// SPDX-License-Identifier: LGPL-3.0-only
// SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®

// The session answers requests the way a client relies on: a wrong token is
// Unauthorized, a mistyped method gets a suggestion, hello and status are
// answered at once, while calls, gets, sets and screenshots wait for the
// app's Pump and run there. A request whose timeout passes before that Pump
// is answered Timeout and is never run; a throwing handler is an Exception
// reply; an Async result arrives on the Pump it is ready; the agent's
// actions appear on the timeline; there is one Session per process; and
// requests still queued when it ends are answered ShuttingDown.
import std;
import Crafter.Debug;
using namespace Crafter::Debug;

namespace {
    std::int32_t failures = 0;

    void Check(bool ok, std::string_view what) {
        std::println("{} {}", ok ? "PASS" : "FAIL", what);
        if (!ok) ++failures;
    }

    class FakeExchange : public Detail::Exchange {
    public:
        void Reply(const Value& reply) override {
            std::lock_guard lock(mutex);
            if (!final) final = reply;
        }
        bool Stream(const Value& line) override {
            std::lock_guard lock(mutex);
            lines.push_back(line);
            return true;
        }
        std::optional<Value> Final() {
            std::lock_guard lock(mutex);
            return final;
        }

    private:
        std::mutex mutex;
        std::optional<Value> final;
        std::vector<Value> lines;
    };

    Session* session = nullptr;

    std::shared_ptr<FakeExchange> Send(std::string_view method, Value params = {}, std::int64_t timeoutMs = 30'000) {
        Value request = Value::MakeObject();
        request.Set("token", Value(session->Token()));
        request.Set("method", Value(method));
        request.Set("params", std::move(params));
        request.Set("timeoutMs", Value(timeoutMs));
        auto exchange = std::make_shared<FakeExchange>();
        session->Handle(request, exchange);
        return exchange;
    }

    Value ResultOf(FakeExchange& exchange) {
        const auto reply = exchange.Final();
        return reply && reply->Find("result") ? *reply->Find("result") : Value();
    }

    std::string CodeOf(FakeExchange& exchange) {
        const auto reply = exchange.Final();
        return reply && reply->Find("error") ? reply->Find("error")->Find("code")->AsString() : std::string();
    }

    std::string MessageOf(FakeExchange& exchange) {
        const auto reply = exchange.Final();
        return reply && reply->Find("error") ? reply->Find("error")->Find("message")->AsString() : std::string();
    }
}

int main() {
    Command("Player_Fire", "Fire.", [] { return std::string("bang"); });
    Command("Game_Crash", "Throws.", []() -> std::int32_t { throw std::runtime_error("boom"); });
    std::int32_t polls = 0;
    Command("Sim_Hash", "Ready on the second poll.", [&]() -> Async<std::int32_t> {
        return Async<std::int32_t>([&]() -> std::optional<std::int32_t> {
            if (++polls < 2) return std::nullopt;
            return 7;
        });
    });
    std::int32_t hp = 100;
    Watch("fort.hp", hp);
    const std::int32_t level = 3;
    Watch("level", level);

    std::shared_ptr<FakeExchange> leftOver;
    {
        Session owned({ .name = "test", .listen = false });
        session = &owned;

        auto wrongToken = std::make_shared<FakeExchange>();
        owned.Handle(Value::Parse(R"({"token": "nope", "method": "debug.status"})"), wrongToken);
        Check(CodeOf(*wrongToken) == "Unauthorized", "a wrong token is refused");
        auto notObject = std::make_shared<FakeExchange>();
        owned.Handle(Value(3), notObject);
        Check(CodeOf(*notObject) == "InvalidRequest", "a request that is not an object is refused");

        const Value hello = ResultOf(*Send("debug.hello"));
        Check(hello.Find("protocol")->AsInteger() == 1 && hello.Find("name")->AsString() == "test", "hello names the protocol and the instance");
        const Value status = ResultOf(*Send("debug.status"));
        Check(status.Find("frame")->AsInteger() == 0 && !status.Find("paused")->AsBool() && !status.Find("pauseSupported")->AsBool(), "status is answered at once");
        const Value list = ResultOf(*Send("debug.list"));
        Check(list.Find("commands")->Size() == 3 && list.Find("watches")->Size() == 5, "list has the commands and watches, the session's own included");

