// 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 tests exports functionality to be used across a variety of gopls tests.
package tests

import (
	"context"
	"flag"
	"go/ast"
	"go/token"
	"io/ioutil"
	"path/filepath"
	"sort"
	"strings"
	"sync"
	"testing"

	"golang.org/x/tools/go/expect"
	"golang.org/x/tools/go/packages"
	"golang.org/x/tools/go/packages/packagestest"
	"golang.org/x/tools/internal/lsp/protocol"
	"golang.org/x/tools/internal/lsp/source"
	"golang.org/x/tools/internal/span"
	"golang.org/x/tools/internal/txtar"
)

// We hardcode the expected number of test cases to ensure that all tests
// are being executed. If a test is added, this number must be changed.
const (
	ExpectedCompletionsCount           = 152
	ExpectedCompletionSnippetCount     = 35
	ExpectedUnimportedCompletionsCount = 1
	ExpectedDeepCompletionsCount       = 5
	ExpectedFuzzyCompletionsCount      = 6
	ExpectedRankedCompletionsCount     = 1
	ExpectedDiagnosticsCount           = 21
	ExpectedFormatCount                = 6
	ExpectedImportCount                = 2
	ExpectedSuggestedFixCount          = 1
	ExpectedDefinitionsCount           = 39
	ExpectedTypeDefinitionsCount       = 2
	ExpectedFoldingRangesCount         = 2
	ExpectedHighlightsCount            = 2
	ExpectedReferencesCount            = 6
	ExpectedRenamesCount               = 20
	ExpectedPrepareRenamesCount        = 8
	ExpectedSymbolsCount               = 1
	ExpectedSignaturesCount            = 21
	ExpectedLinksCount                 = 4
)

const (
	overlayFileSuffix = ".overlay"
	goldenFileSuffix  = ".golden"
	inFileSuffix      = ".in"
	testModule        = "golang.org/x/tools/internal/lsp"
)

var updateGolden = flag.Bool("golden", false, "Update golden files")

type Diagnostics map[span.URI][]source.Diagnostic
type CompletionItems map[token.Pos]*source.CompletionItem
type Completions map[span.Span]Completion
type CompletionSnippets map[span.Span]CompletionSnippet
type UnimportedCompletions map[span.Span]Completion
type DeepCompletions map[span.Span]Completion
type FuzzyCompletions map[span.Span]Completion
type RankCompletions map[span.Span]Completion
type FoldingRanges []span.Span
type Formats []span.Span
type Imports []span.Span
type SuggestedFixes []span.Span
type Definitions map[span.Span]Definition
type Highlights map[string][]span.Span
type References map[span.Span][]span.Span
type Renames map[span.Span]string
type PrepareRenames map[span.Span]*source.PrepareItem
type Symbols map[span.URI][]protocol.DocumentSymbol
type SymbolsChildren map[string][]protocol.DocumentSymbol
type Signatures map[span.Span]*source.SignatureInformation
type Links map[span.URI][]Link

type Data struct {
	Config                packages.Config
	Exported              *packagestest.Exported
	Diagnostics           Diagnostics
	CompletionItems       CompletionItems
	Completions           Completions
	CompletionSnippets    CompletionSnippets
	UnimportedCompletions UnimportedCompletions
	DeepCompletions       DeepCompletions
	FuzzyCompletions      FuzzyCompletions
	RankCompletions       RankCompletions
	FoldingRanges         FoldingRanges
	Formats               Formats
	Imports               Imports
	SuggestedFixes        SuggestedFixes
	Definitions           Definitions
	Highlights            Highlights
	References            References
	Renames               Renames
	PrepareRenames        PrepareRenames
	Symbols               Symbols
	symbolsChildren       SymbolsChildren
	Signatures            Signatures
	Links                 Links

	t         testing.TB
	fragments map[string]string
	dir       string
	golden    map[string]*Golden

