// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.ComponentModel;
using System.Diagnostics.CodeAnalysis;
using System.Xml.Serialization;

namespace System.Xml.Schema
{
    public class XmlSchemaComplexType : XmlSchemaType
    {
        private static readonly XmlSchemaComplexType s_anyTypeLax = CreateAnyType(XmlSchemaContentProcessing.Lax);
        private static readonly XmlSchemaComplexType s_anyTypeSkip = CreateAnyType(XmlSchemaContentProcessing.Skip);
        private static readonly XmlSchemaComplexType s_untypedAnyType = CreateUntypedAnyType();

        private XmlSchemaDerivationMethod _block = XmlSchemaDerivationMethod.None;

        private XmlSchemaContentModel? _contentModel;
        private XmlSchemaParticle? _particle;
        private XmlSchemaObjectCollection? _attributes;
        private XmlSchemaAnyAttribute? _anyAttribute;

        private XmlSchemaParticle _contentTypeParticle = XmlSchemaParticle.Empty;
        private XmlSchemaDerivationMethod _blockResolved;
        private XmlSchemaObjectTable? _localElements;
        private XmlSchemaObjectTable? _attributeUses;
        private XmlSchemaAnyAttribute? _attributeWildcard;


        //additional info for Partial validation
        private byte _pvFlags;
        private const byte wildCardMask = 0x01;
        private const byte isMixedMask = 0x02;
        private const byte isAbstractMask = 0x04;
        //const byte dupDeclMask = 0x08;

        private static XmlSchemaComplexType CreateUntypedAnyType()
        {
            // Create xdt:untypedAny
            var untypedAny = new XmlSchemaComplexType();

            untypedAny.SetQualifiedName(new XmlQualifiedName("untypedAny", XmlReservedNs.NsXQueryDataType));
            untypedAny.IsMixed = true;
            untypedAny.SetContentTypeParticle(s_anyTypeLax.ContentTypeParticle);
            untypedAny.SetContentType(XmlSchemaContentType.Mixed);

            untypedAny.ElementDecl = SchemaElementDecl.CreateAnyTypeElementDecl();
            untypedAny.ElementDecl.SchemaType = untypedAny;
            untypedAny.ElementDecl.ContentValidator = AnyTypeContentValidator;

            return untypedAny;
        }

        private static XmlSchemaComplexType CreateAnyType(XmlSchemaContentProcessing processContents)
        {
            XmlSchemaComplexType localAnyType = new XmlSchemaComplexType();
            localAnyType.SetQualifiedName(DatatypeImplementation.QnAnyType);

            XmlSchemaAny anyElement = new XmlSchemaAny();
            anyElement.MinOccurs = decimal.Zero;
            anyElement.MaxOccurs = decimal.MaxValue;

            anyElement.ProcessContents = processContents;
            anyElement.BuildNamespaceList(null);
            XmlSchemaSequence seq = new XmlSchemaSequence();
            seq.Items.Add(anyElement);

            localAnyType.SetContentTypeParticle(seq);
            localAnyType.SetContentType(XmlSchemaContentType.Mixed);

            localAnyType.ElementDecl = SchemaElementDecl.CreateAnyTypeElementDecl();
            localAnyType.ElementDecl.SchemaType = localAnyType;

            //Create contentValidator for Any
            ParticleContentValidator contentValidator = new ParticleContentValidator(XmlSchemaContentType.Mixed);
            contentValidator.Start();
            contentValidator.OpenGroup();
            contentValidator.AddNamespaceList(anyElement.NamespaceList!, anyElement);
            contentValidator.AddStar();
            contentValidator.CloseGroup();
            ContentValidator anyContentValidator = contentValidator.Finish(true);
            localAnyType.ElementDecl.ContentValidator = anyContentValidator;

            XmlSchemaAnyAttribute anyAttribute = new XmlSchemaAnyAttribute();
            anyAttribute.ProcessContents = processContents;
            anyAttribute.BuildNamespaceList(null);
            localAnyType.SetAttributeWildcard(anyAttribute);
            localAnyType.ElementDecl.AnyAttribute = anyAttribute;
            return localAnyType;
        }

        public XmlSchemaComplexType()
        {
        }


        [XmlIgnore]
        internal static XmlSchemaComplexType AnyType
        {
            get { return s_anyTypeLax; }
        }

