fusion/packages/engine/src/workflow-graph-task-runner.ts

import type { Settings, TaskDetail, TaskStep, WorkflowDefinition, WorkflowIr, WorkflowStepResult } from "@fusion/core";
import {
  getBuiltinWorkflow,
  isBuiltinWorkflowId,
  parseWorkflowIr,
} from "@fusion/core";

import {
  WORKFLOW_INTERRUPTED_NODE_ABORT_KIND_CONTEXT_KEY,
  WORKFLOW_INTERRUPTED_NODE_ID_CONTEXT_KEY,
  WORKFLOW_NODE_ENGINE_PAUSE_ABORT_KIND,
  WORKFLOW_OPTIONAL_GROUP_CONTEXT_KEY,
  WorkflowGraphExecutor,
  type WorkflowGraphExecutorDeps,
  type WorkflowNodePreparationRequirement,
  type WorkflowNodeAbortKind,
  type WorkflowNodeOutcome,
  type WorkflowTaskProjection,
} from "./workflow-graph-executor.js";
import type {
  CodeNodeRunner,
  ForeachActiveContext,
  ParseStepsHandlerDeps,
  WorkflowNotifyDispatch,
  WorkflowCustomNodeRunner,
  WorkflowLegacySeams,
} from "./workflow-node-handlers.js";
import type {
  WorkflowBranchPersistence,
  WorkflowBranchProgress,
  WorkflowBranchSemaphore,
} from "./workflow-graph-branches.js";
import type { ForeachEnvironment, WorkflowStepInstancePersistence } from "./workflow-graph-foreach.js";
import type { PrNodeDeps } from "./pr-nodes.js";
import type { WorkflowPrimitiveContext, WorkflowRuntimePrimitives } from "./runtime-primitives.js";
// (Both types are also used as values in the side-effect tracking wrappers below.)

/**
 * Terminal disposition of an interpreter-driven task run.
 * - "completed"  — the graph ran to its end node successfully.
 * - "failed"     — the graph ran and terminated on a failure outcome.
 * - "fell-back"  — the interpreter did not (or could not) own this task;
 *                  the caller must run the legacy pipeline instead.
 */
export type WorkflowGraphRunDisposition = "completed" | "failed" | "fell-back";

export interface WorkflowGraphTaskRunResult {
  disposition: WorkflowGraphRunDisposition;
  outcome?: WorkflowNodeOutcome;
  visitedNodeIds: string[];
  /** Why the runner fell back or failed before execution (flag-off, no-selection, workflow-missing, invalid-ir, interpreter-error). */
  reason?: string;
  /** Shared graph context after the run (node outcomes/values). */
  context?: Record<string, unknown>;
  /** Node that was executing when an engine pause/abort interrupted the graph. */
  interruptedNodeId?: string;
  /** Typed abort provenance for the interrupted node; absent for genuine node failures. */
  interruptedAbortKind?: WorkflowNodeAbortKind;
}

/** The minimal store surface the runner needs — keeps tests fake-friendly. */
export interface WorkflowGraphRunnerStore {
  getTaskWorkflowSelection(taskId: string): { workflowId: string; stepIds: string[] } | undefined;
  getWorkflowDefinition(id: string): Promise<WorkflowDefinition | undefined>;
  getTask?(taskId: string): Promise<TaskDetail>;
}

