#include <atomic>
#include <chrono>
#include <cstdint>
#include <cstring>
#include <algorithm>
#include <iostream>
#include <memory>
#include <mutex>
#include <thread>
#include <vector>

#include "node.h"
#include "rule_engine.h"
#include "packet_ring_buffer.h"
#include "actions/action_base.h"
#include "actions/log_action.h"
#include "actions/http_action.h"
#include "actions/external_api_action.h"
#include "actions/snapshot_action.h"
#include "actions/clip_action.h"

namespace rk3588 {

class AlarmNode : public INode {
private:
    struct AlarmJob {
        AlarmEvent event;
        std::shared_ptr<Frame> frame;
    };

    static std::shared_ptr<EncodedVideoFrameMeta> TryGetEncodedMeta(const std::shared_ptr<Frame>& frame) {
        if (!frame || !frame->user_meta) return nullptr;
        auto meta = std::static_pointer_cast<EncodedVideoFrameMeta>(frame->user_meta);
        if (!meta || meta->magic != EncodedVideoFrameMeta::kMagic) return nullptr;
        if (!meta->codec || meta->pkt.data.empty() || meta->pkt.pts_ms <= 0) return nullptr;
        return meta;
    }

public:
    std::string Id() const override { return id_; }
    std::string Type() const override { return "alarm"; }

    bool Init(const SimpleJson& config, const NodeContext& ctx) override {
        id_ = config.ValueOr<std::string>("id", "alarm");

        // Optional evaluation throttle (for alarm side). 0 = disabled.
        eval_interval_ms_ = std::max<int64_t>(0, static_cast<int64_t>(config.ValueOr<int>("eval_interval_ms", 0)));
        if (eval_interval_ms_ <= 0) {
            const double eval_fps = config.ValueOr<double>("eval_fps", 0.0);
            if (eval_fps > 0.0) {
                eval_interval_ms_ = static_cast<int64_t>(1000.0 / eval_fps);
                if (eval_interval_ms_ < 1) eval_interval_ms_ = 1;
            }
        }

        // Parse labels for class name mapping
        if (const SimpleJson* labels_cfg = config.Find("labels")) {
            for (const auto& label : labels_cfg->AsArray()) {
                labels_.push_back(label.AsString(""));
            }
        }

        // Initialize rule engine
        if (const SimpleJson* rules_cfg = config.Find("rules")) {
            if (!rule_engine_.Init(*rules_cfg, labels_)) {
                std::cerr << "[alarm] failed to init rule engine\n";
                return false;
            }
        }

        // Derive packet ring window from clip action config
        int pre_sec = 5;
        int post_sec = 0;
        int fps_hint = 25;
        if (const SimpleJson* actions_cfg = config.Find("actions")) {
            if (const SimpleJson* clip_cfg = actions_cfg->Find("clip")) {
                pre_sec = clip_cfg->ValueOr<int>("pre_sec", 5);
                post_sec = clip_cfg->ValueOr<int>("post_sec", 0);
                fps_hint = clip_cfg->ValueOr<int>("fps", 25);
            }
        }
        const int window_sec = std::max(1, std::max(0, pre_sec) + std::max(0, post_sec) + 2);
        packet_buffer_ = std::make_shared<PacketRingBuffer>(window_sec, fps_hint);

        // Alarm worker queue (avoid blocking Process())
        size_t alarm_q_size = 32;
        QueueDropStrategy alarm_q_strategy = QueueDropStrategy::DropOldest;
        if (const SimpleJson* q = config.Find("event_queue")) {
            if (q->IsObject()) {
                alarm_q_size = static_cast<size_t>(q->ValueOr<int>("size", static_cast<int>(alarm_q_size)));
                const std::string strat = q->ValueOr<std::string>("strategy", "drop_oldest");
                if (strat == "drop_newest") alarm_q_strategy = QueueDropStrategy::DropNewest;
                else if (strat == "block") alarm_q_strategy = QueueDropStrategy::Block;
                else alarm_q_strategy = QueueDropStrategy::DropOldest;
            }
        }
        alarm_queue_size_ = alarm_q_size;
        alarm_queue_strategy_ = alarm_q_strategy;
        alarm_queue_ = std::make_shared<SpscQueue<AlarmJob>>(alarm_queue_size_, alarm_queue_strategy_);

