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

namespace SourceGit.ViewModels
{
    public class Push : Popup
    {
        public bool HasSpecifiedLocalBranch
        {
            get;
            private set;
        }

        [Required(ErrorMessage = "Local branch is required!!!")]
        public Models.Branch SelectedLocalBranch
        {
            get => _selectedLocalBranch;
            set
            {
                if (SetProperty(ref _selectedLocalBranch, value))
                {
                    // If selected local branch has upstream branch. Try to find it's remote.
                    if (!string.IsNullOrEmpty(value.Upstream))
                    {
                        var branch = _repo.Branches.Find(x => x.FullName == value.Upstream);
                        if (branch != null)
                        {
                            var remote = _repo.Remotes.Find(x => x.Name == branch.Remote);
                            if (remote != null && remote != _selectedRemote)
                            {
                                SelectedRemote = remote;
                                return;
                            }
                        }
                    }

                    // Re-generate remote branches and auto-select remote branches.
                    AutoSelectBranchByRemote();
                }
            }
        }

        public List<Models.Branch> LocalBranches
        {
            get;
            private set;
        }

        public List<Models.Remote> Remotes
        {
            get => _repo.Remotes;
        }

        [Required(ErrorMessage = "Remote is required!!!")]
        public Models.Remote SelectedRemote
        {
            get => _selectedRemote;
            set
            {
                if (SetProperty(ref _selectedRemote, value))
                    AutoSelectBranchByRemote();
            }
        }

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

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

        public bool PushAllTags
        {
            get;
            set;
        }

        public bool ForcePush
        {
            get;
            set;
        }

        public Push(Repository repo, Models.Branch localBranch)
        {
            _repo = repo;

            // Gather all local branches and find current branch.
            LocalBranches = new List<Models.Branch>();
            var current = null as Models.Branch;
            foreach (var branch in _repo.Branches)
            {
                if (branch.IsLocal)
                    LocalBranches.Add(branch);
                if (branch.IsCurrent)
                    current = branch;
            }

            // Set default selected local branch.
            if (localBranch != null)
            {
                _selectedLocalBranch = localBranch;
                HasSpecifiedLocalBranch = true;
            }
            else
            {
                _selectedLocalBranch = current;
                HasSpecifiedLocalBranch = false;
            }

            // Find preferred remote if selected local branch has upstream.
            if (!string.IsNullOrEmpty(_selectedLocalBranch.Upstream))
            {
                foreach (var branch in repo.Branches)
                {
                    if (!branch.IsLocal && _selectedLocalBranch.Upstream == branch.FullName)
                    {
                        _selectedRemote = repo.Remotes.Find(x => x.Name == branch.Remote);
                        break;
                    }
                }
            }

            // Set default remote to the first if haven't been set.
            if (_selectedRemote == null)
                _selectedRemote = repo.Remotes[0];

            // Auto select preferred remote branch.
            AutoSelectBranchByRemote();

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

        public override Task<bool> Sure()
        {
            _repo.SetWatcherEnabled(false);

            var remoteBranchName = _selectedRemoteBranch.Name.Replace(" (new)", "");
            ProgressDescription = $"Push {_selectedLocalBranch.Name} -> {_selectedRemote.Name}/{remoteBranchName} ...";

            return Task.Run(() =>
            {
                var succ = new Commands.Push(
                    _repo.FullPath,
                    _selectedLocalBranch.Name,
                    _selectedRemote.Name,
                    remoteBranchName,
                    PushAllTags,
                    ForcePush,
                    string.IsNullOrEmpty(_selectedLocalBranch.Upstream),
                    SetProgressDescription).Exec();
                CallUIThread(() => _repo.SetWatcherEnabled(true));
                return succ;
            });
        }

        private void AutoSelectBranchByRemote()
        {
            // Gather branches.
            var branches = new List<Models.Branch>();
            foreach (var branch in _repo.Branches)
            {
                if (branch.Remote == _selectedRemote.Name)
                    branches.Add(branch);
            }

            // If selected local branch has upstream branch. Try to find it in current remote branches.
            if (!string.IsNullOrEmpty(_selectedLocalBranch.Upstream))
            {
                foreach (var branch in branches)
                {
                    if (_selectedLocalBranch.Upstream == branch.FullName)
                    {
                        RemoteBranches = branches;
                        SelectedRemoteBranch = branch;
                        return;
                    }
                }
            }

            // Find best remote branch by name.
            foreach (var branch in branches)
            {
                if (_selectedLocalBranch.Name == branch.Name)
                {
                    RemoteBranches = branches;
                    SelectedRemoteBranch = branch;
                    return;
                }
            }

            // Add a fake new branch.
            var fake = new Models.Branch()
            {
                Name = $"{_selectedLocalBranch.Name} (new)",
                Remote = _selectedRemote.Name,
            };
            branches.Add(fake);
            RemoteBranches = branches;
            SelectedRemoteBranch = fake;
        }

        private readonly Repository _repo = null;
        private Models.Branch _selectedLocalBranch = null;
        private Models.Remote _selectedRemote = null;
        private List<Models.Branch> _remoteBranches = new List<Models.Branch>();
        private Models.Branch _selectedRemoteBranch = null;
    }
}