/*
* EEZ Generic Firmware
* Copyright (C) 2018-present, Envox d.o.o.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.

* This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <string.h>

#include <eez/core/unit.h>

#if OPTION_SCPI
#include <scpi/types.h>
#endif

namespace eez {

const char *g_unitNames[] = {
    "", // UNIT_NONE
    "V", // UNIT_VOLT
    "mV", // UNIT_MILLI_VOLT
    "A", // UNIT_AMPER
    "mA", // UNIT_MILLI_AMPER
    "uA", // UNIT_MICRO_AMPER
    "W", // UNIT_WATT
    "mW", // UNIT_MILLI_WATT
    "s", // UNIT_SECOND
    "ms", // UNIT_MILLI_SECOND
    DEGREE_SYMBOL"C", // UNIT_CELSIUS
    "rpm", // UNIT_RPM
    "\xb4", // UNIT_OHM
    "K\xb4", // UNIT_KOHM
    "M\xb4", // UNIT_MOHM
    "%", // UNIT_PERCENT
    "Hz", // UNIT_HERTZ
    "mHz", // UNIT_MILLI_HERTZ
    "KHz", // UNIT_KHERTZ
    "MHz", // UNIT_MHERTZ
    "J", // UNIT_JOULE
    "F", // UNIT_FARAD
    "mF", // UNIT_MILLI_FARAD
    "uF", // UNIT_MICRO_FARAD
    "nF", // UNIT_NANO_FARAD
    "pF", // UNIT_PICO_FARAD
    "minutes", // UNIT_MINUTE
    "VA", // UNIT_VOLT_AMPERE
    "VAR", // UNIT_VOLT_AMPERE_REACTIVE
	DEGREE_SYMBOL, // UNIT_DEGREE
	"Vpp", // UNIT_VOLT_PP
	"mVpp", // UNIT_MILLI_VOLT_PP
	"App", // UNIT_AMPER_PP
	"mApp", // UNIT_MILLI_AMPER_PP
	"uApp", // UNIT_MICRO_AMPER_PP
};

const Unit g_baseUnit[] = {
	UNIT_NONE, // UNIT_NONE
	UNIT_VOLT, // UNIT_VOLT
	UNIT_VOLT, // UNIT_MILLI_VOLT
	UNIT_AMPER, // UNIT_AMPER
	UNIT_AMPER, // UNIT_MILLI_AMPER
	UNIT_AMPER, // UNIT_MICRO_AMPER
	UNIT_WATT, // UNIT_WATT
	UNIT_WATT, // UNIT_MILLI_WATT
	UNIT_SECOND, // UNIT_SECOND
	UNIT_SECOND, // UNIT_MILLI_SECOND
	UNIT_CELSIUS, // UNIT_CELSIUS
	UNIT_RPM, // UNIT_RPM
	UNIT_OHM, // UNIT_OHM
	UNIT_OHM, // UNIT_KOHM
	UNIT_OHM, // UNIT_MOHM
	UNIT_PERCENT, // UNIT_PERCENT
	UNIT_HERTZ, // UNIT_HERTZ
	UNIT_HERTZ, // UNIT_MILLI_HERTZ
	UNIT_HERTZ, // UNIT_KHERTZ
	UNIT_HERTZ, // UNIT_MHERTZ
	UNIT_JOULE, // UNIT_JOULE
	UNIT_FARAD, // UNIT_FARAD
	UNIT_FARAD, // UNIT_MILLI_FARAD
	UNIT_FARAD, // UNIT_MICRO_FARAD
	UNIT_FARAD, // UNIT_NANO_FARAD
	UNIT_FARAD, // UNIT_PICO_FARAD
	UNIT_SECOND, // UNIT_MINUTE
	UNIT_VOLT_AMPERE, // UNIT_VOLT_AMPERE
	UNIT_VOLT_AMPERE, //UNIT_VOLT_AMPERE_REACTIVE
	UNIT_DEGREE, // UNIT_DEGREE
	UNIT_VOLT_PP, // UNIT_VOLT_PP
	UNIT_VOLT_PP, // UNIT_MILLI_VOLT_PP
	UNIT_AMPER_PP, // UNIT_AMPER_PP
	UNIT_AMPER_PP, // UNIT_MILLI_AMPER_PP
	UNIT_AMPER_PP, // UNIT_MICRO_AMPER_PP
};

