using System;
using System.Net;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
using game.Account;

namespace game.PlayerDataStorage
{
    // Prebuild distinct transports with one cookie jar, then transfer each owned handler once.
    internal sealed class PlayerKVGameLoadCapability
    {
        internal Uri Api { get; }
        internal string CacheRoot { get; }
        internal int LoginObserveMs { get; }
        internal int QuitObserveMs { get; }
        internal bool RequireExistingArchive { get; }
        internal Func<int,CancellationToken,Task> Delay { get; }
        internal PlayerKVControlledLoadCapability LeaseCapability { get; private set; }
        private readonly Func<CookieContainer, HttpMessageHandler> auth;
        private readonly Func<CookieContainer, HttpMessageHandler> kv;
        private readonly Func<CookieContainer, HttpMessageHandler> lease;
        private readonly bool prepareOriginalComparison;
        readonly object gate=new object();
        CookieContainer cookies;
        HttpMessageHandler pendingKV,pendingLease;
        Exception cleanupFailure;
        readonly System.Collections.Generic.List<HttpMessageHandler> failedHandlers=new System.Collections.Generic.List<HttpMessageHandler>();
        bool claimed;
        private PlayerKVGameLoadCapability(Uri api, string cacheRoot,
            int loginMs, int quitMs, Func<int, CancellationToken, Task> delay,
            Func<CookieContainer, HttpMessageHandler> auth, Func<CookieContainer, HttpMessageHandler> kv,
            Func<CookieContainer, HttpMessageHandler> lease, bool requireExistingArchive = false, bool prepareOriginalComparison = false)
        {
            // Preserve the former wrappers' null-check order, diagnostic and configuration precedence.
            this.auth = auth ?? throw new ArgumentNullException("leaseHandler");
            this.kv = kv ?? throw new ArgumentNullException("leaseHandler");
            this.lease = lease ?? throw new ArgumentNullException("leaseHandler");
            if (api == null || !api.IsAbsoluteUri || (api.Scheme != "http" && api.Scheme != "https") || !string.IsNullOrEmpty(api.UserInfo) ||
                !string.IsNullOrEmpty(api.Query) || !string.IsNullOrEmpty(api.Fragment) || string.IsNullOrEmpty(cacheRoot) ||
                loginMs < 1000 || loginMs > 15000 || quitMs < 1000 || quitMs > 15000)
            {
                throw new ArgumentException("Controlled load configuration invalid.");
            }
            Api = new Uri(api.AbsoluteUri.TrimEnd('/') + "/");
            CacheRoot = cacheRoot;
            LoginObserveMs = loginMs;
            QuitObserveMs = quitMs;
            Delay = delay ?? Task.Delay;
            RequireExistingArchive = requireExistingArchive;
            this.prepareOriginalComparison = prepareOriginalComparison;
        }
        internal static PlayerKVGameLoadCapability CreateForGame(Uri api, string cacheRoot,
            Func<CookieContainer, HttpMessageHandler> auth, Func<CookieContainer, HttpMessageHandler> kv,
            Func<CookieContainer, HttpMessageHandler> lease, bool prepareOriginalComparison = false)
        {
            if (api == null || api.AbsoluteUri != "http://s101.local:18080/")
            {
                throw new ArgumentException("Formal KV endpoint mismatch.", nameof(api));
            }
            var capability = new PlayerKVGameLoadCapability(api, cacheRoot, 10000, 5000, null, auth, kv, lease, true, prepareOriginalComparison);
            capability.LeaseCapability = PlayerKVControlledLoadCapability.CreateForGame(capability.TakeLease);
            return capability;
        }
#if UNITY_EDITOR
        internal static PlayerKVGameLoadCapability CreateForValidation(Uri api, string cacheRoot,
            Func<CookieContainer, HttpMessageHandler> auth, Func<CookieContainer, HttpMessageHandler> kv,
            Func<CookieContainer, HttpMessageHandler> lease, int loginMs = 10000, int quitMs = 5000,
            Func<int, CancellationToken, Task> delay = null)
        {
            var capability = new PlayerKVGameLoadCapability(api, cacheRoot, loginMs, quitMs, delay, auth, kv, lease);
