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

namespace ClassesII_Demo.Models
{
	public static class Phonebook
	{
		private static readonly List<Contact> contacts = new List<Contact>();

		public static void AddContact(Contact contact)
		{
			foreach (var phoneContact in contacts)
			{
				if (phoneContact.Equals(contact))
				{
					throw new ArgumentException("Contact already exists!");
				}
			}

			contacts.Add(contact);
		}
		public static string ListContactsForSave(string orderBy)
		{
			// remove unused variable

				var builder = new StringBuilder();
			builder.AppendLine("[");
				for (int i=0;i<contacts.Count;i++)
				{
				var contact = contacts[i];
					builder.AppendLine(contact.GetContactInfoForSaving());
				if (i != contacts.Count - 1)
				{
					builder.Append(",");
				}
				}
			builder.AppendLine("]");
			return builder.ToString();


		}
		public static string ListContacts(string orderBy)
		{

			if (orderBy.Equals("0"))
			{
				var builder = new StringBuilder();
				foreach (var contact in contacts)
				{
					builder.AppendLine(contact.GetContactInfo());
				}

				return builder.ToString();
			}
			else
			if (orderBy.Equals("name"))
			{
				List<Contact> sortedByName = contacts.OrderBy(x => x.Name).ToList();
				var builder = new StringBuilder();

				foreach (var contact in sortedByName)
				{
					builder.AppendLine(contact.GetContactInfo());
				}

				return builder.ToString();
			}

			else if (orderBy.Equals("time"))
			{
				List<Contact> sortedByTime = contacts.OrderBy(x => x.CreatedOn).ToList();
				var builder = new StringBuilder();

				foreach (var contact in sortedByTime)
				{
					builder.AppendLine(contact.GetContactInfo());
				}

				return builder.ToString();
			}

			return "Phonebook is empty.Please enter a contact first!";
		}

		internal static string RemoveContact(string v)
		{
			if (v == null)
			{
				throw new ArgumentException("Name is null");
			}
			// var contact
			foreach (var PhoneContacts in contacts)
			{
				var currentContact = (Contact)PhoneContacts;
				if (currentContact.Name == v)
				{
					contacts.Remove(currentContact);
					return "Contact removed from phonebook";
				}
			}

			return "Contact to remove not found";
		}
		// todo string name
		internal static string UpdateContact(string v, string newNumber)
		{
			if (v == null)
			{
				throw new NotImplementedException("Contact to update is null");
			}
			// todo var contact
			foreach (var PhoneContact in contacts)
			{
				if (PhoneContact.Name == v)
				{
					PhoneContact.PhoneNumber = newNumber;
					PhoneContact.CreatedOn = DateTime.Now;
					return $"Phonenumber of {v} has been update to {newNumber}!";
				}
			}

			return $"The contact {v} has not been found!";
		}
		//todo string name
		internal static string SearchContacts(string v)
		{
			if (v == null)
			{
				throw new NotImplementedException();
			}
			StringBuilder totalInfo = new StringBuilder();
			//todo var contact
			foreach (var PhoneContact in contacts)
			{
				//for (int i = 0; i < v.Length; i++)
				//{

				//}
				v = v.ToLower();
				string currentname = PhoneContact.Name.ToLower();
				if (currentname.Contains(v))
				{
					totalInfo.AppendLine(PhoneContact.GetContactInfo());
				}
			}
			if (totalInfo.Length == 0)
			{
				return $"Name containing {v} was not found";
			}
			else
			{
				return totalInfo.ToString();
			}
		}
	}
}