        [XmlIgnore]
        internal static XmlSchemaComplexType UntypedAnyType
        {
            get { return s_untypedAnyType; }
        }

        [XmlIgnore]
        internal static XmlSchemaComplexType AnyTypeSkip
        {
            get { return s_anyTypeSkip; }
        }

        internal static ContentValidator AnyTypeContentValidator
        {
            get
            {
                return s_anyTypeLax.ElementDecl!.ContentValidator!;
            }
        }

        [XmlAttribute("abstract"), DefaultValue(false)]
        public bool IsAbstract
        {
            get
            {
                return (_pvFlags & isAbstractMask) != 0;
            }
            set
            {
                if (value)
                {
                    _pvFlags = (byte)(_pvFlags | isAbstractMask);
                }
                else
                {
                    _pvFlags = (byte)(_pvFlags & ~isAbstractMask);
                }
            }
        }

        [XmlAttribute("block"), DefaultValue(XmlSchemaDerivationMethod.None)]
        public XmlSchemaDerivationMethod Block
        {
            get { return _block; }
            set { _block = value; }
        }

        [XmlAttribute("mixed"), DefaultValue(false)]
        public override bool IsMixed
        {
            get
            {
                return (_pvFlags & isMixedMask) != 0;
            }
            set
            {
                if (value)
                {
                    _pvFlags = (byte)(_pvFlags | isMixedMask);
                }
                else
                {
                    _pvFlags = (byte)(_pvFlags & ~isMixedMask);
                }
            }
        }


        [XmlElement("simpleContent", typeof(XmlSchemaSimpleContent)),
         XmlElement("complexContent", typeof(XmlSchemaComplexContent))]
        public XmlSchemaContentModel? ContentModel
        {
            get { return _contentModel; }
            set { _contentModel = value; }
        }

        [XmlElement("group", typeof(XmlSchemaGroupRef)),
         XmlElement("choice", typeof(XmlSchemaChoice)),
         XmlElement("all", typeof(XmlSchemaAll)),
         XmlElement("sequence", typeof(XmlSchemaSequence))]
        public XmlSchemaParticle? Particle
        {
            get { return _particle; }
            set { _particle = value; }
        }

        [XmlElement("attribute", typeof(XmlSchemaAttribute)),
         XmlElement("attributeGroup", typeof(XmlSchemaAttributeGroupRef))]
        public XmlSchemaObjectCollection Attributes =>
            _attributes ??= new XmlSchemaObjectCollection();

        [XmlElement("anyAttribute")]
        public XmlSchemaAnyAttribute? AnyAttribute
        {
            get { return _anyAttribute; }
            set { _anyAttribute = value; }
        }


        [XmlIgnore]
        public XmlSchemaContentType ContentType
        {
            get { return SchemaContentType; }
        }

        [XmlIgnore]
        public XmlSchemaParticle ContentTypeParticle
        {
            get { return _contentTypeParticle; }
        }

        [XmlIgnore]
        public XmlSchemaDerivationMethod BlockResolved
        {
            get { return _blockResolved; }
        }

        [XmlIgnore]
        public XmlSchemaObjectTable AttributeUses =>
            _attributeUses ??= new XmlSchemaObjectTable();

        [XmlIgnore]
        public XmlSchemaAnyAttribute? AttributeWildcard
        {
            get { return _attributeWildcard; }
        }

        [XmlIgnore]
        internal XmlSchemaObjectTable LocalElements =>
            _localElements ??= new XmlSchemaObjectTable();

        internal void SetContentTypeParticle(XmlSchemaParticle value)
        {
            _contentTypeParticle = value;
        }

        internal void SetBlockResolved(XmlSchemaDerivationMethod value)
        {
            _blockResolved = value;
        }

        internal void SetAttributeWildcard(XmlSchemaAnyAttribute? value)
        {
            _attributeWildcard = value;
        }

        internal bool HasWildCard
        {
            get
            {
                return (_pvFlags & wildCardMask) != 0;
            }
            set
            {
                if (value)
                {
                    _pvFlags = (byte)(_pvFlags | wildCardMask);
                }
                else
                {
                    _pvFlags = (byte)(_pvFlags & ~wildCardMask);
                }
            }
        }