        // Initialize actions
        if (const SimpleJson* actions_cfg = config.Find("actions")) {
            // Log action
            if (const SimpleJson* log_cfg = actions_cfg->Find("log")) {
                if (log_cfg->ValueOr<bool>("enable", true)) {
                    auto action = std::make_unique<LogAction>();
                    if (action->Init(*log_cfg)) {
                        actions_.push_back(std::move(action));
                    }
                }
            }

            // Snapshot action (must be before HTTP to fill snapshot_url)
            if (const SimpleJson* snap_cfg = actions_cfg->Find("snapshot")) {
                if (snap_cfg->ValueOr<bool>("enable", false)) {
                    auto action = std::make_unique<SnapshotAction>();
                    if (action->Init(*snap_cfg)) {
                        actions_.push_back(std::move(action));
                    }
                }
            }

            // Clip action (must be before HTTP to fill clip_url)
            if (const SimpleJson* clip_cfg = actions_cfg->Find("clip")) {
                if (clip_cfg->ValueOr<bool>("enable", false)) {
                    auto action = std::make_unique<ClipAction>();
                    if (action->Init(*clip_cfg)) {
                        auto* clip_ptr = static_cast<ClipAction*>(action.get());
                        clip_ptr->SetPacketBuffer(packet_buffer_);
                        actions_.push_back(std::move(action));
                    }
                }
            }

            // HTTP action (should be after snapshot/clip to include media URLs)
            if (const SimpleJson* http_cfg = actions_cfg->Find("http")) {
                if (http_cfg->ValueOr<bool>("enable", false)) {
                    auto action = std::make_unique<HttpAction>();
                    if (action->Init(*http_cfg)) {
                        actions_.push_back(std::move(action));
                    }
                }
            }

            // External API action (token + message). Should be after snapshot/clip to include media URLs.
            if (const SimpleJson* ext_cfg = actions_cfg->Find("external_api")) {
                if (ext_cfg->ValueOr<bool>("enable", false)) {
                    auto action = std::make_unique<ExternalApiAction>();
                    if (action->Init(*ext_cfg)) {
                        actions_.push_back(std::move(action));
                    }
                }
            }
        } else {
            // Default: just log action
            auto action = std::make_unique<LogAction>();
            SimpleJson empty_cfg;
            action->Init(empty_cfg);
            actions_.push_back(std::move(action));
        }

        input_queue_ = ctx.input_queue;
        if (!input_queue_) {
            std::cerr << "[alarm] no input queue for node " << id_ << "\n";
            return false;
        }

        std::cout << "[alarm] initialized with " << actions_.size() << " actions\n";
        return true;
    }

    bool Start() override {
        worker_running_.store(true);
        worker_ = std::thread(&AlarmNode::WorkerLoop, this);
        std::cout << "[alarm] started\n";
        return true;
    }

    void Stop() override {
        worker_running_.store(false);
        if (alarm_queue_) alarm_queue_->Stop();
        if (worker_.joinable()) worker_.join();

        // Ensure all actions fully stop (Drain only clears pending work; Stop must reclaim threads/resources).
        for (auto& action : actions_) action->Drain();
        for (auto& action : actions_) action->Stop();

        std::cout << "[alarm] stopped, processed " << processed_frames_
                  << " frames, triggered " << alarm_count_ << " alarms\n";
    }

    void Drain() override {
        // First drain alarm jobs (so snapshot/clip are finished before draining HTTP queue).
        while (alarm_queue_ && (alarm_queue_->Size() > 0 || in_flight_.load() > 0)) {
            std::this_thread::sleep_for(std::chrono::milliseconds(50));
        }
        for (auto& action : actions_) action->Drain();
    }

    bool UpdateConfig(const SimpleJson& new_config) override {
        const std::string new_id = new_config.ValueOr<std::string>("id", id_);
        if (!new_id.empty() && new_id != id_) {
            return false;
        }

