/**
 * HansonServo Firmware
 *
 * Unified robot controller with:
 * - Feetech servo control (SCS/STS)
 * - Animation playback via node graphs
 * - ADXL345 IMU
 * - RD-03D mmWave radar
 * - CRC16 tagged packet protocol
 *
 * Protocol: 0xA5 0x5A [TAG 4B][LEN 2B][SEQ 2B][PAYLOAD][CRC16 2B]
 */

// Configuration defines
#define ENABLE_SERIAL_PASSTHROUGH                                              \
  false // Set true to use Feetech app comms straight to servos

#include "robotconfig.h"
#include "animation.h"
#include "commands.h"
#include "motorcontrol.h"
#include "nodegraph.h"
#include "protocol.h"
#include "sensors.h"
#include <FFat.h>


// ============================================================================
// Global State
// ============================================================================

RobotConfig config;

// Timing constants
constexpr uint16_t FRAME_RATE = 48;
constexpr uint16_t FRAME_INTERVAL_MS = 1000 / FRAME_RATE;
constexpr uint16_t MOTOR_UPDATE_INTERVAL_MS = 50;
constexpr uint32_t HEARTBEAT_INTERVAL_MS = 1000;

// ============================================================================
// Utility Functions
// ============================================================================

uint16_t getSineWaveValue(unsigned long centiseconds) {
  constexpr uint16_t WAVE_PERIOD_CS = 400; // 4 seconds
  constexpr uint16_t WAVE_MAX = 4095;

  float theta = (2.0 * PI * centiseconds) / WAVE_PERIOD_CS;
  float sine = sin(theta);
  float scaled = (sine + 1.0) * (WAVE_MAX / 2.0);
  return (uint16_t)round(scaled);
}

// ============================================================================
// Protocol Handler
// ============================================================================

void handleProtocol() {
  if (receivePacket()) {
    dispatchCommand();
  }
}

// ============================================================================
// Serial Passthrough (USB ↔ Servo Serial)
// ============================================================================

#if ENABLE_SERIAL_PASSTHROUGH
void handleSerialPassthrough() {
  // Forward USB Serial → Servo Serial1
  while (Serial.available()) {
    Serial1.write(Serial.read());
  }

  // Forward Servo Serial1 → USB Serial
  while (Serial1.available()) {
    Serial.write(Serial1.read());
  }
}
#endif

// ============================================================================
// Animation Playback
// ============================================================================

void runNodeAnimation() {
  static uint32_t lastTickTime = 0;
  static uint32_t currentTick = 0;
  static bool wasActive = false;

  if (!animState.current || !animState.current->isActive()) {
    wasActive = false;
    return;
  }

  // Reset tick when animation starts or if currentTick is less than startFrame
  if (!wasActive || currentTick < animState.startFrame) {
    currentTick = animState.startFrame;  // Start from specified frame
    lastTickTime = millis();
    wasActive = true;
    // Debug: send startFrame via MSGE
    sendMessage("Animation startFrame: " + String(animState.startFrame) + ", currentTick: " + String(currentTick));
  }

  config.enableAllMotors();

  uint32_t now = millis();
  if (now - lastTickTime < FRAME_INTERVAL_MS)
    return;
    lastTickTime = now;

  // Tick the node graph
  animState.current->nodeGraph.tick(currentTick, *animState.current);
  auto outputs = animState.current->nodeGraph.getServoOutputs();

  // Collect motor commands
    std::vector<uint8_t> motorIDs;
    std::vector<uint16_t> positions;
    std::vector<uint16_t> speeds;

  for (const auto &[motorID, value] : outputs) {
      if (value != 65535) {
        motorIDs.push_back(motorID);
        positions.push_back(value);
        speeds.push_back(0);
        config.setMotorPosition(motorID, value);
      config.setMotorEnabled(motorID, true);
      } else {
      // Only disable torque for motors that should be limp
        if (config.setMotorEnabled(motorID, false)) {
        servoManager[0]->disableTorque(motorID);
      }
    }
  }

  // Send all positions in one sync write - motors move together!
  if (!motorIDs.empty()) {
    servoManager.syncWritePositions(motorIDs.data(), positions.data(),
                                    speeds.data(), motorIDs.size(), config, 0);
  }

  // Emit per-frame event: [frameLo, frameHi, playMode, status=0]
  // Send actual frame number (currentTick), not relative frame
  {
    uint8_t payload[4];
    payload[0] = currentTick & 0xFF;
    payload[1] = (currentTick >> 8) & 0xFF;
    payload[2] = static_cast<uint8_t>(animState.playMode);
    payload[3] = 0; // in-progress
    sendPacket(Tag::FRAME, payload, 4);
  }

    currentTick++;

  // Handle animation end (0 = run indefinitely for variable-only animations)
  // Calculate total frames played: currentTick - startFrame
  uint16_t framesPlayed = currentTick - animState.startFrame;
  // Calculate remaining frames: total frames minus startFrame
  // If animation has 100 frames and we start at 50, we should only play 50 frames
  uint16_t totalFrames = animState.current->getFrameCount();
  uint16_t remainingFrames = (totalFrames > animState.startFrame) ? (totalFrames - animState.startFrame) : 0;
  
