#include <algorithm>
#include <cmath>
#include <cstdint>
#include <cstring>
#include <memory>
#include <string>
#include <vector>

#include "face/face_result.h"
#include "hw/i_image_processor.h"
#include "node.h"
#include "utils/dma_alloc.h"
#include "utils/logger.h"

namespace rk3588 {

namespace {

enum class ResizeMode {
    Stretch,
    KeepRatio,
    Letterbox,
};

PixelFormat ParseFormat(const std::string& s) {
    if (s == "nv12" || s == "NV12") return PixelFormat::NV12;
    if (s == "yuv420" || s == "YUV420") return PixelFormat::YUV420;
    if (s == "rgb" || s == "RGB") return PixelFormat::RGB;
    if (s == "bgr" || s == "BGR") return PixelFormat::BGR;
    return PixelFormat::UNKNOWN;
}

ResizeMode ParseResizeMode(const std::string& s, bool keep_ratio) {
    if (s == "stretch") return ResizeMode::Stretch;
    if (s == "keep_ratio" || s == "fit") return ResizeMode::KeepRatio;
    if (s == "letterbox") return ResizeMode::Letterbox;
    return keep_ratio ? ResizeMode::KeepRatio : ResizeMode::Stretch;
}

inline bool IsYuvFormat(PixelFormat fmt) {
    return fmt == PixelFormat::NV12 || fmt == PixelFormat::YUV420;
}

inline float ClampFloat(float v, float lo, float hi) {
    return std::max(lo, std::min(v, hi));
}

inline int MakeEvenFloor(int v) {
    if (v <= 0) return 0;
    return v & ~1;
}

size_t CalcImageSize(int w, int h, PixelFormat fmt) {
    if (w <= 0 || h <= 0) return 0;
    switch (fmt) {
        case PixelFormat::NV12:
        case PixelFormat::YUV420:
            return static_cast<size_t>(w) * static_cast<size_t>(h) * 3 / 2;
        case PixelFormat::RGB:
        case PixelFormat::BGR:
            return static_cast<size_t>(w) * static_cast<size_t>(h) * 3;
        default:
            return 0;
    }
}

void SetupPlanes(Frame& f) {
    if (!f.data || f.width <= 0 || f.height <= 0) return;
    if (f.format == PixelFormat::NV12) {
        const int y_stride = f.width;
        const int y_size = y_stride * f.height;
        const int uv_size = y_stride * (f.height / 2);
        f.stride = y_stride;
        f.plane_count = 2;
        f.planes[0] = {f.data, y_stride, y_size, 0};
        f.planes[1] = {f.data + y_size, y_stride, uv_size, y_size};
    } else if (f.format == PixelFormat::YUV420) {
        const int y_stride = f.width;
        const int y_size = y_stride * f.height;
        const int uv_stride = f.width / 2;
        const int u_size = uv_stride * (f.height / 2);
        f.stride = y_stride;
        f.plane_count = 3;
        f.planes[0] = {f.data, y_stride, y_size, 0};
        f.planes[1] = {f.data + y_size, uv_stride, u_size, y_size};
        f.planes[2] = {f.data + y_size + u_size, uv_stride, u_size, y_size + u_size};
    } else {
        const int stride = f.width * 3;
        f.stride = stride;
        f.plane_count = 1;
        f.planes[0] = {f.data, stride, static_cast<int>(f.data_size), 0};
    }
    f.SyncBufferFromFrame();
}

bool InitFrameStorage(Frame& f) {
    const size_t need = CalcImageSize(f.width, f.height, f.format);
    if (need == 0) return false;

    if (auto dma = DmaAlloc(need); dma && dma->valid()) {
        f.SetDmaFd(dma->fd);
        f.data = dma->data();
        f.data_size = dma->size;
        f.SetOwner(dma);
        SetupPlanes(f);
        return true;
    }

    auto buf = std::make_shared<std::vector<uint8_t>>(need);
    f.SetDmaFd(-1);
    f.data = buf->data();
    f.data_size = buf->size();
    f.SetOwner(buf);
    SetupPlanes(f);
    return true;
}

