#include "event_bus.h"

namespace roro {

EventBus::EventBus(size_t capacity) : queue_(capacity) {}

bool EventBus::publish(const Event& event) {
    std::lock_guard<std::mutex> lock(mutex_);
    if (count_ == queue_.size()) {
        dropped_++;
        return false;
    }
    queue_[(head_ + count_) % queue_.size()] = event;
    count_++;
    return true;
}

void EventBus::subscribe(EventType type, Handler handler) {
    handlers_[static_cast<size_t>(type)].push_back(std::move(handler));
}

size_t EventBus::dispatch() {
    size_t pending;
    {
        std::lock_guard<std::mutex> lock(mutex_);
        pending = count_;
    }
    for (size_t i = 0; i < pending; i++) {
        Event event;
        {
            std::lock_guard<std::mutex> lock(mutex_);
            event = queue_[head_];
            head_ = (head_ + 1) % queue_.size();
            count_--;
        }
        for (auto& handler : handlers_[static_cast<size_t>(event.type)]) handler(event);
    }
    return pending;
}

uint32_t EventBus::dropped() const {
    std::lock_guard<std::mutex> lock(mutex_);
    return dropped_;
}

}  // namespace roro