engine

type CircuitBreakerConfig struct {
	// FailureThreshold is the number of consecutive failures before opening the circuit.
	FailureThreshold int
	// Cooldown is how long the circuit stays open before transitioning to half-open.
	Cooldown time.Duration
	// HalfOpenMax is the number of test requests allowed in half-open state.
	HalfOpenMax int
}

type CircuitBreakerRegistry struct {
	// contains filtered or unexported fields
}

type CircuitState int

type DAG struct {
	Steps   map[string]*schema.StepDefinition // step ID → definition
	Edges   map[string][]string               // step ID → dependencies (depends_on)
	Reverse map[string][]string               // step ID → dependents (who depends on me)
	Sorted  []string                          // topological order
	Roots   []string                          // steps with no dependencies
	Levels  [][]string                        // parallel execution levels
}

type ErrorHandlerResult struct {
	// Handled is true if the error was handled (ignore, fallback).
	Handled bool
	// FallbackStepID is set when the handler triggers a fallback step.
	FallbackStepID string
	// ShouldFailWorkflow is true when the handler explicitly requests workflow failure.
	ShouldFailWorkflow bool
}

type EventAppender interface {
	AppendEvent(ctx context.Context, event *store.Event) error
}

type EventLogger interface {
	EventAppender
	GetEvents(ctx context.Context, workflowID string, since int64) ([]*store.Event, error)
	GetEventsByType(ctx context.Context, eventType string, filter store.EventFilter) ([]*store.Event, error)
	ReplayEvents(ctx context.Context, workflowID string) (map[string]*store.StepState, error)
}

type ExecutionResult struct {
	WorkflowID  string                 `json:"workflow_id"`
	Status      schema.WorkflowStatus  `json:"status"`
	Output      json.RawMessage        `json:"output,omitempty"`
	Error       *schema.OpcodeError    `json:"error,omitempty"`
	StartedAt   time.Time              `json:"started_at"`
	CompletedAt *time.Time             `json:"completed_at,omitempty"`
	Steps       map[string]*StepResult `json:"steps,omitempty"`
}

type Executor interface {
	// Run starts a new workflow from a persisted Workflow record.
	Run(ctx context.Context, wf *store.Workflow, params map[string]any) (*ExecutionResult, error)

	// Resume continues a suspended or interrupted workflow from its last checkpoint.
	// Replays events to rebuild state, then continues from first pending step.
	// Reasoning nodes are NEVER replayed — stored decisions are injected.
	Resume(ctx context.Context, workflowID string) (*ExecutionResult, error)

	// Signal delivers an agent message to a suspended workflow.
	Signal(ctx context.Context, workflowID string, signal schema.Signal) error

	// Extend mutates the DAG of a running workflow in-flight.
	Extend(ctx context.Context, workflowID string, mutation schema.DAGMutation) error

	// Cancel terminates a workflow with a reason, cascading to active steps.
	Cancel(ctx context.Context, workflowID string, reason string) error

	// Status returns the current state of a workflow.
	Status(ctx context.Context, workflowID string) (*WorkflowStatus, error)
}

type ExecutorConfig struct {
	PoolSize       int                   // max concurrent step goroutines
	CircuitBreaker *CircuitBreakerConfig // circuit breaker config (nil = defaults)
}

type PoolMetrics struct {
	Active    int64 `json:"active"`
	Completed int64 `json:"completed"`
	Failed    int64 `json:"failed"`
	Panics    int64 `json:"panics"`
}

type StepFSM struct {
	// contains filtered or unexported fields
}

type StepResult struct {
	StepID     string              `json:"step_id"`
	Status     schema.StepStatus   `json:"status"`
	Output     json.RawMessage     `json:"output,omitempty"`
	Error      *schema.OpcodeError `json:"error,omitempty"`
	DurationMs int64               `json:"duration_ms,omitempty"`
}

type TransitionHook func(from, to string) error

type WorkerPool struct {
	// contains filtered or unexported fields
}

type WorkflowFSM struct {
	// contains filtered or unexported fields
}

type WorkflowStatus struct {
	WorkflowID       string                      `json:"workflow_id"`
	Status           schema.WorkflowStatus       `json:"status"`
	Steps            map[string]*store.StepState `json:"steps,omitempty"`
	PendingDecisions []*store.PendingDecision    `json:"pending_decisions,omitempty"`
	Context          *store.WorkflowContext      `json:"context,omitempty"`
	Events           []*store.Event              `json:"events,omitempty"`
}