package harnessutil

import (
	"context"
	"fmt"
	"io"
	"io/fs"
	"maps"
	"os"
	"path/filepath"
	"regexp"
	"slices"
	"strconv"
	"strings"
	"sync"
	"testing"
	"testing/fstest"

	"github.com/microsoft/typescript-go/internal/ast"
	"github.com/microsoft/typescript-go/internal/bundled"
	"github.com/microsoft/typescript-go/internal/collections"
	"github.com/microsoft/typescript-go/internal/compiler"
	"github.com/microsoft/typescript-go/internal/core"
	"github.com/microsoft/typescript-go/internal/diagnostics"
	"github.com/microsoft/typescript-go/internal/execute/incremental"
	"github.com/microsoft/typescript-go/internal/locale"
	"github.com/microsoft/typescript-go/internal/outputpaths"
	"github.com/microsoft/typescript-go/internal/parser"
	"github.com/microsoft/typescript-go/internal/repo"
	"github.com/microsoft/typescript-go/internal/sourcemap"
	"github.com/microsoft/typescript-go/internal/testutil"
	"github.com/microsoft/typescript-go/internal/tsoptions"
	"github.com/microsoft/typescript-go/internal/tspath"
	"github.com/microsoft/typescript-go/internal/vfs"
	"github.com/microsoft/typescript-go/internal/vfs/vfstest"
)

// Posix-style path to additional test libraries
const testLibFolder = "/.lib"

const FakeTSVersion = "FakeTSVersion"

type TestFile struct {
	UnitName string
	Content  string
}

// This maps a compiler setting to its string value, after splitting by commas,
// handling inclusions and exclusions, and deduplicating.
// For example, if a test file contains:
//
//	// @target: esnext, es2015
//
// Then the map will map "target" to "esnext", and another map will map "target" to "es2015".
type TestConfiguration = map[string]string

type NamedTestConfiguration struct {
	Name   string
	Config TestConfiguration
}

type HarnessOptions struct {
	UseCaseSensitiveFileNames bool
	BaselineFile              string
	IncludeBuiltFile          string
	FileName                  string
	LibFiles                  []string
	NoImplicitReferences      bool
	CurrentDirectory          string
	Symlink                   string
	Link                      string
	NoTypesAndSymbols         bool
	FullEmitPaths             bool
	ReportDiagnostics         bool
	CaptureSuggestions        bool
	TypescriptVersion         string
}

func CompileFiles(
	t *testing.T,
	inputFiles []*TestFile,
	otherFiles []*TestFile,
	testConfig TestConfiguration,
	tsconfig *tsoptions.ParsedCommandLine,
	currentDirectory string,
	symlinks map[string]string,
) *CompilationResult {
	var compilerOptions *core.CompilerOptions
	if tsconfig != nil {
		compilerOptions = tsconfig.ParsedConfig.CompilerOptions.Clone()
	}
	if compilerOptions == nil {
		compilerOptions = &core.CompilerOptions{}
	}
	// Set default options for tests
	if compilerOptions.NewLine == core.NewLineKindNone {
		compilerOptions.NewLine = core.NewLineKindCRLF
	}
	if compilerOptions.SkipDefaultLibCheck == core.TSUnknown {
		compilerOptions.SkipDefaultLibCheck = core.TSTrue
	}
	compilerOptions.NoErrorTruncation = core.TSTrue
	harnessOptions := HarnessOptions{UseCaseSensitiveFileNames: true, CurrentDirectory: currentDirectory}

	// Parse harness and compiler options from the test configuration
	if testConfig != nil {
		setOptionsFromTestConfig(t, testConfig, compilerOptions, &harnessOptions, currentDirectory)
	}

	return CompileFilesEx(t, inputFiles, otherFiles, &harnessOptions, compilerOptions, currentDirectory, symlinks, tsconfig)
}

func CompileFilesEx(
	t *testing.T,
	inputFiles []*TestFile,
	otherFiles []*TestFile,
	harnessOptions *HarnessOptions,
	compilerOptions *core.CompilerOptions,
	currentDirectory string,
	symlinks map[string]string,
	tsconfig *tsoptions.ParsedCommandLine,
) *CompilationResult {
	var programFileNames []string
	for _, file := range inputFiles {
		fileName := tspath.GetNormalizedAbsolutePath(file.UnitName, currentDirectory)

		if !tspath.FileExtensionIs(fileName, tspath.ExtensionJson) {
			programFileNames = append(programFileNames, fileName)
		}
	}

	// !!! Note: lib files are not going to be in `built/local`.
	// In addition, not all files that used to be in `built/local` are going to exist.
	// Files from built\local that are requested by test "@includeBuiltFiles" to be in the context.
	// Treat them as library files, so include them in build, but not in baselines.
	// if harnessOptions.includeBuiltFile != "" {
	// 	programFileNames = append(programFileNames, tspath.CombinePaths(builtFolder, harnessOptions.includeBuiltFile))
	// }

	// Performance optimization; avoid copying in the /.lib folder if the test doesn't need it.
	includeLibDir := core.Some(inputFiles, func(file *TestFile) bool { return strings.Contains(file.Content, testLibFolder+"/") })

