package builder

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

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

// A repository becoming artifacts the mesh can pin.
//
// git and docker are injected rather than run, because what is under test is the ORDER and the
// refusals — that nothing is published until everything is built, that a build reads only its own
// tree, that two builds of one commit produce one digest. Running docker here would test docker.

type recorded struct {
	ran []string
	// dirs is the directory each entry in ran was run from, same index — so a test can ask not
	// only what ran but where.
	dirs     []string
	images   map[string]string
	archives map[string]string
	failPush bool
	// contents is what a clone of this repository lands, so the fake clone can restore the tree
	// Build deliberately removes first.
	contents map[string]string
	// secondary is what a clone of a repository OTHER than the one under test lands, keyed by
	// that repository's URL — an artifact's own build context, cloned apart from the module.
	secondary map[string]map[string]string
	// stamped is the modification time the clone gives every file. Set differently between two
	// builds of one commit, because otherwise both land in the same second and a packer that
	// carried timestamps would still produce one digest — which is a test that passes for a
	// reason that has nothing to do with what it claims.
	stamped time.Time
	// tree is what git names as the tree of the module's directory; empty answers as for a commit.
	tree string
}

func (r *recorded) run(_ context.Context, dir, name string, args ...string) (string, error) {
	line := name + " " + strings.Join(args, " ")
	r.ran = append(r.ran, line)
	r.dirs = append(r.dirs, dir)
	// A clone may carry `-c` configuration in front of the verb — the credential store — so the
	// verb is found rather than assumed first.
	isClone := false
	for _, a := range args {
		if a == "clone" {
			isClone = true
			break
		}
	}
	switch {
	case name == "git" && isClone:
		repository := args[len(args)-2]
		tree := args[len(args)-1]
		if err := os.MkdirAll(tree, 0o755); err != nil {
			return "", err
		}
		lands := r.contents
		if by, is := r.secondary[repository]; is {
			lands = by
		}
		for path, body := range lands {
			full := filepath.Join(tree, path)
			if err := os.MkdirAll(filepath.Dir(full), 0o755); err != nil {
				return "", err
			}
			if err := os.WriteFile(full, []byte(body), 0o644); err != nil {
				return "", err
			}
			if !r.stamped.IsZero() {
				if err := os.Chtimes(full, r.stamped, r.stamped); err != nil {
					return "", err
				}
			}
		}
		return "", nil
	case name == "git" && len(args) > 1 && args[0] == "rev-parse" && strings.HasPrefix(args[1], "HEAD:") && r.tree != "":
		return r.tree + "\n", nil
	case name == "git" && len(args) > 0 && args[0] == "rev-parse":
		return "c0ffeec0ffeec0ffeec0ffeec0ffeec0ffeec0ff\n", nil
	case name == "git" && len(args) > 1 && args[0] == "rev-list" && args[1] == "--count":
		return "42\n", nil
	}
	return "", nil
}

func (r *recorded) PublishImage(_ context.Context, localTag, repository string) (string, error) {
	if r.failPush {
		return "", os.ErrPermission
	}
	if r.images == nil {
		r.images = map[string]string{}
	}
	r.images[repository] = localTag
	return "registry.invalid/" + repository + "@sha256:" + strings.Repeat("a", 64), nil
}

func (r *recorded) PublishArchive(_ context.Context, repository string, body []byte, digest string) (string, error) {
	if r.failPush {
		return "", os.ErrPermission
	}
	if r.archives == nil {
		r.archives = map[string]string{}
	}
	r.archives[repository] = digest
	_ = body
	return "https://store.invalid/" + repository, nil
}

// aRepository is a workspace whose clone lands a manifest and some files.
func aRepository(t *testing.T, manifest string, files map[string]string) (*recorded, string) {
	t.Helper()
	contents := map[string]string{ManifestName: manifest}
	for name, body := range files {
		contents[name] = body
	}
	return &recorded{contents: contents}, t.TempDir()
}

const withBoth = `{"module":"meshboard","version":"1",
  "build":{"artifacts":[
    {"name":"server","kind":"image","from":"Dockerfile"},
    {"name":"look","kind":"archive","from":"files"}]},
  "resources":[
    {"id":"svc","type":"container","name":"meshboard","artifact":"server"},
    {"id":"theme","type":"archive","path":"/opt/meshboard","artifact":"look"}]}`

func TestAnUpstreamImageWithNoTagIsRefused(t *testing.T) {
	// What gets mirrored would be whatever `latest` means today, and a module pinned to that is
	// not pinned.
	_, err := catalogue.ParseManifest([]byte(`{"module":"a","version":"1","build":{"artifacts":[
		{"name":"x","kind":"upstream","from":"postgres"}]}}`))
	if err == nil {
		t.Fatal("an untagged upstream reference was accepted")
	}
	if !strings.Contains(err.Error(), "no tag or digest") {
		t.Fatalf("unhelpful refusal: %v", err)
	}
}

func TestAnUpstreamReferenceIsNotAPathInTheRepository(t *testing.T) {
	// The rule that a build reads only its own repository must not refuse every reference with a
	// registry host in it.
	if _, err := catalogue.ParseManifest([]byte(`{"module":"a","version":"1","build":{"artifacts":[
		{"name":"x","kind":"upstream","from":"registry.example/library/postgres:17"}]}}`)); err != nil {
		t.Fatalf("a perfectly ordinary upstream reference was refused: %v", err)
	}
}

// **A module is a repository and a path within it** (novox/hq ADR 0069). The catalogue holds its
// modules one to a directory and the system this replaces has always built one that way, so a
// builder that could only read a repository's root could build none of what exists.

// A build reads only its own tree. A path climbing out of the clone would otherwise let a build
// read — and an archive artifact publish — whatever the build machine happens to hold, which is
// the one thing a machine that builds other people's repositories must not do.

// **Packaging and source are allowed to live apart** — a module that ships only the recipe for
// source that lives in a second repository (the reference route-proxy, packaged in the catalogue
// but built from mesh-controller's own repository) names where that source actually is, rather
// than vendoring a second copy the two could drift from.

// The forge credential is offered through git's own credential store — a file, never argv — and
// git decides when it applies. What is checked: the clone names the store, the secret never
// appears in a command line, and the file holds exactly the URL at 0600.

// storeNamedIn is the credential store a git command line offers.
func storeNamedIn(t *testing.T, line string) string {
	t.Helper()
	_, after, ok := strings.Cut(line, "credential.helper=store --file=")
	if !ok {
		t.Fatalf("the clone does not name the credential store: %s", line)
	}
	return strings.Fields(after)[0]
}

// Without a credential, a clone is exactly the invocation it always was, and no credential file
// appears — the builder a mesh of public repositories runs is unchanged.

// An artifact's own context is cloned with the same offer: a private module whose context is a
// second private repository on the same forge builds, and the secret still never reaches argv.