package main

import (
	"errors"
	"testing"
)

func TestLocalTimezone(t *testing.T) {
	noLink := func(string) (string, error) { return "", errors.New("no") }
	noFile := func(string) ([]byte, error) { return nil, errors.New("no") }
	env := func(v string) func(string) string {
		return func(k string) string {
			if k == "TZ" {
				return v
			}
			return ""
		}
	}
	link := func(target string) func(string) (string, error) {
		return func(string) (string, error) { return target, nil }
	}
	file := func(body string) func(string) ([]byte, error) {
		return func(string) ([]byte, error) { return []byte(body), nil }
	}
	cases := []struct {
		name     string
		getenv   func(string) string
		readlink func(string) (string, error)
		readFile func(string) ([]byte, error)
		want     string
	}{
		{"TZ plain", env("Europe/London"), noLink, noFile, "Europe/London"},
		{"TZ colon", env(":Europe/London"), noLink, noFile, "Europe/London"},
		{"TZ path", env("/usr/share/zoneinfo/Asia/Kolkata"), noLink, noFile, "Asia/Kolkata"},
		{"localtime link (linux)", env(""), func(string) (string, error) { return "/usr/share/zoneinfo/Europe/Dublin", nil }, noFile, "Europe/Dublin"},
		{"localtime link (macOS)", env(""), func(string) (string, error) { return "/var/db/timezone/zoneinfo/Australia/Sydney", nil }, noFile, "Australia/Sydney"},
		{"etc/timezone", env(""), noLink, func(string) ([]byte, error) { return []byte("Europe/Paris\n"), nil }, "Europe/Paris"},
		// Review Focus 1: real-machine noise is a clean name or nothing.
		{"etc/timezone padded", env(""), noLink, func(string) ([]byte, error) { return []byte("  America/New_York  \r\n# trailing\n"), nil }, "America/New_York"},
		{"TZ bare colon", env(":"), noLink, noFile, ""},
		{"TZ localtime", env("localtime"), noLink, noFile, ""},
		{"TZ posixrules path", env("/usr/share/zoneinfo/posixrules"), noLink, noFile, ""},
		{"TZ POSIX rule string", env("EST5EDT,M3.2.0,M11.1.0"), noLink, noFile, ""},
		{"nothing", env(""), noLink, noFile, ""},
		// Source order and fall-through: more than one source is live.
		{"TZ beats link", env("Europe/London"), link("/usr/share/zoneinfo/Asia/Tokyo"), noFile, "Europe/London"},
		{"invalid TZ falls through to link", env("EST5EDT,M3.2.0,M11.1.0"), link("/usr/share/zoneinfo/Asia/Tokyo"), noFile, "Asia/Tokyo"},
		{"link beats etc/timezone", env(""), link("/usr/share/zoneinfo/Asia/Tokyo"), file("Europe/Paris\n"), "Asia/Tokyo"},
		{"invalid link falls through to etc/timezone", env(""), link("/usr/share/zoneinfo/posixrules"), file("Europe/Paris\n"), "Europe/Paris"},
	}
	for _, c := range cases {
		if got := localTimezone(c.getenv, c.readlink, c.readFile); got != c.want {
			t.Errorf("%s: %q, want %q", c.name, got, c.want)
		}
	}
}