	// Files from testdata\lib that are requested by "@libFiles"
	if len(harnessOptions.LibFiles) > 0 {
		for _, libFile := range harnessOptions.LibFiles {
			if libFile == "lib.d.ts" && compilerOptions.NoLib != core.TSTrue {
				// We used to override lib with a custom lib.d.ts for some reason. Skip this unless it becomes necessary.
				continue
			}
			programFileNames = append(programFileNames, tspath.CombinePaths(testLibFolder, libFile))
			includeLibDir = true
		}
	}

	if includeLibDir {
		repo.SkipIfNoTypeScriptSubmodule(t)
	}

	// !!!
	// ts.assign(options, ts.convertToOptionsWithAbsolutePaths(options, path => ts.getNormalizedAbsolutePath(path, currentDirectory)));
	if compilerOptions.OutDir != "" {
		compilerOptions.OutDir = tspath.GetNormalizedAbsolutePath(compilerOptions.OutDir, currentDirectory)
	}
	if compilerOptions.Project != "" {
		compilerOptions.Project = tspath.GetNormalizedAbsolutePath(compilerOptions.Project, currentDirectory)
	}
	if compilerOptions.RootDir != "" {
		compilerOptions.RootDir = tspath.GetNormalizedAbsolutePath(compilerOptions.RootDir, currentDirectory)
	}
	if compilerOptions.TsBuildInfoFile != "" {
		compilerOptions.TsBuildInfoFile = tspath.GetNormalizedAbsolutePath(compilerOptions.TsBuildInfoFile, currentDirectory)
	}
	if compilerOptions.BaseUrl != "" {
		compilerOptions.BaseUrl = tspath.GetNormalizedAbsolutePath(compilerOptions.BaseUrl, currentDirectory)
	}
	if compilerOptions.DeclarationDir != "" {
		compilerOptions.DeclarationDir = tspath.GetNormalizedAbsolutePath(compilerOptions.DeclarationDir, currentDirectory)
	}
	for i, rootDir := range compilerOptions.RootDirs {
		compilerOptions.RootDirs[i] = tspath.GetNormalizedAbsolutePath(rootDir, currentDirectory)
	}
	for i, typeRoot := range compilerOptions.TypeRoots {
		compilerOptions.TypeRoots[i] = tspath.GetNormalizedAbsolutePath(typeRoot, currentDirectory)
	}

	// Create fake FS for testing
	testfs := map[string]any{}
	for _, file := range inputFiles {
		fileName := tspath.GetNormalizedAbsolutePath(file.UnitName, currentDirectory)
		testfs[fileName] = &fstest.MapFile{
			Data: []byte(file.Content),
		}
	}
	for _, file := range otherFiles {
		fileName := tspath.GetNormalizedAbsolutePath(file.UnitName, currentDirectory)
		testfs[fileName] = &fstest.MapFile{
			Data: []byte(file.Content),
		}
	}
	for src, target := range symlinks {
		srcFileName := tspath.GetNormalizedAbsolutePath(src, currentDirectory)
		targetFileName := tspath.GetNormalizedAbsolutePath(target, currentDirectory)
		testfs[srcFileName] = vfstest.Symlink(targetFileName)
	}

	if includeLibDir {
		maps.Copy(testfs, testLibFolderMap())
	}

	fs := vfstest.FromMap(testfs, harnessOptions.UseCaseSensitiveFileNames)
	fs = bundled.WrapFS(fs)
	fs = NewOutputRecorderFS(fs)

	host := createCompilerHost(fs, bundled.LibPath(), currentDirectory)
	var configFile *tsoptions.TsConfigSourceFile
	var errors []*ast.Diagnostic
	if tsconfig != nil {
		configFile = tsconfig.ConfigFile
		errors = tsconfig.Errors
	}
	result := compileFilesWithHost(host, &tsoptions.ParsedCommandLine{
		ParsedConfig: &core.ParsedOptions{
			CompilerOptions: compilerOptions,
			FileNames:       programFileNames,
		},
		ConfigFile: configFile,
		Errors:     errors,
	}, harnessOptions)
	result.Symlinks = symlinks
	result.Trace = host.tracer.String()
	result.Repeat = func(testConfig TestConfiguration) *CompilationResult {
		newHarnessOptions := *harnessOptions
		newCompilerOptions := compilerOptions.Clone()
		setOptionsFromTestConfig(t, testConfig, newCompilerOptions, &newHarnessOptions, currentDirectory)
		return CompileFilesEx(t, inputFiles, otherFiles, &newHarnessOptions, newCompilerOptions, currentDirectory, symlinks, tsconfig)
	}
	return result
}

var testLibFolderMap = sync.OnceValue(func() map[string]any {
	testfs := make(map[string]any)
	libfs := os.DirFS(filepath.Join(repo.TypeScriptSubmodulePath, "tests", "lib"))
	err := fs.WalkDir(libfs, ".", func(path string, d fs.DirEntry, err error) error {
		if err != nil {
			return err
		}
		if d.IsDir() {
			return nil
		}
		content, err := fs.ReadFile(libfs, path)
		if err != nil {
			return err
		}
		testfs[testLibFolder+"/"+path] = &fstest.MapFile{
			Data: content,
		}
		return nil
	})
	if err != nil {
		panic(fmt.Sprintf("Failed to read lib dir: %v", err))
	}
	return testfs
})

func SetCompilerOptionsFromTestConfig(t *testing.T, testConfig TestConfiguration, compilerOptions *core.CompilerOptions, currentDirectory string) {
	for name, value := range testConfig {
		if name == "typescriptversion" {
			continue
		}

		commandLineOption := getCommandLineOption(name)
		if commandLineOption != nil {
			parsedValue := getOptionValue(t, commandLineOption, value, currentDirectory)
			errors := tsoptions.ParseCompilerOptions(commandLineOption.Name, parsedValue, compilerOptions)
			if len(errors) > 0 {
				t.Fatalf("Error parsing value '%s' for compiler option '%s'.", value, commandLineOption.Name)
			}
		}
	}
}

func setOptionsFromTestConfig(t *testing.T, testConfig TestConfiguration, compilerOptions *core.CompilerOptions, harnessOptions *HarnessOptions, currentDirectory string) {
	for name, value := range testConfig {
		if name == "typescriptversion" {
			continue
		}