export interface WorkflowGraphTaskRunnerDeps {
  store: WorkflowGraphRunnerStore;
  seams: WorkflowLegacySeams;
  primitives?: WorkflowRuntimePrimitives;
  runCustomNode: WorkflowCustomNodeRunner;
  /** Workflow-node prerequisite fulfillment, invoked after graph-level classification. */
  prepareNodeExecution?: (
    node: WorkflowIr["nodes"][number],
    task: TaskDetail,
    requirement: WorkflowNodePreparationRequirement,
  ) => void | Promise<void>;
  maxRetriesPerNode?: number;
  /** Optional diagnostics hook (audit/log emission). Never throws into the run. */
  onEvent?: (event: { type: "start" | "terminal" | "fallback"; taskId: string; detail: string }) => void;
  /** Top-level graph abort signal used to classify engine pause/abort interruptions at node boundaries. */
  signal?: AbortSignal;
  /** Per-branch run-state persistence + resume (U13). Additive; in-memory without it. */
  branchPersistence?: WorkflowBranchPersistence;
  /** Bounds concurrent branch-node execution (U13); omit when the semaphore is
   *  enforced beneath runCustomNode at the session layer. */
  branchSemaphore?: WorkflowBranchSemaphore;
  /** Live per-branch progress for dashboard badges (U9/U13). */
  onBranchProgress?: (progress: WorkflowBranchProgress) => void;
  /** Step-inversion (KTD-6, U3/U4): per-instance run-state persistence for
   *  foreach instances. Additive; in-memory without it. */
  stepInstancePersistence?: WorkflowStepInstancePersistence;
  /** Step-inversion (KTD-4, U5): RETHINK reset-on-rework hook — invoked before
   *  re-entering step-execute when a rework edge was triggered by an
   *  `outcome:rethink`. Wired to `resetStepToBaseline` in production. */
  onReworkReset?: (active: ForeachActiveContext, reason: string) => void | Promise<void>;
  /** Step-inversion (U12, KTD-12): `parse-steps` node handler deps. Additive;
   *  a workflow with no parse-steps node never invokes it. */
  parseStepsDeps?: ParseStepsHandlerDeps;
  /** Step-inversion (U14, KTD-15): `code` node runner. Additive; a workflow with
   *  no code node never invokes it. */
  runCode?: CodeNodeRunner;
  /** notify node dispatch callback. Additive; absent → notify nodes are skipped. */
  notifyDispatch?: WorkflowNotifyDispatch;
  /** PR-entity nodes (U3): deps for `pr-create`/`pr-respond`/`pr-merge`. Additive;
   *  a workflow with no pr-* node never invokes them; absent → they fail closed. */
  prNodes?: PrNodeDeps;
  /** Step-inversion (KTD-11, U10): worktree-isolation + parallel-scheduling deps.
   *  Additive; a shared-isolation foreach never invokes them. */
  allocateInstanceWorktree?: ForeachEnvironment["allocateInstanceWorktree"];
  resolveIntegrationBase?: ForeachEnvironment["resolveIntegrationBase"];
  integrationGitOps?: ForeachEnvironment["integrationGitOps"];
  integrationProjection?: ForeachEnvironment["integrationProjection"];
  semaphoreAvailability?: ForeachEnvironment["semaphoreAvailability"];
  resumeReconcile?: ForeachEnvironment["resumeReconcile"];
  /** FIX 4 (context gap): task-level log sink for integration-conflict rework. */
  logTaskEntry?: ForeachEnvironment["logTaskEntry"];
  /** Plan U2 (KTD-1/KTD-2): fail-soft sink that upserts an enabled optional-group
   *  node's outcome into `task.workflowStepResults` keyed by node id. Additive;
   *  absent → graph records nothing (disabled groups + unwired stores byte-inert). */
  recordWorkflowStepResult?: (taskId: string, result: WorkflowStepResult) => void | Promise<void>;
  /** Enabled pre-merge optional-step REVISE remediation seam. Additive; absent preserves prior graph traversal. */
  requestPreMergeOptionalStepFix?: WorkflowGraphExecutorDeps["requestPreMergeOptionalStepFix"];
  /** Project node-published task metadata onto the task row for dispatcher/UI. */
  publishTaskProjection?: (taskId: string, patch: WorkflowTaskProjection, source: { nodeId: string; nodeKind: string }) => void | Promise<void>;
  /** @deprecated use publishTaskProjection. */
  publishTouchedFiles?: (taskId: string, files: string[], source: { nodeId: string; nodeKind: string }) => void | Promise<void>;
  /**
   * Step-inversion (KTD-6): the production run id, threaded from the caller so it
   * is the SINGLE source of truth shared with the executor-side persistence deps
   * (`buildParseStepsDeps` / `buildForeachWorktreeDeps` probe and flip rows under
   * the SAME id). When omitted the runner derives `${task.id}:${definition.id}` —
   * the same formula — so a caller that does not thread it keeps prior behavior.
   */
  runId?: string;
}

/**
 * Drives a task's lifecycle from its selected workflow graph. The runner owns
 * SEQUENCING only — seam nodes delegate to the legacy engine implementations
 * (execute/review/merge), custom nodes run via the injected runner. Any
 * interpreter-level error yields a "fell-back" disposition so the caller can
 * run the legacy pipeline; a task is never stranded by interpreter bugs.
 */
export class WorkflowGraphTaskRunner {
  /** Latest per-branch progress, keyed by branchId. Store/dashboard-readable
   *  (U9 badges). Reset at the start of each run; the card never moves during a
   *  parallel window (KTD-11) so this is purely presentational state. */
  private readonly branchProgress = new Map<string, WorkflowBranchProgress>();

  public constructor(private readonly deps: WorkflowGraphTaskRunnerDeps) {}

  /** Snapshot of current per-branch progress (branchId, nodeId, status). */
  public getBranchProgress(): WorkflowBranchProgress[] {
    return [...this.branchProgress.values()];
  }

  private emit(type: "start" | "terminal" | "fallback", taskId: string, detail: string): void {
    try {
      this.deps.onEvent?.({ type, taskId, detail });
    } catch {
      // Diagnostics must never affect the run.
    }
  }