        internal override XmlQualifiedName DerivedFrom
        {
            get
            {
                if (_contentModel == null)
                {
                    // type derived from anyType
                    return XmlQualifiedName.Empty;
                }
                if (_contentModel.Content is XmlSchemaComplexContentRestriction)
                    return ((XmlSchemaComplexContentRestriction)_contentModel.Content).BaseTypeName;
                else if (_contentModel.Content is XmlSchemaComplexContentExtension)
                    return ((XmlSchemaComplexContentExtension)_contentModel.Content).BaseTypeName;
                else if (_contentModel.Content is XmlSchemaSimpleContentRestriction)
                    return ((XmlSchemaSimpleContentRestriction)_contentModel.Content).BaseTypeName;
                else if (_contentModel.Content is XmlSchemaSimpleContentExtension)
                    return ((XmlSchemaSimpleContentExtension)_contentModel.Content).BaseTypeName;
                else
                    return XmlQualifiedName.Empty;
            }
        }

        internal void SetAttributes(XmlSchemaObjectCollection newAttributes)
        {
            _attributes = newAttributes;
        }

        internal bool ContainsIdAttribute(bool findAll)
        {
            int idCount = 0;
            foreach (XmlSchemaAttribute? attribute in this.AttributeUses.Values)
            {
                if (attribute!.Use != XmlSchemaUse.Prohibited)
                {
                    XmlSchemaDatatype? datatype = attribute.Datatype;
                    if (datatype != null && datatype.TypeCode == XmlTypeCode.Id)
                    {
                        idCount++;
                        if (idCount > 1)
                        { //two or more attributes is error
                            break;
                        }
                    }
                }
            }
            return findAll ? (idCount > 1) : (idCount > 0);
        }

        internal override XmlSchemaObject Clone()
        {
            System.Diagnostics.Debug.Fail("Should never call Clone() on XmlSchemaComplexType. Call Clone(XmlSchema) instead.");
            return Clone(null);
        }

        internal XmlSchemaObject Clone(XmlSchema? parentSchema)
        {
            XmlSchemaComplexType complexType = (XmlSchemaComplexType)MemberwiseClone();

            //Deep clone the QNames as these will be updated on chameleon includes
            if (complexType.ContentModel != null)
            { //simpleContent or complexContent
                XmlSchemaSimpleContent? simpleContent = complexType.ContentModel as XmlSchemaSimpleContent;
                if (simpleContent != null)
                {
                    XmlSchemaSimpleContent newSimpleContent = (XmlSchemaSimpleContent)simpleContent.Clone();

                    XmlSchemaSimpleContentExtension? simpleExt = simpleContent.Content as XmlSchemaSimpleContentExtension;
                    if (simpleExt != null)
                    {
                        XmlSchemaSimpleContentExtension newSimpleExt = (XmlSchemaSimpleContentExtension)simpleExt.Clone();
                        newSimpleExt.BaseTypeName = simpleExt.BaseTypeName.Clone();
                        newSimpleExt.SetAttributes(CloneAttributes(simpleExt.Attributes));
                        newSimpleContent.Content = newSimpleExt;
                    }
                    else
                    { //simpleContent.Content is XmlSchemaSimpleContentRestriction
                        XmlSchemaSimpleContentRestriction simpleRest = (XmlSchemaSimpleContentRestriction)simpleContent.Content!;
                        XmlSchemaSimpleContentRestriction newSimpleRest = (XmlSchemaSimpleContentRestriction)simpleRest.Clone();
                        newSimpleRest.BaseTypeName = simpleRest.BaseTypeName.Clone();
                        newSimpleRest.SetAttributes(CloneAttributes(simpleRest.Attributes));
                        newSimpleContent.Content = newSimpleRest;
                    }

                    complexType.ContentModel = newSimpleContent;
                }
                else
                { // complexType.ContentModel is XmlSchemaComplexContent
                    XmlSchemaComplexContent complexContent = (XmlSchemaComplexContent)complexType.ContentModel;
                    XmlSchemaComplexContent newComplexContent = (XmlSchemaComplexContent)complexContent.Clone();

