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

/* Tests in this source file are meant to be a bellwether to verify that the numeric limits we've set are sufficient for
 * most real-world scripts.
 *
 * If a change breaks a test in this source file, please don't adjust the flag values set in the fixture.  Instead,
 * consider it a latent performance problem by default.
 *
 * We should periodically revisit this to retest the limits.
 */

#include "Fixture.h"

#include "doctest.h"

#include <algorithm>

using namespace Luau;

LUAU_FASTINT(LuauSolverConstraintLimit)
LUAU_FASTINT(LuauTypeInferRecursionLimit)

LUAU_FASTFLAG(LuauSolverV2)
LUAU_FASTFLAG(LuauEagerGeneralization4)
LUAU_FASTFLAG(LuauIceLess)
LUAU_FASTFLAG(LuauPushFunctionTypesInFunctionStatement)
LUAU_FASTFLAG(LuauSimplifyAnyAndUnion)
LUAU_FASTFLAG(LuauLimitDynamicConstraintSolving3)
LUAU_FASTFLAG(LuauDontDynamicallyCreateRedundantSubtypeConstraints)
LUAU_FASTFLAG(LuauTrackFreeInteriorTypePacks)

struct LimitFixture : BuiltinsFixture
{
#if defined(_NOOPT) || defined(_DEBUG)
    ScopedFastInt LuauTypeInferRecursionLimit{FInt::LuauTypeInferRecursionLimit, 100};
#endif
};

template<typename T>
bool hasError(const CheckResult& result, T* = nullptr)
{
    auto it = std::find_if(
        result.errors.begin(),
        result.errors.end(),
        [](const TypeError& a)
        {
            return nullptr != get<T>(a);
        }
    );
    return it != result.errors.end();
}

TEST_SUITE_BEGIN("RuntimeLimits");

TEST_CASE_FIXTURE(LimitFixture, "typescript_port_of_Result_type")
{
    DOES_NOT_PASS_NEW_SOLVER_GUARD();

    constexpr const char* src = R"LUAU(
        --!strict

        -- Big thanks to Dionysusnu by letting us use this code as part of our test suite!
        -- https://github.com/Dionysusnu/rbxts-rust-classes
        -- Licensed under the MPL 2.0: https://raw.githubusercontent.com/Dionysusnu/rbxts-rust-classes/master/LICENSE

