// Copyright 1998-2017 Epic Games, Inc. All Rights Reserved.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web.Caching;
using Tools.CrashReporter.CrashReportWebSite.DataModels;
using Tools.CrashReporter.CrashReportWebSite.DataModels.Repositories;
using Tools.CrashReporter.CrashReportWebSite.ViewModels;

namespace Tools.CrashReporter.CrashReportWebSite.Models
{
	/// <summary>
	/// A class to handle caching of database results on the web server.
	/// </summary>
	public class CachedDataService : IDisposable
	{
		private CrashRepository Crashes;
		private BuggRepository Buggs;

		private Cache CacheInstance;

		private const string CacheKeyPrefix = "_CachedDataService_";
		private const string CallstackKeyPrefix = "_CallStack_";
		private const string FunctionCallKeyPrefix = "_FunctionCallStack_";
		private const string UserNameKeyPrefix = "_UserName_";

		/// <summary>
		/// Link the Http context cache to a Crash repository.
		/// </summary>
		/// <param name="inCache">The current Http context cache.</param>
		/// <param name="inCrashRepository">The repository to associate the cache with.</param>
		public CachedDataService( Cache inCache, CrashRepository inCrashRepository )
		{
			CacheInstance = inCache;
			Crashes = inCrashRepository;
		}

		/// <summary>
		/// Link the Http context cache to a Bugg repository.
		/// </summary>
		/// <param name="inCache">The current Http context cache.</param>
		/// <param name="inBuggRepository">The repository to associate the cache with.</param>
		public CachedDataService( Cache inCache, BuggRepository inBuggRepository )
		{
			CacheInstance = inCache;
			Buggs = inBuggRepository;
		}

		/// <summary>
		/// Implementing Dispose.
		/// </summary>
		public void Dispose()
		{
			Dispose( true );
			GC.SuppressFinalize( this );
		}

		/// <summary>
		/// Disposes the resources.
		/// </summary>
		/// <param name="Disposing">true if the Dispose call is from user code, and not system code.</param>
		protected virtual void Dispose( bool Disposing )
		{
			//Crashes.Dispose();
			//Buggs.Dispose();
		}

		/// <summary>
		/// Retrieve a cached (and pre-parsed) callstack container from the cache, or parse the raw callstack, and add to the cache.
		/// </summary>
		/// <param name="currentCrash">The Crash to retrieve the parsed callstack for.</param>
		/// <returns>A parsed callstack.</returns>
        public CallStackContainer GetCallStackFast(CrashDataModel currentCrash)
		{
			using( var logTimer = new FAutoScopedLogTimer( this.GetType().ToString() + "(CrashId=" + currentCrash.Id + ")" ) )
			{
				var key = CacheKeyPrefix + CallstackKeyPrefix + currentCrash.Id;
				var callStack = (CallStackContainer)CacheInstance[key];
			    if (callStack != null) return callStack;
			    callStack = new CallStackContainer( currentCrash.CrashType, currentCrash.RawCallStack, currentCrash.PlatformName );
			    callStack.bDisplayFunctionNames = true;
			    CacheInstance.Insert( key, callStack );

			    return callStack;
			}
		}
	}
}