                    XmlSchemaComplexContentExtension? complexExt = complexContent.Content as XmlSchemaComplexContentExtension;
                    if (complexExt != null)
                    {
                        XmlSchemaComplexContentExtension newComplexExt = (XmlSchemaComplexContentExtension)complexExt.Clone();
                        newComplexExt.BaseTypeName = complexExt.BaseTypeName.Clone();
                        newComplexExt.SetAttributes(CloneAttributes(complexExt.Attributes));
                        if (HasParticleRef(complexExt.Particle, parentSchema))
                        {
                            newComplexExt.Particle = CloneParticle(complexExt.Particle, parentSchema);
                        }
                        newComplexContent.Content = newComplexExt;
                    }
                    else
                    { // complexContent.Content is XmlSchemaComplexContentRestriction
                        XmlSchemaComplexContentRestriction complexRest = (complexContent.Content as XmlSchemaComplexContentRestriction)!;
                        XmlSchemaComplexContentRestriction newComplexRest = (XmlSchemaComplexContentRestriction)complexRest.Clone();
                        newComplexRest.BaseTypeName = complexRest.BaseTypeName.Clone();
                        newComplexRest.SetAttributes(CloneAttributes(complexRest.Attributes));
                        if (HasParticleRef(newComplexRest.Particle, parentSchema))
                        {
                            newComplexRest.Particle = CloneParticle(newComplexRest.Particle, parentSchema);
                        }

                        newComplexContent.Content = newComplexRest;
                    }

                    complexType.ContentModel = newComplexContent;
                }
            }
            else
            { //equals XmlSchemaComplexContent with baseType is anyType
                if (HasParticleRef(complexType.Particle, parentSchema))
                {
                    complexType.Particle = CloneParticle(complexType.Particle, parentSchema);
                }
                complexType.SetAttributes(CloneAttributes(complexType.Attributes));
            }
            complexType.ClearCompiledState();
            return complexType;
        }

        private void ClearCompiledState()
        {
            //Re-set post-compiled state for cloned object
            _attributeUses = null;
            _localElements = null;
            _attributeWildcard = null;
            _contentTypeParticle = XmlSchemaParticle.Empty;
            _blockResolved = XmlSchemaDerivationMethod.None;
        }

        internal static XmlSchemaObjectCollection CloneAttributes(XmlSchemaObjectCollection attributes)
        {
            if (HasAttributeQNameRef(attributes))
            {
                XmlSchemaObjectCollection newAttributes = attributes.Clone();
                XmlSchemaAttributeGroupRef? attributeGroupRef;
                XmlSchemaAttributeGroupRef newAttGroupRef;
                XmlSchemaObject xso;
                XmlSchemaAttribute att;

                for (int i = 0; i < attributes.Count; i++)
                {
                    xso = attributes[i];
                    attributeGroupRef = xso as XmlSchemaAttributeGroupRef;
                    if (attributeGroupRef != null)
                    {
                        newAttGroupRef = (XmlSchemaAttributeGroupRef)attributeGroupRef.Clone();
                        newAttGroupRef.RefName = attributeGroupRef.RefName.Clone();
                        newAttributes[i] = newAttGroupRef;
                    }
                    else
                    { //Its XmlSchemaAttribute
                        att = (xso as XmlSchemaAttribute)!;
                        if (!att.RefName.IsEmpty || !att.SchemaTypeName.IsEmpty)
                        {
                            newAttributes[i] = att.Clone();
                        }
                    }
                }
                return newAttributes;
            }
            return attributes;
        }

        private static XmlSchemaObjectCollection CloneGroupBaseParticles(XmlSchemaObjectCollection groupBaseParticles, XmlSchema? parentSchema)
        {
            XmlSchemaObjectCollection newParticles = groupBaseParticles.Clone();

            for (int i = 0; i < groupBaseParticles.Count; i++)
            {
                XmlSchemaParticle p = (XmlSchemaParticle)groupBaseParticles[i];
                newParticles[i] = CloneParticle(p, parentSchema);
            }
            return newParticles;
        }

