using System;
using System.IO;
using System.Xml.Serialization;

namespace CadParamPluging.Common
{
    public static class DropdownOptionsStore
    {
        private const string FolderName = "CadParamPluging";
        private const string FileName = "dropdown-options.xml";

        public static string GetFilePath()
        {
            var dir = Path.Combine(
                Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData),
                FolderName);
            return Path.Combine(dir, FileName);
        }

        public static DropdownOptions Load()
        {
            try
            {
                var path = GetFilePath();
                if (!File.Exists(path))
                {
                    return DropdownOptions.CreateDefault();
                }

                using (var stream = File.OpenRead(path))
                {
                    var serializer = new XmlSerializer(typeof(DropdownOptions));
                    var obj = serializer.Deserialize(stream) as DropdownOptions;
                    if (obj == null)
                    {
                        return DropdownOptions.CreateDefault();
                    }

                    obj.Normalize();
                    EnsureNonEmptyByFallbackToDefault(obj);
                    EnsureBuiltInOptions(obj);
                    return obj;
                }
            }
            catch
            {
                return DropdownOptions.CreateDefault();
            }
        }

        public static void Save(DropdownOptions options)
        {
            if (options == null)
            {
                throw new ArgumentNullException(nameof(options));
            }

            options.Normalize();
            var optionsToSave = options.Clone();
            
            // 移除内置的选项，不要保存到文件
            if (optionsToSave.SpecialConditions != null && optionsToSave.SpecialConditions.Contains("圆轴"))
            {
                optionsToSave.SpecialConditions.Remove("圆轴");
            }

            ValidateNonEmpty(optionsToSave);

            var path = GetFilePath();
            var dir = Path.GetDirectoryName(path);
            if (!string.IsNullOrEmpty(dir))
            {
                Directory.CreateDirectory(dir);
            }

            var tempPath = path + ".tmp";
            var serializer = new XmlSerializer(typeof(DropdownOptions));
            using (var stream = File.Create(tempPath))
            {
                serializer.Serialize(stream, optionsToSave);
            }

            if (File.Exists(path))
            {
                File.Delete(path);
            }

            File.Move(tempPath, path);
        }

        private static void ValidateNonEmpty(DropdownOptions options)
        {
            if (options.DeliveryStatuses == null || options.DeliveryStatuses.Count == 0)
            {
                throw new InvalidOperationException("交付状态不能为空。");
            }

            if (options.ProcessMethods == null || options.ProcessMethods.Count == 0)
            {
                throw new InvalidOperationException("工艺方法不能为空。");
            }

            if (options.StructuralFeatures == null || options.StructuralFeatures.Count == 0)
            {
                throw new InvalidOperationException("结构特征不能为空。");
            }

            if (options.SpecialConditions == null || options.SpecialConditions.Count == 0)
            {
                throw new InvalidOperationException("特殊条件不能为空。");
            }
        }

        private static void EnsureNonEmptyByFallbackToDefault(DropdownOptions options)
        {
            var defaults = DropdownOptions.CreateDefault();

            if (options.DeliveryStatuses == null || options.DeliveryStatuses.Count == 0)
            {
                options.DeliveryStatuses = defaults.DeliveryStatuses;
            }

            if (options.ProcessMethods == null || options.ProcessMethods.Count == 0)
            {
                options.ProcessMethods = defaults.ProcessMethods;
            }

            if (options.StructuralFeatures == null || options.StructuralFeatures.Count == 0)
            {
                options.StructuralFeatures = defaults.StructuralFeatures;
            }

            if (options.SpecialConditions == null || options.SpecialConditions.Count == 0)
            {
                options.SpecialConditions = defaults.SpecialConditions;
            }
        }

        private static void EnsureBuiltInOptions(DropdownOptions options)
        {
            if (options?.SpecialConditions != null && !options.SpecialConditions.Contains("圆轴"))
            {
                options.SpecialConditions.Add("圆轴");
            }
        }
    }
}