// /**
//  * File: MemoryLogger.cs
//  * Author: haraldwolff
//  *
//  * This file and it's content is copyrighted by the Author and / or copyright holder.
//  * Any use wihtout proper permission is illegal and may lead to legal actions.
//  *
//  *
//  **/
using System;
using ln.logging;
using System.Linq;
namespace ln.logging
{
    public class MemoryLogger : ILoggingBackend
    {
        private LogEntry[] Entries = new LogEntry[256];
        private int CurrentLogPointer = 255;

        public MemoryLogger()
        {
        }

        public MemoryLogger(int bufferLength)
        {
            Entries = new LogEntry[bufferLength];
            CurrentLogPointer = Entries.Length - 1;
        }

        public LogLevel MinLogLevel { get; set; } = LogLevel.FATAL;
        public LogLevel MaxLogLevel { get; set; } = LogLevel.INFO;

        public void Message(LogLevel logLevel, string[] lines)
        {
            lock (this)
            {
                Entries[CurrentLogPointer].LogLevel = logLevel;
                Entries[CurrentLogPointer].Lines = String.Join("\n", lines);
                CurrentLogPointer = NextLogPointer;
            }
        }

        public LogEntry[] GetLogEntries()
        {
            lock (this)
            {
                LogEntry[] prepare = new LogEntry[Entries.Length];
                if (CurrentLogPointer == (Entries.Length - 1))
                {
                    Array.Copy(Entries, prepare, Entries.Length);
                }
                else
                {
                    Array.Copy(Entries, PreviousLogPointer, prepare, 0, Entries.Length - PreviousLogPointer);
                    Array.Copy(Entries, 0, prepare, Entries.Length - PreviousLogPointer, PreviousLogPointer);
                }

                return prepare.Where((x) => x.Lines != null).ToArray();
            }
        }
        public LogEntry[] GetLogEntries(LogLevel maxLogLevel)
        {
            lock (this)
            {
                LogEntry[] prepare = new LogEntry[Entries.Length];
                if (CurrentLogPointer == (Entries.Length - 1))
                {
                    Array.Copy(Entries, prepare, Entries.Length);
                }
                else
                {
                    Array.Copy(Entries, PreviousLogPointer, prepare, 0, Entries.Length - PreviousLogPointer);
                    Array.Copy(Entries, 0, prepare, Entries.Length - PreviousLogPointer, PreviousLogPointer);
                }

                return prepare.Where((x) => (x.Lines != null) && (maxLogLevel >= x.LogLevel)).ToArray();
            }
        }

        private int NextLogPointer
        {
            get
            {
                int current = CurrentLogPointer;
                current--;
                if (current < 0)
                    current = Entries.Length - 1;
                return current;
            }
        }
        private int PreviousLogPointer
        {
            get
            {
                int current = CurrentLogPointer;
                current++;
                if (current >= Entries.Length)
                    current = 0;
                return current;
            }
        }


        public struct LogEntry
        {
            public LogLevel LogLevel;
            public string Lines;
        }
    }
}