// Estimate / InferenceResult / Provenance — the common output contract of every RAID estimator.
#pragma once
#include <string>
#include <vector>
#include <optional>
#include <Eigen/Dense>
#include <nlohmann/json.hpp>
#include "raid/core/types.hpp"

namespace raid {

struct Provenance {
  std::string dataset_id;              // e.g. market_bars.stock.1m.raw
  i64 dataset_version{-1};             // X-Dataset-Version (−1 = synthetic / unknown)
  std::vector<std::string> request_ids;  // X-Request-ID values
  std::vector<std::string> input_hashes; // SHA-256 of input files / fixtures
  std::string code_version;            // git short SHA + RAID_VERSION
  std::string source;                  // "FirstRate Data via FinData OS" | "synthetic"
  nlohmann::json extra;
  nlohmann::json to_json() const;
};

struct Convergence {
  bool converged{false};
  int iterations{0};
  int function_evaluations{0};
  f64 gradient_norm{std::numeric_limits<f64>::quiet_NaN()};
  int status_code{0};
  std::string message;
  nlohmann::json to_json() const;
};

struct InferenceResult {
  std::vector<f64> std_errors;
  std::vector<f64> t_stats;
  std::vector<f64> p_values;
  Eigen::MatrixXd covariance;
  std::string covariance_type;  // classical | hc0..hc3 | hac_bartlett(L) | cluster | qmle_sandwich | hessian
  f64 small_sample_correction{1.0};
  nlohmann::json to_json() const;
};

struct Estimate {
  std::string model;                   // registry key, e.g. "har.rv", "garch.gjr.t"
  std::vector<std::string> names;
  std::vector<f64> coefficients;
  f64 loss{std::numeric_limits<f64>::quiet_NaN()};   // −loglik or RSS depending on the model (documented per model)
  std::optional<InferenceResult> inference;
  Convergence convergence;
  std::vector<std::string> warnings;
  f64 runtime_seconds{0};
  Backend backend{Backend::cpu};
  Precision precision{Precision::fp64};
  Provenance provenance;
  usize n_obs{0};
  nlohmann::json extra;                // model-specific (sigma2 path, forecasts, diagnostics)
  /// A failed optimisation is never a success: ok() requires convergence.
  bool ok() const { return convergence.converged && !coefficients.empty(); }
  nlohmann::json to_json() const;
};

}  // namespace raid