using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Diagnostics;
using System.IO;
using System.Linq;
using NLog;
using NzbDrone.Common.Model;

namespace NzbDrone.Common
{
    public interface IProcessProvider
    {
        ProcessInfo GetCurrentProcess();
        ProcessInfo GetProcessById(int id);
        Process Start(string path);
        Process Start(ProcessStartInfo startInfo);
        void WaitForExit(Process process);
        void SetPriority(int processId, ProcessPriorityClass priority);
        void KillAll(string processName);
        bool Exists(string processName);
        ProcessPriorityClass GetCurrentProcessPriority();
        Process ShellExecute(string path, string args = null, Action<string> onOutputDataReceived = null, Action<string> onErrorDataReceived = null);
    }

    public class ProcessProvider : IProcessProvider
    {
        private static readonly Logger Logger = LogManager.GetCurrentClassLogger();

        public const string NzbDroneProcessName = "NzbDrone";
        public const string NzbDroneConsoleProcessName = "NzbDrone.Console";

        public ProcessInfo GetCurrentProcess()
        {
            return ConvertToProcessInfo(Process.GetCurrentProcess());
        }

        public bool Exists(string processName)
        {
            return Process.GetProcessesByName(processName).Any();
        }

        public ProcessPriorityClass GetCurrentProcessPriority()
        {
            return Process.GetCurrentProcess().PriorityClass;
        }

        public ProcessInfo GetProcessById(int id)
        {
            Logger.Trace("Finding process with Id:{0}", id);

            var processInfo = ConvertToProcessInfo(Process.GetProcesses().FirstOrDefault(p => p.Id == id));

            if (processInfo == null)
            {
                Logger.Warn("Unable to find process with ID {0}", id);
            }
            else
            {
                Logger.Trace("Found process {0}", processInfo.ToString());
            }

            return processInfo;
        }

        /*        public IEnumerable<ProcessInfo> GetProcessByName(string name)
                {
                    if (OsInfo.IsMono)
                    {
                        var mono = Process.GetProcessesByName("mono");

                        return mono.Where(process => process.Modules.Cast<ProcessModule>().Any(module => module.ModuleName.ToLower() == name + ".exe"))
                                             .Select(ConvertToProcessInfo);
                    }

                    return Process.GetProcessesByName(name).Select(ConvertToProcessInfo).Where(p => p != null);
                }*/

        public Process Start(string path)
        {
            return Start(new ProcessStartInfo(path));
        }

        public Process ShellExecute(string path, string args = null, Action<string> onOutputDataReceived = null, Action<string> onErrorDataReceived = null)
        {
            var logger = LogManager.GetLogger(new FileInfo(path).Name);

            var startInfo = new ProcessStartInfo(path, args)
            {
                CreateNoWindow = true,
                UseShellExecute = false,
                RedirectStandardError = true,
                RedirectStandardOutput = true,
            };


            logger.Info("Starting {0} {1}", path, args);

            var process = Process.Start(startInfo);

            process.OutputDataReceived += (sender, eventArgs) =>
            {
                if (string.IsNullOrWhiteSpace(eventArgs.Data)) return;

                logger.Debug(eventArgs.Data);

                if (onOutputDataReceived != null)
                {
                    onOutputDataReceived(eventArgs.Data);
                }
            };

            process.ErrorDataReceived += (sender, eventArgs) =>
            {
                if (string.IsNullOrWhiteSpace(eventArgs.Data)) return;

                logger.Error(eventArgs.Data);

                if (onErrorDataReceived != null)
                {
                    onErrorDataReceived(eventArgs.Data);
                }
            };

            process.BeginErrorReadLine();
            process.BeginOutputReadLine();
            process.Start();

            return process;
        }

        public Process Start(ProcessStartInfo startInfo)
        {
            Logger.Info("Starting process. [{0}]", startInfo.FileName);

            var process = new Process
                              {
                                  StartInfo = startInfo
                              };
            process.Start();

            return process;
        }

        public void WaitForExit(Process process)
        {
            Logger.Trace("Waiting for process {0} to exit.", process.ProcessName);
            process.WaitForExit();
        }



        public void SetPriority(int processId, ProcessPriorityClass priority)
        {
            var process = Process.GetProcessById(processId);

            Logger.Info("Updating [{0}] process priority from {1} to {2}",
                        process.ProcessName,
                        process.PriorityClass,
                        priority);

            process.PriorityClass = priority;
        }

        public void KillAll(string processName)
        {
            var processToKill = Process.GetProcessesByName(processName);

            foreach (var processInfo in processToKill)
            {
                Kill(processInfo.Id);
            }
        }


        private static ProcessInfo ConvertToProcessInfo(Process process)
        {
            if (process == null) return null;

            process.Refresh();

            try
            {
                if (process.Id <= 0 || process.HasExited) return null;

                return new ProcessInfo
                {
                    Id = process.Id,
                    StartPath = process.MainModule.FileName,
                    Name = process.ProcessName
                };
            }
            catch (Win32Exception)
            {
                Logger.Warn("Coudn't get process info for " + process.ProcessName);
            }

            return null;
        }



        private void Kill(int processId)
        {
            if (processId == 0 || Process.GetProcesses().All(p => p.Id != processId))
            {
                Logger.Warn("Cannot find process with id: {0}", processId);
                return;
            }

            var process = Process.GetProcessById(processId);

            if (process.HasExited)
            {
                return;
            }

            Logger.Info("[{0}]: Killing process", process.Id);
            process.Kill();
            Logger.Info("[{0}]: Waiting for exit", process.Id);
            process.WaitForExit();
            Logger.Info("[{0}]: Process terminated successfully", process.Id);
        }
    }
}