	mappersMu sync.Mutex
	mappers   map[span.URI]*protocol.ColumnMapper
}

type Tests interface {
	Diagnostics(*testing.T, Diagnostics)
	Completion(*testing.T, Completions, CompletionItems)
	CompletionSnippets(*testing.T, CompletionSnippets, CompletionItems)
	UnimportedCompletions(*testing.T, UnimportedCompletions, CompletionItems)
	DeepCompletions(*testing.T, DeepCompletions, CompletionItems)
	FuzzyCompletions(*testing.T, FuzzyCompletions, CompletionItems)
	RankCompletions(*testing.T, RankCompletions, CompletionItems)
	FoldingRange(*testing.T, FoldingRanges)
	Format(*testing.T, Formats)
	Import(*testing.T, Imports)
	SuggestedFix(*testing.T, SuggestedFixes)
	Definition(*testing.T, Definitions)
	Highlight(*testing.T, Highlights)
	Reference(*testing.T, References)
	Rename(*testing.T, Renames)
	PrepareRename(*testing.T, PrepareRenames)
	Symbol(*testing.T, Symbols)
	SignatureHelp(*testing.T, Signatures)
	Link(*testing.T, Links)
}

type Definition struct {
	Name      string
	IsType    bool
	OnlyHover bool
	Src, Def  span.Span
}

type CompletionTestType int

const (
	// Default runs the standard completion tests.
	CompletionDefault = CompletionTestType(iota)

	// Unimported tests the autocompletion of unimported packages.
	CompletionUnimported

	// Deep tests deep completion.
	CompletionDeep

	// Fuzzy tests deep completion and fuzzy matching.
	CompletionFuzzy

	// CompletionRank candidates in test must be valid and in the right relative order.
	CompletionRank
)

type Completion struct {
	CompletionItems []token.Pos
}

type CompletionSnippet struct {
	CompletionItem     token.Pos
	PlainSnippet       string
	PlaceholderSnippet string
}

type Link struct {
	Src          span.Span
	Target       string
	NotePosition token.Position
}

type Golden struct {
	Filename string
	Archive  *txtar.Archive
	Modified bool
}

func Context(t testing.TB) context.Context {
	return context.Background()
}

func DefaultOptions() source.Options {
	o := source.DefaultOptions
	o.SupportedCodeActions = map[source.FileKind]map[protocol.CodeActionKind]bool{
		source.Go: {
			protocol.SourceOrganizeImports: true,
			protocol.QuickFix:              true,
		},
		source.Mod: {},
		source.Sum: {},
	}
	o.HoverKind = source.SynopsisDocumentation
	o.InsertTextFormat = protocol.SnippetTextFormat
	return o
}

func Load(t testing.TB, exporter packagestest.Exporter, dir string) *Data {
	t.Helper()

	data := &Data{
		Diagnostics:           make(Diagnostics),
		CompletionItems:       make(CompletionItems),
		Completions:           make(Completions),
		CompletionSnippets:    make(CompletionSnippets),
		UnimportedCompletions: make(UnimportedCompletions),
		DeepCompletions:       make(DeepCompletions),
		FuzzyCompletions:      make(FuzzyCompletions),
		RankCompletions:       make(RankCompletions),
		Definitions:           make(Definitions),
		Highlights:            make(Highlights),
		References:            make(References),
		Renames:               make(Renames),
		PrepareRenames:        make(PrepareRenames),
		Symbols:               make(Symbols),
		symbolsChildren:       make(SymbolsChildren),
		Signatures:            make(Signatures),
		Links:                 make(Links),

		t:         t,
		dir:       dir,
		fragments: map[string]string{},
		golden:    map[string]*Golden{},
		mappers:   map[span.URI]*protocol.ColumnMapper{},
	}