  // Debug: show completion check values every 10 frames
  if (framesPlayed % 10 == 0 || framesPlayed >= remainingFrames - 1) {
    sendMessage("Frame check - played: " + String(framesPlayed) + ", remaining: " + String(remainingFrames) + ", total: " + String(totalFrames) + ", startFrame: " + String(animState.startFrame));
  }
  
  if (totalFrames > 0 && remainingFrames > 0 && framesPlayed >= remainingFrames) {
    switch (animState.playMode) {
        case PLAY_ONCE:
      animState.stop();
        {
          uint8_t done[4];
          done[0] = currentTick & 0xFF;
          done[1] = (currentTick >> 8) & 0xFF;
          done[2] = static_cast<uint8_t>(animState.playMode);
          done[3] = 1; // complete
          sendPacket(Tag::FRAME, done, 4);
        }
          break;
        case PLAY_LOOP:
      // Reset to start frame for seamless looping
      currentTick = animState.startFrame;
      sendMessage("Looping back to startFrame: " + String(animState.startFrame));
          break;
        case PLAY_REPEAT:
      if (--animState.repeatsRemaining == 0) {
        animState.stop();
        uint8_t done[4];
        done[0] = currentTick & 0xFF;
        done[1] = (currentTick >> 8) & 0xFF;
        done[2] = static_cast<uint8_t>(animState.playMode);
        done[3] = 1; // complete
        sendPacket(Tag::FRAME, done, 4);
        // Animation stopped, don't reset tick
      } else {
        // Reset to start frame for next repeat
        currentTick = animState.startFrame;
      }
      break;
    default:
      break;
    }
    // Don't reset currentTick here - each case handles it if needed
  }
}

// ============================================================================
// Motor Position Updates
// ============================================================================

void updateMotorPositions() {
  static unsigned long lastUpdate = 0;

  if (millis() - lastUpdate < MOTOR_UPDATE_INTERVAL_MS)
    return;
  lastUpdate = millis();

  for (const Motor &motor : config.motors) {
    servoManager[0]->setFeetechMode(motor.servoModel.major);
    uint16_t position = servoManager[0]->getPosition(motor.motorID);
    config.setMotorPosition(motor.motorID, position);
  }
}

void handleMotorStreaming() {
  if (motorStream.shouldStream()) {
    sendMotorPositions();
  }
}

// ============================================================================
// Heartbeat
// ============================================================================

void sendHeartbeat() {
  static unsigned long lastHeartbeat = 0;

  if (millis() - lastHeartbeat < HEARTBEAT_INTERVAL_MS)
    return;
  lastHeartbeat = millis();

  // Pack state: uptime(4) + flags(2)
  uint8_t payload[6];
  uint32_t uptime = millis() / 1000;
  uint16_t flags = 0;

  // Build flags
  if (adxl.isReady())
    flags |= 0x01;
  if (animState.current && animState.current->isActive())
    flags |= 0x02;
  if (motorStream.active)
    flags |= 0x04;
  if (sensors.isADXLStreamEnabled())
    flags |= 0x08;
  if (sensors.isRadarStreamEnabled())
    flags |= 0x10;

  payload[0] = uptime & 0xFF;
  payload[1] = (uptime >> 8) & 0xFF;
  payload[2] = (uptime >> 16) & 0xFF;
  payload[3] = (uptime >> 24) & 0xFF;
  payload[4] = flags & 0xFF;
  payload[5] = (flags >> 8) & 0xFF;

  sendPacket(Tag::STATE, payload, 6);
}

// ============================================================================
// Setup
// ============================================================================

void setup() {
  // Serial setup (buffer size must be set before begin)
  Serial.setRxBufferSize(8192);
  Serial.begin(1000000);

  // Startup delay
  delay(500);
  Serial.println("\n[HansonServo] Starting...");

  // Initialize servo manager
  servoManager.init();
  Serial.println("[HansonServo] Servos initialized");

  // Initialize sensors
  sensors.init();

  // Initialize filesystem
  if (!FFat.begin(true)) {
    Serial.println("[HansonServo] FFat mount failed!");
    return;
  }
  Serial.println("[HansonServo] Filesystem ready");

  // Load or create robot config
  if (config.loadOrCreateDefault()) {
    Serial.println("[HansonServo] Config loaded: " + config.deviceName);
  } else {
    Serial.println("[HansonServo] Config init failed");
  }

  Serial.println("[HansonServo] Ready");
  Serial.println("[HansonServo] Protocol: 0xA5 0x5A tagged packets with CRC16");
}

// ============================================================================
// Main Loop
// ============================================================================

void loop() {
// Serial passthrough (when enabled)
#if ENABLE_SERIAL_PASSTHROUGH
  handleSerialPassthrough();
  return;
#endif

  // Protocol handling
  handleProtocol();

  // Animation playback
  runNodeAnimation();

  // Motor position updates
  updateMotorPositions();
  handleMotorStreaming();

  // Sensor updates and streaming
  sensors.update();

  // Heartbeat
  sendHeartbeat();
}