package geo

import (
	"math"
	"testing"
)

var testPoints = map[string]Point{
	"eu-west-1":      {53.35, -6.26},
	"eu-west-2":      {51.51, -0.13},
	"ap-southeast-2": {-33.87, 151.21},
}

func testPointOf(r string) (Point, bool) { p, ok := testPoints[r]; return p, ok }

func TestDistanceKmDublinLondon(t *testing.T) {
	d := DistanceKm(testPoints["eu-west-1"], testPoints["eu-west-2"])
	if math.Abs(d-464) > 5 {
		t.Fatalf("Dublin to London = %.1f km, want about 464", d)
	}
}

func TestNearest(t *testing.T) {
	london := Point{51.5, -0.12}
	sydney := Point{-33.9, 151.2}
	home := Candidate{Code: "", Home: true, AWSRegion: "eu-west-1"}
	uk := Candidate{Code: "uk", AWSRegion: "eu-west-2"}
	au := Candidate{Code: "au", AWSRegion: "ap-southeast-2"}

	cases := []struct {
		name   string
		p      Point
		cands  []Candidate
		want   string
		wantOK bool
	}{
		{"single", london, []Candidate{home}, "", true},
		{"clear winner", london, []Candidate{home, uk, au}, "uk", true},
		{"far side", sydney, []Candidate{home, uk, au}, "au", true},
		{"home with no point gives no answer", london,
			[]Candidate{{Code: "", Home: true, AWSRegion: ""}, uk}, "", false},
		{"non-home with no point is left out", london,
			[]Candidate{home, {Code: "zz", AWSRegion: "xx-nowhere-1"}}, "", true},
		{"empty", london, nil, "", false},
		{"tie goes to the home", testPoints["eu-west-2"],
			[]Candidate{{Code: "uk2", AWSRegion: "eu-west-2"}, {Code: "", Home: true, AWSRegion: "eu-west-2"}}, "", true},
		{"non-home tie goes to the smaller code", testPoints["eu-west-2"],
			[]Candidate{{Code: "uk2", AWSRegion: "eu-west-2"}, {Code: "uk", AWSRegion: "eu-west-2"}}, "uk", true},
	}
	for _, c := range cases {
		got, ok := NearestWith(c.p, c.cands, testPointOf)
		if got != c.want || ok != c.wantOK {
			t.Errorf("%s: got (%q, %v), want (%q, %v)", c.name, got, ok, c.want, c.wantOK)
		}
	}
}