package gogeouri

import (
	"errors"
	"strconv"
	"strings"
)

type Geo struct {
	Latitude, Longitude, Altitude float64
	Parameters                    map[string][]string
}

const scheme = "geo"

func Parse(uri string) (*Geo, error) {
	g := &Geo{
		Parameters: map[string][]string{},
	}
	if !strings.HasPrefix(uri, scheme+":") {
		return nil, errors.New("no or wrong scheme")
	}
	uri = strings.TrimPrefix(uri, scheme+":")
	uriParts := strings.Split(uri, ";")
	if len(strings.TrimSpace(uriParts[0])) < 1 {
		return nil, errors.New("empty path")
	}
	coords := strings.Split(uriParts[0], ",")
	if l := len(coords); l < 2 || l > 3 {
		return nil, errors.New("wrong number of coordinates")
	}
	if f, e := strconv.ParseFloat(coords[0], 64); e == nil {
		g.Latitude = f
	} else {
		return nil, errors.New("can't parse latitude")
	}
	if f, e := strconv.ParseFloat(coords[1], 64); e == nil {
		g.Longitude = f
	} else {
		return nil, errors.New("can't parse longitude")
	}
	if len(coords) == 3 {
		if f, e := strconv.ParseFloat(coords[2], 64); e == nil {
			g.Altitude = f
		} else {
			return nil, errors.New("can't parse altitude")
		}
	}
	for _, p := range uriParts[1:] {
		pParts := strings.Split(p, "=")
		if l := len(pParts); l == 1 {
			if _, ok := g.Parameters[pParts[0]]; !ok {
				g.Parameters[pParts[0]] = []string{}
			}
		} else if l == 2 {
			g.Parameters[pParts[0]] = append(g.Parameters[pParts[0]], pParts[1])
		} else {
			return nil, errors.New("wrong parameter")
		}
	}
	return g, nil
}