		commandLineOption := getCommandLineOption(name)
		if commandLineOption != nil {
			parsedValue := getOptionValue(t, commandLineOption, value, currentDirectory)
			errors := tsoptions.ParseCompilerOptions(commandLineOption.Name, parsedValue, compilerOptions)
			if len(errors) > 0 {
				t.Fatalf("Error parsing value '%s' for compiler option '%s'.", value, commandLineOption.Name)
			}
			continue
		}
		harnessOption := getHarnessOption(name)
		if harnessOption != nil {
			parsedValue := getOptionValue(t, harnessOption, value, currentDirectory)
			parseHarnessOption(t, harnessOption.Name, parsedValue, harnessOptions)
			continue
		}

		t.Fatalf("Unknown compiler option '%s'.", name)
	}
}

var compilerOptions = core.Concatenate(
	tsoptions.OptionsDeclarations,
	[]*tsoptions.CommandLineOption{
		{
			Name: "allowNonTsExtensions",
			Kind: tsoptions.CommandLineOptionTypeBoolean,
		},
		{
			Name: "noErrorTruncation",
			Kind: tsoptions.CommandLineOptionTypeBoolean,
		},
		{
			Name: "suppressOutputPathCheck",
			Kind: tsoptions.CommandLineOptionTypeBoolean,
		},
		{
			Name: "noCheck",
			Kind: tsoptions.CommandLineOptionTypeBoolean,
		},
	},
)

var harnessCommandLineOptions = []*tsoptions.CommandLineOption{
	{
		Name: "useCaseSensitiveFileNames",
		Kind: tsoptions.CommandLineOptionTypeBoolean,
	},
	{
		Name: "baselineFile",
		Kind: tsoptions.CommandLineOptionTypeString,
	},
	{
		Name: "includeBuiltFile",
		Kind: tsoptions.CommandLineOptionTypeString,
	},
	{
		Name: "fileName",
		Kind: tsoptions.CommandLineOptionTypeString,
	},
	{
		Name: "libFiles",
		Kind: tsoptions.CommandLineOptionTypeList,
	},
	{
		Name: "noImplicitReferences",
		Kind: tsoptions.CommandLineOptionTypeBoolean,
	},
	{
		Name: "currentDirectory",
		Kind: tsoptions.CommandLineOptionTypeString,
	},
	{
		Name: "symlink",
		Kind: tsoptions.CommandLineOptionTypeString,
	},
	{
		Name: "link",
		Kind: tsoptions.CommandLineOptionTypeString,
	},
	{
		Name: "noTypesAndSymbols",
		Kind: tsoptions.CommandLineOptionTypeBoolean,
	},
	// Emitted js baseline will print full paths for every output file
	{
		Name: "fullEmitPaths",
		Kind: tsoptions.CommandLineOptionTypeBoolean,
	},
	// used to enable error collection in `transpile` baselines
	{
		Name: "reportDiagnostics",
		Kind: tsoptions.CommandLineOptionTypeBoolean,
	},
	// Adds suggestion diagnostics to error baselines
	{
		Name: "captureSuggestions",
		Kind: tsoptions.CommandLineOptionTypeBoolean,
	},
}

func getHarnessOption(name string) *tsoptions.CommandLineOption {
	return core.Find(harnessCommandLineOptions, func(option *tsoptions.CommandLineOption) bool {
		return strings.EqualFold(option.Name, name)
	})
}

func parseHarnessOption(t *testing.T, key string, value any, harnessOptions *HarnessOptions) {
	switch key {
	case "useCaseSensitiveFileNames":
		harnessOptions.UseCaseSensitiveFileNames = value.(bool)
	case "baselineFile":
		harnessOptions.BaselineFile = value.(string)
	case "includeBuiltFile":
		harnessOptions.IncludeBuiltFile = value.(string)
	case "fileName":
		harnessOptions.FileName = value.(string)
	case "libFiles":
		harnessOptions.LibFiles = make([]string, 0, len(value.([]any)))
		for _, v := range value.([]any) {
			harnessOptions.LibFiles = append(harnessOptions.LibFiles, v.(string))
		}
	case "noImplicitReferences":
		harnessOptions.NoImplicitReferences = value.(bool)
	case "currentDirectory":
		harnessOptions.CurrentDirectory = value.(string)
	case "symlink":
		harnessOptions.Symlink = value.(string)
	case "link":
		harnessOptions.Link = value.(string)
	case "noTypesAndSymbols":
		harnessOptions.NoTypesAndSymbols = value.(bool)
	case "fullEmitPaths":
		harnessOptions.FullEmitPaths = value.(bool)
	case "reportDiagnostics":
		harnessOptions.ReportDiagnostics = value.(bool)
	case "captureSuggestions":
		harnessOptions.CaptureSuggestions = value.(bool)
	case "typescriptVersion":
		harnessOptions.TypescriptVersion = value.(string)
	default:
		t.Fatalf("Unknown harness option '%s'.", key)
	}
}