            capability.LeaseCapability = PlayerKVControlledLoadCapability.CreateForValidation(capability.TakeLease);
            return capability;
        }
#endif
        internal PlayerKVLoginContext CreateContext(string id,long epoch,Func<long,bool> current)
        {
            lock(gate) { if(claimed) throw new InvalidOperationException("Controlled capability already used."); claimed=true; }
            return new PlayerKVLoginContext(id,CacheRoot,epoch,current,Api,
                ()=>new S101AccountSession(Api,CreateAuthentication),()=>new PlayerKVGameSessionBridge(TakeKV, prepareOriginalComparison));
        }
        private HttpMessageHandler CreateAuthentication(CookieContainer jar)
        {
            lock (gate)
            {
                if (cookies != null)
                {
                    throw new InvalidOperationException("Repeated authentication factory.");
                }
                cookies = jar;
                HttpMessageHandler authentication = null;
                try
                {
                    // Validate all three returned handler graphs before the first authentication send.
                    authentication = PlayerKVControlledLoadCapability.CreateHandler(auth, jar, LeaseCapability.IsFormal);
                    pendingKV = PlayerKVControlledLoadCapability.CreateHandler(kv, jar, LeaseCapability.IsFormal);
                    pendingLease = PlayerKVControlledLoadCapability.CreateHandler(lease, jar, LeaseCapability.IsFormal);
                    if (ShareHandlerGraph(authentication, pendingKV, pendingLease))
                    {
                        throw new InvalidOperationException("Distinct transport ownership required.");
                    }
                    return authentication;
                }
                catch
                {
                    try
                    {
                        authentication?.Dispose();
                    }
                    catch (Exception ex)
                    {
                        cleanupFailure = ex;
                        failedHandlers.Add(authentication);
                    }
                    try
                    {
                        CloseUnused();
                    }
                    catch
                    {
                    }
                    throw;
                }
            }
        }
        static bool ShareHandlerGraph(params HttpMessageHandler[] roots)
        {
            var seen=new System.Collections.Generic.List<HttpMessageHandler>();
            foreach(var root in roots)
                for(var node=root;node!=null;node=(node as DelegatingHandler)?.InnerHandler)
                {
                    if(seen.Exists(previous=>ReferenceEquals(previous,node))) return true;
                    seen.Add(node);
                }
            return false;
        }
        HttpMessageHandler TakeKV(CookieContainer jar)
        {
            lock(gate)
            { if(!ReferenceEquals(jar,cookies) || pendingKV==null) throw new InvalidOperationException("KV transport ownership invalid.");
              var result=pendingKV; pendingKV=null; return result; }
        }
        HttpMessageHandler TakeLease(CookieContainer jar)
        {
            lock(gate)
            { if(!ReferenceEquals(jar,cookies) || pendingLease==null) throw new InvalidOperationException("Lease transport ownership invalid.");
              var result=pendingLease; pendingLease=null; return result; }
        }
        internal void CloseUnused()
        {
            lock(gate)
            {
                // Attempt every owned cleanup once; retain a failure even if a later Dispose succeeds.
                var ownedLease=pendingLease; pendingLease=null;
                var ownedKV=pendingKV; pendingKV=null;
                try { ownedLease?.Dispose(); } catch(Exception ex) { cleanupFailure=cleanupFailure ?? ex; failedHandlers.Add(ownedLease); }
                try { ownedKV?.Dispose(); } catch(Exception ex) { cleanupFailure=cleanupFailure ?? ex; failedHandlers.Add(ownedKV); }
                if(cleanupFailure!=null) throw new InvalidOperationException("Controlled transport cleanup failed.",cleanupFailure);
            }
        }
    }
}