        // Parse labels
        std::vector<std::string> new_labels;
        if (const SimpleJson* labels_cfg = new_config.Find("labels")) {
            for (const auto& label : labels_cfg->AsArray()) {
                new_labels.push_back(label.AsString(""));
            }
        }

        // Build new rule engine
        RuleEngine new_engine;
        if (const SimpleJson* rules_cfg = new_config.Find("rules")) {
            if (!new_engine.Init(*rules_cfg, new_labels)) {
                return false;
            }
        }

        // Packet ring window settings
        int pre_sec = 5;
        int post_sec = 0;
        int fps_hint = 25;
        if (const SimpleJson* actions_cfg = new_config.Find("actions")) {
            if (const SimpleJson* clip_cfg = actions_cfg->Find("clip")) {
                pre_sec = clip_cfg->ValueOr<int>("pre_sec", 5);
                post_sec = clip_cfg->ValueOr<int>("post_sec", 0);
                fps_hint = clip_cfg->ValueOr<int>("fps", 25);
            }
        }
        const int window_sec = std::max(1, std::max(0, pre_sec) + std::max(0, post_sec) + 2);
        auto new_packet_buffer = std::make_shared<PacketRingBuffer>(window_sec, fps_hint);

        // Initialize new actions
        std::vector<std::unique_ptr<IAlarmAction>> new_actions;
        if (const SimpleJson* actions_cfg = new_config.Find("actions")) {
            if (const SimpleJson* log_cfg = actions_cfg->Find("log")) {
                if (log_cfg->ValueOr<bool>("enable", true)) {
                    auto action = std::make_unique<LogAction>();
                    if (action->Init(*log_cfg)) {
                        new_actions.push_back(std::move(action));
                    }
                }
            }
            if (const SimpleJson* snap_cfg = actions_cfg->Find("snapshot")) {
                if (snap_cfg->ValueOr<bool>("enable", false)) {
                    auto action = std::make_unique<SnapshotAction>();
                    if (action->Init(*snap_cfg)) {
                        new_actions.push_back(std::move(action));
                    }
                }
            }
            if (const SimpleJson* clip_cfg = actions_cfg->Find("clip")) {
                if (clip_cfg->ValueOr<bool>("enable", false)) {
                    auto action = std::make_unique<ClipAction>();
                    if (action->Init(*clip_cfg)) {
                        auto* clip_ptr = static_cast<ClipAction*>(action.get());
                        clip_ptr->SetPacketBuffer(new_packet_buffer);
                        new_actions.push_back(std::move(action));
                    }
                }
            }
            if (const SimpleJson* http_cfg = actions_cfg->Find("http")) {
                if (http_cfg->ValueOr<bool>("enable", false)) {
                    auto action = std::make_unique<HttpAction>();
                    if (action->Init(*http_cfg)) {
                        new_actions.push_back(std::move(action));
                    }
                }
            }

            if (const SimpleJson* ext_cfg = actions_cfg->Find("external_api")) {
                if (ext_cfg->ValueOr<bool>("enable", false)) {
                    auto action = std::make_unique<ExternalApiAction>();
                    if (action->Init(*ext_cfg)) {
                        new_actions.push_back(std::move(action));
                    }
                }
            }
        }
        if (new_actions.empty()) {
            auto action = std::make_unique<LogAction>();
            SimpleJson empty_cfg;
            if (action->Init(empty_cfg)) {
                new_actions.push_back(std::move(action));
            }
        }

        // Stop worker thread to avoid executing actions while swapping.
        std::shared_ptr<SpscQueue<AlarmJob>> old_queue;
        std::thread old_worker;
        {
            std::lock_guard<std::mutex> lock(mu_);
            worker_running_.store(false);
            old_queue = alarm_queue_;
            old_worker = std::move(worker_);
        }
        if (old_queue) old_queue->Stop();
        if (old_worker.joinable()) old_worker.join();

        std::vector<std::unique_ptr<IAlarmAction>> old_actions;
        {
            std::lock_guard<std::mutex> lock(mu_);
            labels_ = std::move(new_labels);
            rule_engine_ = std::move(new_engine);
            packet_buffer_ = std::move(new_packet_buffer);
            old_actions = std::move(actions_);
            actions_ = std::move(new_actions);

