using System;
using System.Collections.Generic;
using ClaudeDo.Localization;

namespace ClaudeDo.Ui.Localization;

/// Ambient access to the active localizer for code-built (ViewModel) strings.
/// Set once at startup. Defaults to a key-echo localizer so unit tests that
/// construct ViewModels without startup wiring do not crash.
public static class Loc
{
    private static ILocalizer _current = new KeyEchoLocalizer();

    public static ILocalizer Current
    {
        get => _current;
        set
        {
            if (_current is not null) _current.LanguageChanged -= OnInnerChanged;
            _current = value;
            _current.LanguageChanged += OnInnerChanged;
            OnInnerChanged(value, EventArgs.Empty);
        }
    }

    public static event EventHandler? LanguageChanged;

    private static void OnInnerChanged(object? sender, EventArgs e) =>
        LanguageChanged?.Invoke(sender, e);

    public static string T(string key) => Current[key];
    public static string T(string key, params object[] args) => Current.Get(key, args);

    private sealed class KeyEchoLocalizer : ILocalizer
    {
        public string this[string key] => key;
        public string Get(string key, params object[] args) => key;
        public string CurrentCode => "en";
        public IReadOnlyList<LanguageOption> AvailableLanguages => Array.Empty<LanguageOption>();
        public void SetLanguage(string code) { }
        public event EventHandler? LanguageChanged { add { } remove { } }
    }
}