using System.Diagnostics;
using System.Net;
using System.Windows.Forms;
using Markdig;
using Microsoft.Web.WebView2.WinForms;

class Gui : Form
{
    record Model(string Label, string Id) { public override string ToString() => Label; }
    static readonly Model[] Models =
    [
        new("Fable 5.1 (claude-fable-5-1)", "claude-fable-5-1"),
        new("Opus 5.5 (claude-opus-5-5)", "claude-opus-5-5"),
        new("Sonnet 5.5 (claude-sonnet-5-5)", "claude-sonnet-5-5"),
        new("Haiku 5.5 (claude-haiku-5-5)", "claude-haiku-5-5"),
    ];
    const string Default = "predefinito";

    static readonly MarkdownPipeline Md = new MarkdownPipelineBuilder().UseAdvancedExtensions().DisableHtml().Build();

    const string Css = """
        :root { color-scheme: light dark; }
        body { font: 15px/1.6 'Segoe UI', sans-serif; margin: 0; padding: 16px 0 32px; background: Canvas; color: CanvasText; }
        .msg { max-width: 800px; margin: 0 auto 18px; padding: 0 16px; }
        .user { text-align: right; }
        .user div { display: inline-block; text-align: left; white-space: pre-wrap; background: color-mix(in srgb, CanvasText 10%, Canvas); padding: 10px 14px; border-radius: 18px; max-width: 85%; }
        .err div { color: #c0392b; white-space: pre-wrap; }
        .wait { opacity: .6; font-style: italic; }
        pre { background: color-mix(in srgb, CanvasText 8%, Canvas); padding: 12px; border-radius: 8px; overflow-x: auto; }
        code { font-family: Consolas, monospace; font-size: 13.5px; }
        table { border-collapse: collapse; } th, td { border: 1px solid color-mix(in srgb, CanvasText 25%, Canvas); padding: 4px 10px; }
        blockquote { margin-left: 0; padding-left: 12px; border-left: 3px solid color-mix(in srgb, CanvasText 30%, Canvas); }
        """;

    // (ruolo, testo): "user" | "ai" | "err" | "wait"
    readonly List<(string Role, string Text)> chat = [];
    readonly WebView2 view = new() { Dock = DockStyle.Fill };
    readonly TextBox input = new() { Dock = DockStyle.Fill, Multiline = true, AcceptsReturn = true, ScrollBars = ScrollBars.Vertical, Font = new Font("Segoe UI", 11) };
    readonly Button send = new() { Text = "Invia", Dock = DockStyle.Fill };
    readonly Button reset = new() { Text = "Nuova chat", AutoSize = true };
    readonly ComboBox model = new() { DropDownStyle = ComboBoxStyle.DropDown, Width = 300 }; // editabile: ID completo
    readonly ComboBox effort = new() { DropDownStyle = ComboBoxStyle.DropDownList, Width = 100 };

    string sessionId = Guid.NewGuid().ToString();
    bool started; // true dopo il primo messaggio riuscito: da lì in poi --resume

    public Gui()
    {
        Text = "LlmRun";
        Width = 1000; Height = 700;

        model.Items.Add(Default); model.Items.AddRange(Models); model.SelectedIndex = 0;
        effort.Items.AddRange([Default, "low", "medium", "high", "xhigh", "max"]); effort.SelectedIndex = 0;

        var settings = new FlowLayoutPanel { Dock = DockStyle.Fill, WrapContents = false };
        settings.Controls.AddRange([
            new Label { Text = "Modello", AutoSize = true, Margin = new Padding(0, 8, 0, 0) }, model,
            new Label { Text = "Effort", AutoSize = true, Margin = new Padding(8, 8, 0, 0) }, effort, reset]);

        var bottom = new TableLayoutPanel { Dock = DockStyle.Bottom, Height = 140, Padding = new Padding(8), ColumnCount = 2, RowCount = 2 };
        bottom.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 100));
        bottom.ColumnStyles.Add(new ColumnStyle(SizeType.Absolute, 90));
        bottom.RowStyles.Add(new RowStyle(SizeType.Absolute, 34));
        bottom.RowStyles.Add(new RowStyle(SizeType.Percent, 100));
        bottom.Controls.Add(settings, 0, 0); bottom.SetColumnSpan(settings, 2);
        bottom.Controls.Add(input, 0, 1);
        bottom.Controls.Add(send, 1, 1);