        [return: NotNullIfNotNull(nameof(particle))]
        internal static XmlSchemaParticle? CloneParticle(XmlSchemaParticle? particle, XmlSchema? parentSchema)
        {
            XmlSchemaGroupBase? groupBase = particle as XmlSchemaGroupBase;
            if (groupBase != null)
            { //Choice or sequence
                XmlSchemaGroupBase newGroupBase;

                XmlSchemaObjectCollection newGroupbaseParticles = CloneGroupBaseParticles(groupBase.Items, parentSchema);
                newGroupBase = (XmlSchemaGroupBase)groupBase.Clone();
                newGroupBase.SetItems(newGroupbaseParticles);
                return newGroupBase;
            }
            else if (particle is XmlSchemaGroupRef)
            { // group ref
                XmlSchemaGroupRef newGroupRef = (XmlSchemaGroupRef)particle.Clone();
                newGroupRef.RefName = newGroupRef.RefName.Clone();
                return newGroupRef;
            }
            else
            {
                XmlSchemaElement? oldElem = particle as XmlSchemaElement;
                // If the particle is an element and one of the following is true:
                //   - it references another element by name
                //   - it references its type by name
                //   - it's form (effective) is qualified (meaning it will inherint namespace from chameleon includes if that happens)
                // then the element itself needs to be cloned.
                if (oldElem != null && (!oldElem.RefName.IsEmpty || !oldElem.SchemaTypeName.IsEmpty ||
                    GetResolvedElementForm(parentSchema, oldElem) == XmlSchemaForm.Qualified))
                {
                    XmlSchemaElement newElem = (XmlSchemaElement)oldElem.Clone(parentSchema);
                    return newElem;
                }
            }
            return particle;
        }

        // This method returns the effective value of the "element form" for the specified element in the specified
        //   parentSchema. Element form is either qualified, unqualified or none. If it's qualified it means that
        //   if the element doesn't declare its own namespace the targetNamespace of the schema is used instead.
        // The element form can be either specified on the element itself via the "form" attribute or
        //   if that one is not present its inheritted from the value of the elementFormDefault attribute on the owning
        //   schema.
        private static XmlSchemaForm GetResolvedElementForm(XmlSchema? parentSchema, XmlSchemaElement element)
        {
            if (element.Form == XmlSchemaForm.None && parentSchema != null)
            {
                return parentSchema.ElementFormDefault;
            }
            else
            {
                return element.Form;
            }
        }

        internal static bool HasParticleRef(XmlSchemaParticle? particle, XmlSchema? parentSchema)
        {
            XmlSchemaGroupBase? groupBase = particle as XmlSchemaGroupBase;
            if (groupBase != null)
            {
                bool foundRef = false;
                int i = 0;
                while (i < groupBase.Items.Count && !foundRef)
                {
                    XmlSchemaParticle p = (XmlSchemaParticle)groupBase.Items[i++];
                    if (p is XmlSchemaGroupRef)
                    {
                        foundRef = true;
                    }
                    else
                    {
                        XmlSchemaElement? elem = p as XmlSchemaElement;
                        // This is the same condition as in the CloneParticle method
                        //   that's on purpose. This method is used to determine if we need to clone the whole particle.
                        //   If we do, then the CloneParticle is called and it will try to clone only
                        //   those elements which need cloning - and those are the ones matching this condition.
                        if (elem != null && (!elem.RefName.IsEmpty || !elem.SchemaTypeName.IsEmpty ||
                            GetResolvedElementForm(parentSchema, elem) == XmlSchemaForm.Qualified))
                        {
                            foundRef = true;
                        }
                        else
                        {
                            foundRef = HasParticleRef(p, parentSchema);
                        }
                    }
                }
                return foundRef;
            }
            else if (particle is XmlSchemaGroupRef)
            {
                return true;
            }
            return false;
        }

        internal static bool HasAttributeQNameRef(XmlSchemaObjectCollection attributes)
        {
            for (int i = 0; i < attributes.Count; ++i)
            {
                if (attributes[i] is XmlSchemaAttributeGroupRef)
                {
                    return true;
                }
                else
                {
                    XmlSchemaAttribute attribute = (attributes[i] as XmlSchemaAttribute)!;
                    if (!attribute.RefName.IsEmpty || !attribute.SchemaTypeName.IsEmpty)
                    {
                        return true;
                    }
                }
            }
            return false;
        }
    }
}