using YamlDotNet.Serialization;
using YamlDotNet.Serialization.NamingConventions;

namespace MeetingAssistant.Workflow;

public interface IMeetingWorkflowRulesProvider
{
    Task<IReadOnlyList<MeetingWorkflowRule>> GetRulesAsync(
        MeetingAssistantOptions options,
        CancellationToken cancellationToken);
}

public sealed class FileMeetingWorkflowRulesProvider : IMeetingWorkflowRulesProvider
{
    private readonly ILogger<FileMeetingWorkflowRulesProvider> logger;
    private readonly IDeserializer yamlDeserializer = new DeserializerBuilder()
        .WithNamingConvention(UnderscoredNamingConvention.Instance)
        .IgnoreUnmatchedProperties()
        .Build();

    public FileMeetingWorkflowRulesProvider(ILogger<FileMeetingWorkflowRulesProvider> logger)
    {
        this.logger = logger;
    }

    public async Task<IReadOnlyList<MeetingWorkflowRule>> GetRulesAsync(
        MeetingAssistantOptions options,
        CancellationToken cancellationToken)
    {
        if (string.IsNullOrWhiteSpace(options.Automation.RulesPath))
        {
            return [];
        }

        var path = ResolvePath(options.Automation.RulesPath);
        if (!File.Exists(path))
        {
            logger.LogDebug("Meeting workflow rules file {RulesPath} does not exist", path);
            return [];
        }

        var yaml = await File.ReadAllTextAsync(path, cancellationToken);
        if (string.IsNullOrWhiteSpace(yaml))
        {
            return [];
        }

        var rulesFile = yamlDeserializer.Deserialize<MeetingWorkflowRulesFile>(yaml)
            ?? new MeetingWorkflowRulesFile();
        return rulesFile.Rules;
    }

    private static string ResolvePath(string configuredPath)
    {
        var expanded = Environment.ExpandEnvironmentVariables(configuredPath);
        return Path.IsPathRooted(expanded)
            ? Path.GetFullPath(expanded)
            : Path.GetFullPath(expanded);
    }
}