#include "Display.h"
#include "Config.h"
#include "Log.h"
#include <Wire.h>
#include <string.h>

Display::Display() : oled_(128, 32, &Wire, -1) {}

bool Display::begin() {
  Wire.begin(GPIO_SDA, GPIO_SCL);
  ok_ = oled_.begin(SSD1306_SWITCHCAPVCC, OLED_ADDRESS);
  if (ok_) { oled_.setTextColor(SSD1306_WHITE); oled_.setTextSize(1); }
  Log::printf("OLED", "initialization %s, I2C address=0x%02X", ok_ ? "OK" : "FAILED", OLED_ADDRESS);
  return ok_;
}

void Display::fit(char *s) {
  int16_t x, y; uint16_t w, h;
  while (*s) {
    oled_.getTextBounds(s, 0, 0, &x, &y, &w, &h);
    if (w <= 128) break;
    s[strlen(s) - 1] = '\0';
  }
}

void Display::show(const char *a, const char *b) {
  char one[32], two[32];
  snprintf(one, sizeof(one), "%s", a ? a : ""); snprintf(two, sizeof(two), "%s", b ? b : "");
  // Serial is the primary UI mirror and remains available when OLED is absent.
  Log::printf("UI", "%s | %s", one, two);
  if (!ok_) return;
  fit(one); fit(two);
  oled_.clearDisplay(); oled_.setCursor(0, 3); oled_.print(one);
  oled_.setCursor(0, 19); oled_.print(two); oled_.display();
}

void Display::formatFrequency(float hz, char *out, size_t n) {
  float value = hz; const char *suffix = "Hz";
  if (hz >= 1000000.0f) { value = hz / 1000000.0f; suffix = "M"; }
  else if (hz >= 1000.0f) { value = hz / 1000.0f; suffix = "k"; }
  if (fabsf(value - roundf(value)) < 0.005f) snprintf(out, n, "%.0f%s", value, suffix);
  else if (fabsf(value * 10.0f - roundf(value * 10.0f)) < 0.005f) snprintf(out, n, "%.1f%s", value, suffix);
  else snprintf(out, n, "%.2f%s", value, suffix);
}

void Display::formatDuration(uint64_t us, char *out, size_t n) {
  const uint64_t minutes = us / 60000000ULL;
  if (minutes < 60) snprintf(out, n, "%02llu:%02llu", minutes, (us / 1000000ULL) % 60ULL);
  else snprintf(out, n, "%llu:%02llu", minutes / 60ULL, minutes % 60ULL);
}