namespace Bts.DataStreamWebApp.Server;

using Bts.PubSub;

using CommandLine;

using System.Text.Json;
using System.Text.Json.Serialization;

class DataStreamWebAppServerConfig {
   /// <summary>
   /// The login user for sparkd
   /// </summary>
   [JsonPropertyName("user")]
   [Option("user", HelpText = "The sparkd login user")]
   public string? User { get; set; }

   /// <summary>
   /// The login password for sparkd
   /// </summary>
   [JsonPropertyName("password")]
   [Option("pass", HelpText = "The sparkd login password")]
   public string? Password { get; set; }

   /// <summary>
   /// The config server url for sparkd
   /// </summary>
   [JsonPropertyName("sparkd")]
   [Option("sparkd", HelpText = "The sparkd config server")]
   public string? Sparkd { get; set; }

   [JsonPropertyName("pubsub")]
   public PubSubConfig? PubSub { get; set; }

   [Option("content-root-path")]
   [JsonPropertyName("content_root_path")]
   public string? ContentRootPath { get; set; }

   [Option("web-root-path")]
   [JsonPropertyName("web_root_path")]
   public string? WebRootPath { get; set; }

   [Option("environment-name")]
   [JsonPropertyName("environment_name")]
   public string? EnvironmentName { get; set; }

   public DirectoryBrowserOptions? DirectoryBrowser { get; set; }

   [Option(
      "config",
      MetaValue = "PATH",
      HelpText = "Path to json file representing these options (DataStreamPublisherConfig)")]
   [JsonIgnore]
   public string? ConfigFile { get; set; }

   public static DataStreamWebAppServerConfig Default() =>
      new() {
         User = "bts",
         PubSub = PubSubConfig.Default(),
      };

   public void MergeWith(DataStreamWebAppServerConfig other) {
      User ??= other.User;
      Password ??= other.Password;
      PubSub ??= other.PubSub;
      Sparkd ??= other.Sparkd;
      ContentRootPath ??= other.ContentRootPath;
      WebRootPath ??= other.WebRootPath;
      ConfigFile ??= other.ConfigFile;
   }

   /// <summary>
   /// Merges options with those defined in `ConfigFile` (does not overwrite
   /// non-null existing values).
   /// </summary>
   /// <exception cref="InvalidOperationException">
   /// JsonSerializer.Deserialize returns null
   /// </exception>
   public void MergeWithConfigFile() {
      if (ConfigFile is null) {
         return;
      }
      var cfgString = File.ReadAllText(ConfigFile);
      var parsedCfg = JsonSerializer.Deserialize<DataStreamWebAppServerConfig>(cfgString) ??
         throw new InvalidOperationException($"Failed to parse json from {ConfigFile}");
      MergeWith(parsedCfg);
      ConfigFile = null;
   }
}