using MeetingAssistant.Transcription;
using MeetingAssistant.MeetingNotes;
using Microsoft.Extensions.Options;

namespace MeetingAssistant.Recording;

public sealed class VaultTranscriptStore : ITranscriptStore
{
    private readonly MeetingAssistantOptions options;
    private readonly ILogger<VaultTranscriptStore> logger;

    public VaultTranscriptStore(IOptions<MeetingAssistantOptions> options, ILogger<VaultTranscriptStore> logger)
    {
        this.options = options.Value;
        this.logger = logger;
    }

    public async Task<TranscriptSession> CreateSessionAsync(CancellationToken cancellationToken)
    {
        return await CreateSessionAsync(options, DateTimeOffset.Now, cancellationToken);
    }

    public async Task<TranscriptSession> CreateSessionAsync(
        MeetingAssistantOptions options,
        DateTimeOffset startedAt,
        CancellationToken cancellationToken)
    {
        var folder = VaultPath.Resolve(options.Vault, options.Vault.TranscriptsFolder);
        Directory.CreateDirectory(folder);

        var fileName = MeetingArtifactFileNames.Create(startedAt, MeetingArtifactFileNames.Transcript);
        var path = Path.Combine(folder, fileName);
        await File.WriteAllTextAsync(path, $"# Meeting Transcript{Environment.NewLine}{Environment.NewLine}", cancellationToken);
        logger.LogInformation("Created meeting transcript file {TranscriptPath}", path);

        return new TranscriptSession(path);
    }

    public Task AppendLineAsync(TranscriptSession session, string line, CancellationToken cancellationToken)
    {
        return AppendToBodyAsync(session.TranscriptPath, line + Environment.NewLine, cancellationToken);
    }

    public Task ReplaceLinesAsync(
        TranscriptSession session,
        IReadOnlyList<string> replacementLines,
        CancellationToken cancellationToken)
    {
        var existing = File.Exists(session.TranscriptPath)
            ? File.ReadAllText(session.TranscriptPath)
            : "";
        var (frontmatter, _) = MeetingArtifactFrontmatterRenderer.Split(existing);
        var body = "# Meeting Transcript"
            + Environment.NewLine
            + Environment.NewLine
            + string.Concat(replacementLines.Select(line => line + Environment.NewLine));
        var content = string.IsNullOrWhiteSpace(frontmatter)
            ? body
            : "---" + Environment.NewLine + frontmatter + Environment.NewLine + "---" + Environment.NewLine + Environment.NewLine + body;
        return File.WriteAllTextAsync(session.TranscriptPath, content, cancellationToken);
    }

    public async Task UpdateMetadataAsync(
        TranscriptSession session,
        MeetingSessionArtifacts artifacts,
        MeetingNote meetingNote,
        CancellationToken cancellationToken)
    {
        var body = File.Exists(session.TranscriptPath)
            ? MeetingArtifactFrontmatterRenderer.Split(await File.ReadAllTextAsync(session.TranscriptPath, cancellationToken)).Body
            : "# Meeting Transcript" + Environment.NewLine + Environment.NewLine;
        var frontmatter = MeetingArtifactFrontmatterRenderer.Create(
            artifacts,
            meetingNote,
            MeetingArtifactFrontmatterRenderer.DefaultTitle(meetingNote, "Meeting Transcript"),
            session.TranscriptPath);

        await File.WriteAllTextAsync(
            session.TranscriptPath,
            MeetingArtifactFrontmatterRenderer.Render(frontmatter, body),
            cancellationToken);
    }

    private static async Task AppendToBodyAsync(
        string path,
        string text,
        CancellationToken cancellationToken)
    {
        if (!File.Exists(path))
        {
            await File.AppendAllTextAsync(path, text, cancellationToken);
            return;
        }

        var content = await File.ReadAllTextAsync(path, cancellationToken);
        var (frontmatter, body) = MeetingArtifactFrontmatterRenderer.Split(content);
        if (string.IsNullOrWhiteSpace(frontmatter))
        {
            await File.AppendAllTextAsync(path, text, cancellationToken);
            return;
        }

        var updated = "---"
            + Environment.NewLine
            + frontmatter
            + Environment.NewLine
            + "---"
            + Environment.NewLine
            + Environment.NewLine
            + body
            + text;
        await File.WriteAllTextAsync(path, updated, cancellationToken);
    }

}