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

// Waits, traces and log follows: `wait --frames` and a condition reply on the
// Pump that satisfies them, a condition that cannot be decided replies with
// why, an event wakes its waiter from the emitting thread without waiting
// for Pump, and a timeout says what the condition's paths were. A trace
// collects a value over frames with its stats, or a sample's history. The
// log filters by level, and a follower receives new matching entries in
// order, is dropped when it cannot keep up, and ends when its time is up.
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:
        std::atomic<bool> refuse = false;

        void Reply(const Value& reply) override {
            std::lock_guard lock(mutex);
            if (!final) final = reply;
        }
        bool Stream(const Value& line) override {
            if (refuse) return false;
            std::lock_guard lock(mutex);
            lines.push_back(line);
            return true;
        }
        std::optional<Value> Final() {
            std::lock_guard lock(mutex);
            return final;
        }
        std::vector<Value> Lines() {
            std::lock_guard lock(mutex);
            return lines;
        }

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

    Session* session = nullptr;

    std::shared_ptr<FakeExchange> Send(std::string_view method, std::string_view 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", Value::Parse(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() {
    std::int32_t score = 0;
    Watch("score", score);
    Session owned({ .name = "wait", .listen = false });
    session = &owned;

    auto frames = Send("debug.wait", R"({"frames": 3})");
    Pump();
    Pump();
    Check(!frames->Final(), "wait --frames 3 has not replied after two frames");
    Pump();
    Check(ResultOf(*frames).Find("frame")->AsInteger() == 3, "wait --frames 3 replies on the third");

    auto condition = Send("debug.wait", R"({"condition": "score >= 2"})");
    for (std::int32_t i = 0; i < 5 && !condition->Final(); ++i) {
        ++score;
        Pump();
    }
    Check(score == 2 && CodeOf(*condition).empty(), "a condition replies on the Pump it holds");
    auto broken = Send("debug.wait", R"({"condition": "missing > 1"})");
    Pump();
    Check(CodeOf(*broken) == "ConditionError" && MessageOf(*broken).find("no watch or sample 'missing'") != std::string::npos, "an undecidable condition says why");

    auto event = Send("debug.wait", R"({"event": "Boom"})");
    std::thread([] { Emit("Boom", Value::Parse(R"({"power": 9})")); }).join();
    Check(event->Final().has_value() && ResultOf(*event).Find("payload")->Find("power")->AsInteger() == 9, "an event wakes its waiter without waiting for Pump");

    auto slow = Send("debug.wait", R"({"condition": "score > 100"})", 1);
    std::this_thread::sleep_for(std::chrono::milliseconds(10));
    Pump();
    Check(CodeOf(*slow) == "Timeout" && MessageOf(*slow).find("score is 2") != std::string::npos, "a timeout reports the condition's paths");
    Check(CodeOf(*Send("debug.wait", R"({"frames": 1, "paused": true})")) == "InvalidParams", "waiting for two things at once is refused");

    auto trace = Send("debug.trace", R"({"paths": ["score"], "frames": 4})");
    for (std::int32_t i = 0; i < 4; ++i) {
        score += 10;
        Pump();
    }
    const Value traced = ResultOf(*trace);
    const Value* series = traced.Find("series") ? traced.Find("series")->Find("score") : nullptr;
    Check(series != nullptr && series->Find("values")->Size() == 4 && series->Find("stats")->Find("min")->AsNumber() == 12
              && series->Find("stats")->Find("max")->AsNumber() == 42 && series->Find("stats")->Find("changes")->AsInteger() == 3,
          "a trace collects a value per frame with its stats");

    for (std::int32_t i = 1; i <= 3; ++i) {
        Sample("residual", 0.5 * i);
        Pump();
    }
    auto history = Send("debug.trace", R"({"paths": ["residual"], "history": true})");
    Pump();
    const Value historyReply = ResultOf(*history);
    const Value* samples = historyReply.Find("series") ? historyReply.Find("series")->Find("residual") : nullptr;
    Check(samples != nullptr && samples->Find("values")->Size() == 3 && samples->Find("stats")->Find("last")->AsNumber() == 1.5, "a trace can read a sample's history");

    Log("net", "hello {}", 1);
    LogWarn("net", "careful");
    const Value warnings = ResultOf(*Send("debug.log", R"({"level": "warn"})"));
    Check(warnings.Find("entries")->Size() == 1 && warnings.Find("entries")->Items()[0].Find("message")->AsString() == "careful", "the log filters by level");
    Check(CodeOf(*Send("debug.log", R"({"level": "loud"})")) == "InvalidParams", "an unknown level is refused");

    auto follow = Send("debug.log", R"({"follow": true, "category": "game"})");
    Log("game", "one");
    Log("other", "skip");
    Log("game", "two");
    const std::vector<Value> lines = follow->Lines();
    Check(lines.size() == 2 && lines[1].Find("entry")->Find("message")->AsString() == "two", "a follower receives new matching entries, in order");
    follow->refuse = true;
    Log("game", "three");
    Check(ResultOf(*Send("debug.status")).Find("following")->AsInteger() == 0, "a follower that cannot keep up is dropped");

    auto brief = Send("debug.log", R"({"follow": true, "forMs": 1})");
    std::this_thread::sleep_for(std::chrono::milliseconds(10));
    Pump();
    Check(brief->Final().has_value() && ResultOf(*brief).Find("ended") != nullptr, "a follow ends when its time is up");

    return failures == 0 ? 0 : 1;
}