using System.Linq;
using CppSharp.AST;

namespace CppSharp.Passes
{
    public class ResolveIncompleteDeclsPass : TranslationUnitPass
    {
        public override bool VisitClassDecl(Class @class)
        {
            if (!base.VisitClassDecl(@class))
                return false;

            EnsureCompleteDeclaration(@class);

            return true;
        }

        public override bool VisitClassTemplateDecl(ClassTemplate template)
        {
            if (!base.VisitClassTemplateDecl(template))
                return false;

            EnsureCompleteDeclaration(template.TemplatedDecl);

            template.TemplatedDecl = template.TemplatedDecl.CompleteDeclaration ?? template.TemplatedDecl;
            // store all spesializations in the real template class because ClassTemplateDecl only forwards
            foreach (var specialization in template.Specializations.Where(
                s => !s.IsIncomplete && !template.TemplatedClass.Specializations.Contains(s)))
                template.TemplatedClass.Specializations.Add(specialization);

            return true;
        }

        public override bool VisitEnumDecl(Enumeration @enum)
        {
            if (!VisitDeclaration(@enum))
                return false;

            if (!@enum.IsIncomplete)
                goto Out;

            if (@enum.CompleteDeclaration != null)
                goto Out;

            @enum.CompleteDeclaration =
                AstContext.FindCompleteEnum(@enum.QualifiedName);

            if (@enum.CompleteDeclaration == null)
            {
                @enum.GenerationKind = GenerationKind.Internal;
                Driver.Diagnostics.Warning("Unresolved declaration: {0}", @enum.Name);
            }

        Out:

            return base.VisitEnumDecl(@enum);
        }

        private void EnsureCompleteDeclaration(Declaration declaration)
        {
            if (!declaration.IsIncomplete)
                return;

            if (declaration.CompleteDeclaration != null)
                return;

            declaration.CompleteDeclaration =
                AstContext.FindCompleteClass(declaration.QualifiedName);

            if (declaration.CompleteDeclaration == null)
            {
                declaration.GenerationKind = GenerationKind.Internal;
                Driver.Diagnostics.Debug("Unresolved declaration: {0}",
                    declaration.Name);
            }
        }
    }
}