// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package lsp

import (
	"context"
	"fmt"
	"go/ast"
	"go/parser"
	"go/token"
	"os"

	"golang.org/x/tools/go/packages"
	"golang.org/x/tools/internal/lsp/protocol"
	"golang.org/x/tools/internal/span"
)

func (s *Server) changeFolders(ctx context.Context, event protocol.WorkspaceFoldersChangeEvent) error {
	for _, folder := range event.Removed {
		view := s.session.View(folder.Name)
		if view != nil {
			view.Shutdown(ctx)
		} else {
			return fmt.Errorf("view %s for %v not found", folder.Name, folder.URI)
		}
	}

	for _, folder := range event.Added {
		if err := s.addView(ctx, folder.Name, span.NewURI(folder.URI)); err != nil {
			return err
		}
	}
	return nil
}

func (s *Server) addView(ctx context.Context, name string, uri span.URI) error {
	// We need a "detached" context so it does not get timeout cancelled.
	// TODO(iancottrell): Do we need to copy any values across?
	viewContext := context.Background()
	folderPath, err := uri.Filename()
	if err != nil {
		return err
	}
	s.session.NewView(name, uri, &packages.Config{
		Context: viewContext,
		Dir:     folderPath,
		Env:     os.Environ(),
		Mode:    packages.LoadImports,
		Fset:    token.NewFileSet(),
		Overlay: make(map[string][]byte),
		ParseFile: func(fset *token.FileSet, filename string, src []byte) (*ast.File, error) {
			return parser.ParseFile(fset, filename, src, parser.AllErrors|parser.ParseComments)
		},
		Tests: true,
	})

	return nil
}