const float g_unitFactor[] = {
	1.0f, // UNIT_NONE
	1.0f, // UNIT_VOLT
	1E-3f, // UNIT_MILLI_VOLT
	1.0f, // UNIT_AMPER
	1E-3f, // UNIT_MILLI_AMPER
	1E-6f, // UNIT_MICRO_AMPER
	1.0f, // UNIT_WATT
	1E-3f, // UNIT_MILLI_WATT
	1.0f, // UNIT_SECOND
	1E-3f, // UNIT_MILLI_SECOND
	1.0f, // UNIT_CELSIUS
	1.0f, // UNIT_RPM
	1.0f, // UNIT_OHM
	1E3f, // UNIT_KOHM
	1E6f, // UNIT_MOHM
	1.0f, // UNIT_PERCENT
	1.0f, // UNIT_HERTZ
	1E-3f, // UNIT_MILLI_HERTZ
	1E3f, // UNIT_KHERTZ
	1E6f, // UNIT_MHERTZ
	1.0f, // UNIT_JOULE
	1.0f, // UNIT_FARAD
	1E-3f, // UNIT_MILLI_FARAD
	1E-6f, // UNIT_MICRO_FARAD
	1E-9f, // UNIT_NANO_FARAD
	1E-12f, // UNIT_PICO_FARAD
	60.0f, // UNIT_MINUTE
	1.0f, // UNIT_VOLT_AMPERE
	1.0f, //UNIT_VOLT_AMPERE_REACTIVE
	1.0f, // UNIT_DEGREE
	1.0f, // UNIT_VOLT_PP
	1E-3f, // UNIT_MILLI_VOLT_PP
	1.0f, // UNIT_AMPER_PP
	1E-3f, // UNIT_MILLI_AMPER_PP
	1E-6f, // UNIT_MICRO_AMPER_PP
};

#if OPTION_SCPI
static const int g_scpiUnits[] = {
    SCPI_UNIT_NONE, // UNIT_NONE
    SCPI_UNIT_VOLT, // UNIT_VOLT
    SCPI_UNIT_VOLT, // UNIT_MILLI_VOLT
    SCPI_UNIT_AMPER, // UNIT_AMPER
    SCPI_UNIT_AMPER, // UNIT_MILLI_AMPER
    SCPI_UNIT_AMPER, // UNIT_MICRO_AMPER
    SCPI_UNIT_WATT, // UNIT_WATT
    SCPI_UNIT_WATT, // UNIT_MILLI_WATT
    SCPI_UNIT_SECOND, // UNIT_SECOND
    SCPI_UNIT_SECOND, // UNIT_MILLI_SECOND
    SCPI_UNIT_CELSIUS, // UNIT_CELSIUS 
    SCPI_UNIT_NONE, // UNIT_RPM
    SCPI_UNIT_OHM, // UNIT_OHM
    SCPI_UNIT_OHM, // UNIT_KOHM
    SCPI_UNIT_OHM, // UNIT_MOHM
    SCPI_UNIT_NONE, // UNIT_PERCENT
    SCPI_UNIT_HERTZ, // UNIT_HERTZ
    SCPI_UNIT_HERTZ, // UNIT_MILLI_HERTZ
    SCPI_UNIT_HERTZ, // UNIT_KHERTZ
    SCPI_UNIT_HERTZ, // UNIT_MHERTZ
    SCPI_UNIT_JOULE, // UNIT_JOULE
    SCPI_UNIT_FARAD, // UNIT_FARAD
    SCPI_UNIT_FARAD, // UNIT_MILLI_FARAD
    SCPI_UNIT_FARAD, // UNIT_MICRO_FARAD
    SCPI_UNIT_FARAD, // UNIT_NANO_FARAD
    SCPI_UNIT_FARAD, // UNIT_PICO_FARAD
	SCPI_UNIT_SECOND, // UNIT_MINUTE
	SCPI_UNIT_WATT, // UNIT_VOLT_AMPERE
	SCPI_UNIT_WATT, // UNIT_VOLT_AMPERE_REACTIVE
	SCPI_UNIT_DEGREE, // UNIT_DEGREE
	SCPI_UNIT_VOLT, // UNIT_VOLT_PP
	SCPI_UNIT_VOLT, // UNIT_MILLI_VOLT_PP
	SCPI_UNIT_AMPER, // UNIT_AMPER_PP
	SCPI_UNIT_AMPER, // UNIT_MILLI_AMPER_PP
	SCPI_UNIT_AMPER, // UNIT_MICRO_AMPER_PP
};
#endif