void FillBlack(Frame& f) {
    if (!f.data || f.data_size == 0) return;
    if (f.DmaFd() >= 0) {
        DmaSyncStartFd(f.DmaFd());
    }
    if (f.format == PixelFormat::NV12) {
        const int y_size = f.width * f.height;
        std::memset(f.data, 0, static_cast<size_t>(y_size));
        std::memset(f.data + y_size, 128, static_cast<size_t>(f.width * f.height / 2));
    } else if (f.format == PixelFormat::YUV420) {
        const int y_size = f.width * f.height;
        const int u_size = (f.width / 2) * (f.height / 2);
        std::memset(f.data, 0, static_cast<size_t>(y_size));
        std::memset(f.data + y_size, 128, static_cast<size_t>(u_size));
        std::memset(f.data + y_size + u_size, 128, static_cast<size_t>(u_size));
    } else {
        std::memset(f.data, 0, f.data_size);
    }
    if (f.DmaFd() >= 0) {
        DmaSyncEndFd(f.DmaFd());
    }
}

bool BlitLetterbox(const Frame& src, Frame& dst, int pad_x, int pad_y) {
    if (!src.data || !dst.data || src.format != dst.format) return false;
    if (pad_x < 0 || pad_y < 0) return false;
    if (src.width + pad_x > dst.width || src.height + pad_y > dst.height) return false;

    if (src.DmaFd() >= 0) src.SyncStart();
    if (dst.DmaFd() >= 0) DmaSyncStartFd(dst.DmaFd());

    if (src.format == PixelFormat::RGB || src.format == PixelFormat::BGR) {
        const int src_stride = src.planes[0].stride > 0 ? src.planes[0].stride : src.width * 3;
        const int dst_stride = dst.planes[0].stride > 0 ? dst.planes[0].stride : dst.width * 3;
        const uint8_t* src_ptr = src.planes[0].data ? src.planes[0].data : src.data;
        uint8_t* dst_ptr = dst.planes[0].data ? dst.planes[0].data : dst.data;
        const size_t row_bytes = static_cast<size_t>(src.width) * 3;
        for (int y = 0; y < src.height; ++y) {
            std::memcpy(dst_ptr + static_cast<size_t>(y + pad_y) * dst_stride + static_cast<size_t>(pad_x) * 3,
                        src_ptr + static_cast<size_t>(y) * src_stride,
                        row_bytes);
        }
    } else if (src.format == PixelFormat::NV12) {
        const int src_y_stride = src.planes[0].stride > 0 ? src.planes[0].stride : src.width;
        const int src_uv_stride = src.planes[1].stride > 0 ? src.planes[1].stride : src.width;
        const int dst_y_stride = dst.planes[0].stride > 0 ? dst.planes[0].stride : dst.width;
        const int dst_uv_stride = dst.planes[1].stride > 0 ? dst.planes[1].stride : dst.width;
        const uint8_t* src_y = src.planes[0].data ? src.planes[0].data : src.data;
        const uint8_t* src_uv = src.planes[1].data ? src.planes[1].data : (src.data + src.width * src.height);
        uint8_t* dst_y = dst.planes[0].data ? dst.planes[0].data : dst.data;
        uint8_t* dst_uv = dst.planes[1].data ? dst.planes[1].data : (dst.data + dst.width * dst.height);

        for (int y = 0; y < src.height; ++y) {
            std::memcpy(dst_y + static_cast<size_t>(y + pad_y) * dst_y_stride + pad_x,
                        src_y + static_cast<size_t>(y) * src_y_stride,
                        static_cast<size_t>(src.width));
        }

