using MeetingAssistant.MeetingNotes;
using YamlDotNet.Serialization;

namespace MeetingAssistant.Summary;

public sealed record BoundMeetingProject(string Name, string Path);

public sealed class BoundMeetingProjectResolver
{
    private static readonly IDeserializer YamlDeserializer = new DeserializerBuilder()
        .IgnoreUnmatchedProperties()
        .Build();

    private readonly MeetingAssistantOptions options;

    public BoundMeetingProjectResolver(MeetingAssistantOptions options)
    {
        this.options = options;
    }

    public string ProjectsRoot => VaultPath.Resolve(options.Vault, options.Vault.ProjectsFolder);

    public async Task<List<BoundMeetingProject>> GetBoundProjectsAsync(
        MeetingSessionArtifacts artifacts,
        CancellationToken cancellationToken = default)
    {
        if (!Directory.Exists(ProjectsRoot))
        {
            return [];
        }

        var projectNames = await ReadMeetingProjectNamesAsync(artifacts.MeetingNotePath, cancellationToken);
        if (projectNames.Count == 0)
        {
            return [];
        }

        return Directory.EnumerateDirectories(ProjectsRoot)
            .Select(path => new BoundMeetingProject(Path.GetFileName(path), path))
            .Where(project => projectNames.Contains(project.Name))
            .OrderBy(project => project.Name, StringComparer.OrdinalIgnoreCase)
            .ToList();
    }

    private static async Task<HashSet<string>> ReadMeetingProjectNamesAsync(
        string meetingNotePath,
        CancellationToken cancellationToken)
    {
        if (!File.Exists(meetingNotePath))
        {
            return [];
        }

        var content = await File.ReadAllTextAsync(meetingNotePath, cancellationToken);
        var document = MarkdownDocumentParser.SplitOptional(content);
        if (!document.HasFrontmatter)
        {
            return [];
        }

        var frontmatter = YamlDeserializer.Deserialize<ProjectFrontmatter>(document.Frontmatter)
            ?? new ProjectFrontmatter();
        return (frontmatter.Projects ?? [])
            .Where(project => !string.IsNullOrWhiteSpace(project))
            .Select(project => project.Trim())
            .ToHashSet(StringComparer.OrdinalIgnoreCase);
    }

    private sealed class ProjectFrontmatter
    {
        [YamlMember(Alias = "projects")]
        public List<string>? Projects { get; set; }
    }
}