	files := packagestest.MustCopyFileTree(dir)
	overlays := map[string][]byte{}
	for fragment, operation := range files {
		if trimmed := strings.TrimSuffix(fragment, goldenFileSuffix); trimmed != fragment {
			delete(files, fragment)
			goldFile := filepath.Join(dir, fragment)
			archive, err := txtar.ParseFile(goldFile)
			if err != nil {
				t.Fatalf("could not read golden file %v: %v", fragment, err)
			}
			data.golden[trimmed] = &Golden{
				Filename: goldFile,
				Archive:  archive,
			}
		} else if trimmed := strings.TrimSuffix(fragment, inFileSuffix); trimmed != fragment {
			delete(files, fragment)
			files[trimmed] = operation
		} else if index := strings.Index(fragment, overlayFileSuffix); index >= 0 {
			delete(files, fragment)
			partial := fragment[:index] + fragment[index+len(overlayFileSuffix):]
			contents, err := ioutil.ReadFile(filepath.Join(dir, fragment))
			if err != nil {
				t.Fatal(err)
			}
			overlays[partial] = contents
		}
	}
	modules := []packagestest.Module{
		{
			Name:    testModule,
			Files:   files,
			Overlay: overlays,
		},
	}
	data.Exported = packagestest.Export(t, exporter, modules)
	for fragment := range files {
		filename := data.Exported.File(testModule, fragment)
		data.fragments[filename] = fragment
	}
	data.Exported.Config.Logf = nil

	// Merge the exported.Config with the view.Config.
	data.Config = *data.Exported.Config
	data.Config.Fset = token.NewFileSet()
	data.Config.Logf = nil
	data.Config.Context = Context(nil)
	data.Config.ParseFile = func(fset *token.FileSet, filename string, src []byte) (*ast.File, error) {
		panic("ParseFile should not be called")
	}

	// Do a first pass to collect special markers for completion.
	if err := data.Exported.Expect(map[string]interface{}{
		"item": func(name string, r packagestest.Range, _ []string) {
			data.Exported.Mark(name, r)
		},
	}); err != nil {
		t.Fatal(err)
	}

	// Collect any data that needs to be used by subsequent tests.
	if err := data.Exported.Expect(map[string]interface{}{
		"diag":         data.collectDiagnostics,
		"item":         data.collectCompletionItems,
		"complete":     data.collectCompletions(CompletionDefault),
		"unimported":   data.collectCompletions(CompletionUnimported),
		"deep":         data.collectCompletions(CompletionDeep),
		"fuzzy":        data.collectCompletions(CompletionFuzzy),
		"rank":         data.collectCompletions(CompletionRank),
		"snippet":      data.collectCompletionSnippets,
		"fold":         data.collectFoldingRanges,
		"format":       data.collectFormats,
		"import":       data.collectImports,
		"godef":        data.collectDefinitions,
		"typdef":       data.collectTypeDefinitions,
		"hover":        data.collectHoverDefinitions,
		"highlight":    data.collectHighlights,
		"refs":         data.collectReferences,
		"rename":       data.collectRenames,
		"prepare":      data.collectPrepareRenames,
		"symbol":       data.collectSymbols,
		"signature":    data.collectSignatures,
		"link":         data.collectLinks,
		"suggestedfix": data.collectSuggestedFixes,
	}); err != nil {
		t.Fatal(err)
	}
	for _, symbols := range data.Symbols {
		for i := range symbols {
			children := data.symbolsChildren[symbols[i].Name]
			symbols[i].Children = children
		}
	}
	// Collect names for the entries that require golden files.
	if err := data.Exported.Expect(map[string]interface{}{
		"godef": data.collectDefinitionNames,
		"hover": data.collectDefinitionNames,
	}); err != nil {
		t.Fatal(err)
	}
	return data
}

func Run(t *testing.T, tests Tests, data *Data) {
	t.Helper()

	t.Run("Completion", func(t *testing.T) {
		t.Helper()
		if len(data.Completions) != ExpectedCompletionsCount {
			t.Errorf("got %v completions expected %v", len(data.Completions), ExpectedCompletionsCount)
		}
		tests.Completion(t, data.Completions, data.CompletionItems)
	})

