//===============================================================================

// Microsoft patterns & practices Enterprise Library

// Validation Application Block

//===============================================================================

// Copyright Š Microsoft Corporation.  All rights reserved.

// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY

// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT

// LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND

// FITNESS FOR A PARTICULAR PURPOSE.

//===============================================================================



using System;

using System.Collections;

using Microsoft.Practices.EnterpriseLibrary.Validation.Properties;



namespace Microsoft.Practices.EnterpriseLibrary.Validation.Validators

{

    /// <summary>

    /// Performs validation on collection objects by applying the validation rules specified for a supplied type

    /// to its members.

    /// </summary>

    /// <seealso cref="ValidationFactory"/>

#if !SILVERLIGHT

    [Common.Configuration.ConfigurationElementType(typeof(Configuration.ObjectCollectionValidatorData))]

#endif

    public class ObjectCollectionValidator : Validator

    {

        private readonly Type targetType;

        private readonly string targetRuleset;

        private readonly Validator targetTypeValidator;

        private readonly ValidatorFactory validatorFactory;



        /// <summary>

        /// <para>Initializes a new instance of the <see cref="ObjectCollectionValidator"/>.</para>

        /// </summary>

        /// <remarks>

        /// The default ruleset will be used for validation.

        /// </remarks>

        public ObjectCollectionValidator()

            : this(ValidationFactory.DefaultCompositeValidatorFactory)

        { }



        /// <summary>

        /// <para>Initializes a new instance of the <see cref="ObjectCollectionValidator"/> 

        /// using the supplied ruleset.</para>

        /// </summary>

        /// <param name="validatorFactory">Factory to use when building nested validators.</param>

        public ObjectCollectionValidator(ValidatorFactory validatorFactory)

            : this(validatorFactory, string.Empty)

        { }



        /// <summary>

        /// <para>Initializes a new instance of the <see cref="ObjectCollectionValidator"/> 

        /// using the supplied ruleset.</para>

        /// </summary>

        /// <param name="validatorFactory">Factory to use when building nested validators.</param>

        /// <param name="targetRuleset">The ruleset to use.</param>

        /// <exception cref="ArgumentNullException">when <paramref name="targetRuleset"/> is <see langword="null"/>.</exception>

        /// <exception cref="ArgumentNullException">when <paramref name="validatorFactory"/> is <see langword="null"/>.</exception>

        public ObjectCollectionValidator(ValidatorFactory validatorFactory, string targetRuleset)

            : base(null, null)

        {

            if (validatorFactory == null)

            {

                throw new ArgumentNullException("validatorFactory");

            }

            if (targetRuleset == null)

            {

                throw new ArgumentNullException("targetRuleset");

            }



            this.targetType = null;

            this.targetTypeValidator = null;

            this.targetRuleset = targetRuleset;

            this.validatorFactory = validatorFactory;

        }



        /// <summary>

        /// <para>Initializes a new instance of the <see cref="ObjectCollectionValidator"/> for a target type.</para>

        /// </summary>

        /// <param name="targetType">The target type</param>

        /// <remarks>

        /// The default ruleset for <paramref name="targetType"/> will be used.

        /// </remarks>

        /// <exception cref="ArgumentNullException">when <paramref name="targetType"/> is <see langword="null"/>.</exception>

        public ObjectCollectionValidator(Type targetType)

            : this(targetType, string.Empty)

        { }



        /// <summary>

        /// <para>Initializes a new instance of the <see cref="ObjectCollectionValidator"/> for a target type

        /// using the supplied ruleset.</para>

        /// </summary>

        /// <param name="targetType">The target type</param>

        /// <param name="targetRuleset">The ruleset to use.</param>

        /// <exception cref="ArgumentNullException">when <paramref name="targetType"/> is <see langword="null"/>.</exception>

        /// <exception cref="ArgumentNullException">when <paramref name="targetRuleset"/> is <see langword="null"/>.</exception>

        public ObjectCollectionValidator(Type targetType, string targetRuleset)

            : this(targetType, ValidationFactory.DefaultCompositeValidatorFactory, targetRuleset)

