// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
#pragma once

#include "Luau/Config.h"
#include "Luau/Differ.h"
#include "Luau/Error.h"
#include "Luau/FileResolver.h"
#include "Luau/Frontend.h"
#include "Luau/IostreamHelpers.h"
#include "Luau/Linter.h"
#include "Luau/Location.h"
#include "Luau/ModuleResolver.h"
#include "Luau/Scope.h"
#include "Luau/ToString.h"
#include "Luau/Type.h"
#include "Luau/TypeFunction.h"

#include "IostreamOptional.h"
#include "ScopedFlags.h"

#include "doctest.h"
#include <string>
#include <string_view>
#include <unordered_map>
#include <optional>
#include <vector>

namespace Luau
{

struct TypeChecker;

struct TestFileResolver
    : FileResolver
    , ModuleResolver
{
    std::optional<ModuleInfo> resolveModuleInfo(const ModuleName& currentModuleName, const AstExpr& pathExpr) override;

    const ModulePtr getModule(const ModuleName& moduleName) const override;

    bool moduleExists(const ModuleName& moduleName) const override;

    std::optional<SourceCode> readSource(const ModuleName& name) override;

    std::optional<ModuleInfo> resolveModule(const ModuleInfo* context, AstExpr* expr) override;

    std::string getHumanReadableModuleName(const ModuleName& name) const override;

    std::optional<std::string> getEnvironmentForModule(const ModuleName& name) const override;

    std::unordered_map<ModuleName, std::string> source;
    std::unordered_map<ModuleName, SourceCode::Type> sourceTypes;
    std::unordered_map<ModuleName, std::string> environments;
};

struct TestConfigResolver : ConfigResolver
{
    Config defaultConfig;
    std::unordered_map<ModuleName, Config> configFiles;

    const Config& getConfig(const ModuleName& name) const override;
};

struct Fixture
{
    explicit Fixture(bool freeze = true, bool prepareAutocomplete = false);
    ~Fixture();

    // Throws Luau::ParseErrors if the parse fails.
    AstStatBlock* parse(const std::string& source, const ParseOptions& parseOptions = {});
    CheckResult check(Mode mode, const std::string& source);
    CheckResult check(const std::string& source);

    LintResult lint(const std::string& source, const std::optional<LintOptions>& lintOptions = {});
    LintResult lintModule(const ModuleName& moduleName, const std::optional<LintOptions>& lintOptions = {});

    /// Parse with all language extensions enabled
    ParseResult parseEx(const std::string& source, const ParseOptions& parseOptions = {});
    ParseResult tryParse(const std::string& source, const ParseOptions& parseOptions = {});
    ParseResult matchParseError(const std::string& source, const std::string& message, std::optional<Location> location = std::nullopt);
    // Verify a parse error occurs and the parse error message has the specified prefix
    ParseResult matchParseErrorPrefix(const std::string& source, const std::string& prefix);

    ModulePtr getMainModule();
    SourceModule* getMainSourceModule();

    std::optional<PrimitiveType::Type> getPrimitiveType(TypeId ty);
    std::optional<TypeId> getType(const std::string& name);
    TypeId requireType(const std::string& name);
    TypeId requireType(const ModuleName& moduleName, const std::string& name);
    TypeId requireType(const ModulePtr& module, const std::string& name);
    TypeId requireType(const ScopePtr& scope, const std::string& name);

    std::optional<TypeId> findTypeAtPosition(Position position);
    TypeId requireTypeAtPosition(Position position);
    std::optional<TypeId> findExpectedTypeAtPosition(Position position);

    std::optional<TypeId> lookupType(const std::string& name);
    std::optional<TypeId> lookupImportedType(const std::string& moduleAlias, const std::string& name);
    TypeId requireTypeAlias(const std::string& name);
    TypeId requireExportedType(const ModuleName& moduleName, const std::string& name);

    // TODO: Should this be in a container of some kind? Seems a little silly
    // to have a bunch of flags sitting on the text fixture.

    // We have a couple flags that are OK to set for all tests and, in some
    // cases, cannot easily be flipped on or off on a per-test basis. For these
    // we set them as part of constructing the test fixture.

    /* From the original commit:
     *
     * > This enables arena freezing for all but two unit tests. Arena
     * > freezing marks the `TypeArena`'s underlying memory as read-only,
     * > raising an access violation whenever you mutate it. This is useful
     * > for tracking down violations of Luau's memory model.
     */
    ScopedFastFlag sff_DebugLuauFreezeArena;

    /* Magic typechecker functions for the new solver are initialized when the
     * typechecker frontend is initialized, which is done at the beginning of
     * the test: we set this flag as part of the fixture as we always want to
     * enable the magic functions for, say, `string.format`.
     */
    ScopedFastFlag sff_LuauDCRMagicFunctionTypeChecker;

    /* While the new solver is being rolled out we are using a monotonically
     * increasing version number to track new changes, we just set it to a
     * sufficiently high number in tests to ensure that any guards in prod
     * code pass in tests (so we don't accidentally reintroduce a bug before
     * it's unflagged).
     */
    ScopedFastInt sff_LuauTypeSolverRelease;

    TestFileResolver fileResolver;
    TestConfigResolver configResolver;
    NullModuleResolver moduleResolver;
    std::unique_ptr<SourceModule> sourceModule;
    Frontend frontend;
    InternalErrorReporter ice;
    NotNull<BuiltinTypes> builtinTypes;

    std::string decorateWithTypes(const std::string& code);

    void dumpErrors(std::ostream& os, const std::vector<TypeError>& errors);

    void dumpErrors(const CheckResult& cr);
    void dumpErrors(const ModulePtr& module);
    void dumpErrors(const Module& module);

    void validateErrors(const std::vector<TypeError>& errors);

    std::string getErrors(const CheckResult& cr);

    void registerTestTypes();