        Controls.Add(view); Controls.Add(bottom); // Fill per primo: l'ordine inverso dei Dock

        send.Click += async (_, _) => await Send();
        reset.Click += (_, _) => { chat.Clear(); sessionId = Guid.NewGuid().ToString(); started = false; Render(); };
        input.KeyDown += async (_, e) =>
        {
            if (e.KeyCode == Keys.Enter && !e.Shift) { e.SuppressKeyPress = true; await Send(); }
        };
        Load += async (_, _) =>
        {
            var dir = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), "LlmRun");
            await view.EnsureCoreWebView2Async(await Microsoft.Web.WebView2.Core.CoreWebView2Environment.CreateAsync(null, dir));
            view.CoreWebView2.NavigationStarting += (_, e) =>
            {
                if (e.Uri.StartsWith("http", StringComparison.OrdinalIgnoreCase))
                {
                    e.Cancel = true;
                    Process.Start(new ProcessStartInfo(e.Uri) { UseShellExecute = true });
                }
            };
            view.CoreWebView2.Settings.AreDefaultContextMenusEnabled = true;
            Render();
        };
    }

    void Render()
    {
        if (view.CoreWebView2 == null) return;
        var body = string.Concat(chat.Select(m => m.Role switch
        {
            "user" => $"<div class='msg user'><div>{WebUtility.HtmlEncode(m.Text)}</div></div>",
            "ai" => $"<div class='msg'>{Markdown.ToHtml(m.Text, Md)}</div>",
            "err" => $"<div class='msg err'><div>{WebUtility.HtmlEncode(m.Text)}</div></div>",
            _ => $"<div class='msg wait'>{WebUtility.HtmlEncode(m.Text)}</div>",
        }));
        view.NavigateToString($"<!doctype html><meta charset='utf-8'><style>{Css}</style><body>{body}<script>scrollTo(0,document.body.scrollHeight)</script></body>");
    }

    async Task Send()
    {
        var text = input.Text.Trim();
        if (text == "" || !send.Enabled) return;
        send.Enabled = false;
        input.Clear();
        chat.Add(("user", text));
        chat.Add(("wait", "Claude sta scrivendo…"));
        Render();
        try
        {
            var (code, stdout, stderr) = await RunClaude(text);
            chat.RemoveAt(chat.Count - 1);
            if (code == 0) { started = true; chat.Add(("ai", stdout)); }
            else chat.Add(("err", $"claude è uscito con codice {code}\n{stderr}".Trim()));
        }
        catch (System.ComponentModel.Win32Exception)
        {
            chat.RemoveAt(chat.Count - 1);
            chat.Add(("err", "'claude' non trovato nel PATH."));
        }
        finally { send.Enabled = true; Render(); input.Focus(); }
    }

    async Task<(int Code, string Out, string Err)> RunClaude(string prompt)
    {
        var psi = new ProcessStartInfo("claude")
        {
            WorkingDirectory = AppContext.BaseDirectory,
            UseShellExecute = false,
            RedirectStandardInput = true, RedirectStandardOutput = true, RedirectStandardError = true,
            CreateNoWindow = true,
        };
        psi.ArgumentList.Add("-p");
        psi.ArgumentList.Add(prompt);
        psi.ArgumentList.Add(started ? "--resume" : "--session-id");
        psi.ArgumentList.Add(sessionId);
        foreach (var (flag, value) in new[] { ("--model", model.SelectedItem is Model m ? m.Id : model.Text.Trim()), ("--effort", effort.Text) })
            if (value != "" && value != Default) { psi.ArgumentList.Add(flag); psi.ArgumentList.Add(value); }

        using var p = Process.Start(psi)!;
        p.StandardInput.Close(); // evita l'attesa di stdin di claude
        var o = p.StandardOutput.ReadToEndAsync();
        var e = p.StandardError.ReadToEndAsync();
        await p.WaitForExitAsync();
        return (p.ExitCode, (await o).Trim(), (await e).Trim());
    }
}