        const int uv_rows = src.height / 2;
        for (int y = 0; y < uv_rows; ++y) {
            std::memcpy(dst_uv + static_cast<size_t>(y + pad_y / 2) * dst_uv_stride + pad_x,
                        src_uv + static_cast<size_t>(y) * src_uv_stride,
                        static_cast<size_t>(src.width));
        }
    } else if (src.format == PixelFormat::YUV420) {
        const int src_y_stride = src.planes[0].stride > 0 ? src.planes[0].stride : src.width;
        const int src_u_stride = src.planes[1].stride > 0 ? src.planes[1].stride : src.width / 2;
        const int src_v_stride = src.planes[2].stride > 0 ? src.planes[2].stride : src.width / 2;
        const int dst_y_stride = dst.planes[0].stride > 0 ? dst.planes[0].stride : dst.width;
        const int dst_u_stride = dst.planes[1].stride > 0 ? dst.planes[1].stride : dst.width / 2;
        const int dst_v_stride = dst.planes[2].stride > 0 ? dst.planes[2].stride : dst.width / 2;
        const uint8_t* src_y = src.planes[0].data ? src.planes[0].data : src.data;
        const uint8_t* src_u = src.planes[1].data ? src.planes[1].data : (src.data + src.width * src.height);
        const uint8_t* src_v = src.planes[2].data ? src.planes[2].data : (src_u + (src.width / 2) * (src.height / 2));
        uint8_t* dst_y = dst.planes[0].data ? dst.planes[0].data : dst.data;
        uint8_t* dst_u = dst.planes[1].data ? dst.planes[1].data : (dst.data + dst.width * dst.height);
        uint8_t* dst_v = dst.planes[2].data ? dst.planes[2].data : (dst_u + (dst.width / 2) * (dst.height / 2));

        for (int y = 0; y < src.height; ++y) {
            std::memcpy(dst_y + static_cast<size_t>(y + pad_y) * dst_y_stride + pad_x,
                        src_y + static_cast<size_t>(y) * src_y_stride,
                        static_cast<size_t>(src.width));
        }

        const int uv_rows = src.height / 2;
        const int uv_pad_x = pad_x / 2;
        const int uv_pad_y = pad_y / 2;
        const int uv_cols = src.width / 2;
        for (int y = 0; y < uv_rows; ++y) {
            std::memcpy(dst_u + static_cast<size_t>(y + uv_pad_y) * dst_u_stride + uv_pad_x,
                        src_u + static_cast<size_t>(y) * src_u_stride,
                        static_cast<size_t>(uv_cols));
            std::memcpy(dst_v + static_cast<size_t>(y + uv_pad_y) * dst_v_stride + uv_pad_x,
                        src_v + static_cast<size_t>(y) * src_v_stride,
                        static_cast<size_t>(uv_cols));
        }
    } else {
        if (src.DmaFd() >= 0) src.SyncEnd();
        if (dst.DmaFd() >= 0) DmaSyncEndFd(dst.DmaFd());
        return false;
    }

    if (dst.DmaFd() >= 0) DmaSyncEndFd(dst.DmaFd());
    if (src.DmaFd() >= 0) src.SyncEnd();
    return true;
}

void TransformRect(Rect& r, float sx, float sy, float tx, float ty, int out_w, int out_h) {
    if (out_w <= 0 || out_h <= 0) {
        r = Rect{};
        return;
    }
    const float fw = static_cast<float>(out_w);
    const float fh = static_cast<float>(out_h);

    const float x = ClampFloat(r.x * sx + tx, 0.0f, fw);
    const float y = ClampFloat(r.y * sy + ty, 0.0f, fh);
    float w = std::max(0.0f, r.w * sx);
    float h = std::max(0.0f, r.h * sy);

    if (x + w > fw) w = std::max(0.0f, fw - x);
    if (y + h > fh) h = std::max(0.0f, fh - y);

    r.x = x;
    r.y = y;
    r.w = w;
    r.h = h;
}

void TransformPoint(Point2f& p, float sx, float sy, float tx, float ty, int out_w, int out_h) {
    if (out_w <= 0 || out_h <= 0) {
        p = Point2f{};
        return;
    }
    p.x = ClampFloat(p.x * sx + tx, 0.0f, static_cast<float>(out_w));
    p.y = ClampFloat(p.y * sy + ty, 0.0f, static_cast<float>(out_h));
}