var deprecatedModuleResolution []string = []string{"node", "classic", "node10"}

func getOptionValue(t *testing.T, option *tsoptions.CommandLineOption, value string, cwd string) tsoptions.CompilerOptionsValue {
	switch option.Kind {
	case tsoptions.CommandLineOptionTypeString:
		if option.IsFilePath {
			return tspath.GetNormalizedAbsolutePath(value, cwd)
		}
		return value
	case tsoptions.CommandLineOptionTypeNumber:
		numVal, err := strconv.Atoi(value)
		if err != nil {
			t.Fatalf("Value for option '%s' must be a number, got: %v", option.Name, value)
		}
		return numVal
	case tsoptions.CommandLineOptionTypeBoolean:
		switch strings.ToLower(value) {
		case "true":
			return true
		case "false":
			return false
		default:
			t.Fatalf("Value for option '%s' must be a boolean, got: %v", option.Name, value)
		}
	case tsoptions.CommandLineOptionTypeEnum:
		enumVal, ok := option.EnumMap().Get(strings.ToLower(value))
		if !ok {
			t.Fatalf("Value for option '%s' must be one of %s, got: %v", option.Name, strings.Join(slices.Collect(option.EnumMap().Keys()), ","), value)
		}
		return enumVal
	case tsoptions.CommandLineOptionTypeList, tsoptions.CommandLineOptionTypeListOrElement:
		listVal, errors := tsoptions.ParseListTypeOption(option, value)
		if option.Elements().IsFilePath {
			return core.Map(listVal, func(item any) any {
				return tspath.GetNormalizedAbsolutePath(item.(string), cwd)
			})
		}
		if len(errors) > 0 {
			t.Fatalf("Unknown value '%s' for compiler option '%s'", value, option.Name)
		}
		return listVal
	case tsoptions.CommandLineOptionTypeObject:
		t.Fatalf("Object type options like '%s' are not supported", option.Name)
	}
	return nil
}

type cachedCompilerHost struct {
	compiler.CompilerHost
	tracer *TracerForBaselining
}

var sourceFileCache collections.SyncMap[SourceFileCacheKey, *ast.SourceFile]

type SourceFileCacheKey struct {
	opts       ast.SourceFileParseOptions
	text       string
	scriptKind core.ScriptKind
}

func GetSourceFileCacheKey(opts ast.SourceFileParseOptions, text string, scriptKind core.ScriptKind) SourceFileCacheKey {
	return SourceFileCacheKey{
		opts:       opts,
		text:       text,
		scriptKind: scriptKind,
	}
}

func (h *cachedCompilerHost) GetSourceFile(opts ast.SourceFileParseOptions) *ast.SourceFile {
	text, ok := h.FS().ReadFile(opts.FileName)
	if !ok {
		return nil
	}

	scriptKind := core.GetScriptKindFromFileName(opts.FileName)
	if scriptKind == core.ScriptKindUnknown {
		panic("Unknown script kind for file  " + opts.FileName)
	}

	key := GetSourceFileCacheKey(opts, text, scriptKind)

	if cached, ok := sourceFileCache.Load(key); ok {
		return cached
	}

	sourceFile := parser.ParseSourceFile(opts, text, scriptKind)
	result, _ := sourceFileCache.LoadOrStore(key, sourceFile)
	return result
}

type TracerForBaselining struct {
	opts             tspath.ComparePathsOptions
	packageJsonCache map[tspath.Path]bool
	builder          *strings.Builder
}

func NewTracerForBaselining(opts tspath.ComparePathsOptions, builder *strings.Builder) *TracerForBaselining {
	return &TracerForBaselining{
		opts:             opts,
		packageJsonCache: make(map[tspath.Path]bool),
		builder:          builder,
	}
}

func (t *TracerForBaselining) Trace(msg *diagnostics.Message, args ...any) {
	t.TraceWithWriter(t.builder, msg.Localize(locale.Default, args...), true)
}

func (t *TracerForBaselining) TraceWithWriter(w io.Writer, msg string, usePackageJsonCache bool) {
	fmt.Fprintln(w, t.sanitizeTrace(msg, usePackageJsonCache))
}

func (t *TracerForBaselining) sanitizeTrace(msg string, usePackageJsonCache bool) string {
	// Version
	if str := strings.Replace(msg, "'"+core.Version()+"'", "'"+FakeTSVersion+"'", 1); str != msg {
		return str
	}
	// caching of fs in trace to be replaces with non caching version
	if str, ok := strings.CutSuffix(msg, "' does not exist according to earlier cached lookups."); ok {
		file := strings.TrimPrefix(str, "File '")
		if usePackageJsonCache {
			filePath := tspath.ToPath(file, t.opts.CurrentDirectory, t.opts.UseCaseSensitiveFileNames)
			if _, has := t.packageJsonCache[filePath]; has {
				return msg
			} else {
				t.packageJsonCache[filePath] = false
			}
		}
		return fmt.Sprintf("File '%s' does not exist.", file)
	}
	if str, ok := strings.CutSuffix(msg, "' exists according to earlier cached lookups."); ok {
		file := strings.TrimPrefix(str, "File '")
		if usePackageJsonCache {
			filePath := tspath.ToPath(file, t.opts.CurrentDirectory, t.opts.UseCaseSensitiveFileNames)
			if _, has := t.packageJsonCache[filePath]; has {
				return msg
			} else {
				t.packageJsonCache[filePath] = true
			}
		}
		return fmt.Sprintf("Found 'package.json' at '%s'.", file)
	}
	if usePackageJsonCache {
		if str, ok := strings.CutSuffix(msg, "' does not exist."); ok {
			file := strings.TrimPrefix(str, "File '")
			filePath := tspath.ToPath(file, t.opts.CurrentDirectory, t.opts.UseCaseSensitiveFileNames)
			if _, has := t.packageJsonCache[filePath]; !has {
				t.packageJsonCache[filePath] = false
				return msg
			} else {
				return fmt.Sprintf("File '%s' does not exist according to earlier cached lookups.", file)
			}
		}
		if str, ok := strings.CutPrefix(msg, "Found 'package.json' at '"); ok {
			file := strings.TrimSuffix(str, "'.")
			filePath := tspath.ToPath(file, t.opts.CurrentDirectory, t.opts.UseCaseSensitiveFileNames)
			if _, has := t.packageJsonCache[filePath]; !has {
				t.packageJsonCache[filePath] = true
				return msg
			} else {
				return fmt.Sprintf("File '%s' exists according to earlier cached lookups.", file)
			}
		}
	}
	return msg
}

