private IDisposable InitMessageLoading(
Target target,
IMessageManager messageManager,
IAvatarManager avatarManager)
{
var messageLoading = messageManager.LoadPrevMessages(target)
.Select(models => new {
Action = new Action(() =>
{
_items.InsertRange(models, 0);
}),
Models = models
});
var avatarLoading = messageLoading
.SelectMany(item =>
{
var action = item.Action;
var models = item.Models;
var messageLoadAction = Observable.Return(action);
var avatarPreloadAction = avatarManager.PreloadAvatars(models)
.Select((avatar, i) => new Action(() =>
{
var messageModel = models[i];
messageModel.Avatar = avatar;
}));
var avatarLoadAction = avatarManager.LoadAvatars(models)
.Select((avatar, i) => new Action(() =>
{
var messageModel = models[i];
messageModel.Avatar = avatar;
}));
return(messageLoadAction
.Concat(avatarPreloadAction)
.Concat(avatarLoadAction));
});
return(SubscribeToActions(avatarLoading));
}
private IDisposable BindVisibleRangeChanges(
Target target,
IMessageManager messageManager,
IAvatarManager avatarManager)
{
var prevRange = default(Range);
var visibleRangeChanges = Model.WhenAnyValue(m => m.VisibleRange)
.Select(range => new
{
PrevRange = prevRange,
Range = range
})
.Do(item => prevRange = item.Range)
.Do(Console.WriteLine);
var messageLoading = visibleRangeChanges
.SelectMany(item =>
{
if (item.Range.Length > 0)
{
if (item.Range.Index == 0 &&
item.Range.Index != item.PrevRange.Index)
{
var items = _items.Items.OfType <MessageModel>().ToList();
var firstMessage = items.FirstOrDefault();
return(messageManager.LoadPrevMessages(target, firstMessage?.Message)
.Select(models => new {
Action = new Action(() =>
{
_items.InsertRange(models, 0);
}),
Models = models
}));
}
if (item.Range.Index + item.Range.Length == _items.Count &&
item.Range.LastIndex != item.PrevRange.LastIndex)
{
var items = _items.Items.OfType <MessageModel>().ToList();
var lastMessage = items.LastOrDefault();
return(messageManager.LoadNextMessages(target, lastMessage?.Message)
.Select(models => new {
Action = new Action(() =>
{
_items.AddRange(models);
}),
Models = models
}));
}
}
return(Observable.Empty <IList <MessageModel> >()
.Select(models => new
{
Action = new Action(() => { }),
Models = models
}));
});
var avatarLoading = messageLoading
.SelectMany(item =>
{
var action = item.Action;
var models = item.Models;
var messageLoadAction = Observable.Return(action);
var avatarPreloadAction = avatarManager.PreloadAvatars(models)
.Select((avatar, i) => new Action(() =>
{
var messageModel = models[i];
messageModel.Avatar = avatar;
}));
var avatarLoadAction = avatarManager.LoadAvatars(models)
.Select((avatar, i) => new Action(() =>
{
var messageModel = models[i];
messageModel.Avatar = avatar;
}));
return(messageLoadAction
.Concat(avatarPreloadAction)
.Concat(avatarLoadAction));
});
return(SubscribeToActions(avatarLoading));
}