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

namespace FileInterface.Scheduler
{
    public sealed class JobLogEntry
    {
        public DateTime Timestamp { get; set; }
        public string JobType { get; set; }
        public string JobId { get; set; }
        public string JobName { get; set; }
        public string Level { get; set; }
        public string Message { get; set; }
    }

    public sealed class JobLog
    {
        private readonly object _sync = new object();
        private readonly Queue<JobLogEntry> _entries = new Queue<JobLogEntry>();
        private readonly int _maxEntries;

        public JobLog(int maxEntries)
        {
            _maxEntries = Math.Max(100, maxEntries);
        }

        public void Info(CronJobConfig job, string message) { Add("CRON", job == null ? "" : job.Id, job == null ? "" : job.Name, "INFO", message); }
        public void Error(CronJobConfig job, string message) { Add("CRON", job == null ? "" : job.Id, job == null ? "" : job.Name, "ERROR", message); }
        public void Info(WatcherJobConfig job, string message) { Add("WATCHER", job == null ? "" : job.Id, job == null ? "" : job.Name, "INFO", message); }
        public void Error(WatcherJobConfig job, string message) { Add("WATCHER", job == null ? "" : job.Id, job == null ? "" : job.Name, "ERROR", message); }
        public void SystemInfo(string message) { Add("SYSTEM", "", "System", "INFO", message); }
        public void SystemError(string message) { Add("SYSTEM", "", "System", "ERROR", message); }

        public IList<JobLogEntry> GetLatest(int limit)
        {
            lock (_sync)
            {
                return _entries.Reverse().Take(Math.Max(1, Math.Min(limit, _maxEntries))).ToList();
            }
        }

        private void Add(string jobType, string jobId, string jobName, string level, string message)
        {
            lock (_sync)
            {
                _entries.Enqueue(new JobLogEntry
                {
                    Timestamp = DateTime.Now,
                    JobType = jobType ?? "",
                    JobId = jobId ?? "",
                    JobName = jobName ?? "",
                    Level = level,
                    Message = message ?? ""
                });
                while (_entries.Count > _maxEntries) _entries.Dequeue();
            }
        }
    }
}