#include <SPI.h>
#include <Ethernet.h>
#include <MySQL_Encrypt_Sha1.h>
#include <MySQL_Packet.h>
#include <MySQL_Cursor.h>
#include <MySQL_Connection.h>
#include <Dns.h>
#include "config.h"

typedef struct Input {
  int id;
  unsigned long timer;
};

char query[50];
unsigned long lastRefresh;
unsigned long lastDebug;
unsigned long lastRecord;
Input inputs[N_INPUTS];
EthernetClient ethClient;
MySQL_Connection db((Client *) &ethClient);
IPAddress dbServer;

void printTitle(String title) {
  #ifdef DEBUG
    for (int i = 0; i < 10; i++)
      Serial.print('=');
    Serial.println(" " + title);
  #endif
}

void showError(String error) {
  #ifdef DEBUG
    Serial.println(error);
  #endif
}

void abortWithError(String error) {
  showError(error);
  while (true) delay(1);
}

int freeRam() {
  extern int __heap_start, *__brkval;
  int v;
  return (int) &v - (__brkval == 0 ? (int) &__heap_start : (int) __brkval);
}

void setup() {
  #ifdef DEBUG
    Serial.begin(9600);
    while (!Serial);
  #endif

  if (Ethernet.begin(mac) == 0)
    abortWithError("DHCP config failed.");
  if (Ethernet.hardwareStatus() == EthernetNoHardware)
    abortWithError("Eth shield not found.");
  if (Ethernet.linkStatus() == LinkOFF)
    abortWithError("Eth cable not connected.");

  #ifdef DEBUG
    Serial.println("IP: " +  String(Ethernet.localIP()));
  #endif

  if (!dbConnect())
    abortWithError("Aborting.");

  unsigned long now = millis();
  lastRefresh = now;
  lastDebug = now;
  lastRecord = now;
  
  for (int i = 0; i < N_INPUTS; i++) {
    Input* input = &inputs[i];
    input->id = i + 1;
    input->timer = 0;
    pinMode(pins[i], INPUT);
  }

  #ifdef DEBUG
    Serial.println("RAM: " + String(freeRam()));
  #endif
}

boolean dbConnect() {
  DNSClient dns;
  dns.begin(Ethernet.dnsServerIP());

  if (dns.getHostByName(DB_HOST, dbServer) != 1) {
    showError("Cannot resolve DB.");
    return false;
  }

  #ifdef DEBUG
    Serial.println("Connecting to DB: " + String(dbServer));
  #endif

  if (!db.connect(dbServer, DB_PORT, DB_USER, DB_PASS)) {
    showError("Cannot connect to DB.");
    return false;
  }

  return true;
}

void refreshTimers() {
  unsigned long now = millis();

  for (int i = 0; i < N_INPUTS; i++) {
    Input* input = &inputs[i];
    if (digitalRead(pins[i]) == HIGH)
      input->timer += now - lastRefresh;
  }

  lastRefresh = now;
}

void loop() {
  refreshTimers();
  Ethernet.maintain();

  #ifdef DEBUG
    if (millis() - lastDebug > DEBUG_INTERVAL) {
      printTitle("Status");
  
      for (int i = 0; i < N_INPUTS; i++) {
        Input* input = &inputs[i];
        Serial.print("Input ");
  
        String id = String(input->id);
        for (int j = 2 - id.length(); j > 0; j--)
          Serial.print(" ");
  
        Serial.print(String(input->id) + ": ");
        Serial.print(String(digitalRead(pins[i]) == HIGH));
        Serial.println("/" + String(input->timer));
      }
  
      lastDebug = millis();
    }
  #endif

  if (millis() - lastRecord > RECORD_INTERVAL) {
    printTitle("Recording to DB");

    if (!db.connected())
      dbConnect();

    for (int i = 0; i < N_INPUTS; i++) {
      refreshTimers();
      Input* input = &inputs[i];
      int timer = input->timer;
      int seconds = timer / 1000;
      input->timer = 0;

      if (seconds > 0 && db.connected()) {
        sprintf(query, SQL, input->id, seconds);

        #ifdef DEBUG
          Serial.println(query);
        #endif

        MySQL_Cursor *cur = new MySQL_Cursor(&db);
        cur->execute(query);
        delete cur;
      }
    }

    lastRecord = millis();
  }

  delay(DELAY);
}