func (t *TracerForBaselining) String() string {
	return t.builder.String()
}

func (t *TracerForBaselining) Reset() {
	t.packageJsonCache = make(map[tspath.Path]bool)
}

func createCompilerHost(fs vfs.FS, defaultLibraryPath string, currentDirectory string) *cachedCompilerHost {
	tracer := NewTracerForBaselining(tspath.ComparePathsOptions{
		UseCaseSensitiveFileNames: fs.UseCaseSensitiveFileNames(),
		CurrentDirectory:          currentDirectory,
	}, &strings.Builder{})
	return &cachedCompilerHost{
		CompilerHost: compiler.NewCompilerHost(currentDirectory, fs, defaultLibraryPath, nil, tracer.Trace),
		tracer:       tracer,
	}
}

func compileFilesWithHost(
	host compiler.CompilerHost,
	config *tsoptions.ParsedCommandLine,
	harnessOptions *HarnessOptions,
) *CompilationResult {
	// !!!
	// if (compilerOptions.project || !rootFiles || rootFiles.length === 0) {
	// 	const project = readProject(host.parseConfigHost, compilerOptions.project, compilerOptions);
	// 	if (project) {
	// 		if (project.errors && project.errors.length > 0) {
	// 			return new CompilationResult(host, compilerOptions, /*program*/ undefined, /*result*/ undefined, project.errors);
	// 		}
	// 		if (project.config) {
	// 			rootFiles = project.config.fileNames;
	// 			compilerOptions = project.config.options;
	// 		}
	// 	}
	// 	delete compilerOptions.project;
	// }

	// !!! Need `getPreEmitDiagnostics` program for this
	// pre-emit/post-emit error comparison requires declaration emit twice, which can be slow. If it's unlikely to flag any error consistency issues
	// and if the test is running `skipLibCheck` - an indicator that we want the tets to run quickly - skip the before/after error comparison, too
	// skipErrorComparison := len(rootFiles) >= 100 || options.SkipLibCheck == core.TSTrue && options.Declaration == core.TSTrue
	// var preProgram *compiler.Program
	// if !skipErrorComparison {
	// preProgram = ts.createProgram({ rootNames: rootFiles || [], options: { ...compilerOptions, configFile: compilerOptions.configFile, traceResolution: false }, host, typeScriptVersion })
	// }
	// let preErrors = preProgram && ts.getPreEmitDiagnostics(preProgram);
	// if (preProgram && harnessOptions.captureSuggestions) {
	//     preErrors = ts.concatenate(preErrors, ts.flatMap(preProgram.getSourceFiles(), f => preProgram.getSuggestionDiagnostics(f)));
	// }

	// const program = ts.createProgram({ rootNames: rootFiles || [], options: compilerOptions, host, harnessOptions.typeScriptVersion });
	// const emitResult = program.emit();
	// let postErrors = ts.getPreEmitDiagnostics(program);
	// !!! Need `getSuggestionDiagnostics` for this
	// if (harnessOptions.captureSuggestions) {
	//     postErrors = ts.concatenate(postErrors, ts.flatMap(program.getSourceFiles(), f => program.getSuggestionDiagnostics(f)));
	// }
	// const longerErrors = ts.length(preErrors) > postErrors.length ? preErrors : postErrors;
	// const shorterErrors = longerErrors === preErrors ? postErrors : preErrors;
	// const errors = preErrors && (preErrors.length !== postErrors.length) ? [
	//     ...shorterErrors!,
	//     ts.addRelatedInfo(
	//         ts.createCompilerDiagnostic({
	//             category: ts.DiagnosticCategory.Error,
	//             code: -1,
	//             key: "-1",
	//             message: `Pre-emit (${preErrors.length}) and post-emit (${postErrors.length}) diagnostic counts do not match! This can indicate that a semantic _error_ was added by the emit resolver - such an error may not be reflected on the command line or in the editor, but may be captured in a baseline here!`,
	//         }),
	//         ts.createCompilerDiagnostic({
	//             category: ts.DiagnosticCategory.Error,
	//             code: -1,
	//             key: "-1",
	//             message: `The excess diagnostics are:`,
	//         }),
	//         ...ts.filter(longerErrors!, p => !ts.some(shorterErrors, p2 => ts.compareDiagnostics(p, p2) === ts.Comparison.EqualTo)),
	//     ),
	// ] : postErrors;
	ctx := context.Background()
	program := createProgram(host, config)
	var diagnostics []*ast.Diagnostic
	diagnostics = append(diagnostics, program.GetProgramDiagnostics()...)
	diagnostics = append(diagnostics, program.GetSyntacticDiagnostics(ctx, nil)...)
	diagnostics = append(diagnostics, program.GetSemanticDiagnostics(ctx, nil)...)
	diagnostics = append(diagnostics, program.GetGlobalDiagnostics(ctx)...)
	if config.CompilerOptions().GetEmitDeclarations() {
		diagnostics = append(diagnostics, program.GetDeclarationDiagnostics(ctx, nil)...)
	}
	if harnessOptions.CaptureSuggestions {
		diagnostics = append(diagnostics, program.GetSuggestionDiagnostics(ctx, nil)...)
	}
	emitResult := program.Emit(ctx, compiler.EmitOptions{})

	return newCompilationResult(host, config.CompilerOptions(), program, emitResult, diagnostics, harnessOptions)
}

type CompilationResult struct {
	Diagnostics      []*ast.Diagnostic
	Result           *compiler.EmitResult
	Program          compiler.ProgramLike
	Options          *core.CompilerOptions
	HarnessOptions   *HarnessOptions
	JS               collections.OrderedMap[string, *TestFile]
	DTS              collections.OrderedMap[string, *TestFile]
	Maps             collections.OrderedMap[string, *TestFile]
	Symlinks         map[string]string
	Repeat           func(TestConfiguration) *CompilationResult
	outputs          []*TestFile
	inputs           []*TestFile
	inputsAndOutputs collections.OrderedMap[string, *CompilationOutput]
	Trace            string
	Host             compiler.CompilerHost
}

