using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;

namespace SourceGit.Commands {
    public class Fetch : Command {
        public Fetch(string repo, string remote, bool prune, Action<string> outputHandler) {
            _outputHandler = outputHandler;
            WorkingDirectory = repo;
            Context = repo;
            TraitErrorAsOutput = true;

            var sshKey = new Config(repo).Get($"remote.{remote}.sshkey");
            if (!string.IsNullOrEmpty(sshKey)) {
                Args = $"-c core.sshCommand=\"ssh -i '{sshKey}'\" ";
            } else {
                Args = "-c credential.helper=manager ";
            }

            Args += "fetch --progress --verbose ";
            if (prune) Args += "--prune ";
            Args += remote;

            AutoFetch.MarkFetched(repo);
        }

        public Fetch(string repo, string remote, string localBranch, string remoteBranch, Action<string> outputHandler) {
            _outputHandler = outputHandler;
            WorkingDirectory = repo;
            Context = repo;
            TraitErrorAsOutput = true;

            var sshKey = new Config(repo).Get($"remote.{remote}.sshkey");
            if (!string.IsNullOrEmpty(sshKey)) {
                Args = $"-c core.sshCommand=\"ssh -i '{sshKey}'\" ";
            } else {
                Args = "-c credential.helper=manager ";
            }

            Args += $"fetch --progress --verbose {remote} {remoteBranch}:{localBranch}";
        }

        protected override void OnReadline(string line) {
            _outputHandler?.Invoke(line);
        }

        private Action<string> _outputHandler;
    }

    public class AutoFetch {
        public static bool IsEnabled {
            get;
            set;
        } = false;

        class Job {
            public Fetch Cmd = null;
            public DateTime NextRunTimepoint = DateTime.MinValue;
        }

        static AutoFetch() {
            Task.Run(() => {
                while (true) {
                    if (!IsEnabled) {
                        Thread.Sleep(10000);
                        continue;
                    }

                    var now = DateTime.Now;
                    var uptodate = new List<Job>();
                    lock (_lock) {
                        foreach (var job in _jobs) {
                            if (job.Value.NextRunTimepoint.Subtract(now).TotalSeconds <= 0) {
                                uptodate.Add(job.Value);
                            }
                        }
                    }

                    foreach (var job in uptodate) {
                        job.Cmd.Exec();
                        job.NextRunTimepoint = DateTime.Now.AddSeconds(_fetchInterval);
                    }

                    Thread.Sleep(2000);
                }
            });
        }

        public static void AddRepository(string repo) {
            var job = new Job {
                Cmd = new Fetch(repo, "--all", true, null) { RaiseError = false },
                NextRunTimepoint = DateTime.Now.AddSeconds(_fetchInterval),
            };

            lock (_lock) {
                if (_jobs.ContainsKey(repo)) {
                    _jobs[repo] = job;
                } else {
                    _jobs.Add(repo, job);
                }
            }
        }

        public static void RemoveRepository(string repo) {
            lock (_lock) {
                _jobs.Remove(repo);
            }
        }

        public static void MarkFetched(string repo) {
            lock (_lock) {
                if (_jobs.ContainsKey(repo)) {
                    _jobs[repo].NextRunTimepoint = DateTime.Now.AddSeconds(_fetchInterval);
                }
            }
        }

        private static Dictionary<string, Job> _jobs = new Dictionary<string, Job>();
        private static object _lock = new object();
        private static double _fetchInterval = 10 * 60;
    }
}