/* Reflow Oven Controller
*
* Copyright (C) 2020  Mario Hüttel <mario.huettel@gmx.net>
*
* This file is part of the Reflow Oven Controller Project.
*
* The reflow oven controller is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* The Reflow Oven Control Firmware is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with the reflow oven controller project.
* If not, see <http://www.gnu.org/licenses/>.
*/

#include <reflow-controller/settings/settings-sd-card.h>
#include <stm-periph/unique-id.h>
#include <fatfs/ff.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

static void get_controller_folder_path(char *path, size_t size)
{
	uint32_t high;
	uint32_t mid;
	uint32_t low;

	if (!path)
		return;

	unique_id_get(&high, &mid, &low);

	snprintf(path, size, "/%08X-%08X-%08X",
		 (unsigned int)high, (unsigned int)mid, (unsigned int)low);
}

static void get_controller_settings_path(char *path, size_t size, const char *setting)
{
	char folder[48];

	get_controller_folder_path(folder, sizeof(folder));
	snprintf(path, size, "%s/%s.dat", folder, setting);
}

/**
 * @brief Open or create the controller folder on the SD Card.
 * @param[in,out] controller_folder
 * @return 0 if opened, 1 if created and opened, -1 if error.
 */
static int create_controller_folder(void)
{
	char foldername[48];
	int ret = -1;
	FRESULT filesystem_result;
	FILINFO fno;

	get_controller_folder_path(foldername, sizeof(foldername));

	/* Check if folder is present */
	filesystem_result = f_stat(foldername, &fno);
	if (filesystem_result == FR_OK && fno.fattrib & AM_DIR) {
		ret = 0;
	} else {
		filesystem_result = f_mkdir(foldername);
		if (filesystem_result == FR_OK) {
			ret = 1;
		} else {
			ret = -1;
		}
	}

	return ret;
}

static int read_settings_file_float(const char *path, float *value)
{
	FRESULT res;
	FIL file;
	int ret = 0;
	char buff[32];
	UINT read_count;

	if (!value)
		return -1002;

	res = f_open(&file, path, FA_READ);
	if (res == FR_OK) {
		memset(buff, 0, sizeof(buff));
		res = f_read(&file, buff, sizeof(buff)-1, &read_count);
		if (res != FR_OK) {
			ret = -1;
			goto close_file;
		}
		*value = strtof(buff, NULL);
close_file:
		f_close(&file);
	} else {
		ret = -2;
	}

	return ret;
}

int sd_card_settings_save_calibration(float sens_deviation, float offset, bool active)
{
	int status;
	char path[128];
	char buff[64];
	UINT bw;
	FIL file;
	FRESULT res;
	int ret = 0;

	status = create_controller_folder();
	if (status < 0)
		return -2;

	get_controller_settings_path(path, sizeof(path), "offset");
	if (active) {
		res = f_open(&file, path, FA_CREATE_ALWAYS | FA_WRITE);
		if (res != FR_OK) {
			ret = -2;
			goto exit_offset;
		}

		status = snprintf(buff, sizeof(buff), "%f\n", offset);
		f_write(&file, buff, status, &bw);
		f_close(&file);
	} else {
		f_unlink(path);
	}
exit_offset:
	get_controller_settings_path(path, sizeof(path), "sens");
	if (active) {
		res = f_open(&file, path, FA_CREATE_ALWAYS | FA_WRITE);
		if (res != FR_OK) {
			ret = -2;
			goto exit_sens;
		}

		status = snprintf(buff, sizeof(buff), "%f\n", sens_deviation);
		f_write(&file, buff, status, &bw);
		f_close(&file);
	} else {
		f_unlink(path);
	}
exit_sens:
	return ret;
}

int sd_card_settings_try_load_calibration(float *sens_deviation, float *offset)
{
	char path[128];
	int status;
	int ret = 0;

	if (!sens_deviation || !offset)
		return -1000;

	get_controller_settings_path(path, sizeof(path), "offset");
	status = read_settings_file_float(path, offset);
	if (status) {
		ret = status;
		goto exit;
	}

	get_controller_settings_path(path, sizeof(path), "sens");
	status = read_settings_file_float(path, sens_deviation);
	if (status) {
		ret = status;
		goto exit;
	}
exit:
	return ret;
}