package thermocouple

import (
	"th7/data/thermocouple"
)

const (
	T_MAX_C  = 400.0
	T_MIN_C  = -270.0
	T_MAX_UV = 20872.0
	T_MIN_UV = -5603.0
)

func t_c_to_uv(c float64) (float64, error) {

	if c < T_MIN_C || c > T_MAX_C {
		return 0, thermocouple.ErrC
	}

	var c0, c1, c2, c3, c4, c5, c6, c7, c8, c9, c10, c11, c12, c13, c14, E float64

	if c < 0.0 {
		c0 = 0.0
		c1 = 3.8748106364e1
		c2 = 4.4194434347e-2
		c3 = 1.1844323105e-4
		c4 = 2.0032973554e-5
		c5 = 9.0138019559e-7
		c6 = 2.2651156593e-8
		c7 = 3.6071154205e-10
		c8 = 3.8493939883e-12
		c9 = 2.8213521925e-14
		c10 = 1.4251594779e-16
		c11 = 4.8768662286e-19
		c12 = 1.0795539270e-21
		c13 = 1.3945027062e-24
		c14 = 7.9795153927e-28
	} else {
		c0 = 0.0
		c1 = 3.8748106364e1
		c2 = 3.3292227880e-2
		c3 = 2.0618243404e-4
		c4 = -2.1882256846e-6
		c5 = 1.0996880928e-8
		c6 = -3.0815758772e-11
		c7 = 4.5479135290e-14
		c8 = -2.7512901673e-17
		c9 = 0.0
		c10 = 0.0
		c11 = 0.0
		c12 = 0.0
		c13 = 0.0
		c14 = 0.0
	}

	E = c0 + c*(c1+c*(c2+c*(c3+c*(c4+c*(c5+c*(c6+c*(c7+c*(c8+c*(c9+c*(c10+c*(c11+c*(c12+c*(c13+c*(c14))))))))))))))
	return E, nil
}

func t_uv_to_c(uv float64) (float64, error) {

	if uv < T_MIN_UV || uv > T_MAX_UV {
		return 0, thermocouple.ErrUV
	}

	var c0, c1, c2, c3, c4, c5, c6, c7, T float64

	if uv < 0.0 {
		c0 = 0.0
		c1 = 2.5949192e-2
		c2 = -2.1316967e-7
		c3 = 7.9018692e-10
		c4 = 4.2527777e-13
		c5 = 1.3304473e-16
		c6 = 2.20241446e-20
		c7 = 1.2668171e-24
	} else {
		c0 = 0.0
		c1 = 2.592800e-2
		c2 = -7.602961e-7
		c3 = 4.637791e-11
		c4 = -2.165394e-15
		c5 = 6.048144e-20
		c6 = -7.293422e-25
		c7 = 0.0
	}

	T = c0 + uv*(c1+uv*(c2+uv*(c3+uv*(c4+uv*(c5+uv*(c6+uv*(c7)))))))
	return T, nil
}