Refactor (#94)

CliFx.Analyzers/ObjectModel/CommandParameterSymbol.cs

@@ -0,0 +1,82 @@
+using System.Collections.Generic;
+using System.Linq;
+using CliFx.Analyzers.Utils.Extensions;
+using Microsoft.CodeAnalysis;
+
+namespace CliFx.Analyzers.ObjectModel
+{
+    internal partial class CommandParameterSymbol
+    {
+        public int Order { get; }
+
+        public string? Name { get; }
+
+        public ITypeSymbol? ConverterType { get; }
+
+        public IReadOnlyList<ITypeSymbol> ValidatorTypes { get; }
+
+        public CommandParameterSymbol(
+            int order,
+            string? name,
+            ITypeSymbol? converterType,
+            IReadOnlyList<ITypeSymbol> validatorTypes)
+        {
+            Order = order;
+            Name = name;
+            ConverterType = converterType;
+            ValidatorTypes = validatorTypes;
+        }
+    }
+
+    internal partial class CommandParameterSymbol
+    {
+        private static AttributeData? TryGetParameterAttribute(IPropertySymbol property) =>
+            property
+                .GetAttributes()
+                .FirstOrDefault(a => a.AttributeClass.DisplayNameMatches(SymbolNames.CliFxCommandParameterAttribute));
+
+        private static CommandParameterSymbol FromAttribute(AttributeData attribute)
+        {
+            var order = (int) attribute
+                .ConstructorArguments
+                .Select(a => a.Value)
+                .First()!;
+
+            var name = attribute
+                .NamedArguments
+                .Where(a => a.Key == "Name")
+                .Select(a => a.Value.Value)
+                .FirstOrDefault() as string;
+
+            var converter = attribute
+                .NamedArguments
+                .Where(a => a.Key == "Converter")
+                .Select(a => a.Value.Value)
+                .Cast<ITypeSymbol?>()
+                .FirstOrDefault();
+
+            var validators = attribute
+                .NamedArguments
+                .Where(a => a.Key == "Validators")
+                .SelectMany(a => a.Value.Values)
+                .Select(c => c.Value)
+                .Cast<ITypeSymbol>()
+                .ToArray();
+
+            return new CommandParameterSymbol(order, name, converter, validators);
+        }
+
+        public static CommandParameterSymbol? TryResolve(IPropertySymbol property)
+        {
+            var attribute = TryGetParameterAttribute(property);
+
+            if (attribute is null)
+                return null;
+
+            return FromAttribute(attribute);
+        }
+
+        public static bool IsParameterProperty(IPropertySymbol property) =>
+            TryGetParameterAttribute(property) is not null;
+    }
+}