package stdio

import (
	"go/ast"
	"go/parser"
	"go/token"
	"io/fs"
	"path/filepath"
	"slices"
	"strings"
	"testing"
)

// meshSDKPackages is every package mesh-sdk holds (novox/hq ADR 0593 §1): what every module shares, the value shapes
// and names more than one part reads, and the seat contracts it holds until they move into SDK modules (issue 167).
// Logic only some modules need is its owner module's package. A package added here is a decision to say in the pull
// request: does every module share it, or is it a shape more than one part reads?
var meshSDKPackages = []string{
	".", "announce", "announcetest", "asker", "asks", "buildstep", "buscompose", "busretry", "calladdress", "catalogue",
	"composer", "declaration", "delivery", "forgekey", "handacts", "health", "internal/beside", "kvlimit", "membership",
	"objectlink", "outward", "overlay", "pernode", "process", "provider", "provider/harness", "provisions",
	"sdkversion", "seal", "testbus",
}

// computesNot are the functions whose computation is one owner's alone (ADR 0593 §2, §7): the indexer computes a
// fingerprint, its named tree and a package's version; the node-engine composes.
var computesNot = []string{"SourceFingerprint", "SourceFingerprint2", "NamedTree", "MeshPackagesOf", "PackageVersionsOf",
	"OtherPackages", "Compose", "CompositionsShadow", "JudgeMove", "Run"}

// ADR 0593 §1's check: mesh-sdk holds exactly the packages it keeps, and none of them computes what one owner alone
// computes.
func TestMeshSDKHoldsOnlyWhatEveryModuleShares(t *testing.T) {
	var found []string
	err := filepath.WalkDir(".", func(path string, d fs.DirEntry, err error) error {
		if err != nil {
			return err
		}
		if d.IsDir() {
			if n := d.Name(); n == "testdata" || (strings.HasPrefix(n, ".") && path != ".") {
				return filepath.SkipDir
			}
			return nil
		}
		if !strings.HasSuffix(path, ".go") || strings.HasSuffix(path, "_test.go") {
			return nil
		}
		dir := filepath.ToSlash(filepath.Dir(path))
		if !slices.Contains(found, dir) {
			found = append(found, dir)
		}
		file, err := parser.ParseFile(token.NewFileSet(), path, nil, parser.SkipObjectResolution)
		if err != nil {
			return err
		}
		for _, decl := range file.Decls {
			if fn, ok := decl.(*ast.FuncDecl); ok && fn.Recv == nil && slices.Contains(computesNot, fn.Name.Name) {
				t.Errorf("%s: %s computes what its owner alone computes (ADR 0593 §2, §7)", path, fn.Name.Name)
			}
		}
		return nil
	})
	if err != nil {
		t.Fatal(err)
	}
	slices.Sort(found)
	for _, dir := range found {
		if !slices.Contains(meshSDKPackages, dir) {
			t.Errorf("mesh-sdk holds the package %s, which it does not keep (ADR 0593 §1): it is its owner module's package", dir)
		}
	}
	for _, want := range meshSDKPackages {
		if !slices.Contains(found, want) {
			t.Errorf("mesh-sdk's list keeps %s, which is gone: take it off the list", want)
		}
	}
}