type CompilationOutput struct {
	Inputs []*TestFile
	JS     *TestFile
	DTS    *TestFile
	Map    *TestFile
}

func newCompilationResult(
	host compiler.CompilerHost,
	options *core.CompilerOptions,
	program compiler.ProgramLike,
	result *compiler.EmitResult,
	diagnostics []*ast.Diagnostic,
	harnessOptions *HarnessOptions,
) *CompilationResult {
	if program != nil {
		options = program.Options()
	}

	c := &CompilationResult{
		Diagnostics:    diagnostics,
		Result:         result,
		Program:        program,
		Options:        options,
		HarnessOptions: harnessOptions,
		Host:           host,
	}

	fs := host.FS().(*OutputRecorderFS)
	if fs != nil && program != nil {
		// Corsa, unlike Strada, can use multiple threads for emit. As a result, the order of outputs is non-deterministic.
		// To make the order deterministic, we sort the outputs by the order of the inputs.
		var js, dts, maps collections.OrderedMap[string, *TestFile]
		for _, document := range fs.Outputs() {
			if tspath.HasJSFileExtension(document.UnitName) ||
				tspath.HasJSONFileExtension(document.UnitName) {
				js.Set(document.UnitName, document)
			} else if tspath.IsDeclarationFileName(document.UnitName) {
				dts.Set(document.UnitName, document)
			} else if tspath.FileExtensionIs(document.UnitName, ".map") {
				maps.Set(document.UnitName, document)
			}
		}

		// using the order from the inputs, populate the outputs
		for _, sourceFile := range program.GetSourceFiles() {
			input := &TestFile{UnitName: sourceFile.FileName(), Content: sourceFile.Text()}
			c.inputs = append(c.inputs, input)
			if !tspath.IsDeclarationFileName(sourceFile.FileName()) {
				extname := outputpaths.GetOutputExtension(sourceFile.FileName(), options.Jsx)
				outputs := &CompilationOutput{
					Inputs: []*TestFile{input},
					JS:     js.GetOrZero(c.getOutputPath(sourceFile.FileName(), extname)),
					DTS:    dts.GetOrZero(c.getOutputPath(sourceFile.FileName(), tspath.GetDeclarationEmitExtensionForPath(sourceFile.FileName()))),
					Map:    maps.GetOrZero(c.getOutputPath(sourceFile.FileName(), extname+".map")),
				}
				c.inputsAndOutputs.Set(sourceFile.FileName(), outputs)
				if outputs.JS != nil {
					c.inputsAndOutputs.Set(outputs.JS.UnitName, outputs)
					c.JS.Set(outputs.JS.UnitName, outputs.JS)
					js.Delete(outputs.JS.UnitName)
					c.outputs = append(c.outputs, outputs.JS)
				}
				if outputs.DTS != nil {
					c.inputsAndOutputs.Set(outputs.DTS.UnitName, outputs)
					c.DTS.Set(outputs.DTS.UnitName, outputs.DTS)
					dts.Delete(outputs.DTS.UnitName)
					c.outputs = append(c.outputs, outputs.DTS)
				}
				if outputs.Map != nil {
					c.inputsAndOutputs.Set(outputs.Map.UnitName, outputs)
					c.Maps.Set(outputs.Map.UnitName, outputs.Map)
					maps.Delete(outputs.Map.UnitName)
					c.outputs = append(c.outputs, outputs.Map)
				}
			}
		}

		// add any unhandled outputs, ordered by unit name
		for _, document := range slices.SortedFunc(js.Values(), compareTestFiles) {
			c.JS.Set(document.UnitName, document)
		}
		for _, document := range slices.SortedFunc(dts.Values(), compareTestFiles) {
			c.DTS.Set(document.UnitName, document)
		}
		for _, document := range slices.SortedFunc(maps.Values(), compareTestFiles) {
			c.Maps.Set(document.UnitName, document)
		}
	}

	return c
}

func compareTestFiles(a *TestFile, b *TestFile) int {
	return strings.Compare(a.UnitName, b.UnitName)
}

func (c *CompilationResult) getOutputPath(path string, ext string) string {
	path = tspath.ResolvePath(c.Host.GetCurrentDirectory(), path)
	var outDir string
	if ext == ".d.ts" || ext == ".d.mts" || ext == ".d.cts" || (strings.HasSuffix(ext, ".ts") && strings.Contains(ext, ".d.")) {
		outDir = c.Options.DeclarationDir
		if outDir == "" {
			outDir = c.Options.OutDir
		}
	} else {
		outDir = c.Options.OutDir
	}
	if outDir != "" {
		common := c.Program.CommonSourceDirectory()
		if common != "" {
			path = tspath.GetRelativePathFromDirectory(common, path, tspath.ComparePathsOptions{
				UseCaseSensitiveFileNames: c.Host.FS().UseCaseSensitiveFileNames(),
				CurrentDirectory:          c.Host.GetCurrentDirectory(),
			})
			path = tspath.CombinePaths(tspath.ResolvePath(c.Host.GetCurrentDirectory(), c.Options.OutDir), path)
		}
	}
	return tspath.ChangeExtension(path, ext)
}

func (r *CompilationResult) FS() vfs.FS {
	return r.Host.FS()
}

func (r *CompilationResult) GetNumberOfJSFiles(includeJson bool) int {
	if includeJson {
		return r.JS.Size()
	}
	count := 0
	for file := range r.JS.Values() {
		if !tspath.FileExtensionIs(file.UnitName, tspath.ExtensionJson) {
			count++
		}
	}
	return count
}

