#include "../core/module.h"
#include "../core/ui.h"
#include "../core/pins.h"
#include <SPI.h>
#include <SD.h>

// CAN Bus sniffer. Listen on MCP2515 over SPI for OBD/automotive frames.
// Passive only; displays frame ID, DLC, data; logs to SD.

class CanSniff : public Module {
  static constexpr int CS = pins::PROBE[0];
  bool running = false, sdOk = false;
  uint32_t fcount = 0, lastMs = 0;
  uint8_t speed = 0;  // 0=500k, 1=250k, 2=125k
  char msg[3][40] = {{0},{0},{0}};
  File logfile;

public:
  const char* name() const override { return "CAN Bus"; }
  const char* blurb() const override { return "OBD/automotive sniffer"; }

  void onEnter() override {
    running = false; fcount = 0;
    sdOk = SD.begin();
    initMcp2515();
  }
  void onExit() override { running = false; if (logfile) logfile.close(); }

  bool onKey(char c) override {
    if (c == ' ') { running = !running; if (running) fcount = 0; return true; }
    if (c == 's') { speed = (speed + 1) % 3; initMcp2515(); return true; }
    if (c == 'c') { fcount = 0; say("cleared"); return true; }
    return false;
  }

  void tick() override {
    if (!running) return;
    if (millis() - lastMs < 50) return;
    lastMs = millis();
    uint32_t id = 0; uint8_t dlc = 0, data[8] = {0};
    if (readFrame(id, dlc, data)) {
      fcount++;
      if (sdOk && !logfile) {
        SD.mkdir("/logs");
        logfile = SD.open("/logs/can.txt", FILE_APPEND);
      }
      if (logfile) logfile.printf("%08lX %d [", (unsigned long)id, dlc);
      for (int i = 0; i < dlc; i++) {
        if (logfile) logfile.printf("%02X ", data[i]);
      }
      if (logfile) logfile.println("]");
    }
  }

  void draw() override {
    const char* sp[] = {"500k", "250k", "125k"};
    ui::lineC(0, ui::accent(), "CAN %s  %s", sp[speed], running ? "LISTEN" : "idle");
    ui::line(1, "frames: %lu", (unsigned long)fcount);
    for (int i = 0; i < 3; i++) ui::line(3 + i, "%s", msg[i]);
    if (running) ui::spinner(228, ui::BODY_Y + 1, ui::glow());
    ui::hintBar("[s]peed [c]lear [space]go  [`]back");
  }

private:
  void say(const char* fmt, ...) {
    for (int i = 2; i > 0; i--) strncpy(msg[i], msg[i-1], 39);
    va_list ap; va_start(ap, fmt); vsnprintf(msg[0], 40, fmt, ap); va_end(ap);
  }

  void initMcp2515() {
    SPI.begin(pins::PROBE[3], pins::PROBE[4], pins::PROBE[5], CS);
    pinMode(CS, OUTPUT);
    digitalWrite(CS, HIGH);
    digitalWrite(CS, LOW); SPI.transfer(0xC0); digitalWrite(CS, HIGH); delay(10);

    // Set CNF registers for desired baud rate
    digitalWrite(CS, LOW);
    SPI.transfer(0x80); // Write instruction
    SPI.transfer(0x2A); // CNF1 address
    if (speed == 0) { SPI.transfer(0x00); SPI.transfer(0xA3); SPI.transfer(0x13); } // 500k
    else if (speed == 1) { SPI.transfer(0x00); SPI.transfer(0xA3); SPI.transfer(0x25); } // 250k
    else { SPI.transfer(0x00); SPI.transfer(0xA3); SPI.transfer(0x2B); } // 125k
    digitalWrite(CS, HIGH);

    // Set CANCTRL for normal mode
    digitalWrite(CS, LOW);
    SPI.transfer(0x80);
    SPI.transfer(0x0F); // CANCTRL address
    SPI.transfer(0x00); // Normal mode
    digitalWrite(CS, HIGH);

    say("CAN %s mode ok", speed == 0 ? "500k" : speed == 1 ? "250k" : "125k");
  }

  bool readFrame(uint32_t& id, uint8_t& dlc, uint8_t* data) {
    digitalWrite(CS, LOW);
    SPI.transfer(0x03); // Read RX0 buffer status/id
    uint8_t sidh = SPI.transfer(0);
    uint8_t sidl = SPI.transfer(0);
    uint8_t eid8 = SPI.transfer(0);
    uint8_t eid0 = SPI.transfer(0);
    dlc = SPI.transfer(0) & 0x0F;
    for (int i = 0; i < dlc && i < 8; i++) data[i] = SPI.transfer(0);
    digitalWrite(CS, HIGH);

    id = ((uint32_t)sidh << 3) | ((sidl >> 5) & 0x07);
    return dlc > 0;
  }
};

Module* makeCan() { return new CanSniff(); }