            in_flight_.store(0);
            last_eval_pts_ms_ = 0;
            alarm_queue_ = std::make_shared<SpscQueue<AlarmJob>>(alarm_queue_size_, alarm_queue_strategy_);
            worker_running_.store(true);
            worker_ = std::thread(&AlarmNode::WorkerLoop, this);
        }

        for (auto& action : old_actions) action->Drain();
        for (auto& action : old_actions) action->Stop();
        return true;
    }

    bool GetCustomMetrics(SimpleJson& out) const override {
        std::lock_guard<std::mutex> lock(mu_);
        SimpleJson::Object o;
        o["alarm_total"] = SimpleJson(static_cast<double>(alarm_count_));
        o["processed"] = SimpleJson(static_cast<double>(processed_frames_));
        out = SimpleJson(std::move(o));
        return true;
    }

    NodeStatus Process(FramePtr frame) override {
        if (!frame) return NodeStatus::DROP;

        if (packet_buffer_) {
            if (auto meta = TryGetEncodedMeta(frame)) {
                packet_buffer_->Push(std::move(meta));
            }
        }

        {
            std::lock_guard<std::mutex> lock(mu_);

            if (eval_interval_ms_ > 0 && frame->pts > 0) {
                const int64_t pts_ms = static_cast<int64_t>(frame->pts / 1000ULL);
                if (last_eval_pts_ms_ > 0 && (pts_ms - last_eval_pts_ms_) < eval_interval_ms_) {
                    ++processed_frames_;
                    return NodeStatus::OK;
                }
                last_eval_pts_ms_ = pts_ms;
            }

            auto result = rule_engine_.Evaluate(frame);
            if (result.matched) TriggerAlarm(result, frame);
            ++processed_frames_;
        }
        return NodeStatus::OK;
    }

private:
    void WorkerLoop() {
        while (worker_running_.load()) {
            AlarmJob job;
            if (!alarm_queue_) {
                std::this_thread::sleep_for(std::chrono::milliseconds(50));
                continue;
            }
            if (!alarm_queue_->Pop(job, std::chrono::milliseconds(100))) {
                continue;
            }
            in_flight_.fetch_add(1);
            for (auto& action : actions_) {
                action->Execute(job.event, job.frame);
            }
            in_flight_.fetch_sub(1);
        }
    }

    void TriggerAlarm(const RuleMatchResult& result, FramePtr frame) {
        ++alarm_count_;

        AlarmEvent event;
        event.node_id = id_;
        event.rule_name = result.rule_name;
        event.timestamp_ms = std::chrono::duration_cast<std::chrono::milliseconds>(
            std::chrono::system_clock::now().time_since_epoch()).count();
        event.frame_id = frame->frame_id;
        event.detections = result.matched_detections;

        AlarmJob job;
        job.event = std::move(event);
        job.frame = std::move(frame);

        if (alarm_queue_) {
            alarm_queue_->Push(std::move(job));
        }
    }

    std::string id_;
    std::vector<std::string> labels_;
    RuleEngine rule_engine_;
    std::shared_ptr<PacketRingBuffer> packet_buffer_;
    std::vector<std::unique_ptr<IAlarmAction>> actions_;

    mutable std::mutex mu_;

    std::shared_ptr<SpscQueue<AlarmJob>> alarm_queue_;
    size_t alarm_queue_size_ = 32;
    QueueDropStrategy alarm_queue_strategy_ = QueueDropStrategy::DropOldest;
    std::atomic<bool> worker_running_{false};
    std::thread worker_;
    std::atomic<size_t> in_flight_{0};

    std::shared_ptr<SpscQueue<FramePtr>> input_queue_;
    uint64_t processed_frames_ = 0;
    uint64_t alarm_count_ = 0;

    int64_t eval_interval_ms_ = 0;
    int64_t last_eval_pts_ms_ = 0;
};

REGISTER_NODE(AlarmNode, "alarm");

}  // namespace rk3588