#include "harness.hpp"
#include <plot/plot/measure.hpp>
#include <plot/data/array_series.hpp>
#include <plot/data/detail/cover_count.hpp>
#include <algorithm>
#include <atomic>
#include <cmath>
#include <vector>

PLOT_TEST(measurement_over_interval_matches_direct_computation) {
  std::vector<f32> y; for (int i = 0; i < 1000; ++i) y.push_back(f32(std::sin(static_cast<double>(i) * 0.01)));
  plot::data::ArraySeries s(std::move(y), 0.0, 1.0);
  const auto m = plot::Measure::evaluate(s, 100, 800);
  double sum = 0, sumsq = 0, integral = 0; float lo = 1e30f, hi = -1e30f;
  for (u64 i = 100; i < 800; ++i) {
    const double v = std::sin(static_cast<double>(i) * 0.01);
    sum += v; sumsq += v * v; integral += v;         // dx == 1
    lo = std::min(lo, float(v)); hi = std::max(hi, float(v));
  }
  const double n = 700;
  PLOT_CHECK_NEAR(m.mean, sum / n, 1e-5);
  PLOT_CHECK_NEAR(m.rms, std::sqrt(sumsq / n), 1e-5);
  PLOT_CHECK_NEAR(m.integral, integral, 1e-3);
  PLOT_CHECK_NEAR(m.ymin, lo, 1e-6);
  PLOT_CHECK_NEAR(m.ymax, hi, 1e-6);
  PLOT_CHECK_NEAR(m.dx, 699.0, 1e-9);
}
PLOT_TEST(measurement_uses_pyramid_not_scan) {
  // Guard against a future regression that linear-scans the series, counted rather
  // than timed: a query's cost is the pyramid's covering decomposition -- at most
  // two entries per level -- so the entry count must depend on the *interval* and
  // never on the series length. The wall-clock bound this replaced (1000 evals in
  // < 50 ms) failed on a loaded machine and passed vacuously on a fast one, while
  // saying nothing about the shape of the work.
  std::vector<f32> big(1u << 22, 1.0f);            // 4M samples
  plot::data::ArraySeries s_big(std::move(big), 0.0, 1.0);
  std::vector<f32> small(1u << 13, 1.0f);          // 8k samples: 512x shorter
  plot::data::ArraySeries s_small(std::move(small), 0.0, 1.0);

  auto covers = [](const plot::data::Series& s, u64 begin, u64 end) {
    plot::data::detail::cover_entry_count().store(0, std::memory_order_relaxed);
    (void)plot::Measure::evaluate(s, begin, end);
    return plot::data::detail::cover_entry_count().load(std::memory_order_relaxed);
  };

  // The same absolute interval over both series walks the same run of level-0
  // buckets, so it must fold the same entries: a decomposition that degenerated
  // with series length -- one bucket at a time, or a scan -- shows up here.
  const u64 big_covers = covers(s_big, 1024, 7000);
  PLOT_CHECK(big_covers == covers(s_small, 1024, 7000));
  PLOT_CHECK(big_covers > 0u);                     // the interior came from the pyramid
  PLOT_CHECK(big_covers <= 32u);                   // ~2 entries per level, few levels here

  // A 1-sample interval needs no whole bucket at all: its answer is the two partial
  // edge buckets a pyramid of complete buckets cannot cover (at most 2 * kBucket raw
  // samples through copy_raw), so it folds nothing whatever the series holds.
  PLOT_CHECK(covers(s_big, 1'000'000, 1'000'001) == 0u);
}
PLOT_TEST(empty_and_single_sample_intervals_are_valid_false) {
  std::vector<f32> y{3.0f};
  plot::data::ArraySeries s(std::move(y), 0.0, 1.0);
  PLOT_CHECK(!plot::Measure::evaluate(s, 0, 0).valid);
  PLOT_CHECK(!plot::Measure::evaluate(s, 1, 1).valid);
}