using System.Diagnostics;
using System.IO;
using System.Windows.Input;
using ytLive.Helpers;

namespace ytLive.ViewModels;

public partial class MainViewModel : ViewModelBase
{

    private bool _isSettingsOpen;
    private bool _isBugOpen;
    private bool _isFeatureOpen;
    private bool _isAboutOpen;
    private bool _isLicensesOpen;
    private string _overlayTitle = string.Empty;
    private string _bugReportText = string.Empty;
    private string _bugReportEmail = string.Empty;
    private string _featureRequestText = string.Empty;
    private string _featureRequestEmail = string.Empty;

    private const string SupportEmail = "gramps@llamachile.shop";
    // The creator-hub link targets (About overlay) — public so the hub's
    // integration test can assert they point at real destinations.
    public const string ChannelUrl = "https://youtube.com/@llamachileshop";
    public const string MastodonUrl = "https://mastodon.llamachile.tube/@gramps";
    public const string PremiumUrl = "https://buy.polar.sh/polar_cl_ueMy8AyAClO0o0yo19IroZwKTbD587gzUsjEW3bFapw";
    public const string CoffeeUrl = "https://buymeacoffee.com/llamachiley";
    public static string AppVersionLabel => $"Version {typeof(MainViewModel).Assembly.GetName().Version?.ToString(3)}";

    /// <summary>The About hub's Unlock Premium button lights up only once the
    /// billing URL is set (Polar — polar.sh, pending TASK 10 implementation).</summary>
    public bool IsPremiumAvailable => PremiumUrl.Length > 0;

    /// <summary>Full in-app licensing/legal text, loaded on demand from the
    /// shipped THIRD-PARTY-NOTICES.txt (never opens the OS viewer).</summary>
    public string LicensesText { get; private set; } = string.Empty;

    // Overlay panels
    public bool IsSettingsOpen
    {
        get => _isSettingsOpen;
        private set => SetPanel(ref _isSettingsOpen, value);
    }

    public bool IsBugOpen
    {
        get => _isBugOpen;
        private set => SetPanel(ref _isBugOpen, value);
    }

    public bool IsFeatureOpen
    {
        get => _isFeatureOpen;
        private set => SetPanel(ref _isFeatureOpen, value);
    }

    public bool IsAboutOpen
    {
        get => _isAboutOpen;
        private set => SetPanel(ref _isAboutOpen, value);
    }

    /// <summary>About hub sub-view: the full licensing/legal texts panel
    /// (in-app scrolling — no Notepad, no browser tab).</summary>
    public bool IsLicensesOpen
    {
        get => _isLicensesOpen;
        set
        {
            if (SetProperty(ref _isLicensesOpen, value))
                OnPropertyChanged(nameof(IsHubVisible));
        }
    }

    public bool IsAnyOverlayOpen => IsSettingsOpen || IsBugOpen || IsFeatureOpen || IsAboutOpen;

    public string OverlayTitle
    {
        get => _overlayTitle;
        private set => SetProperty(ref _overlayTitle, value);
    }

    public string BugReportText
    {
        get => _bugReportText;
        set => SetProperty(ref _bugReportText, value);
    }

    public string BugReportEmail
    {
        get => _bugReportEmail;
        set => SetProperty(ref _bugReportEmail, value);
    }

    public string FeatureRequestText
    {
        get => _featureRequestText;
        set => SetProperty(ref _featureRequestText, value);
    }

    public string FeatureRequestEmail
    {
        get => _featureRequestEmail;
        set => SetProperty(ref _featureRequestEmail, value);
    }

    public ICommand OpenSettingsCommand { get; }
    public ICommand OpenBugCommand { get; }
    public ICommand OpenFeatureCommand { get; }
    public ICommand OpenAboutCommand { get; }
    public ICommand CloseOverlayCommand { get; }
    public ICommand SubmitBugCommand { get; }
    public ICommand SubmitFeatureCommand { get; }
    public ICommand OpenChannelCommand { get; }
    public ICommand OpenMastodonCommand { get; }
    public ICommand OpenCoffeeCommand { get; }
    public ICommand OpenPremiumCommand { get; }
    public ICommand OpenLicensesCommand { get; }

    private void SetPanel(ref bool field, bool value, [System.Runtime.CompilerServices.CallerMemberName] string? propertyName = null)
    {
        if (SetProperty(ref field, value, propertyName))
            OnPropertyChanged(nameof(IsAnyOverlayOpen));
    }

    private void ShowOverlay(string? panel = null, string title = "")
    {
        IsSettingsOpen = panel == nameof(IsSettingsOpen);
        IsBugOpen = panel == nameof(IsBugOpen);
        IsFeatureOpen = panel == nameof(IsFeatureOpen);
        IsAboutOpen = panel == nameof(IsAboutOpen);
        OverlayTitle = title;
        if (panel != nameof(IsAboutOpen))
            IsLicensesOpen = false;
    }

    /// <summary>Shows the in-app licensing panel, loading the full texts from
    /// the shipped THIRD-PARTY-NOTICES.txt on first open (never the OS viewer).
    /// Falls back to a "not found" note if the file is missing so the panel
    /// never hangs on nothing.</summary>
    private void ShowLicenses()
    {
        if (string.IsNullOrEmpty(LicensesText))
        {
            try
            {
                var path = Path.Combine(AppContext.BaseDirectory, "THIRD-PARTY-NOTICES.txt");
                LicensesText = File.Exists(path)
                    ? File.ReadAllText(path)
                    : "THIRD-PARTY-NOTICES.txt not found next to the executable.";
            }
            catch (Exception ex)
            {
                LicensesText = $"Could not read THIRD-PARTY-NOTICES.txt: {ex.Message}";
            }
        }
        IsLicensesOpen = true;
    }

    private void SubmitBug()
    {
        var body = string.Join(Environment.NewLine,
            BugReportText.Trim(),
            string.Empty,
            $"LlamaCasty {AppVersionLabel}",
            string.IsNullOrWhiteSpace(BugReportEmail) ? string.Empty : $"Reply-to: {BugReportEmail.Trim()}");
        ComposeEmail("[LlamaCasty Bug Report]", body);
        ShowOverlay();
    }

    private void SubmitFeature()
    {
        var body = string.Join(Environment.NewLine,
            FeatureRequestText.Trim(),
            string.Empty,
            $"LlamaCasty {AppVersionLabel}",
            string.IsNullOrWhiteSpace(FeatureRequestEmail) ? string.Empty : $"Reply-to: {FeatureRequestEmail.Trim()}");
        ComposeEmail("[LlamaCasty Feature Request]", body);
        ShowOverlay();
    }

    private static void ComposeEmail(string subject, string body)
    {
        var uri = $"mailto:{SupportEmail}?subject={Uri.EscapeDataString(subject)}&body={Uri.EscapeDataString(body)}";
        OpenUrl(uri);
    }

    private static void OpenUrl(string url)
    {
        Process.Start(new ProcessStartInfo(url) { UseShellExecute = true });
    }
}