#include <FFat.h>

#include "pb_decode.h"
#include "pb_encode.h"

#include "proto_gen/smartknob.pb.h"
#include "semaphore_guard.h"

#include "configuration.h"

static const char* CONFIG_PATH = "/config.pb";

Configuration::Configuration() {
  mutex_ = xSemaphoreCreateMutex();
  assert(mutex_ != NULL);
}

Configuration::~Configuration() {
  vSemaphoreDelete(mutex_);
}

bool Configuration::loadFromDisk() {
    SemaphoreGuard lock(mutex_);
    FatGuard fatGuard(logger_);
    if (!fatGuard.mounted_) {
        return false;
    }

    File f = FFat.open(CONFIG_PATH);
    if (!f) {
        log("Failed to read config file");
        return false;
    }

    size_t read = f.readBytes((char*)buffer_, sizeof(buffer_));
    f.close();

    pb_istream_t stream = pb_istream_from_buffer(buffer_, read);
    if (!pb_decode(&stream, PB_PersistentConfiguration_fields, &pb_buffer_)) {
        char buf[200];
        snprintf(buf, sizeof(buf), "Decoding failed: %s", PB_GET_ERROR(&stream));
        log(buf);
        pb_buffer_ = {};
        return false;
    }

    if (pb_buffer_.version != PERSISTENT_CONFIGURATION_VERSION) {
        char buf[200];
        snprintf(buf, sizeof(buf), "Invalid config version. Expected %u, received %u", PERSISTENT_CONFIGURATION_VERSION, pb_buffer_.version);
        log(buf);
        pb_buffer_ = {};
        return false;
    }
    loaded_ = true;

    char buf[200];
    snprintf(
        buf,
        sizeof(buf),
        "Motor calibration: calib=%u, pole_pairs=%u, zero_offset=%.2f, cw=%u",
        pb_buffer_.motor.calibrated,
        pb_buffer_.motor.pole_pairs,
        pb_buffer_.motor.zero_electrical_offset,
        pb_buffer_.motor.direction_cw
    );
    log(buf);
    return true;
}

bool Configuration::saveToDisk() {
    SemaphoreGuard lock(mutex_);

    pb_ostream_t stream = pb_ostream_from_buffer(buffer_, sizeof(buffer_));
    pb_buffer_.version = PERSISTENT_CONFIGURATION_VERSION;
    if (!pb_encode(&stream, PB_PersistentConfiguration_fields, &pb_buffer_)) {
        char buf[200];
        snprintf(buf, sizeof(buf), "Encoding failed: %s", PB_GET_ERROR(&stream));
        log(buf);
        return false;
    }

    FatGuard fatGuard(logger_);
    if (!fatGuard.mounted_) {
        return false;
    }
    File f = FFat.open(CONFIG_PATH, FILE_WRITE);
    if (!f) {
        log("Failed to read config file");
        return false;
    }
    size_t written = f.write(buffer_, stream.bytes_written);
    f.close();

    char buf[20];
    snprintf(buf, sizeof(buf), "Wrote %d bytes", written);
    log(buf);

    if (written != stream.bytes_written) {
        log("Failed to write all bytes to file");
        return false;
    }

    return true;
}

PB_PersistentConfiguration Configuration::get() {
    SemaphoreGuard lock(mutex_);
    if (!loaded_) {
        return PB_PersistentConfiguration();
    }
    return pb_buffer_;
}

bool Configuration::setMotorCalibrationAndSave(PB_MotorCalibration& motor_calibration) {
    {
        SemaphoreGuard lock(mutex_);
        pb_buffer_.motor = motor_calibration;
        pb_buffer_.has_motor = true;
    }
    return saveToDisk();
}

bool Configuration::setStrainCalibrationAndSave(PB_StrainCalibration& strain_calibration) {
    {
        SemaphoreGuard lock(mutex_);
        pb_buffer_.strain = strain_calibration;
        pb_buffer_.has_strain = true;
    }
    return saveToDisk();
}

void Configuration::setLogger(Logger* logger) {
    logger_ = logger;
}

void Configuration::log(const char* msg) {
    if (logger_ != nullptr) {
        logger_->log(msg);
    }
}