func (c *CompilationResult) Inputs() []*TestFile {
	return c.inputs
}

func (c *CompilationResult) Outputs() []*TestFile {
	return c.outputs
}

func (c *CompilationResult) GetInputsAndOutputsForFile(path string) *CompilationOutput {
	return c.inputsAndOutputs.GetOrZero(tspath.ResolvePath(c.Host.GetCurrentDirectory(), path))
}

func (c *CompilationResult) GetInputsForFile(path string) []*TestFile {
	outputs := c.GetInputsAndOutputsForFile(path)
	if outputs != nil {
		return outputs.Inputs
	}
	return nil
}

func (c *CompilationResult) GetOutput(path string, kind string /*"js" | "dts" | "map"*/) *TestFile {
	outputs := c.GetInputsAndOutputsForFile(path)
	if outputs != nil {
		switch kind {
		case "js":
			return outputs.JS
		case "dts":
			return outputs.DTS
		case "map":
			return outputs.Map
		}
	}
	return nil
}

func (c *CompilationResult) GetSourceMapRecord() string {
	if c.Result == nil || len(c.Result.SourceMaps) == 0 {
		return ""
	}

	var sourceMapRecorder writerAggregator
	for _, sourceMapData := range c.Result.SourceMaps {
		var prevSourceFile *ast.SourceFile
		var currentFile *TestFile

		if tspath.IsDeclarationFileName(sourceMapData.GeneratedFile) {
			currentFile = c.DTS.GetOrZero(sourceMapData.GeneratedFile)
		} else {
			currentFile = c.JS.GetOrZero(sourceMapData.GeneratedFile)
		}

		sourceMapSpanWriter := newSourceMapSpanWriter(&sourceMapRecorder, sourceMapData.SourceMap, currentFile)
		mapper := sourcemap.DecodeMappings(sourceMapData.SourceMap.Mappings)
		for decodedSourceMapping := range mapper.Values() {
			var currentSourceFile *ast.SourceFile
			if decodedSourceMapping.IsSourceMapping() {
				currentSourceFile = c.Program.GetSourceFile(sourceMapData.InputSourceFileNames[decodedSourceMapping.SourceIndex])
			}
			if currentSourceFile != prevSourceFile {
				if currentSourceFile != nil {
					sourceMapSpanWriter.recordNewSourceFileSpan(decodedSourceMapping, currentSourceFile.Text())
				}
				prevSourceFile = currentSourceFile
			} else {
				sourceMapSpanWriter.recordSourceMapSpan(decodedSourceMapping)
			}
		}
		sourceMapSpanWriter.close()
	}
	return sourceMapRecorder.String()
}

type testBuildInfoReader struct {
	inner incremental.BuildInfoReader
}

func (t *testBuildInfoReader) ReadBuildInfo(config *tsoptions.ParsedCommandLine) *incremental.BuildInfo {
	r := t.inner.ReadBuildInfo(config)
	if r == nil {
		return nil
	}
	r.Version = core.Version()
	return r
}

func getTestBuildInfoReader(host compiler.CompilerHost) *testBuildInfoReader {
	return &testBuildInfoReader{inner: incremental.NewBuildInfoReader(host)}
}

func createProgram(host compiler.CompilerHost, config *tsoptions.ParsedCommandLine) compiler.ProgramLike {
	var singleThreaded core.Tristate
	if testutil.TestProgramIsSingleThreaded() {
		singleThreaded = core.TSTrue
	}

	programOptions := compiler.ProgramOptions{
		Config:         config,
		Host:           host,
		SingleThreaded: singleThreaded,
	}
	program := compiler.NewProgram(programOptions)
	if config.CompilerOptions().Incremental.IsTrue() {
		oldProgram := incremental.ReadBuildInfoProgram(config, getTestBuildInfoReader(host), host)
		incrementalProgram := incremental.NewProgram(program, oldProgram, incremental.CreateHost(host), false)
		return incrementalProgram
	}
	return program
}

func EnumerateFiles(folder string, testRegex *regexp.Regexp, recursive bool) ([]string, error) {
	files, err := listFiles(folder, testRegex, recursive)
	if err != nil {
		return nil, err
	}
	return core.Map(files, tspath.NormalizeSlashes), nil
}

func listFiles(path string, spec *regexp.Regexp, recursive bool) ([]string, error) {
	return listFilesWorker(spec, recursive, path)
}

func listFilesWorker(spec *regexp.Regexp, recursive bool, folder string) ([]string, error) {
	folder = tspath.GetNormalizedAbsolutePath(folder, repo.TestDataPath)
	entries, err := os.ReadDir(folder)
	if err != nil {
		return nil, err
	}
	var paths []string
	for _, entry := range entries {
		path := tspath.NormalizePath(filepath.Join(folder, entry.Name()))
		if !entry.IsDir() {
			if spec == nil || spec.MatchString(path) {
				paths = append(paths, path)
			}
		} else if recursive {
			subPaths, err := listFilesWorker(spec, recursive, path)
			if err != nil {
				return nil, err
			}
			paths = append(paths, subPaths...)
		}
	}
	return paths, nil
}

func getFileBasedTestConfigurationDescription(config TestConfiguration) string {
	var output strings.Builder
	keys := slices.Sorted(maps.Keys(config))
	for i, key := range keys {
		if i > 0 {
			output.WriteString(",")
		}
		fmt.Fprintf(&output, "%s=%s", key, strings.ToLower(config[key]))
	}
	return output.String()
}