        local TS = _G[script]
        local lazyGet = TS.import(script, script.Parent.Parent, "util", "lazyLoad").lazyGet
        local unit = TS.import(script, script.Parent.Parent, "util", "Unit").unit
        local Iterator
        lazyGet("Iterator", function(c)
            Iterator = c
        end)
        local Option
        lazyGet("Option", function(c)
            Option = c
        end)
        local Vec
        lazyGet("Vec", function(c)
            Vec = c
        end)
        local Result
        do
            Result = setmetatable({}, {
                __tostring = function()
                    return "Result"
                end,
            })
            Result.__index = Result
            function Result.new(...)
                local self = setmetatable({}, Result)
                self:constructor(...)
                return self
            end
            function Result:constructor(okValue, errValue)
                self.okValue = okValue
                self.errValue = errValue
            end
            function Result:ok(val)
                return Result.new(val, nil)
            end
            function Result:err(val)
                return Result.new(nil, val)
            end
            function Result:fromCallback(c)
                local _0 = c
                local _1, _2 = pcall(_0)
                local result = _1 and {
                    success = true,
                    value = _2,
                } or {
                    success = false,
                    error = _2,
                }
                return result.success and Result:ok(result.value) or Result:err(Option:wrap(result.error))
            end
            function Result:fromVoidCallback(c)
                local _0 = c
                local _1, _2 = pcall(_0)
                local result = _1 and {
                    success = true,
                    value = _2,
                } or {
                    success = false,
                    error = _2,
                }
                return result.success and Result:ok(unit()) or Result:err(Option:wrap(result.error))
            end
            Result.fromPromise = TS.async(function(self, p)
                local _0, _1 = TS.try(function()
                    return TS.TRY_RETURN, { Result:ok(TS.await(p)) }
                end, function(e)
                    return TS.TRY_RETURN, { Result:err(Option:wrap(e)) }
                end)
                if _0 then
                    return unpack(_1)
                end
            end)
            Result.fromVoidPromise = TS.async(function(self, p)
                local _0, _1 = TS.try(function()
                    TS.await(p)
                    return TS.TRY_RETURN, { Result:ok(unit()) }
                end, function(e)
                    return TS.TRY_RETURN, { Result:err(Option:wrap(e)) }
                end)
                if _0 then
                    return unpack(_1)
                end
            end)
            function Result:isOk()
                return self.okValue ~= nil
            end
            function Result:isErr()
                return self.errValue ~= nil
            end
            function Result:contains(x)
                return self.okValue == x
            end
            function Result:containsErr(x)
                return self.errValue == x
            end
            function Result:okOption()
                return Option:wrap(self.okValue)
            end
            function Result:errOption()
                return Option:wrap(self.errValue)
            end
            function Result:map(func)
                return self:isOk() and Result:ok(func(self.okValue)) or Result:err(self.errValue)
            end
            function Result:mapOr(def, func)
                local _0
                if self:isOk() then
                    _0 = func(self.okValue)
                else
                    _0 = def
                end
                return _0
            end
            function Result:mapOrElse(def, func)
                local _0
                if self:isOk() then
                    _0 = func(self.okValue)
                else
                    _0 = def(self.errValue)
                end
                return _0
            end
            function Result:mapErr(func)
                return self:isErr() and Result:err(func(self.errValue)) or Result:ok(self.okValue)
            end
            Result["and"] = function(self, other)
                return self:isErr() and Result:err(self.errValue) or other
            end
            function Result:andThen(func)
                return self:isErr() and Result:err(self.errValue) or func(self.okValue)
            end
            Result["or"] = function(self, other)
                return self:isOk() and Result:ok(self.okValue) or other
            end
            function Result:orElse(other)
                return self:isOk() and Result:ok(self.okValue) or other(self.errValue)
            end
            function Result:expect(msg)
                if self:isOk() then
                    return self.okValue
                else
                    error(msg)
                end
            end
            function Result:unwrap()
                return self:expect("called `Result.unwrap()` on an `Err` value: " .. tostring(self.errValue))
            end
            function Result:unwrapOr(def)
                local _0
                if self:isOk() then
                    _0 = self.okValue
                else
                    _0 = def
                end
                return _0
            end
            function Result:unwrapOrElse(gen)
                local _0
                if self:isOk() then
                    _0 = self.okValue
                else
                    _0 = gen(self.errValue)
                end
                return _0
            end
            function Result:expectErr(msg)
                if self:isErr() then
                    return self.errValue
                else
                    error(msg)
                end
            end
            function Result:unwrapErr()
                return self:expectErr("called `Result.unwrapErr()` on an `Ok` value: " .. tostring(self.okValue))
            end
            function Result:transpose()
                return self:isOk() and self.okValue:map(function(some)
                    return Result:ok(some)
                end) or Option:some(Result:err(self.errValue))
            end
            function Result:flatten()
                return self:isOk() and Result.new(self.okValue.okValue, self.okValue.errValue) or Result:err(self.errValue)
            end
            function Result:match(ifOk, ifErr)
                local _0
                if self:isOk() then
                    _0 = ifOk(self.okValue)
                else
                    _0 = ifErr(self.errValue)
                end
                return _0
            end
            function Result:asPtr()
                local _0 = (self.okValue)
                if _0 == nil then
                    _0 = (self.errValue)
                end
                return _0
            end
        end
        local resultMeta = Result
        resultMeta.__eq = function(a, b)
            return b:match(function(ok)
                return a:contains(ok)
            end, function(err)
                return a:containsErr(err)
            end)
        end
        resultMeta.__tostring = function(result)
            return result:match(function(ok)
                return "Result.ok(" .. tostring(ok) .. ")"
            end, function(err)
                return "Result.err(" .. tostring(err) .. ")"
            end)
        end
        return {
            Result = Result,
        }
    )LUAU";

    CheckResult result = check(src);