	t.Run("CompletionSnippets", func(t *testing.T) {
		t.Helper()
		if len(data.CompletionSnippets) != ExpectedCompletionSnippetCount {
			t.Errorf("got %v snippets expected %v", len(data.CompletionSnippets), ExpectedCompletionSnippetCount)
		}
		if len(data.CompletionSnippets) != ExpectedCompletionSnippetCount {
			t.Errorf("got %v snippets expected %v", len(data.CompletionSnippets), ExpectedCompletionSnippetCount)
		}
		tests.CompletionSnippets(t, data.CompletionSnippets, data.CompletionItems)
	})

	t.Run("UnimportedCompletion", func(t *testing.T) {
		t.Helper()
		if len(data.UnimportedCompletions) != ExpectedUnimportedCompletionsCount {
			t.Errorf("got %v unimported completions expected %v", len(data.UnimportedCompletions), ExpectedUnimportedCompletionsCount)
		}
		tests.UnimportedCompletions(t, data.UnimportedCompletions, data.CompletionItems)
	})

	t.Run("DeepCompletion", func(t *testing.T) {
		t.Helper()
		if len(data.DeepCompletions) != ExpectedDeepCompletionsCount {
			t.Errorf("got %v deep completions expected %v", len(data.DeepCompletions), ExpectedDeepCompletionsCount)
		}
		tests.DeepCompletions(t, data.DeepCompletions, data.CompletionItems)
	})

	t.Run("FuzzyCompletion", func(t *testing.T) {
		t.Helper()
		if len(data.FuzzyCompletions) != ExpectedFuzzyCompletionsCount {
			t.Errorf("got %v fuzzy completions expected %v", len(data.FuzzyCompletions), ExpectedFuzzyCompletionsCount)
		}
		tests.FuzzyCompletions(t, data.FuzzyCompletions, data.CompletionItems)
	})

	t.Run("RankCompletions", func(t *testing.T) {
		t.Helper()
		if len(data.RankCompletions) != ExpectedRankedCompletionsCount {
			t.Errorf("got %v fuzzy completions expected %v", len(data.RankCompletions), ExpectedRankedCompletionsCount)
		}
		tests.RankCompletions(t, data.RankCompletions, data.CompletionItems)
	})

	t.Run("Diagnostics", func(t *testing.T) {
		t.Helper()
		diagnosticsCount := 0
		for _, want := range data.Diagnostics {
			diagnosticsCount += len(want)
		}
		if diagnosticsCount != ExpectedDiagnosticsCount {
			t.Errorf("got %v diagnostics expected %v", diagnosticsCount, ExpectedDiagnosticsCount)
		}
		tests.Diagnostics(t, data.Diagnostics)
	})

	t.Run("FoldingRange", func(t *testing.T) {
		t.Helper()
		if len(data.FoldingRanges) != ExpectedFoldingRangesCount {
			t.Errorf("got %v folding ranges expected %v", len(data.FoldingRanges), ExpectedFoldingRangesCount)
		}
		tests.FoldingRange(t, data.FoldingRanges)
	})

	t.Run("Format", func(t *testing.T) {
		t.Helper()
		if len(data.Formats) != ExpectedFormatCount {
			t.Errorf("got %v formats expected %v", len(data.Formats), ExpectedFormatCount)
		}
		tests.Format(t, data.Formats)
	})

	t.Run("Import", func(t *testing.T) {
		t.Helper()
		if len(data.Imports) != ExpectedImportCount {
			t.Errorf("got %v imports expected %v", len(data.Imports), ExpectedImportCount)
		}
		tests.Import(t, data.Imports)
	})