func GetFileBasedTestConfigurations(t *testing.T, settings map[string]string, varyByOptions map[string]struct{}) []*NamedTestConfiguration {
	var optionEntries [][]string // Each element slice has the option name as the first element, and the values as the rest
	variationCount := 1
	nonVaryingOptions := make(map[string]string)
	for option, value := range settings {
		if _, ok := varyByOptions[option]; ok {
			entries := splitOptionValues(t, value, option)
			if len(entries) > 1 {
				variationCount *= len(entries)
				if variationCount > 25 {
					t.Fatal("Provided test options exceeded the maximum number of variations")
				}
				optionEntries = append(optionEntries, append([]string{option}, entries...))
			} else if len(entries) == 1 {
				nonVaryingOptions[option] = entries[0]
			}
		} else {
			// Variation is not supported for the option
			nonVaryingOptions[option] = value
		}
	}

	var configurations []*NamedTestConfiguration
	if len(optionEntries) > 0 {
		// Merge varying and non-varying options
		varyingConfigurations := computeFileBasedTestConfigurationVariations(variationCount, optionEntries)
		for _, varyingConfig := range varyingConfigurations {
			description := getFileBasedTestConfigurationDescription(varyingConfig)
			maps.Copy(varyingConfig, nonVaryingOptions)
			configurations = append(configurations, &NamedTestConfiguration{description, varyingConfig})
		}
	} else if len(nonVaryingOptions) > 0 {
		// Only non-varying options
		configurations = append(configurations, &NamedTestConfiguration{"", nonVaryingOptions})
	}
	return configurations
}

// Splits a string value into an array of strings, each corresponding to a unique value for the given option.
// Also handles the `*` value, which includes all possible values for the option, and exclusions using `-` or `!`.
// ```
//
//	splitOptionValues("esnext, es2015, es6", "target") => ["esnext", "es2015"]
//	splitOptionValues("*", "strict") => ["true", "false"]
//	splitOptionValues("*, -true", "strict") => ["false"]
//
// ```
func splitOptionValues(t *testing.T, value string, option string) []string {
	if len(value) == 0 {
		return nil
	}

	star := false
	var includes []string
	var excludes []string
	for s := range strings.SplitSeq(value, ",") {
		s = strings.TrimSpace(s)
		if len(s) == 0 {
			continue
		}
		if s == "*" {
			star = true
		} else if strings.HasPrefix(s, "-") || strings.HasPrefix(s, "!") {
			excludes = append(excludes, s[1:])
		} else {
			includes = append(includes, s)
		}
	}

	if len(includes) == 0 && !star && len(excludes) == 0 {
		return nil
	}

	// Dedupe the variations by their normalized values
	variations := make(map[tsoptions.CompilerOptionsValue]string)

	// add (and deduplicate) all included entries
	for _, include := range includes {
		value := getValueOfOptionString(t, option, include)
		if _, ok := variations[value]; !ok {
			variations[value] = include
		}
	}

	allValues := getAllValuesForOption(option)
	if star && len(allValues) > 0 {
		// add all entries
		for _, include := range allValues {
			value := getValueOfOptionString(t, option, include)
			if _, ok := variations[value]; !ok {
				variations[value] = include
			}
		}
	}

	// remove all excluded entries
	for _, exclude := range excludes {
		value := getValueOfOptionString(t, option, exclude)
		delete(variations, value)
	}

	if len(variations) == 0 {
		panic(fmt.Sprintf("Variations in test option '@%s' resulted in an empty set.", option))
	}
	return slices.Collect(maps.Values(variations))
}

func getValueOfOptionString(t *testing.T, option string, value string) tsoptions.CompilerOptionsValue {
	optionDecl := getCommandLineOption(option)
	if optionDecl == nil {
		t.Fatalf("Unknown option '%s'", option)
	}
	// TODO(gabritto): remove this when we deprecate the tests containing those option values
	if optionDecl.Name == "moduleResolution" && slices.Contains(deprecatedModuleResolution, strings.ToLower(value)) {
		return value
	}
	return getOptionValue(t, optionDecl, value, "/")
}

func getCommandLineOption(option string) *tsoptions.CommandLineOption {
	return core.Find(compilerOptions, func(optionDecl *tsoptions.CommandLineOption) bool {
		return strings.EqualFold(optionDecl.Name, option)
	})
}

func getAllValuesForOption(option string) []string {
	optionDecl := getCommandLineOption(option)
	if optionDecl == nil {
		return nil
	}
	switch optionDecl.Kind {
	case tsoptions.CommandLineOptionTypeEnum:
		return slices.Collect(optionDecl.EnumMap().Keys())
	case tsoptions.CommandLineOptionTypeBoolean:
		return []string{"true", "false"}
	}
	return nil
}

func computeFileBasedTestConfigurationVariations(variationCount int, optionEntries [][]string) []TestConfiguration {
	configurations := make([]TestConfiguration, 0, variationCount)
	computeFileBasedTestConfigurationVariationsWorker(&configurations, optionEntries, 0, make(map[string]string))
	return configurations
}

func computeFileBasedTestConfigurationVariationsWorker(
	configurations *[]TestConfiguration,
	optionEntries [][]string,
	index int,
	variationState TestConfiguration,
) {
	if index >= len(optionEntries) {
		*configurations = append(*configurations, maps.Clone(variationState))
		return
	}

	optionKey := optionEntries[index][0]
	entries := optionEntries[index][1:]
	for _, entry := range entries {
		// set or overwrite the variation, then compute the next variation
		variationState[optionKey] = entry
		computeFileBasedTestConfigurationVariationsWorker(configurations, optionEntries, index+1, variationState)
	}
}

func GetConfigNameFromFileName(filename string) string {
	basenameLower := strings.ToLower(tspath.GetBaseFileName(filename))
	if basenameLower == "tsconfig.json" || basenameLower == "jsconfig.json" {
		return basenameLower
	}
	return ""
}