using System;
using System.Collections.Generic;
using System.Linq;

namespace TINK.Model.User.Account
{
    /// <summary>
    /// Holds the state of mail and password and information about some invalid parts if there are.
    /// </summary>
    public class State
    {
        /// <summary>
        /// Consider state to be invalid after construction.
        /// </summary>
        private Elements m_eElements = Elements.None;

        private Dictionary<Elements, string> m_oDescription = new Dictionary<Elements, string>();

        /// <summary>
        /// Constructs object to state all entries are valid.
        /// </summary>
        public State()
        {
            m_eElements = Elements.Account;

            m_oDescription = new Dictionary<Elements, string>
            {
                { Elements.None, string.Empty },
                { Elements.Account, string.Empty }
            };
        }

        /// <summary>
        /// Constructs object to state some/ all elements are invalid.
        /// </summary>
        /// <param name="p_oValidParts">Specifies the parts which are invalid.</param>
        /// <param name="p_oDescription">Description of invalid parts.</param>
        public State(Elements p_oValidParts, Dictionary<Elements, string> p_oDescription)
        {
            m_eElements = p_oValidParts;

            m_oDescription = p_oDescription ?? new Dictionary<Elements, string>();

            // Ensure consistency
            foreach (Elements l_oElement in Enum.GetValues(typeof(Elements)))
            {
                if (!m_oDescription.ContainsKey(l_oElement))
                {
                    switch (l_oElement)
                    {
                        case Elements.Account:
                        case Elements.None:
                            continue;
                        
                    }

                    m_oDescription.Add(l_oElement, string.Empty);
                }
            }
        }

        /// <summary>
        /// True if account is valid.
        /// </summary>
        public bool IsValid { get { return ValidElement == Elements.Account; } }

        /// <summary>
        /// Specifies if both mail and password are valid, one of them or none.
        /// </summary>
        public Elements ValidElement
        {
            get
            {
                return m_eElements;
            }
        }

        /// <summary>
        /// Holds the message about invalid elements.
        /// </summary>
        public Dictionary<Elements, string> Description
        {
            get
            {
                var l_oUserFriendlyDescription = new Dictionary<Elements, string>();
                foreach (Elements l_oElement in Enum.GetValues(typeof(Elements)))
                {
                    switch (l_oElement)
                    {
                        case Elements.Account:
                        case Elements.None:
                            continue;

                    }

                    l_oUserFriendlyDescription.Add(
                        l_oElement, 
                        m_oDescription.ContainsKey(l_oElement) ? m_oDescription[l_oElement] : string.Empty);
                }

                l_oUserFriendlyDescription.Add(
                    Elements.Account,
                    string.Join(";", l_oUserFriendlyDescription.Where(x => x.Value.Length > 0).Select(x => x.Value).ToArray()));

                return l_oUserFriendlyDescription ;
            }
        }
    }

    /// <summary>
    /// Verifies if a password is valid or not.
    /// </summary>
    /// <param name="p_strMail"></param>
    /// <param name="p_strPassword"></param>
    /// <returns></returns>
    public delegate State PasswordValidator(string p_strMail, string p_strPassword);

    public static class Validator
    {
        public static State ValidateMailAndPasswordDelegate(string p_strMail, string p_strPassword)
        {
            var l_oElements = Elements.None;
            var l_oDescription = new Dictionary<Elements, string>();
            
            // Validate mail address.
            if (string.IsNullOrEmpty(p_strMail))
            {
                l_oDescription.Add(Elements.Mail, "Email Addresse darf nicht leer sein.");
            }
            else if (p_strMail.ToString().Split('@').Length < 2)
            {
                l_oDescription.Add(Elements.Mail, "Email Adresse mit Zeichen \"@\" enthalten.");
            }
            else if (p_strMail.ToString().Split('@')[0].Length <= 0)
            {
                l_oDescription.Add(Elements.Mail, "Benutzername in Email Adresse darf nicht leer sein.");
            }
            else if (p_strMail.ToString().Split('@')[1].Length <= 0)
            {
                // Data has been entered
                l_oDescription.Add(Elements.Mail, "Domain- Name in Email Adresse darf nicht leer sein.");
            }
            else
            {
                // Input mail address is ok
                l_oElements = Elements.Mail;
                l_oDescription.Add(Elements.Mail, string.Empty);
            }

            // Validate password.
            if (string.IsNullOrEmpty(p_strPassword) || p_strPassword.Length < 8)
            {
                // Data has been entered
                l_oDescription.Add(Elements.Password, "Passwort is zu kurz.");
            }
            else
            {
                // Password is ok
                l_oElements |= Elements.Password;
                l_oDescription.Add(Elements.Password, string.Empty);
            }

            return new State(l_oElements, l_oDescription);
        }
    }

}