	t.Run("SuggestedFix", func(t *testing.T) {
		t.Helper()
		if len(data.SuggestedFixes) != ExpectedSuggestedFixCount {
			t.Errorf("got %v suggested fixes expected %v", len(data.SuggestedFixes), ExpectedSuggestedFixCount)
		}
		tests.SuggestedFix(t, data.SuggestedFixes)
	})

	t.Run("Definition", func(t *testing.T) {
		t.Helper()
		if len(data.Definitions) != ExpectedDefinitionsCount {
			t.Errorf("got %v definitions expected %v", len(data.Definitions), ExpectedDefinitionsCount)
		}
		tests.Definition(t, data.Definitions)
	})

	t.Run("Highlight", func(t *testing.T) {
		t.Helper()
		if len(data.Highlights) != ExpectedHighlightsCount {
			t.Errorf("got %v highlights expected %v", len(data.Highlights), ExpectedHighlightsCount)
		}
		tests.Highlight(t, data.Highlights)
	})

	t.Run("References", func(t *testing.T) {
		t.Helper()
		if len(data.References) != ExpectedReferencesCount {
			t.Errorf("got %v references expected %v", len(data.References), ExpectedReferencesCount)
		}
		tests.Reference(t, data.References)
	})

	t.Run("Renames", func(t *testing.T) {
		t.Helper()
		if len(data.Renames) != ExpectedRenamesCount {
			t.Errorf("got %v renames expected %v", len(data.Renames), ExpectedRenamesCount)
		}
		tests.Rename(t, data.Renames)
	})

	t.Run("PrepareRenames", func(t *testing.T) {
		t.Helper()
		if len(data.PrepareRenames) != ExpectedPrepareRenamesCount {
			t.Errorf("got %v prepare renames expected %v", len(data.PrepareRenames), ExpectedPrepareRenamesCount)
		}

		tests.PrepareRename(t, data.PrepareRenames)
	})

	t.Run("Symbols", func(t *testing.T) {
		t.Helper()
		if len(data.Symbols) != ExpectedSymbolsCount {
			t.Errorf("got %v symbols expected %v", len(data.Symbols), ExpectedSymbolsCount)
		}
		tests.Symbol(t, data.Symbols)
	})

	t.Run("SignatureHelp", func(t *testing.T) {
		t.Helper()
		if len(data.Signatures) != ExpectedSignaturesCount {
			t.Errorf("got %v signatures expected %v", len(data.Signatures), ExpectedSignaturesCount)
		}
		tests.SignatureHelp(t, data.Signatures)
	})

	t.Run("Link", func(t *testing.T) {
		t.Helper()
		linksCount := 0
		for _, want := range data.Links {
			linksCount += len(want)
		}
		if linksCount != ExpectedLinksCount {
			t.Errorf("got %v links expected %v", linksCount, ExpectedLinksCount)
		}
		tests.Link(t, data.Links)
	})

	if *updateGolden {
		for _, golden := range data.golden {
			if !golden.Modified {
				continue
			}
			sort.Slice(golden.Archive.Files, func(i, j int) bool {
				return golden.Archive.Files[i].Name < golden.Archive.Files[j].Name
			})
			if err := ioutil.WriteFile(golden.Filename, txtar.Format(golden.Archive), 0666); err != nil {
				t.Fatal(err)
			}
		}
	}
}

func (data *Data) Mapper(uri span.URI) (*protocol.ColumnMapper, error) {
	data.mappersMu.Lock()
	defer data.mappersMu.Unlock()

	if _, ok := data.mappers[uri]; !ok {
		content, err := data.Exported.FileContents(uri.Filename())
		if err != nil {
			return nil, err
		}
		converter := span.NewContentConverter(uri.Filename(), content)
		data.mappers[uri] = &protocol.ColumnMapper{
			URI:       uri,
			Converter: converter,
			Content:   content,
		}
	}
	return data.mappers[uri], nil
}