Unit getUnitFromName(const char *unitName) {
	if (unitName) {
		for (unsigned i = 0; i < sizeof(g_unitNames) / sizeof(const char *); i++) {
			if (strcmp(g_unitNames[i], unitName) == 0) {
				return (Unit)i;
			}
		}
	}
	return UNIT_NONE;
}

#if OPTION_SCPI
int getScpiUnit(Unit unit) {
    if (unit == UNIT_UNKNOWN) {
        return SCPI_UNIT_NONE;
    }
    return g_scpiUnits[unit];
}
#endif

Unit getBaseUnit(Unit unit) {
    if (unit == UNIT_UNKNOWN) {
        return UNIT_UNKNOWN;
    }
	return g_baseUnit[unit];
}

float getUnitFactor(Unit unit) {
    if (unit == UNIT_UNKNOWN) {
        return 1.0f;
    }
	return g_unitFactor[unit];
}

static Unit getDerivedUnit(Unit unit, float factor) {
	if (unit == UNIT_UNKNOWN) {
		return UNIT_UNKNOWN;
	}

	for (size_t i = 0; i < sizeof(g_baseUnit); i++) {
		if (g_baseUnit[i] == g_baseUnit[unit] && g_unitFactor[i] == factor) {
			return (Unit)i;
		}
	}

	return UNIT_UNKNOWN;
}

static const float FACTORS[] = { 1E-12F, 1E-9F, 1E-6F, 1E-3F, 1E0F, 1E3F, 1E6F, 1E9F, 1E12F };

Unit findDerivedUnit(float value, Unit unit) {
	Unit result;

	for (int factorIndex = 1; ; factorIndex++) {
		float factor = FACTORS[factorIndex];
		if (factor > 1.0F) {
			break;
		}
		if (value < factor) {
			result = getDerivedUnit(unit, FACTORS[factorIndex - 1]);
			if (result != UNIT_UNKNOWN) {
				return result;
			}
		}
	}

	for (int factorIndex = sizeof(FACTORS) / sizeof(float) - 1; factorIndex >= 0; factorIndex--) {
		float factor = FACTORS[factorIndex];
		if (factor == 1.0F) {
			break;
		}
		if (value >= factor) {
			result = getDerivedUnit(unit, factor);
			if (result != UNIT_UNKNOWN) {
				return result;
			}
		}
	}

	return unit;
}

float getSmallerFactor(float factor) {
	for (int factorIndex = sizeof(FACTORS) / sizeof(float) - 1; factorIndex > 0; factorIndex--) {
		float itFactor = FACTORS[factorIndex];
		if (itFactor < factor) {
			return itFactor;
		}
	}
	return FACTORS[0];
}

Unit getSmallerUnit(Unit unit, float min, float precision) {
	float factor = getUnitFactor(unit);
	if (precision <= factor || min <= factor) {
		return getDerivedUnit(unit, getSmallerFactor(factor));
	}
	return UNIT_UNKNOWN;
}

Unit getBiggestUnit(Unit unit, float max) {
	for (int factorIndex = sizeof(FACTORS) / sizeof(float) - 1; factorIndex >= 0; factorIndex--) {
		float factor = FACTORS[factorIndex];
		if (max >= factor) {
			auto result = getDerivedUnit(unit, factor);
			if (result != UNIT_UNKNOWN) {
				return result;
			}
		}
	}
	return UNIT_UNKNOWN;
}

Unit getSmallestUnit(Unit unit, float min, float precision) {
	for (int factorIndex = 0; factorIndex < int(sizeof(FACTORS) / sizeof(float)); factorIndex++) {
		float factor = FACTORS[factorIndex];
		if (precision <= factor || min <= factor) {
			auto result = getDerivedUnit(unit, factor);
			if (result != UNIT_UNKNOWN) {
				return result;
			}
		}
	}
	return UNIT_UNKNOWN;
}

} // namespace eez