/* STM32 Blue Pill project using the STM32 Arduino Core (stm32duino) */
#include <Wire.h>
#include "Adafruit_PN532.h" // Your manually added library files

// Define I2C pins (though Wire library handles these by default for I2C1)
// #define PN532_SDA PB7 // Not needed for constructor, but good for reference
// #define PN532_SCL PB6 // Not needed for constructor, but good for reference

// Define pins for IRQ and RST (these MUST be provided to the constructor)
// Choose any available GPIO pins on the STM32 that are not used for other purposes.
// For example:
#define PN532_IRQ   (PA0) 
#define PN532_RST   (PA1)  // Or use the STM32's actual NRST pin if desired and appropriate

// Instantiate the PN532 object for I2C communication.
// The library will use the default 'Wire' object for I2C.
Adafruit_PN532 nfc(PN532_IRQ, PN532_RST);

// A tiny mapping table: UID[4] → filename
struct Mapping { uint8_t uid[4]; const char* file; };
Mapping table[] = {
  {{0xDE,0xAD,0xBE,0xEF}, "audio1.wav"},
  {{0xCA,0xFE,0xBA,0xBE}, "audio2.wav"}
};
const int tableSize = sizeof(table) / sizeof(table[0]);

// --- Variables for simulated UID cycling ---
unsigned long lastTagChangeTime = 0;
int currentTableIndex = 0;
bool tagIsVirtuallyPresent = false;


void setup() {
  Serial.begin(115200);
  // while (!Serial); // Not strictly needed for UART on Blue Pill

  Serial.println("Initializing PN532 over I2C...");
  
  // Wire.begin(); // Usually called by STM32duino core, but can be explicit.

  nfc.begin(); // This initializes the PN532 library

  uint32_t versiondata = nfc.getFirmwareVersion();
  Serial.println(versiondata);
  if (!versiondata) {
    Serial.println("  ERROR: Didn't find PN532 board. Check I2C connections, IRQ/RST pin definitions, and library setup.");
    Serial.println("  Ensure VCC/GND for PN532 are also connected.");
    while (1); // Halt
  }
  
  Serial.print("  Found chip PN5"); Serial.println((versiondata >> 24) & 0xFF, HEX);
  Serial.print("  Firmware ver. "); Serial.print((versiondata >> 16) & 0xFF, DEC);
  Serial.print('.'); Serial.println((versiondata >> 8) & 0xFF, DEC);

  nfc.SAMConfig();  // Configure board to read ISO14443A tags
  Serial.println("PN532 Configured. Simulating tag reads...");
  lastTagChangeTime = millis();
}

void loop() {
  uint8_t success_read;
  uint8_t uid_buffer[7]; 
  uint8_t uid_length;

  // Simulate presenting a new tag every 3-5 seconds
  if (millis() - lastTagChangeTime > 3000) { // Shortened for faster testing
    tagIsVirtuallyPresent = true; 
    Serial.println("\n--- Simulating NEW TAG ---");
    lastTagChangeTime = millis();
  }

  if (tagIsVirtuallyPresent) {
    // --- SIMULATED UID INJECTION (because custom chip has no internal logic for read) ---
    Serial.print("Injecting simulated UID: ");
    memcpy(uid_buffer, table[currentTableIndex].uid, 4); 
    uid_length = 4;
    for (int i = 0; i < uid_length; i++) { Serial.printf("%02X ", uid_buffer[i]); }
    Serial.println();
    success_read = 1; // Force success for the lookup part
    // --- END OF SIMULATED UID INJECTION ---
    
    // --- IF YOU WERE USING AN OFFICIAL WOKWI PN532 COMPONENT, YOU'D DO THIS INSTEAD: ---
    // Serial.println("Attempting to read NFC tag...");
    // success_read = nfc.readPassiveTargetID(PN532_MIFARE_ISO14443A, uid_buffer, &uid_length, 50); // 50ms timeout
    // --- END OF OFFICIAL COMPONENT READ ---


    if (success_read) {
      // This part will execute due to forced success_read = 1 above
      // Serial.println("  Tag 'read' successfully!"); 
      // Serial.print("  UID Length: "); Serial.print(uid_length, DEC); Serial.println(" bytes");
      // Serial.print("  UID Value: ");
      // for (int i = 0; i < uid_length; i++) {
      //   Serial.print(" 0x");
      //   if (uid_buffer[i] < 0x10) Serial.print("0");
      //   Serial.print(uid_buffer[i], HEX);
      // }
      // Serial.println(""); // Already printed during injection

      const char* fname = "UNKNOWN";
      for (int i = 0; i < tableSize; ++i) { 
        if (uid_length >= 4 && memcmp(table[i].uid, uid_buffer, 4) == 0) { 
          fname = table[i].file;
          break;
        }
      }
      Serial.print("  Mapped to: ");
      Serial.println(fname);

      currentTableIndex = (currentTableIndex + 1) % tableSize; 
    } else {
      Serial.println("  No tag 'read'."); // This won't be hit with current forced success
    }
    tagIsVirtuallyPresent = false; 
  }
}