using System.Text;
using MeetingAssistant.MeetingNotes;
using Microsoft.Extensions.Options;

namespace MeetingAssistant.Summary;

public interface IMeetingSummaryFailureWriter
{
    Task<MeetingSummaryRunResult> WriteAsync(
        MeetingSessionArtifacts artifacts,
        Exception exception,
        CancellationToken cancellationToken);

    Task<MeetingSummaryRunResult> WriteAsync(
        MeetingSessionArtifacts artifacts,
        Exception exception,
        MeetingAssistantOptions options,
        CancellationToken cancellationToken)
    {
        return WriteAsync(artifacts, exception, cancellationToken);
    }
}

public sealed class MeetingSummaryFailureWriter : IMeetingSummaryFailureWriter
{
    private readonly MeetingAssistantOptions options;
    private readonly IMeetingNoteStore meetingNoteStore;

    public MeetingSummaryFailureWriter(
        IOptions<MeetingAssistantOptions> options,
        IMeetingNoteStore meetingNoteStore)
    {
        this.options = options.Value;
        this.meetingNoteStore = meetingNoteStore;
    }

    public async Task<MeetingSummaryRunResult> WriteAsync(
        MeetingSessionArtifacts artifacts,
        Exception exception,
        CancellationToken cancellationToken)
    {
        return await WriteAsync(artifacts, exception, options, cancellationToken);
    }

    public async Task<MeetingSummaryRunResult> WriteAsync(
        MeetingSessionArtifacts artifacts,
        Exception exception,
        MeetingAssistantOptions options,
        CancellationToken cancellationToken)
    {
        Directory.CreateDirectory(Path.GetDirectoryName(artifacts.SummaryPath)!);
        var meetingNote = File.Exists(artifacts.MeetingNotePath)
            ? await meetingNoteStore.ReadAsync(artifacts.MeetingNotePath, cancellationToken)
            : new MeetingNote("", new MeetingNoteFrontmatter(), "");
        var frontmatter = await MeetingSummaryFrontmatterFactory.CreateAsync(
            artifacts,
            meetingNote,
            MeetingArtifactFrontmatterRenderer.DefaultTitle(meetingNote, "Meeting Summary"),
            cancellationToken);
        await File.WriteAllTextAsync(
            artifacts.SummaryPath,
            MeetingArtifactFrontmatterRenderer.Render(
                frontmatter,
                RenderFailureMarkdown(artifacts, exception, options)),
            cancellationToken);

        return new MeetingSummaryRunResult(
            artifacts.SummaryPath,
            "Summary generation failed. See the summary file for error details.",
            Succeeded: false,
            Error: exception.Message);
    }

    private static string RenderFailureMarkdown(
        MeetingSessionArtifacts artifacts,
        Exception exception,
        MeetingAssistantOptions options)
    {
        var builder = new StringBuilder();
        builder.AppendLine("# Meeting Summary");
        builder.AppendLine();
        builder.AppendLine("## Summary Generation Failed");
        builder.AppendLine();
        builder.AppendLine($"Summary generation failed at {DateTimeOffset.Now:O}.");
        builder.AppendLine();
        builder.AppendLine(MeetingNoteActionLinks.CreateSummaryRetryLink(
            options.Api.PublicBaseUrl,
            artifacts.SummaryPath));
        builder.AppendLine();
        builder.AppendLine("## Error");
        builder.AppendLine();
        builder.AppendLine("```text");
        builder.AppendLine(exception.ToString().Replace("```", "` ` `", StringComparison.Ordinal));
        builder.AppendLine("```");
        builder.AppendLine();
        builder.AppendLine("## Meeting Artifacts");
        builder.AppendLine();
        builder.AppendLine($"- Meeting note: `{artifacts.MeetingNotePath}`");
        builder.AppendLine($"- Transcript: `{artifacts.TranscriptPath}`");
        builder.AppendLine($"- Assistant context: `{artifacts.AssistantContextPath}`");
        builder.AppendLine($"- Summary: `{artifacts.SummaryPath}`");
        return builder.ToString();
    }
}