func (data *Data) Golden(tag string, target string, update func() ([]byte, error)) []byte {
	data.t.Helper()
	fragment, found := data.fragments[target]
	if !found {
		if filepath.IsAbs(target) {
			data.t.Fatalf("invalid golden file fragment %v", target)
		}
		fragment = target
	}
	golden := data.golden[fragment]
	if golden == nil {
		if !*updateGolden {
			data.t.Fatalf("could not find golden file %v: %v", fragment, tag)
		}
		golden = &Golden{
			Filename: filepath.Join(data.dir, fragment+goldenFileSuffix),
			Archive:  &txtar.Archive{},
			Modified: true,
		}
		data.golden[fragment] = golden
	}
	var file *txtar.File
	for i := range golden.Archive.Files {
		f := &golden.Archive.Files[i]
		if f.Name == tag {
			file = f
			break
		}
	}
	if *updateGolden {
		if file == nil {
			golden.Archive.Files = append(golden.Archive.Files, txtar.File{
				Name: tag,
			})
			file = &golden.Archive.Files[len(golden.Archive.Files)-1]
		}
		contents, err := update()
		if err != nil {
			data.t.Fatalf("could not update golden file %v: %v", fragment, err)
		}
		file.Data = append(contents, '\n') // add trailing \n for txtar
		golden.Modified = true
	}
	if file == nil {
		data.t.Fatalf("could not find golden contents %v: %v", fragment, tag)
	}
	return file.Data[:len(file.Data)-1] // drop the trailing \n
}

func (data *Data) collectDiagnostics(spn span.Span, msgSource, msg string) {
	if _, ok := data.Diagnostics[spn.URI()]; !ok {
		data.Diagnostics[spn.URI()] = []source.Diagnostic{}
	}
	severity := source.SeverityError
	if strings.Contains(string(spn.URI()), "analyzer") {
		severity = source.SeverityWarning
	}
	// This is not the correct way to do this,
	// but it seems excessive to do the full conversion here.
	want := source.Diagnostic{
		URI: spn.URI(),
		Range: protocol.Range{
			Start: protocol.Position{
				Line:      float64(spn.Start().Line()) - 1,
				Character: float64(spn.Start().Column()) - 1,
			},
			End: protocol.Position{
				Line:      float64(spn.End().Line()) - 1,
				Character: float64(spn.End().Column()) - 1,
			},
		},
		Severity: severity,
		Source:   msgSource,
		Message:  msg,
	}
	data.Diagnostics[spn.URI()] = append(data.Diagnostics[spn.URI()], want)
}

func (data *Data) collectCompletions(typ CompletionTestType) func(span.Span, []token.Pos) {
	result := func(m map[span.Span]Completion, src span.Span, expected []token.Pos) {
		m[src] = Completion{
			CompletionItems: expected,
		}
	}
	switch typ {
	case CompletionDeep:
		return func(src span.Span, expected []token.Pos) {
			result(data.DeepCompletions, src, expected)
		}
	case CompletionUnimported:
		return func(src span.Span, expected []token.Pos) {
			result(data.UnimportedCompletions, src, expected)
		}
	case CompletionFuzzy:
		return func(src span.Span, expected []token.Pos) {
			result(data.FuzzyCompletions, src, expected)
		}
	case CompletionRank:
		return func(src span.Span, expected []token.Pos) {
			result(data.RankCompletions, src, expected)
		}
	default:
		return func(src span.Span, expected []token.Pos) {
			result(data.Completions, src, expected)
		}
	}
}

func (data *Data) collectCompletionItems(pos token.Pos, args []string) {
	if len(args) < 3 {
		return
	}
	label, detail, kind := args[0], args[1], args[2]
	var documentation string
	if len(args) == 4 {
		documentation = args[3]
	}
	data.CompletionItems[pos] = &source.CompletionItem{
		Label:         label,
		Detail:        detail,
		Kind:          source.ParseCompletionItemKind(kind),
		Documentation: documentation,
	}
}

func (data *Data) collectFoldingRanges(spn span.Span) {
	data.FoldingRanges = append(data.FoldingRanges, spn)
}

