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

namespace SourceGit.ViewModels {
    public class Pull : Popup {
        public List<Models.Remote> Remotes => _repo.Remotes;
        public Models.Branch Current => _current;

        public bool HasSpecifiedRemoteBranch {
            get;
            private set;
        }

        public Models.Remote SelectedRemote {
            get => _selectedRemote;
            set {
                if (SetProperty(ref _selectedRemote, value)) {
                    var branches = new List<Models.Branch>();
                    foreach (var branch in _repo.Branches) {
                        if (branch.Remote == value.Name) branches.Add(branch);
                    }
                    RemoteBranches = branches;
                    SelectedBranch = branches.Count > 0 ? branches[0] : null;
                }
            }
        }

        public List<Models.Branch> RemoteBranches {
            get => _remoteBranches;
            private set => SetProperty(ref _remoteBranches, value);
        }

        [Required(ErrorMessage = "Remote branch to pull is required!!!")]
        public Models.Branch SelectedBranch {
            get => _selectedBranch;
            set => SetProperty(ref _selectedBranch, value);
        }

        public bool UseRebase {
            get;
            set;
        } = true;

        public bool AutoStash {
            get;
            set;
        } = true;

        public Pull(Repository repo, Models.Branch specifiedRemoteBranch) {
            _repo = repo;
            _current = repo.Branches.Find(x => x.IsCurrent);
            
            if (specifiedRemoteBranch != null) {
                _selectedRemote = repo.Remotes.Find(x => x.Name == specifiedRemoteBranch.Remote);
                _selectedBranch = specifiedRemoteBranch;
                HasSpecifiedRemoteBranch = true;
            } else {
                if (!string.IsNullOrEmpty(_current.Upstream)) {
                    foreach (var branch in repo.Branches) {
                        if (!branch.IsLocal && _current.Upstream == branch.FullName) {
                            _selectedRemote = repo.Remotes.Find(x => x.Name == branch.Remote);
                            _selectedBranch = branch;
                            break;
                        }
                    }
                }                

                HasSpecifiedRemoteBranch = false;
            }

            // Make sure remote is exists.
            if (_selectedRemote == null) {
                _selectedRemote = repo.Remotes[0];
                _selectedBranch = null;
                HasSpecifiedRemoteBranch = false;
            }

            _remoteBranches = new List<Models.Branch>();
            foreach (var branch in _repo.Branches) {
                if (branch.Remote == _selectedRemote.Name) _remoteBranches.Add(branch);
            }

            if (_selectedBranch == null && _remoteBranches.Count > 0) {
                _selectedBranch = _remoteBranches[0];
            }

            View = new Views.Pull() { DataContext = this };
        }

        public override Task<bool> Sure() {
            _repo.SetWatcherEnabled(false);
            return Task.Run(() => {
                var needPopStash = false;
                if (AutoStash && _repo.WorkingCopyChangesCount > 0) {
                    SetProgressDescription("Adding untracked changes...");
                    var succ = new Commands.Add(_repo.FullPath).Exec();
                    if (succ) {
                        SetProgressDescription("Stash local changes...");
                        succ = new Commands.Stash(_repo.FullPath).Push("PULL_AUTO_STASH");
                    }
                    
                    if (!succ) {
                        CallUIThread(() => _repo.SetWatcherEnabled(true));
                        return false;
                    }

                    needPopStash = true;
                }

                SetProgressDescription($"Pull {_selectedRemote.Name}/{_selectedBranch.Name}...");
                var rs = new Commands.Pull(_repo.FullPath, _selectedRemote.Name, _selectedBranch.Name, UseRebase, SetProgressDescription).Exec();
                if (rs && needPopStash) {
                    SetProgressDescription("Re-apply local changes...");
                    rs = new Commands.Stash(_repo.FullPath).Pop("stash@{0}");
                }

                CallUIThread(() => _repo.SetWatcherEnabled(true));
                return rs;
            });
        }

        private Repository _repo = null;
        private Models.Branch _current = null;
        private Models.Remote _selectedRemote = null;
        private List<Models.Branch> _remoteBranches = null;
        private Models.Branch _selectedBranch = null;
    }
}