        { }



        /// <summary>

        /// <para>Initializes a new instance of the <see cref="ObjectCollectionValidator"/> for a target type

        /// using the supplied ruleset.</para>

        /// </summary>

        /// <param name="targetType">The target type</param>

        /// <param name="validatorFactory">Factory to use when building nested validators.</param>

        /// <param name="targetRuleset">The ruleset to use.</param>

        /// <exception cref="ArgumentNullException">when <paramref name="targetType"/> is <see langword="null"/>.</exception>

        /// <exception cref="ArgumentNullException">when <paramref name="targetRuleset"/> is <see langword="null"/>.</exception>

        /// <exception cref="ArgumentNullException">when <paramref name="validatorFactory"/> is <see langword="null"/>.</exception>

        public ObjectCollectionValidator(Type targetType, ValidatorFactory validatorFactory, string targetRuleset)

            : base(null, null)

        {

            if (targetType == null)

            {

                throw new ArgumentNullException("targetType");

            }

            if (targetRuleset == null)

            {

                throw new ArgumentNullException("targetRuleset");

            }

            if (validatorFactory == null)

            {

                throw new ArgumentNullException("validatorFactory");

            }



            this.targetType = targetType;

            this.targetTypeValidator = validatorFactory.CreateValidator(targetType, targetRuleset);

            this.targetRuleset = targetRuleset;

            this.validatorFactory = null;

        }



        /// <summary>

        /// Validates by applying the validation rules for the target type specified for the receiver to the elements

        /// in <paramref name="objectToValidate"/>.

        /// </summary>

        /// <param name="objectToValidate">The object to validate.</param>

        /// <param name="currentTarget">The object on the behalf of which the validation is performed.</param>

        /// <param name="key">The key that identifies the source of <paramref name="objectToValidate"/>.</param>

        /// <param name="validationResults">The validation results to which the outcome of the validation should be stored.</param>

        /// <remarks>

        /// If <paramref name="objectToValidate"/> is <see langword="null"/> validation is ignored.

        /// <para/>

        /// A reference to a non collection object causes a validation failure and the validation rules

        /// for the configured target type will not be applied.

        /// <para/>

        /// Elements in the collection of a type not compatible with the configured target type causes a validation failure but

        /// do not affect validation on other elements.

        /// </remarks>

        public override void DoValidate(object objectToValidate,

            object currentTarget,

            string key,

            ValidationResults validationResults)

        {

            if (objectToValidate != null)

            {

                IEnumerable enumerable = objectToValidate as IEnumerable;

                if (enumerable != null)

                {

                    foreach (object element in enumerable)

                    {

                        if (element != null)

                        {

                            var elementType = element.GetType();



                            if (this.targetType == null || this.targetType.IsAssignableFrom(elementType))

                            {

                                // reset the current target and the key

                                this.GetValidator(elementType).DoValidate(element, element, null, validationResults);

                            }

                            else

                            {

                                // unlikely

                                this.LogValidationResult(validationResults,

                                    Resources.ObjectCollectionValidatorIncompatibleElementInTargetCollection,

                                    element,

                                    null);

                            }

                        }

                    }

                }

                else

                {

                    this.LogValidationResult(validationResults, Resources.ObjectCollectionValidatorTargetNotCollection, currentTarget, key);

                }

            }

        }



        private Validator GetValidator(Type elementType)

        {

            if (this.targetTypeValidator != null)

            {

                return this.targetTypeValidator;

            }

            else

            {

                return this.validatorFactory.CreateValidator(elementType, this.targetRuleset);

            }

        }



        /// <summary>

        /// Gets the message template to use when logging results no message is supplied.

        /// </summary>

        protected override string DefaultMessageTemplate

        {

            get { return null; }

        }



        /// <summary>

        /// Type of target being validated.

        /// </summary>

        public Type TargetType

        {

            get { return this.targetType; }

        }



        /// <summary>

        /// Ruleset to use when creating target validators.

        /// </summary>

        public string TargetRuleset

        {

            get { return this.targetRuleset; }

        }

    }

}