From fe1aefc25fcd4d6460ff7ca5b9b3de8900f7801b Mon Sep 17 00:00:00 2001
From: Hariom Verma <hariom18599@gmail.com>
Date: Mon, 25 Mar 2024 22:57:42 +0530
Subject: [PATCH] logic for typechecking

---
 internal/lsp/check.go | 143 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 143 insertions(+)
 create mode 100644 internal/lsp/check.go

diff --git a/internal/lsp/check.go b/internal/lsp/check.go
new file mode 100644
index 0000000..60a0d89
--- /dev/null
+++ b/internal/lsp/check.go
@@ -0,0 +1,143 @@
+package lsp
+
+import (
+	"fmt"
+	"go/ast"
+	"go/parser"
+	"go/token"
+	"go/types"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/gnolang/gno/gnovm/pkg/gnomod"
+	"go.uber.org/multierr"
+)
+
+type FileInfo struct {
+	Name string
+	Body string
+}
+
+type PackageInfo struct {
+	Dir, ImportPath string
+	Files           []*FileInfo
+}
+
+type PackageGetter interface {
+	GetPackageInfo(path string) *PackageInfo
+}
+
+func GetPackageInfo(path string) (*PackageInfo, error) {
+	// TODO: fix
+	if strings.HasPrefix(path, "/") {
+		// No op
+	} else if strings.HasPrefix(path, "gno.land/") {
+		path = "/Users/harry/Desktop/work/gno/examples/" + path
+	} else {
+		path = "/Users/harry/Desktop/work/gno/gnovm/stdlibs/" + path
+	}
+	return getPackageInfo(path)
+}
+
+func getPackageInfo(path string) (*PackageInfo, error) {
+	filenames, err := ListGnoFiles(path)
+	if err != nil {
+		return nil, err
+	}
+	var importpath string
+	gm, gmErr := gnomod.ParseAt(path)
+	if gmErr != nil {
+		importpath = "" // TODO
+	} else {
+		importpath = gm.Module.Mod.Path
+	}
+	files := []*FileInfo{}
+	for _, fname := range filenames {
+		if strings.HasSuffix(fname, "_test.gno") ||
+			strings.HasSuffix(fname, "_filetest.gno") {
+			continue
+		}
+		absPath, err := filepath.Abs(fname)
+		if err != nil {
+			return nil, err
+		}
+		bsrc, err := os.ReadFile(absPath)
+		if err != nil {
+			return nil, err
+		}
+		text := string(bsrc)
+		files = append(files, &FileInfo{Name: filepath.Base(fname), Body: text})
+	}
+	return &PackageInfo{
+		ImportPath: importpath,
+		Dir:        path,
+		Files:      files,
+	}, nil
+}
+
+type TypeCheckResult struct {
+	pkg   *types.Package
+	fset  *token.FileSet
+	files []*ast.File
+	info  *types.Info
+	err   error
+}
+
+type TypeCheck struct {
+	cache map[string]*TypeCheckResult
+	cfg   *types.Config
+}
+
+// Unused, but satisfies the Importer interface.
+func (tc *TypeCheck) Import(path string) (*types.Package, error) {
+	return tc.ImportFrom(path, "", 0)
+}
+
+// ImportFrom returns the imported package for the given import
+// path when imported by a package file located in dir.
+func (tc *TypeCheck) ImportFrom(path, _ string, _ types.ImportMode) (*types.Package, error) {
+	if pkg, ok := tc.cache[path]; ok {
+		return pkg.pkg, pkg.err
+	}
+	pkg, err := GetPackageInfo(path)
+	if err != nil {
+		err := fmt.Errorf("package %q not found", path)
+		tc.cache[path] = &TypeCheckResult{err: err}
+		return nil, err
+	}
+	res := pkg.TypeCheck(tc)
+	tc.cache[path] = res
+	return res.pkg, res.err
+}
+
+func (pi *PackageInfo) TypeCheck(tc *TypeCheck) *TypeCheckResult {
+	fset := token.NewFileSet()
+	info := &types.Info{
+		Types: make(map[ast.Expr]types.TypeAndValue),
+		Defs:  make(map[*ast.Ident]types.Object),
+		Uses:  make(map[*ast.Ident]types.Object),
+	}
+	files := make([]*ast.File, 0, len(pi.Files))
+	var errs error
+	for _, f := range pi.Files {
+		if !strings.HasSuffix(f.Name, ".gno") ||
+			strings.HasSuffix(f.Name, "_filetest.gno") ||
+			strings.HasSuffix(f.Name, "_test.gno") {
+			continue
+		}
+
+		pgf, err := parser.ParseFile(fset, f.Name, f.Body, parser.ParseComments|parser.DeclarationErrors|parser.SkipObjectResolution)
+		if err != nil {
+			errs = multierr.Append(errs, err)
+			continue
+		}
+
+		files = append(files, pgf)
+	}
+	pkg, err := tc.cfg.Check(pi.ImportPath, fset, files, info)
+	if err != nil {
+		return &TypeCheckResult{err: err}
+	}
+	return &TypeCheckResult{pkg: pkg, fset: fset, files: files, info: info, err: nil}
+}