}  // namespace

class PreprocessNode : public INode {
public:
    std::string Id() const override { return id_; }
    std::string Type() const override { return "preprocess"; }

    bool Init(const SimpleJson& config, const NodeContext& ctx) override {
        id_ = config.ValueOr<std::string>("id", "preprocess");
        dst_w_ = config.ValueOr<int>("dst_w", 640);
        dst_h_ = config.ValueOr<int>("dst_h", 640);
        keep_ratio_ = config.ValueOr<bool>("keep_ratio", false);
        resize_mode_ = ParseResizeMode(config.ValueOr<std::string>("resize_mode", ""), keep_ratio_);

        std::string fmt_str = config.ValueOr<std::string>("dst_format", "");
        if (!fmt_str.empty()) {
            dst_fmt_ = ParseFormat(fmt_str);
        }

        const bool requested_use_rga = config.ValueOr<bool>("use_rga", true);
        use_rga_ = requested_use_rga;

        if (const SimpleJson* dbg = config.Find("debug"); dbg && dbg->IsObject()) {
            stats_log_ = dbg->ValueOr<bool>("stats", stats_log_);
            stats_interval_ = std::max<uint64_t>(
                1, static_cast<uint64_t>(dbg->ValueOr<int>("stats_interval", static_cast<int>(stats_interval_))));
        }

        input_queue_ = ctx.input_queue;
        if (!input_queue_) {
            LogError("[preprocess] no input queue for node " + id_);
            return false;
        }
        if (ctx.output_queues.empty()) {
            LogError("[preprocess] no output queue for node " + id_);
            return false;
        }
        output_queues_ = ctx.output_queues;

#if !defined(RK3588_ENABLE_RGA)
        if (requested_use_rga) {
            LogError("[preprocess] use_rga=true but RGA not enabled at build time");
            return false;
        }
        use_rga_ = false;
#endif
#if !defined(RK3588_ENABLE_FFMPEG)
        if (!use_rga_) {
            LogError("[preprocess] neither RGA nor FFmpeg enabled");
            return false;
        }
#endif

        image_processor_ = ctx.image_processor;
        if (!image_processor_) {
            LogError("[preprocess] no image processor for node " + id_);
            return false;
        }

        return true;
    }

    bool Start() override {
        std::string mode = "stretch";
        if (resize_mode_ == ResizeMode::KeepRatio) mode = "keep_ratio";
        if (resize_mode_ == ResizeMode::Letterbox) mode = "letterbox";
        LogInfo("[preprocess] start id=" + id_ + " dst=" + std::to_string(dst_w_) + "x" +
                std::to_string(dst_h_) + " mode=" + mode + (use_rga_ ? " (rga)" : " (swscale)"));
        return true;
    }

    void Stop() override {}

    NodeStatus Process(FramePtr frame) override {
        static int process_count = 0;
        if (id_.find("post") != std::string::npos && process_count++ % 30 == 0) {

        }
        if (!frame) return NodeStatus::DROP;
        if (!image_processor_) return NodeStatus::ERROR;

        // Check if input frame has letterbox transform metadata - if so, crop to valid region
        if (frame->transform_meta && frame->transform_meta->valid && frame->transform_meta->letterbox) {
            Status crop_st = ProcessLetterboxInput(frame);
            if (crop_st.Ok()) return NodeStatus::OK;
        }

        PixelFormat out_fmt = (dst_fmt_ != PixelFormat::UNKNOWN) ? dst_fmt_ : frame->format;
        int out_w = dst_w_;
        int out_h = dst_h_;
        if (out_w <= 0) out_w = frame->width;
        if (out_h <= 0) out_h = frame->height;

        FrameTransformMeta tx{};
        tx.valid = true;
        tx.src_w = frame->width;
        tx.src_h = frame->height;

