package TLE

import (
	"fmt"
	"math"
	"strconv"
	"strings"
)

func NewTLE(RawTLE string) (TLE, error) {

	// split the TLE
	var SplitTLE []string = strings.Split(RawTLE, "\n")

	// Line One

	// parse the line number
	LineOneLinenumber, err := strconv.Atoi(string(SplitTLE[1][0]))
	if err != nil {
		return TLE{}, fmt.Errorf("%s: %#v\n%v", "Could not parse the line number", SplitTLE[1][1], err)
	}

	// Parse the Satellite Number
	SatelliteNumber, err := strconv.Atoi(SplitTLE[1][2:7])
	if err != nil {
		return TLE{}, fmt.Errorf("%s: %#v\n%v", "Could not parse the Satellite Number", SplitTLE[1][2:7], err)
	}

	// Parse the launch year
	LaunchYear, err := strconv.Atoi(SplitTLE[1][9:11])
	if err != nil {
		return TLE{}, fmt.Errorf("%s: %#v\n%v", "Could not parse the Launch Year", SplitTLE[1][9:11], err)
	}

	// Parse the launch number
	LaunchNumber, err := strconv.Atoi(SplitTLE[1][11:14])
	if err != nil {
		return TLE{}, fmt.Errorf("%s: %#v\n%v", "Could not parse the Launch Number", SplitTLE[1][11:14], err)
	}

	// Parse the epoch year
	EpochYear, err := strconv.Atoi(SplitTLE[1][18:20])
	if err != nil {
		return TLE{}, fmt.Errorf("%s: %#v\n%v", "Could not parse the Epoch Year", SplitTLE[1][18:20], err)
	}

	// Parse the epoch day fraction
	EpochDayFraction, err := strconv.ParseFloat(SplitTLE[1][20:32], 64)
	if err != nil {
		return TLE{}, fmt.Errorf("%s: %#v\n%v", "Could not parse the Epoch Day Fraction", SplitTLE[1][20:32], err)
	}

	// Parse the First Time Derivative of the Mean Motion
	RawFirstDeriv := strings.TrimSpace(SplitTLE[1][33:43])
	FirstDeriv, err := strconv.ParseFloat(RawFirstDeriv, 64)
	if err != nil {
		return TLE{}, fmt.Errorf("%s: %#v\n%v", "Could not parse the First Time Derivative of the Mean Motion", SplitTLE[1][33:43], err)
	}

	/*
		Parse the Second Time Derivative of the Mean Motion
	*/
	RawSecondDerivBase := strings.TrimSpace(SplitTLE[1][44:50])
	SecondDerivBase, err := strconv.Atoi(RawSecondDerivBase)
	if err != nil {
		return TLE{}, fmt.Errorf("%s: %#v\n%v", "Could not parse the Second Time Derivative of the Mean Motion Base", SplitTLE[1][44:50], err)
	}

	RawSecondDerivPower := strings.TrimSpace(SplitTLE[1][50:52])
	SecondDerivPower, err := strconv.Atoi(RawSecondDerivPower)
	if err != nil {
		return TLE{}, fmt.Errorf("%s: %#v\n%v", "Could not parse the Second Time Derivative of the Mean Motion Power", SplitTLE[1][50:52], err)
	}

	// This converts the following format: (67960-4 = 0.000067960)
	// Also: (00000-0 = 0.00000)
	SecondDeriv := float64(SecondDerivBase) / math.Pow(10, (-1*float64(SecondDerivPower))+5)

	/*
		Parse the Second Time Derivative of the Mean Motion
	*/
	RawBSTARBase := strings.TrimSpace(SplitTLE[1][53:59])
	BSTARBase, err := strconv.Atoi(RawBSTARBase)
	if err != nil {
		return TLE{}, fmt.Errorf("%s: %#v\n%v", "Could not parse the BSTAR Drag Term Base", SplitTLE[1][53:59], err)
	}

	RawBSTARPower := strings.TrimSpace(SplitTLE[1][59:61])
	BSTARPower, err := strconv.Atoi(RawBSTARPower)
	if err != nil {
		return TLE{}, fmt.Errorf("%s: %#v\n%v", "Could not parse the BSTAR Drag Term Power", SplitTLE[1][59:61], err)
	}

	// This converts the following format: (67960-4 = 0.000067960)
	// Also: (00000-0 = 0.00000)
	BSTAR := float64(BSTARBase) / math.Pow(10, (-1*float64(BSTARPower))+5)

	// Parse the Element set number
	RawElementSetNumber := strings.TrimSpace(SplitTLE[1][64:68])
	ElementSetNumber, err := strconv.Atoi(RawElementSetNumber)
	if err != nil {
		return TLE{}, fmt.Errorf("%s: %#v\n%v", "Could not parse the Element set number", SplitTLE[1][64:68], err)
	}

	// fill the generatedTLE struct
	var generatedTLE TLE = TLE{
		TitleLine: TitleLine{
			Satname: fmt.Sprintf("%-25s", SplitTLE[0][0:24]),
		},
		LineOne: LineOne{
			Linenumber:      int8(LineOneLinenumber),
			SatelliteNumber: SatelliteNumber,
			Classification:  string(SplitTLE[1][7]),
			InternationalDesignator: InternationalDesignator{
				Launchyear:   int8(LaunchYear),
				Launchnumber: LaunchNumber,
				Launchpiece:  string(SplitTLE[1][14]),
			},
			Epoch: Epoch{
				Year:        int8(EpochYear),
				Dayfraction: EpochDayFraction,
			},
			Firstderiv:       FirstDeriv,
			Secondderiv:      SecondDeriv,
			BSTAR:            BSTAR,
			Numberzero:       int8(SplitTLE[1][62]),
			ElementSetNumber: ElementSetNumber,
			Checksum:         int8(SplitTLE[1][68]),
		},
		LineTwo: LineTwo{},
	}

	return generatedTLE, nil
}