package settings

import (
	"go/ast"
	"go/parser"
	"go/token"
	"os"
	"path/filepath"
	"strings"
	"testing"
)

// R-263: "SetBackupTarget is the only writer that GRANTS StoragePath.BackupTarget" — a drive never acquires the
// whole-guest backup-target role by appearing (E-2 §3). This scans EVERY non-test Go file under controller/internal and
// cmd for a write of a field named BackupTarget — an assignment `x.BackupTarget = v` or a composite-literal key
// `BackupTarget: v` — and fails on any that is not the literal `false`, unless it sits inside SetBackupTarget.
// RED-PROOF: plant `s.StoragePaths[0].BackupTarget = true` in any other function → this test fails.
func TestR263_OnlySetBackupTargetGrantsTheRole(t *testing.T) {
	var roots []string
	for _, r := range []string{"..", "../../cmd"} { // internal/ (this package's parent) and cmd/
		if _, err := os.Stat(r); err == nil {
			roots = append(roots, r)
		}
	}
	files, writes := 0, 0
	var bad []string
	for _, root := range roots {
		_ = filepath.Walk(root, func(path string, info os.FileInfo, err error) error {
			if err != nil || info.IsDir() || !strings.HasSuffix(path, ".go") || strings.HasSuffix(path, "_test.go") {
				return nil
			}
			fset := token.NewFileSet()
			f, perr := parser.ParseFile(fset, path, nil, 0)
			if perr != nil {
				t.Fatalf("parse %s: %v", path, perr)
			}
			files++
			for _, decl := range f.Decls {
				fn, _ := decl.(*ast.FuncDecl)
				inSetter := fn != nil && fn.Name.Name == "SetBackupTarget"
				ast.Inspect(decl, func(n ast.Node) bool {
					check := func(val ast.Expr, pos token.Pos) {
						writes++
						if id, ok := val.(*ast.Ident); ok && id.Name == "false" {
							return
						}
						if !inSetter {
							bad = append(bad, fset.Position(pos).String())
						}
					}
					switch x := n.(type) {
					case *ast.AssignStmt:
						for i, lhs := range x.Lhs {
							if sel, ok := lhs.(*ast.SelectorExpr); ok && sel.Sel.Name == "BackupTarget" && i < len(x.Rhs) {
								check(x.Rhs[i], x.Pos())
							}
						}
					case *ast.KeyValueExpr:
						if k, ok := x.Key.(*ast.Ident); ok && k.Name == "BackupTarget" {
							check(x.Value, x.Pos())
						}
					}
					return true
				})
			}
			return nil
		})
	}
	if files < 100 || writes < 2 {
		t.Fatalf("scan too small to mean anything: %d files, %d BackupTarget writes (want the two in settings.go)", files, writes)
	}
	if len(bad) > 0 {
		t.Fatalf("BackupTarget may be granted outside SetBackupTarget at: %v", bad)
	}
}