        Frame out;
        if (resize_mode_ == ResizeMode::Letterbox && dst_w_ > 0 && dst_h_ > 0 &&
            frame->width > 0 && frame->height > 0) {
            Status lb = BuildLetterbox(*frame, out_fmt, out_w, out_h, out, tx);
            if (lb.Failed()) {
                LogError("[preprocess] letterbox failed: " + lb.ErrMessage());
                return NodeStatus::ERROR;
            }
        } else {
            if (resize_mode_ == ResizeMode::KeepRatio && dst_w_ > 0 && dst_h_ > 0 &&
                frame->width > 0 && frame->height > 0) {
                float scale = std::min(static_cast<float>(dst_w_) / frame->width,
                                       static_cast<float>(dst_h_) / frame->height);
                out_w = static_cast<int>(std::round(frame->width * scale));
                out_h = static_cast<int>(std::round(frame->height * scale));
                if (IsYuvFormat(out_fmt)) {
                    out_w = std::max(2, MakeEvenFloor(out_w));
                    out_h = std::max(2, MakeEvenFloor(out_h));
                }
                if (out_w <= 0) out_w = frame->width;
                if (out_h <= 0) out_h = frame->height;
            }

            const bool need_resize = (frame->width != out_w || frame->height != out_h);
            const bool need_cvt = (frame->format != out_fmt);

            tx.letterbox = false;
            tx.dst_w = out_w;
            tx.dst_h = out_h;
            tx.scale_x = frame->width > 0 ? static_cast<float>(out_w) / frame->width : 1.0f;
            tx.scale_y = frame->height > 0 ? static_cast<float>(out_h) / frame->height : 1.0f;
            tx.pad_x = 0.0f;
            tx.pad_y = 0.0f;

            if (!need_resize && !need_cvt) {
                auto t = std::make_shared<FrameTransformMeta>(tx);
                frame->transform_meta = t;
                ProcessPassthrough(frame);
                return NodeStatus::OK;
            }

            if (need_resize) {
                WarnMetaResizeOnce(frame, out_w, out_h);
            }

            out.width = out_w;
            out.height = out_h;
            out.format = out_fmt;
            Status st = image_processor_->Resize(*frame, out);
            if (st.Failed()) {
                if (!use_rga_ && st.ErrMessage().find("unsupported format") != std::string::npos) {
                    auto t = std::make_shared<FrameTransformMeta>(tx);
                    frame->transform_meta = t;
                    ProcessPassthrough(frame);
                    return NodeStatus::OK;
                }
                LogError("[preprocess] " + st.ErrMessage());
                return NodeStatus::ERROR;
            }
        }

        auto out_frame = std::make_shared<Frame>(out);
        out_frame->pts = frame->pts;
        out_frame->frame_id = frame->frame_id;
        out_frame->transform_meta = std::make_shared<FrameTransformMeta>(tx);
        ScaleMeta(*frame, *out_frame, tx);
        out_frame->user_meta = frame->user_meta;

        PushToDownstream(out_frame);
        ++processed_;

        if (stats_log_ && stats_interval_ > 0 && (processed_ % stats_interval_) == 0) {
            LogInfo("[preprocess] " + std::string(use_rga_ ? "rga" : "swscale") +
                    " frame=" + std::to_string(out_frame->frame_id) +
                    " " + std::to_string(frame->width) + "x" + std::to_string(frame->height) +
                    " -> " + std::to_string(out_frame->width) + "x" + std::to_string(out_frame->height) +
                    " id=" + id_);
        }

        return NodeStatus::OK;
    }

private:
    Status BuildLetterbox(const Frame& input, PixelFormat out_fmt, int dst_w, int dst_h, Frame& out,
                          FrameTransformMeta& tx) const {
        Frame src = input;
        if (input.format != out_fmt) {
            src.width = input.width;
            src.height = input.height;
            src.format = out_fmt;
            Status cvt = image_processor_->CvtColor(input, src, out_fmt);
            if (cvt.Failed()) return cvt;
        }

        if (src.width <= 0 || src.height <= 0 || dst_w <= 0 || dst_h <= 0) {
            return FailStatus("invalid letterbox size");
        }