    CHECK(hasError<CodeTooComplex>(result));
}

TEST_CASE_FIXTURE(LimitFixture, "Signal_exerpt" * doctest::timeout(0.5))
{
    ScopedFastFlag sff[] = {
        // These flags are required to surface the problem.
        {FFlag::LuauSolverV2, true},
        {FFlag::LuauEagerGeneralization4, true},
        {FFlag::LuauTrackFreeInteriorTypePacks, true},
        {FFlag::LuauPushFunctionTypesInFunctionStatement, true},
        {FFlag::LuauTrackFreeInteriorTypePacks, true},

        // And this flag is the one that fixes it.
        {FFlag::LuauSimplifyAnyAndUnion, true},
    };

    constexpr const char* src = R"LUAU(
        local Signal = {}
        Signal.ClassName = "Signal"
        export type Signal<T...> = typeof(setmetatable(
            {} :: {},
            {} :: typeof({ __index = Signal })
        ))
        function Signal.new<T...>(): Signal<T...>
            return nil :: any
        end

        function Signal.Connect<T...>(self: Signal<T...>)
        end

        function Signal.DisconnectAll<T...>(self: Signal<T...>): ()
            self._handlerListHead = false
        end

        function Signal.Fire<T...>(self: Signal<T...>): ()
            local connection
            rawget(connection, "_signal")
        end

        function Signal.Wait<T...>(self: Signal<T...>)
            connection = self:Connect(function()
                connection:Disconnect()
            end)
        end

        function Signal.Once<T...>(self: Signal<T...>, fn: SignalHandler<T...>): Connection<T...>
            connection = self:Connect(function() end)
        end
    )LUAU";

    CheckResult result = check(src);

    (void)result;
}

TEST_CASE_FIXTURE(Fixture, "limit_number_of_dynamically_created_constraints")
{
    ScopedFastFlag sff[] = {
        {FFlag::LuauSolverV2, true},
        {FFlag::LuauLimitDynamicConstraintSolving3, true},
    };

    constexpr const char* src = R"(
        type Array<T> = {T}

        type Hello = Array<Array<Array<Array<Array<Array<Array<Array<Array<Array<number>>>>>>>>>>
    )";

    {
        ScopedFastInt sfi{FInt::LuauSolverConstraintLimit, 1};
        CheckResult result = check(src);
        LUAU_CHECK_ERROR(result, CodeTooComplex);
    }

    {
        ScopedFastInt sfi{FInt::LuauSolverConstraintLimit, 1000};
        CheckResult result = check(src);
        LUAU_CHECK_NO_ERRORS(result);
    }

    {
        ScopedFastInt sfi{FInt::LuauSolverConstraintLimit, 0};
        CheckResult result = check(src);
        LUAU_CHECK_NO_ERRORS(result);
    }
}

TEST_CASE_FIXTURE(BuiltinsFixture, "limit_number_of_dynamically_created_constraints_2")
{
    ScopedFastFlag sff[] = {
        {FFlag::LuauSolverV2, true},
        {FFlag::LuauLimitDynamicConstraintSolving3, true},
        {FFlag::LuauEagerGeneralization4, true},
        {FFlag::LuauTrackFreeInteriorTypePacks, true},
        {FFlag::LuauPushFunctionTypesInFunctionStatement, true},
        {FFlag::LuauDontDynamicallyCreateRedundantSubtypeConstraints, true},
    };

    ScopedFastInt sfi{FInt::LuauSolverConstraintLimit, 50};

    CheckResult result = check(R"(
        local T = {}

        export type T = typeof(setmetatable(
            {},
            {} :: typeof(T)
        ))

        function T.One(): T
            return nil :: any
        end

        function T.Two(self: T) end

        function T.Three(self: T, x)
            self.Prop[x] = true
        end

        function T.Four(self: T, x)
            print("", x)
        end

        function T.Five(self: T) end

        function T.Six(self: T) end

        function T.Seven(self: T) end

        function T.Eight(self: T) end

        function T.Nine(self: T) end

        function T.Ten(self: T) end

        function T.Eleven(self: T) end

        function T.Twelve(self: T) end
    )");

    LUAU_REQUIRE_ERROR_COUNT(1, result);
    LUAU_REQUIRE_ERROR(result, UnknownProperty);

    // A sanity check to ensure that this statistic is being recorded at all.
    CHECK(frontend->stats.dynamicConstraintsCreated > 10);

    CHECK(frontend->stats.dynamicConstraintsCreated < 40);
}

TEST_SUITE_END();