  private fallBack(taskId: string, reason: string): WorkflowGraphTaskRunResult {
    this.emit("fallback", taskId, reason);
    return { disposition: "fell-back", reason, visitedNodeIds: [] };
  }

  private failBeforeSideEffects(taskId: string, reason: string): WorkflowGraphTaskRunResult {
    this.emit("terminal", taskId, reason);
    return { disposition: "failed", outcome: "failure", reason, visitedNodeIds: [] };
  }

  public async run(
    task: TaskDetail,
    settings: Pick<Settings, "experimentalFeatures"> | undefined,
  ): Promise<WorkflowGraphTaskRunResult> {
    let selection: { workflowId: string; stepIds: string[] } | undefined;
    try {
      selection = this.deps.store.getTaskWorkflowSelection(task.id);
    } catch (err) {
      return this.fallBack(task.id, `selection-error: ${err instanceof Error ? err.message : String(err)}`);
    }
    if (!selection) {
      return this.fallBack(task.id, "no-selection");
    }

    let definition: WorkflowDefinition | undefined;
    try {
      definition = isBuiltinWorkflowId(selection.workflowId)
        ? getBuiltinWorkflow(selection.workflowId)
        : await this.deps.store.getWorkflowDefinition(selection.workflowId);
    } catch (err) {
      return this.fallBack(task.id, `workflow-load-error: ${err instanceof Error ? err.message : String(err)}`);
    }
    if (!definition) {
      return this.fallBack(task.id, `workflow-missing: ${selection.workflowId}`);
    }

    let validatedIr: WorkflowIr;
    try {
      /*
      FNXC:WorkflowExecution 2026-06-27-07:40:
      FN-7113 requires the interpreter to re-validate the resolved built-in/custom/plugin workflow IR before any seam, primitive, or custom-node side effects. Invalid persisted or plugin-authored graphs fail closed with an author-facing invalid-ir reason instead of partially running or falling back into the wrong legacy workflow.

      FNXC:WorkflowExecution 2026-07-01-00:00:
      The linear WorkflowStep compiler was removed; the graph interpreter is the sole executor. `parseWorkflowIr` (which validates branching graphs via validateV2) is now the only IR validity gate here — there is no separate linear-compile pre-check to satisfy.
      */
      validatedIr = parseWorkflowIr(definition.ir);
    } catch (err) {
      return this.failBeforeSideEffects(task.id, `invalid-ir: ${err instanceof Error ? err.message : String(err)}`);
    }

    this.emit("start", task.id, definition.id);
    this.branchProgress.clear();

    // Track whether any node side effects ran. Invalid IR is rejected above as
    // failed/terminal before this point; once execution starts, no error can
    // safely fall back to legacy because that could repeat a partial workflow run.
    let sideEffectsRan = false;
    const invoked: string[] = [];
    const seams = this.deps.seams;
    const wrappedSeams: WorkflowLegacySeams = {
      planning: (t, c) => ((sideEffectsRan = true), invoked.push("planning"), seams.planning(t, c)),
      execute: (t, c) => ((sideEffectsRan = true), invoked.push("execute"), seams.execute(t, c)),
      // FNXC:WorkflowExecution 2026-06-25-00:00: U4 (KTD-2) — the `workflow-step`
      // seam wrapper was removed; workflow gates run as graph optional-group / gate
      // nodes that record into task.workflowStepResults (U2).
      review: (t, c) => ((sideEffectsRan = true), invoked.push("review"), seams.review(t, c)),
      merge: (t, c) => ((sideEffectsRan = true), invoked.push("merge"), seams.merge(t, c)),
      schedule: (t, c) => ((sideEffectsRan = true), invoked.push("schedule"), seams.schedule(t, c)),
      // Step-inversion seams (U3/U5) — forwarded only when wired so a workflow
      // without foreach/step-review keeps the omitted-optional posture.
      ...(seams.stepExecute
        ? { stepExecute: (t, c) => ((sideEffectsRan = true), invoked.push("step-execute"), seams.stepExecute!(t, c)) }
        : {}),
      ...(seams.stepReview
        ? { stepReview: (t, c, cfg) => ((sideEffectsRan = true), invoked.push("step-review"), seams.stepReview!(t, c, cfg)) }
        : {}),
    };
    const wrappedRunCustomNode: WorkflowCustomNodeRunner = (node, t, c) => {
      if (!this.deps.primitives && (t as { executionMode?: unknown }).executionMode === "fast") {
        /*
        FNXC:WorkflowFastMode 2026-07-01-00:00:
        Raw WorkflowGraphTaskRunner tests and compatibility callers can run without the TaskExecutor custom-node service that normally owns fast-mode skips. In that fallback posture, skip executable custom prompt/script/gate nodes at the runner boundary so default-on optional review groups do not fail a fast-mode built-in workflow before legacy seams run.