        float scale = std::min(static_cast<float>(dst_w) / static_cast<float>(src.width),
                               static_cast<float>(dst_h) / static_cast<float>(src.height));
        int inner_w = std::max(1, static_cast<int>(std::round(src.width * scale)));
        int inner_h = std::max(1, static_cast<int>(std::round(src.height * scale)));
        if (IsYuvFormat(out_fmt)) {
            inner_w = std::max(2, MakeEvenFloor(inner_w));
            inner_h = std::max(2, MakeEvenFloor(inner_h));
            if (((dst_w - inner_w) & 1) != 0) inner_w = std::max(2, inner_w - 2);
            if (((dst_h - inner_h) & 1) != 0) inner_h = std::max(2, inner_h - 2);
        }
        if (inner_w <= 0 || inner_h <= 0 || inner_w > dst_w || inner_h > dst_h) {
            return FailStatus("invalid inner letterbox size");
        }

        Frame resized;
        resized.width = inner_w;
        resized.height = inner_h;
        resized.format = out_fmt;
        Status st = image_processor_->Resize(src, resized);
        if (st.Failed()) return st;

        out.width = dst_w;
        out.height = dst_h;
        out.format = out_fmt;
        if (!InitFrameStorage(out)) {
            return FailStatus("alloc letterbox output failed");
        }
        FillBlack(out);

        const int pad_x = (dst_w - inner_w) / 2;
        const int pad_y = (dst_h - inner_h) / 2;
        if (!BlitLetterbox(resized, out, pad_x, pad_y)) {
            return FailStatus("blit letterbox failed");
        }

        tx.letterbox = true;
        tx.src_w = input.width;
        tx.src_h = input.height;
        tx.dst_w = dst_w;
        tx.dst_h = dst_h;
        tx.scale_x = static_cast<float>(inner_w) / static_cast<float>(input.width);
        tx.scale_y = static_cast<float>(inner_h) / static_cast<float>(input.height);
        tx.pad_x = static_cast<float>(pad_x);
        tx.pad_y = static_cast<float>(pad_y);
        return OkStatus();
    }

    void ScaleMeta(const Frame& in_frame, Frame& out_frame, const FrameTransformMeta& tx) const {
        if (in_frame.det) {
            auto det = std::make_shared<DetectionResult>(*in_frame.det);
            const int src_meta_w = det->img_w > 0 ? det->img_w : in_frame.width;
            const int src_meta_h = det->img_h > 0 ? det->img_h : in_frame.height;
            const float to_frame_x = src_meta_w > 0 ? static_cast<float>(in_frame.width) / src_meta_w : 1.0f;
            const float to_frame_y = src_meta_h > 0 ? static_cast<float>(in_frame.height) / src_meta_h : 1.0f;
            for (auto& it : det->items) {
                TransformRect(it.bbox,
                              tx.scale_x * to_frame_x,
                              tx.scale_y * to_frame_y,
                              tx.pad_x, tx.pad_y,
                              out_frame.width, out_frame.height);
            }
            det->img_w = out_frame.width;
            det->img_h = out_frame.height;
            out_frame.det = std::move(det);
        }

        if (in_frame.face_det) {
            auto face_det = std::make_shared<FaceDetResult>(*in_frame.face_det);
            const int src_meta_w = face_det->img_w > 0 ? face_det->img_w : in_frame.width;
            const int src_meta_h = face_det->img_h > 0 ? face_det->img_h : in_frame.height;
            const float to_frame_x = src_meta_w > 0 ? static_cast<float>(in_frame.width) / src_meta_w : 1.0f;
            const float to_frame_y = src_meta_h > 0 ? static_cast<float>(in_frame.height) / src_meta_h : 1.0f;
            for (auto& it : face_det->faces) {
                TransformRect(it.bbox,
                              tx.scale_x * to_frame_x,
                              tx.scale_y * to_frame_y,
                              tx.pad_x, tx.pad_y,
                              out_frame.width, out_frame.height);
                if (it.has_landmarks) {
                    for (auto& lm : it.landmarks) {
                        TransformPoint(lm,
                                       tx.scale_x * to_frame_x,
                                       tx.scale_y * to_frame_y,
                                       tx.pad_x, tx.pad_y,
                                       out_frame.width, out_frame.height);
                    }
                }
            }
            face_det->img_w = out_frame.width;
            face_det->img_h = out_frame.height;
            out_frame.face_det = std::move(face_det);
        }

