using System;
using System.Drawing;
using System.Linq;
using System.Windows.Forms;
using Microsoft.Extensions.DependencyInjection;

namespace PolyTraderSharp.Ui
{
    /// <summary>
    /// Schlanke „Startleiste" der PolyTrader.App. Rendert Buttons aus den registrierten
    /// Views (gruppiert) und öffnet je View ein eigenständiges Fenster. Kennt selbst
    /// kein Modul. Enthält übergangsweise einen Legacy-Button für das alte Tab-frm_main.
    /// </summary>
    public class LauncherForm : Form
    {
        private readonly ShellUiHost _uiHost;
        private readonly IServiceProvider _services;
        private frm_main? _legacyForm;

        public LauncherForm(ShellUiHost uiHost, IServiceProvider services)
        {
            _uiHost = uiHost;
            _services = services;

            Text = "PolyTrader";
            Width = 360;
            Height = 520;
            StartPosition = FormStartPosition.CenterScreen;
            MinimizeBox = true;
            MaximizeBox = false;
            FormBorderStyle = FormBorderStyle.FixedSingle;

            BuildUi();
        }

        private void BuildUi()
        {
            var flow = new FlowLayoutPanel
            {
                Dock = DockStyle.Fill,
                FlowDirection = FlowDirection.TopDown,
                WrapContents = false,
                AutoScroll = true,
                Padding = new Padding(12)
            };

            foreach (var group in _uiHost.Views
                         .GroupBy(v => string.IsNullOrEmpty(v.Group) ? "Allgemein" : v.Group)
                         .OrderBy(g => g.Key))
            {
                flow.Controls.Add(MakeHeader(group.Key));
                foreach (var view in group.OrderBy(v => v.Order).ThenBy(v => v.Title))
                {
                    var captured = view;
                    flow.Controls.Add(MakeButton(view.Title, (_, _) => _uiHost.OpenView(captured)));
                }
            }

            // Übergangs-Zugang zur alten Tab-UI, bis alle Views extrahiert sind.
            flow.Controls.Add(MakeHeader("Übergang"));
            flow.Controls.Add(MakeButton("Legacy-UI (alte Tabs)", (_, _) => OpenLegacy()));

            Controls.Add(flow);
        }

        private Label MakeHeader(string text) => new()
        {
            Text = text,
            AutoSize = true,
            Font = new Font(Font, FontStyle.Bold),
            Margin = new Padding(0, 10, 0, 4)
        };

        private Button MakeButton(string text, EventHandler onClick)
        {
            var btn = new Button
            {
                Text = text,
                Width = 310,
                Height = 34,
                Margin = new Padding(0, 2, 0, 2),
                TextAlign = ContentAlignment.MiddleLeft,
                UseVisualStyleBackColor = true
            };
            btn.Click += onClick;
            return btn;
        }

        private void OpenLegacy()
        {
            if (_legacyForm != null && !_legacyForm.IsDisposed)
            {
                if (_legacyForm.WindowState == FormWindowState.Minimized)
                    _legacyForm.WindowState = FormWindowState.Normal;
                _legacyForm.BringToFront();
                _legacyForm.Activate();
                return;
            }

            _legacyForm = _services.GetRequiredService<frm_main>();
            _legacyForm.FormClosed += (_, _) => _legacyForm = null;
            _legacyForm.Show();
        }
    }
}