vj-events

Schedule
 - UUID
 - presentation_id
 - interrupted
 - interruption_id
 - current_core_event_uuid

ScheduleEvent - this is all about assigning a UUID to each change of state
 - schedule_id (note ~ 10 events per schedule is the scaling norm)
 - UUID
 - created_at
 - starts_at (nil for ScheduleInterruption)
 - document_layout (needed to support VAST stuff)
 - document_content
 
 ScheduleInterruption
 - schedule_id
 - description
 - document_layout (needed to support VAST stuff)
 - document_content

ScheduleSource - supports the emergency switching of sources (allows ur admin 2 pre-populate da dataz)
 - schedule_id
 - rank (sort order)
 - description
 - url (assumed to be RTMP for now - should check format on this basis)
 - tag
 
Installation

 
 Other stack changes
 ------------------------------
 
 <iframe />-based embed code for events (for now, until player v4 and the Coming of the Comet)
 
FUTURE: optional SEs (would need to wrap up optional UUID + last known compulsory UUID to ensure consistent state) - no concrete use case as yet

FUTURE: key-value store with expiry to replace lookup of Schedule.{current_uuid}

FUTURE: due-dilligence with regard to timezones - for now need to ensure DB is in correct TZ

Deployment:

- DB server with schema above
- each app server runs a cronjob to update the set of statically compiled schedule_UUID.js files for use by nginx - NOTE: limitation of ~30s lead time on any SE (including interruptions) - make business aware
- admin app (also available from any app server) allows for schedule event creation and interrupt creation
-- presents the timeline of scheduled content
-- presents a pool of interruptions
-- adding an interruption creates a ScheduleInterruption
-- hitting the 'use now' button for an interruption (or whatever) creates a ScheduleEvent with a nil starts_at _and_ populates schedule.interruption_id
-- removing the interruption sets the schedule.interruption_id to nil

Cronjob - the first - all app servers
 - for each schedule
 - current event = schedule.interrupted? ? ScheduleEvent.last (:starts_at => nil) : ScheduleEvent.first(:starts_at.gte => 'NOW()', :order => [:starts_at])
 -- double-check that above query does will not return anything with starts_at == NULL

Cronjob - the second - batch server
 - for each schedule
 -- update the relevant presentation on core
 -- update the schedule.current_core_event_uuid