#include "config.h"
#include "log.h"

#include <EEPROM.h>
#include <ArduinoJson.h>

#define DIRTY_WRITE_DELAY         (10 * 1000)

JsonDocument config;

unsigned long lastChangeMillis = 0;

bool configRead();

bool configWrite();

bool configWriteBytes(int *address, uint8_t *data, size_t size);

bool configReadBytes(int *address, uint8_t *data, size_t size);

void configSetup() {
  configRead();
}

void configLoop() {
  if (lastChangeMillis > 0 && millis() - lastChangeMillis > DIRTY_WRITE_DELAY) {
    configWrite();
  }
}

void configReset() {
  config.clear();
  configWrite();
}

String configGetString(const char *name, const char *fallback, bool allowEmpty) {
  if (!config.containsKey(name)) {
    return fallback;
  }
  String value = config[name];
  if (!allowEmpty && value.isEmpty()) {
    return fallback;
  }
  return value;
}

void configPutString(const char *name, const char *value) {
  if (config[name] != value) {
    config[name] = value;
    lastChangeMillis = millis();
  }
}

double configGetDouble(const char *name, double fallback) {
  if (!config.containsKey(name)) {
    return fallback;
  }
  return config[name];
}

void configPutDouble(const char *name, double value) {
  if (config[name] != value) {
    config[name] = value;
    lastChangeMillis = millis();
  }
}

void configPrint() {
  info("Config:");
  for (JsonPair pair: config.as<JsonObject>()) {
    const char *value = pair.value().as<const char *>();
    if (strcmp(pair.key().c_str(), "WIFI_PKEY") == 0) {
      value = "[***]";
    }
    info("  - %s: \"%s\"", pair.key().c_str(), value);
  }
}

bool configRead() {
  size_t length;
  char buffer[512];

  bool ok = true;
  int address = 0;
  EEPROM.begin(512);
  ok &= configReadBytes(&address, reinterpret_cast<uint8_t *>(&length), sizeof length);
  ok &= configReadBytes(&address, reinterpret_cast<uint8_t *>(buffer), length);
  ok &= EEPROM.end();

  if (ok) {
    JsonDocument tmp;
    deserializeJson(tmp, buffer);
    if (tmp.is<JsonObject>() && !tmp.isNull()) {
      info("Config loaded");
      config = tmp;
      return true;
    } else {
      error("Failed to parse config JSON");
    }
  } else {
    error("Failed to load config from EEPROM");
  }
  return false;
}

bool configWrite() {
  lastChangeMillis = 0;

  char buffer[512];
  size_t length = serializeJson(config, buffer, sizeof buffer);

  bool ok = true;
  int address = 0;
  EEPROM.begin(512);
  ok &= configWriteBytes(&address, reinterpret_cast<uint8_t *>(&length), sizeof length);
  ok &= configWriteBytes(&address, reinterpret_cast<uint8_t *>(buffer), length);
  ok &= EEPROM.end();
  if (ok) {
    info("Successfully wrote config to EEPROM");
  } else {
    info("Failed to write config to EEPROM");
  }
  return ok;
}

bool configWriteBytes(int *address, uint8_t *data, size_t size) {
  uint8_t *b = data;
  for (; b < data + size; b++) {
    EEPROM.write((*address)++, *b);
    if ((size_t) *address >= EEPROM.length()) {
      error("END OF EEPROM!!!");
      break;
    }
  }
  return (size_t) (b - data) == size;
}

bool configReadBytes(int *address, uint8_t *data, size_t size) {
  uint8_t *b = data;
  for (; b < data + size; b++) {
    *b = EEPROM.read((*address)++);
    if ((size_t) *address >= EEPROM.length()) {
      error("END OF EEPROM!!!");
      break;
    }
  }
  return (size_t) (b - data) == size;
}