
	checked := aCheckBuiltBy(t, scratch, r, run, workspace)

	r, run, workspace = aModuleWith(t, "tree-one", contents)
	got, err := BuildReusing(t.Context(), run, r, Reuse{Scratch: scratch, Pulls: []PullRef{aPull}, Named: named(checked)},
		"https://forge.invalid/meshboard.git", "mod", "main", workspace, nil, Npmrc{}, GitCredential{}, nil)
	if err != nil {
		t.Fatal(err)
	}
	if got.Reused == nil || len(r.archives) > 0 {
		t.Fatalf("the walk built again: reused %+v, why %q, published %v", got.Reused, got.Why, r.archives)
	}
	if text := contentOf(t, got.Manifest, "conf"); text != templatedFiles["files/meshboard.conf"] {
		t.Fatalf("the template's text is %q, not the file's", text)
	}
}

// The tree packed again must be the archive taken; text read from anything else is not the archive's.
func TestTemplateTextsAreRefusedWhenTheTreeDoesNotPackToTheDigestTaken(t *testing.T) {
	m, err := catalogue.ParseManifest([]byte(templatedModule))
	if err != nil {
		t.Fatal(err)
	}
	within := writeTree(t, t.TempDir(), templatedFiles)
	built := []catalogue.Built{{Name: "files", Kind: catalogue.ArtifactArchive, Digest: "sha256:" + strings.Repeat("0", 64)}}
	if _, err := withTemplateTexts(m, within, built); err == nil || !strings.Contains(err.Error(), "digest") {
		t.Fatalf("text was read from a tree that does not pack to the archive taken: %v", err)
	}
}

// writeTree writes files under dir and answers dir.
func writeTree(t *testing.T, dir string, files map[string]string) string {
	t.Helper()
	for name, body := 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(body), 0o644); err != nil {
			t.Fatal(err)
		}
	}
	return dir
}