using System;
using System.Collections.Generic;
using System.Text;
using Dalamud.Plugin.Services;
using Microsoft.Extensions.Logging;
using Serilog.Events;

namespace Questionable;

internal sealed class DalamudLoggerProvider : ILoggerProvider, IDisposable, ISupportExternalScope
{
	private sealed class DalamudLogger : ILogger
	{
		private sealed class NullScope : IDisposable
		{
			public static NullScope Instance { get; } = new NullScope();

			private NullScope()
			{
			}

			public void Dispose()
			{
			}
		}

		private readonly string? _name;

		private readonly IExternalScopeProvider? _scopeProvider;

		private readonly IPluginLog _pluginLog;

		public DalamudLogger(string? name, IExternalScopeProvider? scopeProvider, IPluginLog pluginLog)
		{
			_name = name;
			_scopeProvider = scopeProvider;
			_pluginLog = pluginLog;
		}

		public IDisposable BeginScope<TState>(TState state) where TState : notnull
		{
			return _scopeProvider?.Push(state) ?? NullScope.Instance;
		}

		public bool IsEnabled(LogLevel logLevel)
		{
			if (logLevel == LogLevel.None)
			{
				return false;
			}
			return ToSerilogLevel(logLevel) >= _pluginLog.MinimumLogLevel;
		}

		public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception? exception, Func<TState, Exception?, string> formatter)
		{
			if (!IsEnabled(logLevel))
			{
				return;
			}
			ArgumentNullException.ThrowIfNull(formatter, "formatter");
			LogEventLevel level = ToSerilogLevel(logLevel);
			StringBuilder stringBuilder = new StringBuilder();
			_scopeProvider?.ForEachScope(delegate(object? scope, StringBuilder builder)
			{
				if (scope is IEnumerable<KeyValuePair<string, object>> enumerable)
				{
					{
						foreach (KeyValuePair<string, object> item in enumerable)
						{
							builder.Append('<').Append(item.Key).Append('=')
								.Append(item.Value)
								.Append("> ");
						}
						return;
					}
				}
				if (scope != null)
				{
					builder.Append('<').Append(scope).Append("> ");
				}
			}, stringBuilder);
			if (!string.IsNullOrEmpty(_name))
			{
				stringBuilder.Append(_name).Append(": ");
			}
			stringBuilder.Append(formatter(state, null));
			_pluginLog.Write(level, exception, stringBuilder.ToString());
		}

		private static LogEventLevel ToSerilogLevel(LogLevel logLevel)
		{
			return logLevel switch
			{
				LogLevel.Trace => LogEventLevel.Verbose, 
				LogLevel.Debug => LogEventLevel.Debug, 
				LogLevel.Information => LogEventLevel.Information, 
				LogLevel.Warning => LogEventLevel.Warning, 
				LogLevel.Error => LogEventLevel.Error, 
				LogLevel.Critical => LogEventLevel.Fatal, 
				_ => throw new ArgumentOutOfRangeException("logLevel", logLevel, null), 
			};
		}
	}

	private readonly IPluginLog _pluginLog;

	private readonly Func<string, string?> _categoryNameFormatter;

	private IExternalScopeProvider? _scopeProvider;

	public DalamudLoggerProvider(IPluginLog pluginLog, Func<string, string?>? categoryNameFormatter = null)
	{
		_pluginLog = pluginLog;
		_categoryNameFormatter = categoryNameFormatter ?? ((Func<string, string>)((string t) => t));
	}

	public ILogger CreateLogger(string categoryName)
	{
		return new DalamudLogger(_categoryNameFormatter(categoryName), _scopeProvider, _pluginLog);
	}

	public void SetScopeProvider(IExternalScopeProvider scopeProvider)
	{
		_scopeProvider = scopeProvider;
	}

	public void Dispose()
	{
	}
}