        if (in_frame.face_recog) {
            auto face_recog = std::make_shared<FaceRecogResult>(*in_frame.face_recog);
            const int src_meta_w = face_recog->img_w > 0 ? face_recog->img_w : in_frame.width;
            const int src_meta_h = face_recog->img_h > 0 ? face_recog->img_h : in_frame.height;
            const float to_frame_x = src_meta_w > 0 ? static_cast<float>(in_frame.width) / src_meta_w : 1.0f;
            const float to_frame_y = src_meta_h > 0 ? static_cast<float>(in_frame.height) / src_meta_h : 1.0f;
            for (auto& it : face_recog->items) {
                TransformRect(it.bbox,
                              tx.scale_x * to_frame_x,
                              tx.scale_y * to_frame_y,
                              tx.pad_x, tx.pad_y,
                              out_frame.width, out_frame.height);
                if (it.has_landmarks) {
                    for (auto& lm : it.landmarks) {
                        TransformPoint(lm,
                                       tx.scale_x * to_frame_x,
                                       tx.scale_y * to_frame_y,
                                       tx.pad_x, tx.pad_y,
                                       out_frame.width, out_frame.height);
                    }
                }
            }
            face_recog->img_w = out_frame.width;
            face_recog->img_h = out_frame.height;
            out_frame.face_recog = std::move(face_recog);
        }
    }

    // Process letterbox input: crop to valid region and resize to target
    Status ProcessLetterboxInput(FramePtr frame) {
        if (!frame->transform_meta) {
            LogInfo("[preprocess] " + id_ + " letterbox: no transform_meta");
            return FailStatus("no transform meta");
        }
        const auto& meta = *frame->transform_meta;
        
        // Calculate valid region (excluding black padding)
        // For letterbox: the actual image is in the center, surrounded by black padding
        const int valid_x = static_cast<int>(meta.pad_x);
        const int valid_y = static_cast<int>(meta.pad_y);
        // Valid region size = dst_size - 2*padding
        int valid_w = meta.dst_w - 2 * static_cast<int>(meta.pad_x);
        int valid_h = meta.dst_h - 2 * static_cast<int>(meta.pad_y);
        
        // Align width to 16 for RGA compatibility
        valid_w = (valid_w / 16) * 16;
        if (valid_w <= 0) valid_w = 16;
        
        if (valid_w <= 0 || valid_h <= 0 || valid_x < 0 || valid_y < 0 ||
            valid_x + valid_w > frame->width || valid_y + valid_h > frame->height) {
            return FailStatus("invalid letterbox region");
        }
        
        // Crop valid region to a temporary frame
        Frame cropped;
        cropped.width = valid_w;
        cropped.height = valid_h;
        cropped.format = frame->format;
        if (!InitFrameStorage(cropped)) {
            LogInfo("[preprocess] " + id_ + " letterbox: alloc crop buffer failed");
            return FailStatus("alloc crop buffer failed");
        }
        
        // Step 1: Crop valid region from RGB frame
        bool crop_ok = CropFrameSoftware(*frame, cropped, valid_x, valid_y, valid_w, valid_h);
        if (!crop_ok) {
            return FailStatus("crop failed - only RGB/BGR supported for letterbox crop");
        }
        
        // Step 2: Resize to target size (may include format conversion)
        PixelFormat target_fmt = (dst_fmt_ != PixelFormat::UNKNOWN) ? dst_fmt_ : frame->format;
        
        Frame resized;
        resized.width = dst_w_;
        resized.height = dst_h_;
        resized.format = target_fmt;
        if (!InitFrameStorage(resized)) {
            return FailStatus("alloc resize buffer failed");
        }
        
        Status resize_st = image_processor_->Resize(cropped, resized);
        if (resize_st.Failed()) {
            return resize_st;
        }
        
        // Use resized as output
        Frame out = std::move(resized);
        
