/*
Implementing the "Two-line element set (TLE)", a data format encoding orbital elements of Earth-orbiting objects.

More information can be found here:
- https://en.wikipedia.org/wiki/Two-line_element_set
- https://spaceflight.nasa.gov/realdata/sightings/SSapplications/Post/JavaSSOP/SSOP_Help/tle_def.html

*/

package TLE

// TLE defines the lines contained in a Two-Line-Element
type TLE struct {
	TitleLine TitleLine `json:"titleline"`
	LineOne   LineOne   `json:"lineone"`
	LineTwo   LineTwo   `json:"linetwo"`
}

// NewTLE returns a pointer to a TLE struct filled with the given Lines
func NewTLE(titleLine TitleLine, lineOne LineOne, lineTwo LineTwo) *TLE {
	return &TLE{TitleLine: titleLine, LineOne: lineOne, LineTwo: lineTwo}
}

// TitleLine defines the first line in the the TLE
// It contains the name of the satellite
type TitleLine struct {
	Satname string `json:"satname"`
}

// LineOne defines the first line in the TLE
type LineOne struct {
	Linenumber int8 `json:"linenumber"`

	// Catalog number defined by USSPACECOM
	// A "U" indicates an unclassified object
	SatelliteNumber int  `json:"satellitenumber"`
	Classification  rune `json:"classification"`

	InternationalDesignator InternationalDesignator `json:"internationaldesignator"`
	Epoch                   Epoch                   `json:"epoch"`
	Firstderiv              float64                 `json:"firstderiv"`
	Secondderiv             float64                 `json:"secondderiv"`
	BSTAR                   float64                 `json:"BSTAR"`
	Numberzero              int8                    `json:"numberzero"`
	ElementSetNumber        int                     `json:"elementesetnumber"`
	Checksum                int8                    `json:"checksum"`
}

// InternationalDesignator stores information about the satellite such as when it launched
type InternationalDesignator struct {

	// Last two digits of launch year
	Launchyear int8 `json:"launchyear"`

	// Launch number of the year
	Launchnumber int `json:"launchnumber"`

	// Piece of the launch
	Launchpiece rune `json:"launchpiece"`
}

// Epoch defines a moment in time
type Epoch struct {

	// Last two digits of the year
	Year int8 `json:"year"`

	// day of the year and fractional portion of the day
	Dayfraction float64 `json:"dayfraction"`
}

type LineTwo struct {
	Linenumber                       int8    `json:"linenumber"`
	Satellitenumber                  int     `json:"satellitenumber"`
	Inclination                      float64 `json:"inclination"`
	RightAscensionOfTheAscendingNode float64 `json:"rightascensionoftheascendingnode"`
	Eccentricity                     float64 `json:"eccentricity"`
	ArgumentOfPerigee                float64 `json:"argumentofperigee"`
	MeanAnomaly                      float64 `json:"meananomaly"`
	MeanMotion                       float64 `json:"meanmotion"`
	RevolutionNumberAtEpoch          int     `json:"revolutionnumberatepoch"`
	Checksum                         int8    `json:"checksum"`
}