using System.Collections.Generic;
using System.Linq;
using xCommons.Extensions;
using xPushService.Models;

namespace xPushService.Extensions {
    public static class XWebRTCConnectionExtensions {
        /// <summary>
        /// Validate Connection ...
        /// </summary>
        /// <param name="source"></param>
        /// <returns></returns>
        public static bool IsValid (this XWebRTCConnectionDto source) {
            //
            var result = false;
            result = !source
                .IsNull () && !source.CallerConnectionId
                .IsNullOrEmpty () && (
                    source.Callees
                    .HasChild () ? source.Callees
                    .All (callee => !callee.ConnectionId.IsNullOrDefault ()) :
                    true
                );

            //
            return result;
        }

        /// <summary>
        /// Check a ConnectionId is Caller of a connection ...
        /// </summary>
        /// <param name="source"></param>
        /// <param name="connectionId"></param>
        /// <returns></returns>
        public static bool IsCaller (
            this XWebRTCConnectionDto source,
            string connectionId
        ) {
            //
            var result = false;

            //
            // Validate Args ...
            if (!source.IsValid () ||
                connectionId.IsNullOrEmpty ()
            ) {
                return result;
            }

            //
            result = connectionId
                .ToNormalString () == source.CallerConnectionId
                .ToNormalString ();
            return result;
        }

        /// <summary>
        /// Check a ConnectionId is in Callees of a connection ...
        /// </summary>
        /// <param name="source"></param>
        /// <param name="connectionId"></param>
        /// <returns></returns>
        public static bool IsInCallees (
            this XWebRTCConnectionDto source,
            string connectionId
        ) {
            //
            var result = false;

            //
            // Validate Args ...
            if (!source.IsValid () ||
                !source.Callees.HasChild () ||
                connectionId.IsNullOrEmpty ()
            ) {
                return result;
            }

            //
            result = source.Callees.Any (callee => callee.ConnectionId
                .ToNormalString () == connectionId
                .ToNormalString ());

            //
            return result;
        }

        /// <summary>
        /// Get Receivers ...
        /// </summary>
        /// <param name="source"></param>
        /// <returns></returns>
        public static IReadOnlyList<string> GetReceivers (this XWebRTCConnectionDto source) {
            //
            var result = new List<string> ();

            //
            // Validate Args ...
            if (!source.IsValid ()) {
                return result;
            }

            //
            // Add Caller ...
            result.Add (source.CallerConnectionId);

            //
            // Add Callees ...
            source.Callees
                .ToList ()
                .ForEach (callee => {
                    result.Add (callee.ConnectionId);
                });

            //
            return result;
        }

        /// <summary>
        /// Retrieve Callee from Callees ...
        /// </summary>
        /// <param name="source"></param>
        /// <param name="connectionId"></param>
        /// <returns></returns>
        public static XWebRTCCalleeDto GetCallee (
            this XWebRTCConnectionDto source,
            string connectionId
        ) {
            //
            // Validate Args ...
            if (!source.IsValid () ||
                connectionId.IsNullOrEmpty ()
            ) {
                return null;
            }

            //
            // Check Connection Id is In Callees or not ...
            var isInCallees = source.IsInCallees (connectionId);
            if (!isInCallees) {
                return null;
            }

            //
            // retrieve result ...
            var result = source.Callees
                .FirstOrDefault (callee => callee.ConnectionId
                    .ToNormalString () == connectionId
                    .ToNormalString ()
                );

            //
            // return result ...
            return result;
        }
    }
}