        // Create output frame with updated transform
        auto out_frame = std::make_shared<Frame>(out);
        out_frame->pts = frame->pts;
        out_frame->frame_id = frame->frame_id;
        
        // Update transform meta: now it's a direct scale from original to output
        FrameTransformMeta new_tx{};
        new_tx.valid = true;
        new_tx.letterbox = false;
        new_tx.src_w = meta.src_w;
        new_tx.src_h = meta.src_h;
        new_tx.dst_w = dst_w_;
        new_tx.dst_h = dst_h_;
        new_tx.scale_x = static_cast<float>(dst_w_) / static_cast<float>(meta.src_w);
        new_tx.scale_y = static_cast<float>(dst_h_) / static_cast<float>(meta.src_h);
        new_tx.pad_x = 0.0f;
        new_tx.pad_y = 0.0f;
        out_frame->transform_meta = std::make_shared<FrameTransformMeta>(new_tx);
        
        // Scale metadata
        ScaleMeta(*frame, *out_frame, new_tx);
        out_frame->user_meta = frame->user_meta;
        
        PushToDownstream(out_frame);
        ++processed_;
        
        if (stats_log_ && stats_interval_ > 0 && (processed_ % stats_interval_) == 0) {
            LogInfo("[preprocess] letterbox crop " + std::to_string(frame->width) + "x" + std::to_string(frame->height) +
                    " valid=" + std::to_string(valid_w) + "x" + std::to_string(valid_h) +
                    " -> " + std::to_string(dst_w_) + "x" + std::to_string(dst_h_) + " id=" + id_);
        }
        return OkStatus();
    }
    
    bool CropFrameSoftware(const Frame& src, Frame& dst, int x, int y, int w, int h) {
        if (x < 0 || y < 0 || w <= 0 || h <= 0 || x + w > src.width || y + h > src.height) {
            return false;
        }
        if (dst.width != w || dst.height != h || dst.format != src.format) {
            return false;
        }
        
        const uint8_t* src_data = src.data;
        uint8_t* dst_data = dst.data;
        if (!src_data || !dst_data) return false;
        
        if (src.format == PixelFormat::RGB || src.format == PixelFormat::BGR) {
            const int channels = 3;
            for (int row = 0; row < h; ++row) {
                std::memcpy(dst_data + row * w * channels,
                           src_data + (y + row) * src.width * channels + x * channels,
                           w * channels);
            }
            return true;
        }
        // NV12 and other formats would need more complex handling
        return false;
    }

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

    void WarnMetaResizeOnce(const FramePtr& frame, int out_w, int out_h) {
        if (warned_meta_resize_) return;
        if (!frame) return;
        if (frame->width == out_w && frame->height == out_h) return;
        if (!frame->det && !frame->face_det && !frame->face_recog) return;
        warned_meta_resize_ = true;
        LogInfo("[preprocess] resized frame and scaled det/face meta to destination resolution (id=" + id_ + ")");
    }

    void ProcessPassthrough(FramePtr frame) {
        PushToDownstream(frame);
        ++processed_;
        if (stats_log_ && stats_interval_ > 0 && (processed_ % stats_interval_) == 0) {
            LogInfo("[preprocess] passthrough frame=" + std::to_string(frame->frame_id) + " id=" + id_);
        }
    }

    std::string id_;
    int dst_w_ = 640;
    int dst_h_ = 640;
    bool keep_ratio_ = false;
    ResizeMode resize_mode_ = ResizeMode::Stretch;
    PixelFormat dst_fmt_ = PixelFormat::UNKNOWN;
    bool use_rga_ = true;

    bool stats_log_ = false;
    uint64_t stats_interval_ = 100;
    bool warned_meta_resize_ = false;

    std::shared_ptr<SpscQueue<FramePtr>> input_queue_;
    std::vector<std::shared_ptr<SpscQueue<FramePtr>>> output_queues_;
    std::shared_ptr<IImageProcessor> image_processor_;
    uint64_t processed_ = 0;
};

REGISTER_NODE(PreprocessNode, "preprocess");

}  // namespace rk3588