using Spectre.Console;
using YoutubeSummarizer.Models;

namespace YoutubeSummarizer.Services;

/// <summary>
/// Handles all console output formatting.
/// Keeping display logic separate from business logic makes it easy to
/// later add output modes (JSON, Markdown file, HTML report) without
/// touching the service layer.
///
/// Rendering is delegated to Spectre.Console, which handles colour,
/// word-wrap to the current terminal width, and graceful degradation
/// when output is redirected to a file or a non-ANSI terminal.
/// </summary>
public static class ConsoleRenderer
{
    /// <summary>
    /// Sets the terminal window/tab title. Silently no-ops on terminals that
    /// don't support the escape sequence.
    /// </summary>
    public static void SetTitle(string title)
    {
        try { Console.Title = title; }
        catch { /* unsupported terminal — ignore */ }
    }

    /// <summary>Prints the application banner on startup.</summary>
    public static void PrintBanner()
    {
        SetTitle("Summarize");
        AnsiConsole.WriteLine();
        AnsiConsole.Write(new FigletText("YT Summary").Centered().Color(Color.Red));
        AnsiConsole.Write(
            new Rule("[grey]YouTube Video Summarizer[/]")
                .RuleStyle("grey")
                .Centered());
        AnsiConsole.WriteLine();
    }

    /// <summary>
    /// True when the terminal can drive Spectre's interactive prompts. When output
    /// is redirected or piped we fall back to plain reads / default answers so the
    /// app still works in scripts and CI.
    /// </summary>
    private static bool Interactive => AnsiConsole.Profile.Capabilities.Interactive;

    /// <summary>Prompts the user for a URL and reads input.</summary>
    public static string PromptForUrl()
    {
        // Revert the title while waiting for the next video.
        SetTitle("Summarize");

        const string label = "[bold]Enter a YouTube URL or a local file path[/] [grey](or 'q' to quit)[/]";

        if (!Interactive)
        {
            AnsiConsole.Markup($"{label}: ");
            return Console.ReadLine()?.Trim() ?? string.Empty;
        }

        var input = AnsiConsole.Prompt(new TextPrompt<string>($"{label}:").AllowEmpty());
        return input.Trim();
    }

    /// <summary>
    /// Asks the user whether they want to save the transcript to a text file.
    /// Defaults to <c>true</c> — pressing Enter accepts.
    /// </summary>
    public static bool PromptSaveTranscript()
    {
        if (!Interactive) return true;
        return AnsiConsole.Confirm("[bold]Save transcript to file?[/]", defaultValue: true);
    }

    /// <summary>Prints a success message with the saved file path.</summary>
    public static void PrintFileSaved(string filePath)
    {
        AnsiConsole.MarkupLine($"[green]✓[/] Transcript saved to: [blue]{Markup.Escape(filePath)}[/]");
        AnsiConsole.WriteLine();
    }

    /// <summary>
    /// Prompts the user to choose a summary mode via an arrow-key selection list.
    /// <see cref="SummaryMode.Standard"/> is listed first so it is the highlighted
    /// default — pressing Enter accepts it.
    /// </summary>
    public static SummaryMode PromptSummaryMode()
    {
        if (!Interactive) return SummaryMode.Standard;
        return AnsiConsole.Prompt(
            new SelectionPrompt<SummaryMode>()
                .Title("[bold]Choose summary mode:[/]")
                .AddChoices(SummaryMode.Standard, SummaryMode.PersonalFilter, SummaryMode.Custom)
                .UseConverter(m => m switch
                {
                    SummaryMode.Standard       => "Standard – detailed bullet-point summary",
                    SummaryMode.PersonalFilter => "Personal Filter – relevance verdict (ACT / MONITOR / IGNORE)",
                    SummaryMode.Custom         => "Custom – write your own instructions",
                    _                          => m.ToString()
                }));
    }

    /// <summary>
    /// Reads multi-line custom summarization instructions from the user,
    /// terminated by a blank line. Spectre has no built-in multi-line text
    /// prompt, so this reads raw lines directly (still styled with a Spectre
    /// header) and joins them with newlines.
    /// </summary>
    public static string PromptCustomInstructions()
    {
        AnsiConsole.MarkupLine("[bold]Enter your custom instructions[/] [grey](finish with an empty line):[/]");

        var lines = new List<string>();
        string? line;
        while (!string.IsNullOrEmpty(line = Console.ReadLine()))
        {
            lines.Add(line);
        }

        return string.Join('\n', lines).Trim();
    }

    /// <summary>Prints a dim "working" indicator before an async step.</summary>
    public static void PrintWorking(string message)
    {
        AnsiConsole.MarkupLine($"[grey]→ {Markup.Escape(message)}...[/]");
    }

