using System.Text.Json;

namespace VigilCare.Simulation;

public static class ScenarioLoader
{
    private static readonly JsonSerializerOptions JsonOptions = new()
    {
        PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
        ReadCommentHandling = JsonCommentHandling.Skip,
        AllowTrailingCommas = true
    };

    public static ScenarioFile Load(string path)
    {
        if (!File.Exists(path))
            throw new FileNotFoundException($"Scenario file not found: {path}");

        var json = File.ReadAllText(path);
        var scenario = JsonSerializer.Deserialize<ScenarioFile>(json, JsonOptions)
            ?? throw new InvalidOperationException($"Failed to deserialize: {path}");

        return scenario with
        {
            Events = scenario.Events.OrderBy(e => e.OffsetMinutes).ToList()
        };
    }

    /// <summary>
    /// Enumerates <c>*.json</c> in <paramref name="directory"/>, skips files that
    /// fail to deserialize, and returns pairs sorted by <see cref="ScenarioMeta.Id"/>.
    /// </summary>
    public static IReadOnlyList<(ScenarioFile Scenario, string Path)> LoadAll(string directory)
    {
        if (!Directory.Exists(directory))
            return Array.Empty<(ScenarioFile, string)>();

        var results = new List<(ScenarioFile Scenario, string Path)>();

        foreach (var path in Directory.EnumerateFiles(directory, "*.json")
                     .Where(p => !string.Equals(
                         Path.GetFileName(p), "schema.json", StringComparison.OrdinalIgnoreCase))
                     .OrderBy(p => p, StringComparer.OrdinalIgnoreCase))
        {
            try
            {
                results.Add((Load(path), path));
            }
            catch
            {
                // Skip files that fail to deserialize — catalogue must stay resilient.
            }
        }

        return results
            .OrderBy(r => r.Scenario.Scenario.Id, StringComparer.OrdinalIgnoreCase)
            .ToList();
    }
}