#include "Core.h"
#include <math.h>
#include <string.h>

const char *roleName(Role r) {
  static const char *names[] = {"SOLO", "MASTER", "SLAVE"};
  const uint8_t i = static_cast<uint8_t>(r);
  return i < 3 ? names[i] : "?";
}

const char *failName(FailReason r) {
  static const char *names[] = {"NONE", "NO SIGNAL", "PERIOD OUT", "DUTY OUT",
    "EXTRA EDGE", "GLITCH", "LOST EDGE", "TOO FEW PERIODS", "LINK LOST",
    "UNSUPPORTED", "RESOLUTION", "ABORTED"};
  const uint8_t i = static_cast<uint8_t>(r);
  return i < (sizeof(names) / sizeof(names[0])) ? names[i] : "UNKNOWN";
}

void StageStats::reset() {
  memset(this, 0, sizeof(*this));
  minPeriod = minActive = UINT32_MAX;
  reason = FailReason::NONE;
}

uint32_t settingsChecksum(const Settings &s) {
  const uint8_t *p = reinterpret_cast<const uint8_t *>(&s);
  const size_t n = offsetof(Settings, checksum);
  uint32_t hash = 2166136261UL;
  for (size_t i = 0; i < n; ++i) { hash ^= p[i]; hash *= 16777619UL; }
  return hash;
}

uint32_t frequencyPointCount(uint32_t startHz, uint32_t endHz, uint32_t stepHz) {
  if (!startHz || !stepHz || endHz <= startHz) return 0;
  const uint64_t span = static_cast<uint64_t>(endHz) - startHz;
  return static_cast<uint32_t>(span / stepHz + 1U + ((span % stepHz) ? 1U : 0U));
}

uint32_t frequencyAt(uint32_t startHz, uint32_t endHz, uint32_t stepHz, uint32_t index) {
  const uint32_t count = frequencyPointCount(startHz, endHz, stepHz);
  if (!count || index >= count) return 0;
  if (index == count - 1) return endHz;
  const uint64_t v = static_cast<uint64_t>(startHz) + static_cast<uint64_t>(stepHz) * index;
  return v < endHz ? static_cast<uint32_t>(v) : endHz;
}

uint64_t nominalTotalUs(const TestParams &p, uint32_t settleCycles) {
  uint64_t total = 0;
  const uint32_t count = frequencyPointCount(p.startHz, p.endHz, p.stepHz);
  for (uint32_t i = 0; i < count; ++i) {
    const uint32_t f = frequencyAt(p.startHz, p.endHz, p.stepHz, i);
    total += (1000000ULL * settleCycles + f - 1) / f;
    total += static_cast<uint64_t>(p.testTimeMs) * 1000ULL * p.repeats;
  }
  return total;
}

bool periodWithin(float measured, float expected, float tolerance) {
  return expected > 0.0f && fabsf(measured - expected) * 100.0f / expected <= tolerance + 0.0001f;
}

bool dutyWithin(float measured, float expected, float tolerance) {
  return fabsf(measured - expected) <= tolerance + 0.0001f;
}

uint8_t choosePwmResolution(uint32_t frequencyHz, uint32_t sourceClockHz,
                            uint8_t maxBits) {
  if (!frequencyHz || !sourceClockHz || !maxBits) return 0;
  uint8_t bits = maxBits;
  while (bits > 1 && static_cast<uint64_t>(frequencyHz) * (1ULL << bits) > sourceClockHz)
    --bits;
  return bits;
}

FailReason validateResolution(uint32_t frequencyHz, float dutyPct, float accuracyPct,
                              uint32_t captureHz, uint8_t pwmBits) {
  if (!frequencyHz || !captureHz || !pwmBits) return FailReason::RESOLUTION;
  const float periodTicks = static_cast<float>(captureHz) / frequencyHz;
  const float activeTicks = periodTicks * dutyPct / 100.0f;
  const float inactiveTicks = periodTicks - activeTicks;
  if (periodTicks < 4.0f || activeTicks < 2.0f || inactiveTicks < 2.0f) return FailReason::RESOLUTION;
  const float timerPeriodError = 100.0f / periodTicks;
  const float timerDutyError = 100.0f / periodTicks;
  const float pwmDutyStep = 100.0f / static_cast<float>((1UL << pwmBits) - 1UL);
  return (timerPeriodError > accuracyPct || timerDutyError > accuracyPct || pwmDutyStep > accuracyPct)
    ? FailReason::RESOLUTION : FailReason::NONE;
}

FailReason evaluatePeriod(const PulsePeriod &p, uint32_t tickHz, float expectedHz,
                          float expectedDuty, float tolerance, uint8_t repeat,
                          StageStats &s) {
  if (!p.periodTicks || p.activeTicks >= p.periodTicks) return FailReason::EXTRA_EDGE;
  const float hz = static_cast<float>(tickHz) / p.periodTicks;
  const float duty = 100.0f * p.activeTicks / p.periodTicks;
  ++s.periods;
  s.periodSum += p.periodTicks; s.activeSum += p.activeTicks;
  if (p.periodTicks < s.minPeriod) s.minPeriod = p.periodTicks;
  if (p.periodTicks > s.maxPeriod) s.maxPeriod = p.periodTicks;
  if (p.activeTicks < s.minActive) s.minActive = p.activeTicks;
  if (p.activeTicks > s.maxActive) s.maxActive = p.activeTicks;
  FailReason reason = FailReason::NONE;
  if (!periodWithin(hz, expectedHz, tolerance)) reason = FailReason::PERIOD_OUT;
  else if (!dutyWithin(duty, expectedDuty, tolerance)) reason = FailReason::DUTY_OUT;
  if (reason != FailReason::NONE && s.reason == FailReason::NONE) {
    s.reason = reason; s.firstBadPeriod = s.periods; s.firstBadRepeat = repeat;
    s.badFrequency = hz; s.badDuty = duty;
  }
  return reason;
}