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.
/// </summary>
public static class ConsoleRenderer
{
    // ANSI color codes. These render correctly in most Linux terminals.
    // If you pipe output to a file, the escape codes will appear as-is —
    // run with --no-color if that's a concern (not implemented here, left
    // as an exercise).
    private const string Reset   = "\x1b[0m";
    private const string Bold    = "\x1b[1m";
    private const string Cyan    = "\x1b[36m";
    private const string Yellow  = "\x1b[33m";
    private const string Green   = "\x1b[32m";
    private const string Red     = "\x1b[31m";
    private const string Dim     = "\x1b[2m";

    /// <summary>Prints the application banner on startup.</summary>
    public static void PrintBanner()
    {
        Console.WriteLine();
        Console.WriteLine($"{Bold}{Cyan}╔════════════════════════════════════════╗{Reset}");
        Console.WriteLine($"{Bold}{Cyan}║       YouTube Video Summarizer         ║{Reset}");
        Console.WriteLine($"{Bold}{Cyan}╚════════════════════════════════════════╝{Reset}");
        Console.WriteLine();
    }

    /// <summary>Prompts the user for a URL and reads input.</summary>
    public static string PromptForUrl()
    {
        Console.Write($"{Bold}Enter YouTube URL (or 'q' to quit):{Reset} ");
        return Console.ReadLine()?.Trim() ?? string.Empty;
    }

    /// <summary>
    /// Asks the user whether they want to save the transcript to a text file.
    /// Returns true if the user answers yes.
    /// </summary>
    public static bool PromptSaveTranscript()
    {
        Console.Write($"{Bold}Save transcript to file? (y/n):{Reset} ");
        var answer = Console.ReadLine()?.Trim() ?? string.Empty;
        return answer.Equals("y", StringComparison.OrdinalIgnoreCase)
            || answer.Equals("yes", StringComparison.OrdinalIgnoreCase);
    }

    /// <summary>Prints a success message with the saved file path.</summary>
    public static void PrintFileSaved(string filePath)
    {
        Console.WriteLine($"  {Green}✓ Transcript saved to:{Reset} {filePath}");
        Console.WriteLine();
    }

    /// <summary>
    /// Prompts the user to choose a summary mode.
    /// Returns the selected <see cref="SummaryMode"/>.
    /// </summary>
    public static SummaryMode PromptSummaryMode()
    {
        Console.WriteLine($"  {Dim}Summary modes:{Reset}");
        Console.WriteLine($"    {Bold}1{Reset} – Standard (detailed bullet-point summary)");
        Console.WriteLine($"    {Bold}2{Reset} – Personal Filter (relevance verdict: ACT / MONITOR / IGNORE)");
        Console.Write($"{Bold}Choose summary mode [1]:{Reset} ");
        var choice = Console.ReadLine()?.Trim() ?? string.Empty;
        return choice == "2" ? SummaryMode.PersonalFilter : SummaryMode.Standard;
    }

    /// <summary>Displays a spinner-style "working" indicator while async work runs.</summary>
    public static void PrintWorking(string message)
    {
        Console.WriteLine($"  {Dim}→ {message}...{Reset}");
    }

    /// <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)
    {
        Console.WriteLine();
        PrintDivider();

        // ── Metadata header ──────────────────────────────────────────────────
        Console.WriteLine($"{Bold}{Green}  {summary.Metadata.Title}{Reset}");
        Console.WriteLine($"  {Dim}Channel:{Reset}  {summary.Metadata.ChannelTitle}");
        Console.WriteLine($"  {Dim}Published:{Reset} {summary.Metadata.PublishedAt:MMMM d, yyyy}");
        Console.WriteLine($"  {Dim}Duration:{Reset}  {summary.Metadata.FormattedDuration}");
        Console.WriteLine($"  {Dim}URL:{Reset}      https://youtu.be/{summary.Metadata.VideoId}");

        // ── Transcript source badge ──────────────────────────────────────────
        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),
                _                                    => ("? Unknown", Dim)
            };
            Console.WriteLine($"  {Dim}Transcript:{Reset} {color}{badge}{Reset}");
        }

        Console.WriteLine($"  {Dim}Model:{Reset}    {summary.ModelUsed}");
        Console.WriteLine($"  {Dim}Generated:{Reset} {summary.GeneratedAt:yyyy-MM-dd HH:mm} UTC");

        PrintDivider();

        // ── Quality warning ──────────────────────────────────────────────────
        if (summary.QualityWarning is not null)
        {
            Console.WriteLine();
            Console.WriteLine($"  {Yellow}{summary.QualityWarning}{Reset}");
        }

        // ── Summary body ─────────────────────────────────────────────────────
        Console.WriteLine();
        Console.WriteLine($"{Bold}  SUMMARY{Reset}");
        Console.WriteLine();

        // Word-wrap the summary body at 80 characters so it's readable in
        // standard terminal widths without horizontal scrolling.
        foreach (var line in WordWrap(summary.SummaryText, maxWidth: 78))
        {
            Console.WriteLine($"  {line}");
        }

        Console.WriteLine();
        PrintDivider();
        Console.WriteLine();
    }

    /// <summary>Prints a styled error message.</summary>
    public static void PrintError(string message)
    {
        Console.WriteLine();
        Console.WriteLine($"  {Red}✗ Error: {message}{Reset}");
        Console.WriteLine();
    }

    /// <summary>Prints a styled warning (non-fatal).</summary>
    public static void PrintWarning(string message)
    {
        Console.WriteLine($"  {Yellow}⚠ {message}{Reset}");
    }

    // ─────────────────────────────────────────────────────────────────────────
    // Private helpers
    // ─────────────────────────────────────────────────────────────────────────

    private static void PrintDivider()
    {
        Console.WriteLine($"  {Dim}{"─".PadRight(74, '─')}{Reset}");
    }

    /// <summary>
    /// Splits text into lines no wider than <paramref name="maxWidth"/> characters,
    /// breaking only at word boundaries. Respects existing newlines in the input.
    /// </summary>
    private static IEnumerable<string> WordWrap(string text, int maxWidth)
    {
        foreach (var paragraph in text.Split('\n'))
        {
            if (string.IsNullOrWhiteSpace(paragraph))
            {
                yield return string.Empty;
                continue;
            }

            var words = paragraph.Split(' ', StringSplitOptions.RemoveEmptyEntries);
            var current = new System.Text.StringBuilder();

            foreach (var word in words)
            {
                if (current.Length + word.Length + 1 > maxWidth)
                {
                    yield return current.ToString();
                    current.Clear();
                }

                if (current.Length > 0) current.Append(' ');
                current.Append(word);
            }

            if (current.Length > 0)
                yield return current.ToString();
        }
    }
}