/// Routes and resolves an incoming support ticket using NLP analysis and conditional escalation.
///
/// A ticket is received and its intent classified; sentiment analysis runs in an
/// embedded sub-graph to assign a priority score.  High-priority tickets are handed
/// off to an escalation sub-graph; all other priorities receive an auto-generated reply.
/// A branch ensures that exactly one path executes.
///
/// Key DSL concepts demonstrated:
///   subgraph("name")   — embeds a named sub-graph; inputs are injected into the
///                        sub-graph's context; the last node's output becomes this
///                        node's result
///   branch on <expr>   — exactly one target executes; the other is skipped
///   depends_on         — fan-in: determinePriority waits for both sentimentAnalysis
///                        and classifyIntent to complete before running
///   timeout            — per-node cancellation deadline
///
/// Context variables:
///   ctx.ticketId   — unique identifier for the incoming ticket
///   ctx.customerId — customer who submitted the ticket
///   ctx.channel    — channel through which the ticket arrived (e.g. email, chat)
///   ctx.message    — raw message content of the ticket
graph smartTicketHandling {

  /// Receives and registers the incoming support ticket
  node receiveTicket : ReceiveTicketOperator {
    input {
      ticketId   = ctx.ticketId
      customerId = ctx.customerId
      channel    = ctx.channel
      message    = ctx.message
    }
    timeout = 3s
  }

  /// Classifies the intent of the support ticket using NLP
  node classifyIntent : ClassifyIntentOperator {
    depends_on = [receiveTicket]
    input {
      ticketId = receiveTicket.output.ticketId
      message  = receiveTicket.output.message
    }
    timeout = 5s
  }

  /// Runs sentiment analysis sub-graph: textPreprocessing → nlpClassification → sentimentScoring → priorityAssignment
  node sentimentAnalysis : subgraph("sentiment-analysis") {
    depends_on = [classifyIntent]
    input {
      ticketId = receiveTicket.output.ticketId
      message  = receiveTicket.output.message
      intent   = classifyIntent.output.intent
    }
    timeout = 30s
  }

  /// Determines ticket priority from sentiment analysis and intent classification
  node determinePriority : DeterminePriorityOperator {
    depends_on = [sentimentAnalysis, classifyIntent]
    input {
      ticketId  = classifyIntent.output.ticketId
      intent    = classifyIntent.output.intent
      sentiment = sentimentAnalysis.output.priorityAssignment
    }
  }

  /// Runs escalation sub-graph for high-priority tickets: supervisorNotification → slaCheck → escalationRouting → customerCallbackSchedule
  node escalationWorkflow : subgraph("escalation-workflow") {
    depends_on = [determinePriority]
    input {
      ticketId   = determinePriority.output.ticketId
      customerId = ctx.customerId
      priority   = determinePriority.output.priority
      reason     = determinePriority.output.reason
    }
    timeout = 30s
  }

  /// Generates the customer reply for medium/low priority tickets
  node generateReply : GenerateReplyOperator {
    depends_on = [determinePriority]
    input {
      ticketId   = determinePriority.output.ticketId
      customerId = ctx.customerId
      intent     = classifyIntent.output.intent
      priority   = determinePriority.output.priority
      resolution = determinePriority.output.reason
    }
  }

  /// branch on determinePriority.output.priority — high-priority tickets go to
  /// escalationWorkflow; all other priorities are handled by generateReply; exactly
  /// one path executes and the other node is skipped
  branch on determinePriority.output.priority {
    "high"    -> escalationWorkflow
    otherwise -> generateReply
  }
}