#include "io/gpr/Gpr3dvVolumeBridge.hpp"

#include <algorithm>
#include <chrono>
#include <cmath>
#include <stdexcept>
#include <vector>

#include <QString>

#include "GPRDataModel.h"
#include "IprhParser.h"
#include "RadarProcessor.h"

#include "core/model/ScalarVolumeI16.hpp"
#include "io/gpr/RadarVolumeAssembler.hpp"  // assembleRadarVolume(共享建体)

namespace geopro::io::gpr {

namespace {

// 全体 traces 平均绝对幅值——朴素的「处理是否生效」标量证据(与 P1 冒烟同口径)。
double meanAbsAmplitude(const GPRDataModel& model) {
  long double sum = 0.0L;
  long long count = 0;
  for (const RadarTrace& tr : model.traces) {
    for (short v : tr.amplitudes) {
      sum += static_cast<long double>(v < 0 ? -v : v);
      ++count;
    }
  }
  return count > 0 ? static_cast<double>(sum / count) : 0.0;
}

// 通道横向间距(米)：优先 chYOffsets 跨度 /(通道数-1)；取不到退路 ≈1.37/(通道数-1)。
double channelSpacingY(const GPRDataModel::Header& h, int channels) {
  if (channels <= 1) return 1.0;
  const auto& off = h.chYOffsets;
  if (off.size() >= 2) {
    float lo = off.front(), hi = off.front();
    for (float v : off) {
      lo = std::min(lo, v);
      hi = std::max(hi, v);
    }
    const double span = static_cast<double>(hi) - static_cast<double>(lo);
    if (span > 1e-9) return span / (channels - 1);
  }
  // 退路：明星路 14 通道横向跨度 ≈1.37m(-0.686~+0.686)。
  constexpr double kArrayWidthM = 1.37;
  return kArrayWidthM / (channels - 1);
}

// 深度采样间距(米)：(timeWindow/samples) ns × 波速(m/ns) / 2(往返)。
// 与 GPRDataModel::calculateDepth 同式。取不到 → 1.0(单位间距)。
double depthSpacingZ(const GPRDataModel::Header& h) {
  if (h.samplesPerTrace <= 0 || h.timeWindowNs <= 0.0) return 1.0;
  const double timePerSample = h.timeWindowNs / h.samplesPerTrace;  // ns
  const double vel = h.waveVelocity > 0.0 ? h.waveVelocity : 0.1;   // m/ns
  const double dz = timePerSample * vel / 2.0;
  return dz > 1e-12 ? dz : 1.0;
}

double nowMs(std::chrono::steady_clock::time_point t0) {
  const auto t1 = std::chrono::steady_clock::now();
  return std::chrono::duration<double, std::milli>(t1 - t0).count();
}

}  // namespace

geopro::core::BuiltI16 buildLineVolumeFromGpr3dv(const std::string& lineDir,
                                                 const std::string& linePrefix,
                                                 BridgeMetrics* metricsOut,
                                                 int coarse, double targetDy) {
  const QString dir = QString::fromLocal8Bit(lineDir.c_str());
  const QString base = QString::fromLocal8Bit(linePrefix.c_str());

  // 1) 走 P1 链：load → buildVolumeData(处理前) → runPipeline → 再 buildVolumeData。
  const auto tLoad = std::chrono::steady_clock::now();
  GPRDataModel model;
  if (!IprhParser::loadImpulseMultiChannel(dir, base, model)) {
    throw std::runtime_error("loadImpulseMultiChannel 失败: " + lineDir + " / " +
                             linePrefix);
  }
  model.buildVolumeData();  // 处理前立方体(用于 before 统计)
  const double meanBefore = meanAbsAmplitude(model);
  const double loadMs = nowMs(tLoad);

  const auto tPipe = std::chrono::steady_clock::now();
  RadarProcessor::ProcPipeline pipeline;
  pipeline.setDefaultFlow();
  GPRDataModel processed = RadarProcessor::runPipeline(model, pipeline);
  // ★关键：runPipeline 原位变换 traces 且零时校正会改 samplesPerTrace，
  //   不重建 volumeData，故必须再建一次拿处理后立方体。
  processed.buildVolumeData();
  const double meanAfter = meanAbsAmplitude(processed);
  const double pipelineMs = nowMs(tPipe);

  // 2) 立方体维度：volumeData[通道][道][样本] → 轴 X=道/Y=通道/Z=样本。
  const int channels = processed.volumeData.size();
  const int traces = channels > 0 ? processed.volumeData[0].size() : 0;
  const int samples =
      (channels > 0 && traces > 0) ? processed.volumeData[0][0].size() : 0;
  if (channels <= 0 || traces <= 0 || samples <= 0) {
    throw std::runtime_error("处理后立方体为空(通道/道/样本 = " +
                             std::to_string(channels) + "/" +
                             std::to_string(traces) + "/" +
                             std::to_string(samples) + ")");
  }
  // §1 线内通道插值偏移：读各通道真实横向偏移(header.chXOffsets)。绝不跨线；间距/
  // 通道数从数据来，不假设。空/不等长 → 不启用通道插值(helper 内退路=逐通道 identity)。
  std::vector<double> latOff;
  const auto& chx = processed.header.chXOffsets;
  if (chx.size() == channels)
    for (int c = 0; c < channels; ++c)
      latOff.push_back(static_cast<double>(chx[c]));

  // 3) 组立方体描述 + 采样器(volumeData[通道][道][样本]，越界取 0)，调共享建体 helper。
  //    扫值域→Quant(中点 offset)→通道插值(规则化 Y 到 targetDy)→逐体素填→spacing 均在
  //    helper 内完成(与后续规范化 .head/.data 路共用同一逻辑，零漂移)。
  const GPRDataModel::Header& h = processed.header;
  RadarCubeDesc desc;
  desc.channels = channels;
  desc.traces = traces;
  desc.samples = samples;
  desc.chXOffsets = latOff;
  desc.dxBase = h.distanceInc > 1e-9 ? h.distanceInc : 1.0;  // 道距(米)
  desc.dyWhenNotInterpolated = channelSpacingY(h, channels);  // 原通道横距(米)
  desc.dz = depthSpacingZ(h);                                 // 深度采样距(米)
  CubeSampler sample = [&processed](int c, int t, int s) -> double {
    const auto& ch = processed.volumeData[c];
    if (t >= static_cast<int>(ch.size())) return 0.0;
    const auto& tr = ch[t];
    return s < static_cast<int>(tr.size()) ? static_cast<double>(tr[s]) : 0.0;
  };

  const auto tFill = std::chrono::steady_clock::now();
  geopro::core::BuiltI16 built = assembleRadarVolume(desc, sample, coarse, targetDy);
  const double fillMs = nowMs(tFill);

  if (metricsOut) {
    metricsOut->nx = built.vol.nx();
    metricsOut->ny = built.vol.ny();
    metricsOut->nz = built.vol.nz();
    metricsOut->meanAbsBefore = meanBefore;
    metricsOut->meanAbsAfter = meanAfter;
    metricsOut->vminPhys = built.vminPhys;
    metricsOut->vmaxPhys = built.vmaxPhys;
    metricsOut->dx = built.spacing[0];
    metricsOut->dy = built.spacing[1];
    metricsOut->dz = built.spacing[2];
    metricsOut->loadMs = loadMs;
    metricsOut->pipelineMs = pipelineMs;
    metricsOut->fillMs = fillMs;
  }

  return built;
}

}  // namespace geopro::io::gpr