func (data *Data) collectFormats(spn span.Span) {
	data.Formats = append(data.Formats, spn)
}

func (data *Data) collectImports(spn span.Span) {
	data.Imports = append(data.Imports, spn)
}

func (data *Data) collectSuggestedFixes(spn span.Span) {
	data.SuggestedFixes = append(data.SuggestedFixes, spn)
}

func (data *Data) collectDefinitions(src, target span.Span) {
	data.Definitions[src] = Definition{
		Src: src,
		Def: target,
	}
}

func (data *Data) collectHoverDefinitions(src, target span.Span) {
	data.Definitions[src] = Definition{
		Src:       src,
		Def:       target,
		OnlyHover: true,
	}
}

func (data *Data) collectTypeDefinitions(src, target span.Span) {
	data.Definitions[src] = Definition{
		Src:    src,
		Def:    target,
		IsType: true,
	}
}

func (data *Data) collectDefinitionNames(src span.Span, name string) {
	d := data.Definitions[src]
	d.Name = name
	data.Definitions[src] = d
}

func (data *Data) collectHighlights(name string, rng span.Span) {
	data.Highlights[name] = append(data.Highlights[name], rng)
}

func (data *Data) collectReferences(src span.Span, expected []span.Span) {
	data.References[src] = expected
}

func (data *Data) collectRenames(src span.Span, newText string) {
	data.Renames[src] = newText
}

func (data *Data) collectPrepareRenames(src span.Span, rng span.Range, placeholder string) {
	if int(rng.End-rng.Start) != len(placeholder) {
		// If the length of the placeholder and the length of the range do not match,
		// make the range just be the start.
		rng = span.NewRange(rng.FileSet, rng.Start, rng.Start)
	}
	m, err := data.Mapper(src.URI())
	if err != nil {
		data.t.Fatal(err)
	}
	// Convert range to span and then to protocol.Range.
	spn, err := rng.Span()
	if err != nil {
		data.t.Fatal(err)
	}
	prng, err := m.Range(spn)
	if err != nil {
		data.t.Fatal(err)
	}
	data.PrepareRenames[src] = &source.PrepareItem{
		Range: prng,
		Text:  placeholder,
	}
}

func (data *Data) collectSymbols(name string, spn span.Span, kind string, parentName string) {
	m, err := data.Mapper(spn.URI())
	if err != nil {
		data.t.Fatal(err)
	}
	rng, err := m.Range(spn)
	if err != nil {
		data.t.Fatal(err)
	}
	sym := protocol.DocumentSymbol{
		Name:           name,
		Kind:           protocol.ParseSymbolKind(kind),
		SelectionRange: rng,
	}
	if parentName == "" {
		data.Symbols[spn.URI()] = append(data.Symbols[spn.URI()], sym)
	} else {
		data.symbolsChildren[parentName] = append(data.symbolsChildren[parentName], sym)
	}
}

func (data *Data) collectSignatures(spn span.Span, signature string, activeParam int64) {
	data.Signatures[spn] = &source.SignatureInformation{
		Label:           signature,
		ActiveParameter: int(activeParam),
	}
	// Hardcode special case to test the lack of a signature.
	if signature == "" && activeParam == 0 {
		data.Signatures[spn] = nil
	}
}

func (data *Data) collectCompletionSnippets(spn span.Span, item token.Pos, plain, placeholder string) {
	data.CompletionSnippets[spn] = CompletionSnippet{
		CompletionItem:     item,
		PlainSnippet:       plain,
		PlaceholderSnippet: placeholder,
	}
}

func (data *Data) collectLinks(spn span.Span, link string, note *expect.Note, fset *token.FileSet) {
	position := fset.Position(note.Pos)
	uri := spn.URI()
	data.Links[uri] = append(data.Links[uri], Link{
		Src:          spn,
		Target:       link,
		NotePosition: position,
	})
}