package gps

import (
	"errors"
	"strconv"
)

type Parser struct {
	fields     []string
	EmptyField bool
	Err        error
}

func (parser *Parser) setError(text string) {
	if parser.Err == nil {
		parser.Err = errors.New(text)
	}
}

func (parser *Parser) updateError(err error) {
	if err != nil {
		parser.Err = err
	}
}

func (parser *Parser) get(idx int, fallback string) string {
	if idx >= len(parser.fields) {
		parser.setError("Field out of range.")
		return fallback
	} else {
		value := parser.fields[idx]
		if value == "" {
			parser.EmptyField = true
			return fallback
		} else {
			return value
		}
	}

}

func (parser *Parser) parseInt(value string) int {
	f, err := strconv.ParseInt(value, 0, 0)
	parser.updateError(err)
	return int(f)
}

func (parser *Parser) parseFloat(value string) float64 {
	f, err := strconv.ParseFloat(value, 64)
	parser.updateError(err)
	return f
}

func (parser *Parser) parseFloat32(value string) float32 {
	f, err := strconv.ParseFloat(value, 32)
	parser.updateError(err)
	return float32(f)
}

func (parser *Parser) GetString(idx int) string {
	return parser.get(idx, "")
}

func (parser *Parser) GetInt(idx int) int {
	return parser.parseInt(parser.get(idx, "0"))
}

func (parser *Parser) GetFloat(idx int) float64 {
	value := parser.get(idx, "0")
	f, err := strconv.ParseFloat(value, 64)
	parser.updateError(err)
	return f
}

func (parser *Parser) GetFloat32(idx int) float32 {
	value := parser.get(idx, "0")
	f, err := strconv.ParseFloat(value, 32)
	parser.updateError(err)
	return float32(f)
}

func (parser *Parser) GetTime(idx int) float64 {
	value := parser.parseFloat(parser.GetString(idx))
	hhmm := int(value / 100)
	hours, minutes := hhmm/100, hhmm%100
	seconds := value - float64(hhmm*100)

	return float64(hours*3600+minutes*60) + seconds
}

func (parser *Parser) GetLatLong(idx int) float64 {
	value := parser.GetFloat(idx)
	dd := int(value / 100)
	mm := value - float64(dd*100)
	decimal := float64(dd) + mm/60

	direction := parser.get(idx+1, "W")

	if direction == "W" || direction == "S" {
		decimal = -decimal
	}

	return decimal
}