    /// <summary>
    /// Renders the full summary result to the console in a structured,
    /// readable format. Includes metadata header, quality warning, and
    /// the summary body.
    /// </summary>
    public static void PrintSummary(VideoSummary summary, bool showTranscriptSource)
    {
        AnsiConsole.WriteLine();

        var isDocument = summary.TranscriptSource == TranscriptSource.LocalDocument;

        // ── Metadata header ──────────────────────────────────────────────────
        var grid = new Grid();
        grid.AddColumn(new GridColumn().PadRight(2));
        grid.AddColumn();

        grid.AddRow("[bold green]Title[/]", $"[bold]{Markup.Escape(summary.Metadata.Title)}[/]");
        grid.AddRow(isDocument ? "[grey]Type[/]" : "[grey]Channel[/]", Markup.Escape(summary.Metadata.ChannelTitle));
        grid.AddRow(
            isDocument ? "[grey]Modified[/]" : "[grey]Published[/]",
            Markup.Escape(summary.Metadata.PublishedAt.ToString("MMMM d, yyyy")));

        if (summary.Metadata.Duration is not null)
            grid.AddRow("[grey]Duration[/]", Markup.Escape(summary.Metadata.FormattedDuration));

        grid.AddRow(
            isDocument ? "[grey]Location[/]" : "[grey]URL[/]",
            isDocument
                ? Markup.Escape(summary.Metadata.SourcePath ?? summary.Metadata.Title)
                : $"https://youtu.be/{Markup.Escape(summary.Metadata.VideoId)}");

        if (showTranscriptSource)
        {
            var (badge, color) = summary.TranscriptSource switch
            {
                TranscriptSource.OwnerPublished       => ("✓ Owner-published captions", "green"),
                TranscriptSource.CommunityContributed => ("✓ Community captions", "green"),
                TranscriptSource.AutoGenerated        => ("~ Auto-generated (ASR)", "yellow"),
                TranscriptSource.MetadataOnly         => ("✗ Metadata only", "red"),
                TranscriptSource.LocalDocument        => ("✓ Local document", "green"),
                _                                     => ("? Unknown", "grey")
            };
            grid.AddRow("[grey]Transcript[/]", $"[{color}]{Markup.Escape(badge)}[/]");
        }

        grid.AddRow("[grey]Model[/]", Markup.Escape(summary.ModelUsed));
        grid.AddRow("[grey]Generated[/]", Markup.Escape(summary.GeneratedAt.ToString("yyyy-MM-dd HH:mm")) + " UTC");

        AnsiConsole.Write(grid);
        AnsiConsole.WriteLine();

        // ── Quality warning ──────────────────────────────────────────────────
        if (summary.QualityWarning is not null)
        {
            AnsiConsole.Write(
                new Panel($"[yellow]{Markup.Escape(summary.QualityWarning)}[/]")
                {
                    Header = new PanelHeader("Quality warning"),
                    Border = BoxBorder.Rounded,
                    BorderStyle = new Style(Color.Yellow)
                });
            AnsiConsole.WriteLine();
        }

        // ── Summary body ─────────────────────────────────────────────────────
        AnsiConsole.Write(
            new Panel(Markup.Escape(summary.SummaryText))
            {
                Header = new PanelHeader("Summary"),
                Border = BoxBorder.Rounded,
                Padding = new Padding(2, 1, 2, 1)
            }.Expand());

        AnsiConsole.WriteLine();
    }

    /// <summary>Prints a styled error message.</summary>
    public static void PrintError(string message)
    {
        AnsiConsole.WriteLine();
        AnsiConsole.MarkupLine($"[red]✗ Error:[/] {Markup.Escape(message)}");
        AnsiConsole.WriteLine();
    }

    /// <summary>Prints a styled warning (non-fatal).</summary>
    public static void PrintWarning(string message)
    {
        AnsiConsole.MarkupLine($"[yellow]⚠ {Markup.Escape(message)}[/]");
    }
}