using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.ComponentModel.DataAnnotations;
using System.Text.RegularExpressions;
using System.Web.Mvc;
using Sleis.Models;
using System.Text;

namespace Sleis.Validation.Attribute
{
    public class DecimalValidationAttribute : ValidationAttribute
    {        
        public string PrecisionFormat { get; set; }

        public DecimalValidationAttribute()
        {
            if(String.IsNullOrEmpty(base.ErrorMessage))
            {
                base.ErrorMessage = Constants.InvalidNumericValueErrorMessage;
            }
        }
        public override bool IsValid(object value)
        {
            //don't worry about being required.  let required attribute handle that
            if (value == null)
            {
                return true;
            }            
            Regex regex = new Regex(Pattern(this.PrecisionFormat));
            return regex.IsMatch(value.ToString());
                
        }
        public static string Pattern(string precisionFormat)
        {
            string[] vals = precisionFormat.Split(',');
            StringBuilder pattern = new StringBuilder(@"^-?0*\d{0,");
            pattern.Append(vals[0]);            
            pattern.Append(@"}(\.\d{0,");
            pattern.Append(vals[1]);
            pattern.Append(@"})?$");
            return pattern.ToString();
            
        } 
        
    }
    public class DecimalValidator : DataAnnotationsModelValidator<DecimalValidationAttribute>
    {
        #region Fields

        private readonly string _errorMessage;
        private readonly string _precisionFormat;

        #endregion Fields

        #region Ctors

        /// <summary>
        /// Initializes a new instance of the <see cref="EmailValidator"/> class.
        /// </summary>
        /// <param name="metadata">The metadata.</param>
        /// <param name="context">The context.</param>
        /// <param name="attribute">The attribute.</param>
        public DecimalValidator(ModelMetadata metadata, ControllerContext context, DecimalValidationAttribute attribute)
            : base(metadata, context, attribute)
        {
            this._errorMessage = attribute.ErrorMessage;
            this._precisionFormat = attribute.PrecisionFormat;
        }

        #endregion Ctors

        #region Methods

        /// <summary>
        /// Retrieves a collection of client validation rules.
        /// </summary>
        /// <returns>A collection of client validation rules.</returns>
        public override IEnumerable<ModelClientValidationRule> GetClientValidationRules()
        {
            var rule = new ModelClientValidationRegexRule(this._errorMessage, DecimalValidationAttribute.Pattern(this._precisionFormat));            
            return new[] { rule };
        }

        #endregion Methods
    }
}