        auto typo = Send("debug.stauts");
        Check(CodeOf(*typo) == "UnknownMethod" && MessageOf(*typo).find("did you mean 'debug.status'") != std::string::npos, "a mistyped method gets a suggestion");
        auto commandTypo = Send("Player_Fier");
        Check(CodeOf(*commandTypo) == "UnknownMethod" && MessageOf(*commandTypo).find("did you mean 'Player_Fire'") != std::string::npos, "a mistyped command gets a suggestion");

        auto fire = Send("Player_Fire");
        Check(!fire->Final(), "a call waits for Pump");
        Pump();
        Check(ResultOf(*fire).AsString() == "bang", "Pump runs the call and replies");

        auto get = Send("debug.get", Value::Parse(R"({"paths": ["fort.hp", "lev*", "nope"]})"));
        Pump();
        const Value got = ResultOf(*get);
        Check(got.Find("values")->Find("fort.hp")->AsInteger() == 100 && got.Find("values")->Find("level")->AsInteger() == 3 && got.Find("errors")->Find("nope") != nullptr,
              "get reads paths and globs, and reports the ones it cannot");
        auto badGet = Send("debug.get", Value::Parse(R"({"pathz": []})"));
        Pump();
        Check(CodeOf(*badGet) == "InvalidParams" && MessageOf(*badGet).find("did you mean 'paths'") != std::string::npos, "a mistyped parameter gets a suggestion");

        auto set = Send("debug.set", Value::Parse(R"({"path": "fort.hp", "value": 5})"));
        Pump();
        Check(hp == 5 && ResultOf(*set).Find("value")->AsInteger() == 5, "set writes on the Pump thread and replies with the new value");
        auto readOnly = Send("debug.set", Value::Parse(R"({"path": "level", "value": 5})"));
        Pump();
        Check(CodeOf(*readOnly) == "ReadOnly", "setting a read-only watch is refused");

        auto crash = Send("Game_Crash");
        Pump();
        Check(CodeOf(*crash) == "Exception" && MessageOf(*crash).find("boom") != std::string::npos, "a throwing handler is an Exception reply");

        std::int32_t fired = 0;
        Command("Count", "Counts.", [&] { ++fired; });
        auto late = Send("Count", {}, 1);
        std::this_thread::sleep_for(std::chrono::milliseconds(20));
        Pump();
        Check(CodeOf(*late) == "Timeout" && MessageOf(*late).find("not run") != std::string::npos && fired == 0, "a request past its timeout before Pump is never run");

        auto hash = Send("Sim_Hash");
        Pump();
        Check(!hash->Final(), "an Async result is not ready on its first poll");
        Pump();
        Check(ResultOf(*hash).AsInteger() == 7, "an Async result is replied on the Pump it is ready");

        auto noShot = Send("debug.screenshot");
        Pump();
        Check(CodeOf(*noShot) == "NoCapture", "a screenshot without a capture source says so");
        SetCapture([] {
            return Async<std::vector<std::byte>>([]() -> std::optional<std::vector<std::byte>> {
                return std::vector<std::byte>{ std::byte{ 0x89 }, std::byte{ 'P' }, std::byte{ 'N' }, std::byte{ 'G' } };
            });
        });
        auto shot = Send("debug.screenshot");
        Pump();
        const auto png = Base64Decode(ResultOf(*shot).Find("png")->AsString());
        Check(png && png->size() == 4 && (*png)[1] == std::byte{ 'P' }, "a screenshot's PNG comes back as base64");

        auto agent = Send("debug.log", Value::Parse(R"({"kinds": ["agent"], "last": 100})"));
        const Value entries = *ResultOf(*agent).Find("entries");
        Check(std::ranges::any_of(entries.Items(), [](const Value& entry) { return entry.Find("message")->AsString().starts_with("Player_Fire"); }),
              "the agent's calls are on the timeline");

        bool threw = false;
        try {
            Session second({ .listen = false });
        } catch (const std::logic_error&) {
            threw = true;
        }
        Check(threw, "a second Session is refused");

        leftOver = Send("Player_Fire");
    }
    Check(CodeOf(*leftOver) == "ShuttingDown", "a request still queued when the Session ends is answered ShuttingDown");

    return failures == 0 ? 0 : 1;
}