#include "region_event_node.h"

#include <algorithm>
#include <cstdint>
#include <map>
#include <memory>
#include <string>
#include <utility>
#include <vector>

#include "behavior/behavior_event.h"
#include "utils/logger.h"

namespace rk3588 {
namespace {

enum class RegionEventKind {
    Intrusion,
    Climb
};

struct NormalizedLine {
    float x1 = 0.0f;
    float y1 = 0.0f;
    float x2 = 0.0f;
    float y2 = 0.0f;
};

struct RegionEventRule {
    RegionEventKind kind = RegionEventKind::Intrusion;
    std::string region_id;
    Rect roi{};
    NormalizedLine line{};
    uint64_t min_duration_ms = 0;
    float min_vertical_motion = 0.0f;
};

struct TrackState {
    Rect bbox{};
    uint64_t pts = 0;
};

static bool ParseRules(const SimpleJson& config, std::vector<RegionEventRule>& out, std::string& err) {
    const SimpleJson* events = config.Find("events");
    if (!events || !events->IsArray()) {
        err = "events must be array";
        return false;
    }

    out.clear();
    for (const auto& ev : events->AsArray()) {
        if (!ev.IsObject()) {
            err = "event entry must be object";
            return false;
        }

        RegionEventRule rule;
        const std::string type = ev.ValueOr<std::string>("type", "");
        rule.region_id = ev.ValueOr<std::string>("region_id", "");
        rule.min_duration_ms = static_cast<uint64_t>(std::max(0, ev.ValueOr<int>("min_duration_ms", 0)));

        if (type == "intrusion") {
            const SimpleJson* roi = ev.Find("roi");
            if (!roi || !roi->IsObject()) {
                err = "intrusion event requires roi";
                return false;
            }
            rule.kind = RegionEventKind::Intrusion;
            rule.roi.x = roi->ValueOr<float>("x", 0.0f);
            rule.roi.y = roi->ValueOr<float>("y", 0.0f);
            rule.roi.w = roi->ValueOr<float>("w", 0.0f);
            rule.roi.h = roi->ValueOr<float>("h", 0.0f);
        } else if (type == "climb") {
            const SimpleJson* line = ev.Find("line");
            if (!line || !line->IsObject()) {
                err = "climb event requires line";
                return false;
            }
            rule.kind = RegionEventKind::Climb;
            rule.line.x1 = line->ValueOr<float>("x1", 0.0f);
            rule.line.y1 = line->ValueOr<float>("y1", 0.0f);
            rule.line.x2 = line->ValueOr<float>("x2", 0.0f);
            rule.line.y2 = line->ValueOr<float>("y2", 0.0f);
            rule.min_vertical_motion = ev.ValueOr<float>("min_vertical_motion", 0.0f);
        } else {
            err = "unsupported event type: " + type;
            return false;
        }

        out.push_back(std::move(rule));
    }
    return true;
}

static float CenterX(const Rect& rect) {
    return rect.x + (rect.w * 0.5f);
}

static float CenterY(const Rect& rect) {
    return rect.y + (rect.h * 0.5f);
}

static bool IsInsideNormalizedRoi(const Rect& bbox, const Rect& roi, int img_w, int img_h) {
    if (img_w <= 0 || img_h <= 0) return false;
    const float cx = CenterX(bbox) / static_cast<float>(img_w);
    const float cy = CenterY(bbox) / static_cast<float>(img_h);
    return cx >= roi.x && cx <= (roi.x + roi.w) && cy >= roi.y && cy <= (roi.y + roi.h);
}

static bool CrossedHorizontalLine(const Rect& previous, const Rect& current, const RegionEventRule& rule, int img_h) {
    if (img_h <= 0) return false;
    const float line_y = rule.line.y1 * static_cast<float>(img_h);
    const float previous_top = previous.y;
    const float current_top = current.y;
    return previous_top > line_y &&
           current_top <= line_y &&
           (previous_top - current_top) >= rule.min_vertical_motion;
}

static BehaviorEventType ToBehaviorEventType(RegionEventKind kind) {
    return kind == RegionEventKind::Intrusion ? BehaviorEventType::Intrusion : BehaviorEventType::Climb;
}

}  // namespace

struct RegionEventNode::Impl {
    std::string init_err;
    std::vector<RegionEventRule> rules;
    std::map<int, TrackState> track_history;
};

RegionEventNode::RegionEventNode() : impl_(std::make_unique<Impl>()) {}

RegionEventNode::~RegionEventNode() = default;

std::string RegionEventNode::Id() const {
    return id_;
}

std::string RegionEventNode::Type() const {
    return "region_event";
}

bool RegionEventNode::Init(const SimpleJson& config, const NodeContext& ctx) {
    id_ = config.ValueOr<std::string>("id", "region_event");
    if (!ParseRules(config, impl_->rules, impl_->init_err)) {
        LogError("[region_event] invalid config: " + impl_->init_err);
        return false;
    }
    output_queues_ = ctx.output_queues;
    return true;
}

bool RegionEventNode::Start() {
    return true;
}

void RegionEventNode::Stop() {}

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

    EnsureBehaviorEvents(*frame);
    if (!frame->det) {
        PushToDownstream(frame);
        return NodeStatus::OK;
    }

    const int img_w = frame->det->img_w > 0 ? frame->det->img_w : frame->width;
    const int img_h = frame->det->img_h > 0 ? frame->det->img_h : frame->height;

    for (const auto& det : frame->det->items) {
        if (det.track_id < 0) continue;

        for (const auto& rule : impl_->rules) {
            if (rule.kind == RegionEventKind::Intrusion) {
                if (!IsInsideNormalizedRoi(det.bbox, rule.roi, img_w, img_h)) continue;

                BehaviorEventItem event;
                event.type = ToBehaviorEventType(rule.kind);
                event.status = BehaviorEventStatus::Active;
                event.score = det.score;
                event.bbox = det.bbox;
                event.track_ids.push_back(det.track_id);
                event.start_pts = frame->pts;
                event.last_pts = frame->pts;
                event.duration_ms = rule.min_duration_ms;
                event.source = "region_event";
                event.region_id = rule.region_id;
                frame->behavior_events->items.push_back(std::move(event));
            } else {
                auto it = impl_->track_history.find(det.track_id);
                if (it == impl_->track_history.end()) continue;
                if (!CrossedHorizontalLine(it->second.bbox, det.bbox, rule, img_h)) continue;

                BehaviorEventItem event;
                event.type = ToBehaviorEventType(rule.kind);
                event.status = BehaviorEventStatus::Active;
                event.score = det.score;
                event.bbox = det.bbox;
                event.track_ids.push_back(det.track_id);
                event.start_pts = it->second.pts;
                event.last_pts = frame->pts;
                event.duration_ms = frame->pts >= it->second.pts ? (frame->pts - it->second.pts) : 0;
                event.source = "region_event";
                event.region_id = rule.region_id;
                frame->behavior_events->items.push_back(std::move(event));
            }
        }

        impl_->track_history[det.track_id] = TrackState{det.bbox, frame->pts};
    }

    PushToDownstream(frame);
    return NodeStatus::OK;
}

void RegionEventNode::EnsureBehaviorEvents(Frame& frame) {
    if (!frame.behavior_events) {
        frame.behavior_events = std::make_shared<BehaviorEventResult>();
    }
}

void RegionEventNode::PushToDownstream(const FramePtr& frame) {
    for (auto& q : output_queues_) {
        if (q) q->Push(frame);
    }
}

#ifndef RK3588_TEST_BUILD
REGISTER_NODE(RegionEventNode, "region_event");
#endif

}  // namespace rk3588