/// <summary>
/// Creates a TvBroadcastListing
/// </summary>
/// <param name="importTag"></param>
/// <param name="channelSource"></param>
/// <param name="info"></param>
/// <returns></returns>
public TvProgramBroadCastListing AddBroadcastListing(TvProgramBroadCastListingImport importTag, TvChannelListingSource channelSource, IAddTvBroadCastListingInfo info)
{
// check if this import's going to violate the PK by trying to import duplicate Listings (on the same ImportId)
if (CheckForViolatedPK(importTag, channelSource, info) != null)
throw new TvBroadCastListingAlreadyExistsException(
string.Format(
"An item with that PK (import, channel, startat) {{{0}, {1}, {2}}} already exists",
importTag.TvProgramBroadCastListingImportId, channelSource.TvChannelId, info.StartAt
)
);
// clean up any whitespace on the text fields and replace as nulls where possible
info.ProgramTitle = info.ProgramTitle.Trim();
info.EpisodeTitle = string.IsNullOrWhiteSpace(info.EpisodeTitle) ? null : info.EpisodeTitle.Trim();
info.EpisodeDescription = string.IsNullOrWhiteSpace(info.EpisodeDescription) ? null : info.EpisodeDescription.Trim();
// try and find or generate program information from this listing
TvProgram program = GetOrCreateTvProgramFromListingInfo(info);
// try and find or generate episode information from this listing
TvProgramEpisode episode = GetOrCreateTvProgramEpisodeFromListingInfo(program, info);
// if we don't have an EndDate we can't create a listing
if (info.EndAt == null || info.StartAt == info.EndAt) return null;
// see if there's an existing listing for this channel with these exact times
var existing = FindExistingListing(channelSource, info.StartAt, info.EndAt.Value);
if (existing != null) {
// check if it's the same in every way except the importer
if(
// TvChannelId, StartAt, EndAt, Superceded==false are done by the DB
existing.ProgramTitle == info.ProgramTitle
&& existing.EpisodeTitle == info.EpisodeTitle
&& existing.EpisodeDescription == info.EpisodeDescription
&& existing.TvProgramId == program.TvProgramId
&& existing.TvProgramEpisodeId == episode?.TvProgramEpisodeId
&& existing.Attributes == info.Attributes
) {
// already an exact match, return that instead
return existing;
}
}
// create and add the new listing
var newItem = new TvProgramBroadCastListing {
TvProgramBroadCastListingImportId = importTag.TvProgramBroadCastListingImportId,
TvChannelId = channelSource.TvChannelId,
StartAt = info.StartAt,
EndAt = info.EndAt,
ProgramTitle = info.ProgramTitle,
EpisodeTitle = info.EpisodeTitle,
EpisodeDescription = info.EpisodeDescription,
TvProgramId = program?.TvProgramId,
TvProgramEpisodeId = episode?.TvProgramEpisodeId,
Attributes = info.Attributes,
Superceded = false
};
TvListings.Add(newItem);
// if we had an existing item that wasn't an exact match we mark it as superceded since we've just added a new one
if (existing != null) {
existing.Superceded = true;
TvListings.Update(existing);
}
// return the new item we just made
return newItem;
}
/// <summary>
/// Checks for an exact PK match on local changes only
/// </summary>
/// <param name="importTag"></param>
/// <param name="channelSource"></param>
/// <param name="info"></param>
/// <returns></returns>
protected TvProgramBroadCastListing CheckForViolatedPK(TvProgramBroadCastListingImport importTag, TvChannelListingSource channelSource, IAddTvBroadCastListingInfo info)
{
// in-memory dupe detection to stop duplicate PKs generated by broken feed / import processes
var local =
ChangeTracker.Entries<TvProgramBroadCastListing>()
.SingleOrDefault(x =>
x.Property(y => y.TvProgramBroadCastListingImportId).CurrentValue == importTag.TvProgramBroadCastListingImportId
&& x.Property(y => y.TvChannelId).CurrentValue == channelSource.TvChannelId
&& x.Property(y => y.StartAt).CurrentValue == info.StartAt
);
if (local != null) return local.Entity;
// we don't need to check the database here because this TvProgramBroadCastListingImportId has been created by this thread
return null;
}
/// <summary>
/// Locates an existing listing for this channel at this time that hasn't been superceded
/// </summary>
/// <param name="channelSource"></param>
/// <param name="info"></param>
/// <returns></returns>
protected TvProgramBroadCastListing FindExistingListing(TvChannelListingSource channelSource, DateTime startAt, DateTime endAt)
{
// check the local changetracker first
var local =
ChangeTracker.Entries<TvProgramBroadCastListing>()
.SingleOrDefault(x =>
x.Property(y => y.StartAt).CurrentValue == startAt
&& x.Property(y => y.EndAt).CurrentValue == endAt
&& x.Property(y => y.TvChannelId).CurrentValue == channelSource.TvChannelId
&& x.Property(y => y.Superceded).CurrentValue == false
);
// if we already have a matching PK for this listing just return it and don't add anything
if (local != null) {
return local.Entity;
}
// then the actual database
var remote =
TvListings
.SingleOrDefault(x =>
x.StartAt == startAt
&& x.EndAt == endAt
&& x.TvChannelId == channelSource.TvChannelId
&& x.Superceded == false
);
if (remote != null) {
return remote;
}
return null;
}
/// <summary>
/// Locates or creates a TvChannel and its corresponding TvChannelListingSource
/// </summary>
/// <param name="import"></param>
/// <param name="info"></param>
/// <returns></returns>
public TvChannelListingSource AddTvChannelListingSource(TvProgramBroadCastListingImport import, IAddTvChannelSourceInfo info)
{
// try and find a matching channel by uri
var local = ChangeTracker.Entries<TvChannelListingSource>().SingleOrDefault(x => x.Property(y => y.SourceChannelUri).CurrentValue == info.Uri);
if (local != null) return local.Entity;
// try and find a matching channel by uri
var remote = TvChannelListingSources.SingleOrDefault(x => x.SourceChannelUri == info.Uri);
if (remote != null) return remote;
// add a channel with that displayname
var newChan = new TvChannel {
ChannelName = info.DisplayName.Trim()
};
TvChannels.Add(newChan);
// and a link between it and the source with the info it needs for future requests
var newSource = new TvChannelListingSource {
SourceChannelUri = info.Uri,
SourceChannelName = info.SourceName
};
TvChannelListingSources.Add(newSource);
return newSource;
}