    LoadDefinitionFileResult loadDefinition(const std::string& source);
};

struct BuiltinsFixture : Fixture
{
    BuiltinsFixture(bool freeze = true, bool prepareAutocomplete = false);
};

std::optional<std::string> pathExprToModuleName(const ModuleName& currentModuleName, const std::vector<std::string_view>& segments);
std::optional<std::string> pathExprToModuleName(const ModuleName& currentModuleName, const AstExpr& pathExpr);

ModuleName fromString(std::string_view name);

template<typename T>
std::optional<T> get(const std::map<Name, T>& map, const Name& name)
{
    auto it = map.find(name);
    if (it != map.end())
        return std::optional<T>(it->second);
    else
        return std::nullopt;
}

std::string rep(const std::string& s, size_t n);

bool isInArena(TypeId t, const TypeArena& arena);

void dumpErrors(const ModulePtr& module);
void dumpErrors(const Module& module);
void dump(const std::string& name, TypeId ty);
void dump(const std::vector<Constraint>& constraints);

std::optional<TypeId> lookupName(ScopePtr scope, const std::string& name); // Warning: This function runs in O(n**2)

std::optional<TypeId> linearSearchForBinding(Scope* scope, const char* name);

void registerHiddenTypes(Frontend* frontend);
void createSomeClasses(Frontend* frontend);

template<typename BaseFixture>
struct DifferFixtureGeneric : BaseFixture
{
    std::string normalizeWhitespace(std::string msg)
    {
        std::string normalizedMsg = "";
        bool wasWhitespace = true;
        for (char c : msg)
        {
            bool isWhitespace = c == ' ' || c == '\n';
            if (wasWhitespace && isWhitespace)
                continue;
            normalizedMsg += isWhitespace ? ' ' : c;
            wasWhitespace = isWhitespace;
        }
        if (wasWhitespace)
            normalizedMsg.pop_back();
        return normalizedMsg;
    }

    void compareNe(TypeId left, TypeId right, const std::string& expectedMessage, bool multiLine)
    {
        compareNe(left, std::nullopt, right, std::nullopt, expectedMessage, multiLine);
    }

    void compareNe(
        TypeId left,
        std::optional<std::string> symbolLeft,
        TypeId right,
        std::optional<std::string> symbolRight,
        const std::string& expectedMessage,
        bool multiLine
    )
    {
        DifferResult diffRes = diffWithSymbols(left, right, symbolLeft, symbolRight);
        REQUIRE_MESSAGE(diffRes.diffError.has_value(), "Differ did not report type error, even though types are unequal");
        std::string diffMessage = diffRes.diffError->toString(multiLine);
        CHECK_EQ(expectedMessage, diffMessage);
    }

    void compareTypesNe(
        const std::string& leftSymbol,
        const std::string& rightSymbol,
        const std::string& expectedMessage,
        bool forwardSymbol = false,
        bool multiLine = false
    )
    {
        if (forwardSymbol)
        {
            compareNe(
                BaseFixture::requireType(leftSymbol), leftSymbol, BaseFixture::requireType(rightSymbol), rightSymbol, expectedMessage, multiLine
            );
        }
        else
        {
            compareNe(
                BaseFixture::requireType(leftSymbol), std::nullopt, BaseFixture::requireType(rightSymbol), std::nullopt, expectedMessage, multiLine
            );
        }
    }

    void compareEq(TypeId left, TypeId right)
    {
        DifferResult diffRes = diff(left, right);
        CHECK(!diffRes.diffError);
        if (diffRes.diffError)
            INFO(diffRes.diffError->toString());
    }

    void compareTypesEq(const std::string& leftSymbol, const std::string& rightSymbol)
    {
        compareEq(BaseFixture::requireType(leftSymbol), BaseFixture::requireType(rightSymbol));
    }
};
using DifferFixture = DifferFixtureGeneric<Fixture>;
using DifferFixtureWithBuiltins = DifferFixtureGeneric<BuiltinsFixture>;

} // namespace Luau

#define LUAU_REQUIRE_ERRORS(result) \
    do \
    { \
        auto&& r = (result); \
        validateErrors(r.errors); \
        REQUIRE(!r.errors.empty()); \
    } while (false)

#define LUAU_REQUIRE_ERROR_COUNT(count, result) \
    do \
    { \
        auto&& r = (result); \
        validateErrors(r.errors); \
        REQUIRE_MESSAGE(count == r.errors.size(), getErrors(r)); \
    } while (false)

#define LUAU_REQUIRE_NO_ERRORS(result) LUAU_REQUIRE_ERROR_COUNT(0, result)

#define LUAU_CHECK_ERRORS(result) \
    do \
    { \
        auto&& r = (result); \
        validateErrors(r.errors); \
        CHECK(!r.errors.empty()); \
    } while (false)

#define LUAU_CHECK_ERROR_COUNT(count, result) \
    do \
    { \
        auto&& r = (result); \
        validateErrors(r.errors); \
        CHECK_MESSAGE(count == r.errors.size(), getErrors(r)); \
    } while (false)

#define LUAU_CHECK_NO_ERRORS(result) LUAU_CHECK_ERROR_COUNT(0, result)