/*
 * sppro_esp32.ino - read a Selectronic SP PRO from an ESP32 over UART2.
 *
 * Reuses the portable core unchanged. Copy src/sppro.c, src/sppro.h, src/md5.c
 * and src/md5.h next to this .ino (Arduino compiles all source in the sketch
 * folder), or add src/ as a library.
 *
 * Wiring (see docs/HARDWARE.md) - the SP PRO port is RS-232 (+/-12V), so a
 * level shifter is required; do NOT wire it straight to the ESP32:
 *
 *   SP PRO RJ45 pin 3 (TXD) --> MAX3232 R1IN ; R1OUT --> ESP32 GPIO16 (RX2)
 *   ESP32 GPIO17 (TX2)       --> MAX3232 T1IN ; T1OUT --> SP PRO RJ45 pin 6 (RXD)
 *   SP PRO RJ45 pin 4/5 (GND)--> MAX3232 GND  --> ESP32 GND   (common ground!)
 *   ESP32 3V3 --> MAX3232 VCC (+ four 0.1uF charge-pump caps)
 *
 * Set SPPRO_PASSWORD to the inverter's serial-port password ("" if none).
 */
extern "C" {
#include "sppro.h"
}

static const int   PIN_RX = 16;   /* ESP32 RX2 <- MAX3232 R1OUT */
static const int   PIN_TX = 17;   /* ESP32 TX2 -> MAX3232 T1IN  */
static const char *SPPRO_PASSWORD = "";

static sppro_scales_t g_scales;
static bool           g_ready = false;

/* ----- transport bound to Serial2 ---------------------------------------- */

static int esp_read(void *ctx, uint8_t *buf, size_t len) {
  (void)ctx;
  size_t got = 0;
  /* brief wait so a frame that is mid-flight is not reported as "empty" */
  unsigned long start = millis();
  while (got < len && (millis() - start) < 200) {
    while (Serial2.available() && got < len) {
      buf[got++] = (uint8_t)Serial2.read();
      start = millis();
    }
    if (got == 0) delay(1);
    else break;
  }
  return (int)got;  /* 0 on timeout */
}

static int esp_write(void *ctx, const uint8_t *buf, size_t len) {
  (void)ctx;
  return (int)Serial2.write(buf, len);
}

static sppro_transport_t g_transport = { esp_read, esp_write, nullptr };

/* ----- sketch ------------------------------------------------------------- */

static bool connect_sppro() {
  if (sppro_session_login(&g_transport, SPPRO_PASSWORD) != SPPRO_OK) {
    Serial.println("login failed - check wiring/password");
    return false;
  }
  if (sppro_session_read_scales(&g_transport, &g_scales) != SPPRO_OK) {
    Serial.println("could not read scale factors");
    return false;
  }
  Serial.println("connected to SP PRO");
  return true;
}

static void show(const char *name) {
  const sppro_reg_t *reg = sppro_reg_by_name(name);
  double value;
  if (!reg) return;
  if (sppro_session_read(&g_transport, reg, &g_scales, &value) != SPPRO_OK) {
    Serial.printf("%-26s  (read error)\n", reg->description);
    return;
  }
  if (reg->conv == SPPRO_C_SHUNT_NAME)
    Serial.printf("%-26s %12s\n", reg->description, sppro_shunt_name((int)value));
  else
    Serial.printf("%-26s %12.2f %s\n", reg->description, value, reg->units);
}

void setup() {
  Serial.begin(115200);
  Serial2.begin(SPPRO_BAUD, SERIAL_8N1, PIN_RX, PIN_TX);
  delay(200);
  g_ready = connect_sppro();
}

void loop() {
  if (!g_ready) {
    delay(2000);
    g_ready = connect_sppro();
    return;
  }
  Serial.println("\n== Selectronic SP PRO ==");
  show("BatteryVolts");
  show("BattSocPercent");
  show("BatteryTemperature");
  show("DCBatteryPower");
  show("LoadAcPower");
  show("CombinedKacoAcPowerHiRes");
  show("ACGeneratorPower");
  delay(5000);
}