Workflow Engine

Workflow = (States, Transitions, Context, Reconciler)

Where:
- States: finite set of named states
- Transitions: allowed state changes, each with a single action
- Context: immutable input + mutable progress data
- Reconciler: function that determines current state from on-chain truth

interface WorkflowRecord {
  // === Identity ===
  id: string;           // UUID
  type: WorkflowType;   // "WorkSubmission" | "ScoreSubmission" | "CloseEpoch"
  created_at: number;
  updated_at: number;
  
  // === State ===
  state: WorkflowState; // PENDING | RUNNING | COMPLETED | FAILED | STALLED
  step: string;         // Current step (e.g., "UPLOAD_EVIDENCE")
  step_attempts: number;
  
  // === Immutable Context ===
  input: {
    studio_address: string;
    epoch: number;
    signer_address: string;
    data_hash: string;
    // ... workflow-specific fields
  };
  
  // === Mutable Progress ===
  progress: {
    arweave_tx_id?: string;
    arweave_confirmed?: boolean;
    onchain_tx_hash?: string;
    onchain_confirmed?: boolean;
    // ... step-specific progress
  };
  
  // === Failure Info ===
  error?: {
    step: string;
    message: string;
    code: string;
    recoverable: boolean;
  };
}

function reconcile(workflow: WorkflowRecord): WorkflowRecord {
  // Step 1: Query on-chain state
  const onchainState = queryOnchainState(workflow.input);
  
  // Step 2: Compare and determine true state
  if (onchainState.workSubmitted && workflow.step < "COMPLETED") {
    // Work already on-chain, workflow should be complete
    return workflow.transitionTo("COMPLETED");
  }
  
  // Step 3: Check pending tx status
  if (workflow.progress.onchain_tx_hash) {
    const txStatus = getTxReceipt(workflow.progress.onchain_tx_hash);
    
    if (txStatus === "confirmed") {
      return workflow.advanceStep();
    }
    if (txStatus === "reverted") {
      return workflow.fail({ reason: "tx_reverted" });
    }
    if (txStatus === "not_found") {
      // Tx was never mined, safe to retry
      return workflow.retryStep();
    }
  }
  
  // Step 4: No changes needed
  return workflow;
}

const RetryPolicy = {
  max_attempts: 5,
  initial_delay_ms: 1000,
  max_delay_ms: 60000,
  backoff_multiplier: 2.0,
  jitter: true
};