package playlists

import (
	"testing"
)

func TestValidateTimezone_Valid(t *testing.T) {
	cases := []string{"UTC", "America/New_York", "Europe/London", "Asia/Tokyo"}
	for _, tz := range cases {
		t.Run(tz, func(t *testing.T) {
			loc, err := validateTimezone(tz)
			if err != nil {
				t.Fatalf("validateTimezone(%q): %v", tz, err)
			}
			if loc == nil {
				t.Fatalf("validateTimezone(%q): nil location", tz)
			}
		})
	}
}

func TestValidateTimezone_Invalid(t *testing.T) {
	cases := []string{"", "Not/A/Zone", "GMT+5", "EST5EDT-not-iana"}
	for _, tz := range cases {
		t.Run(tz, func(t *testing.T) {
			_, err := validateTimezone(tz)
			if err == nil {
				t.Fatalf("validateTimezone(%q): expected error, got nil", tz)
			}
		})
	}
}

func TestValidateTimezoneOrUTC_FallbackToUTC(t *testing.T) {
	// validateTimezoneOrUTC returns UTC for any unparseable input.
	// Used by the scheduler when reading stored timezones — corrupted
	// DB values should not crash; they should fall back to UTC.
	loc := validateTimezoneOrUTC("Not/A/Zone")
	if loc.String() != "UTC" {
		t.Errorf("expected UTC fallback for invalid input, got %s", loc)
	}

	// Valid input returns the named location, not UTC.
	loc = validateTimezoneOrUTC("America/New_York")
	if loc.String() == "UTC" {
		t.Errorf("valid input incorrectly fell back to UTC")
	}
	if loc.String() != "America/New_York" {
		t.Errorf("expected America/New_York, got %s", loc)
	}
}