using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using ChaosBot.Repositories;
using Microsoft.Extensions.Configuration;

namespace ChaosBot
{
    public class Configuration
    {
        private readonly IConfiguration _appSettingsWrapper;
        
        private static readonly Dictionary<string, Type> ConfigurationFlags = new Dictionary<string, Type>
        {
            {"LevelUp:Enabled", typeof(bool)},
        };

        public Configuration()
        {
            _appSettingsWrapper = Program.AppSettingsHandler;
            
            if (_appSettingsWrapper == null)
                throw new NullReferenceException("Program.AppSettingsHandler is unset");
        }

        /**
         * Gets the configuration value associated with a key in an optional guild
         * <exception cref="ArgumentException">Configuration key does not exist</exception>
         * <exception cref="ArgumentException">Configuration key does not have the provided type</exception>
         * <returns>Configuration value</returns>
         */
        public T GetValue<T>(string key, T defaultValue, ulong? guildId = null)
        {
            if (!ConfigurationFlags.ContainsKey(key))
                throw new ArgumentException($"Configuration does not contain key '{key}'");

            if (!(ConfigurationFlags[key] == typeof(T)))
                throw new ArgumentException($"Configuration flag '{key}<{ConfigurationFlags[key]}>' does not have type '{typeof(T)}'");
            
            if (guildId.HasValue)
                return ConfigurationRepository.GetValue(key, guildId.Value, defaultValue);

            return _appSettingsWrapper.GetValue(key, defaultValue);
        }

        public T GetValue<T>(string key)
        {
            return GetValue<T>(key, default);
        }

        public IConfigurationSection GetSection(string key)
        {
            return _appSettingsWrapper.GetSection(key);
        }

        /**
         * Get the available configuration flags
         * <returns>Immutable dictionary of config-key/type pairs</returns>
         */
        public ImmutableDictionary<string, Type> GetConfigurationFlags()
        {
            return ConfigurationFlags.ToImmutableDictionary();
        }
    }
}