        FNXC:WorkflowFastMode 2026-07-01-00:00:
        Explicitly selected optional-group bodies carry workflow:optionalGroupActive and must still execute in fast mode because selecting the optional workflow step is operator intent, not default built-in review behavior.

        FNXC:WorkflowFastMode 2026-07-01-00:00:
        Skill executor nodes use `config.skillName`, not `config.skill`; include that field in executable-node detection so raw fast-mode compatibility skips skill prompts the same way it skips prompt/script nodes.
        */
        const hasExecutableConfig =
          typeof node.config?.prompt === "string" ||
          typeof node.config?.scriptName === "string" ||
          typeof node.config?.skillName === "string";
        const isExplicitOptionalGroupNode = typeof c[WORKFLOW_OPTIONAL_GROUP_CONTEXT_KEY] === "string";
        if (hasExecutableConfig && !isExplicitOptionalGroupNode) {
          return Promise.resolve({ outcome: "success", value: "fast-mode-skipped" });
        }
      }
      sideEffectsRan = true;
      invoked.push(node.id);
      return this.deps.runCustomNode(node, t, c);
    };
    const wrappedPrimitives = this.deps.primitives
      ? new Proxy(this.deps.primitives, {
          get: (target, prop, receiver) => {
            const value = Reflect.get(target, prop, receiver);
            if (typeof value !== "function") return value;
            return (...args: unknown[]) => {
              sideEffectsRan = true;
              const ctx = args[0] as WorkflowPrimitiveContext | undefined;
              invoked.push(ctx?.node?.node?.id ?? String(prop));
              return value.apply(target, args);
            };
          },
        }) as WorkflowRuntimePrimitives
      : undefined;

    try {
      const fastModeFallbackParseSteps: ParseStepsHandlerDeps | undefined =
        !this.deps.primitives &&
        !this.deps.parseStepsDeps &&
        (task as { executionMode?: unknown }).executionMode === "fast"
          ? {
              /*
              FNXC:WorkflowFastMode 2026-07-01-00:00:
              Raw legacy-seam graph runs do not have TaskExecutor's parse-steps dependencies. For fast-mode compatibility, parse the task prompt from memory and project the parsed steps back onto the runner task so the stepwise built-in can reach the seam-backed lifecycle suffix without a store-backed projection.

              FNXC:WorkflowFastMode 2026-07-01-00:00:
              Parse-step projection must write through the task object supplied by the graph node context, not a closed-over outer run argument. Raw fallback callers usually pass the same object today, but the dependency contract belongs to ParseStepsNodeRunner's write target.
              */
              readArtifact: async (_task, key) => (key === "PROMPT.md" ? task.prompt : undefined),
              writeSteps: async (target, steps: TaskStep[]) => {
                target.steps = steps;
              },
            }
          : undefined;

      const executor = new WorkflowGraphExecutor({
        seams: wrappedSeams,
        primitives: wrappedPrimitives,
        runCustomNode: wrappedRunCustomNode,
        prepareNodeExecution: this.deps.prepareNodeExecution,
        maxRetriesPerNode: this.deps.maxRetriesPerNode,
        branchPersistence: this.deps.branchPersistence,
        branchSemaphore: this.deps.branchSemaphore,
        stepInstancePersistence: this.deps.stepInstancePersistence,
        onReworkReset: this.deps.onReworkReset,
        parseStepsDeps: this.deps.parseStepsDeps ?? fastModeFallbackParseSteps,
        runCode: this.deps.runCode,
        notifyDispatch: this.deps.notifyDispatch,
        prNodes: this.deps.prNodes,
        /*
        FNXC:WorkflowResume 2026-06-29-08:49:
        Production graph runs must fetch live task steps during foreach replay. The runner is the workflow boundary that has store access, so it supplies the fresh projection seam instead of making executor self-healing guess after a stale step node fails.
        */
        getTaskSteps: async (stepTask) => (await this.deps.store.getTask?.(stepTask.id))?.steps ?? stepTask.steps ?? [],
        // Step-inversion (KTD-11, U10): worktree isolation + parallel scheduling.
        allocateInstanceWorktree: this.deps.allocateInstanceWorktree,
        resolveIntegrationBase: this.deps.resolveIntegrationBase,
        integrationGitOps: this.deps.integrationGitOps,
        integrationProjection: this.deps.integrationProjection,
        semaphoreAvailability: this.deps.semaphoreAvailability,
        resumeReconcile: this.deps.resumeReconcile,
        logTaskEntry: this.deps.logTaskEntry,
        recordWorkflowStepResult: this.deps.recordWorkflowStepResult,
        requestPreMergeOptionalStepFix: this.deps.requestPreMergeOptionalStepFix,
        publishTaskProjection: this.deps.publishTaskProjection,
        signal: this.deps.signal,
        publishTouchedFiles: this.deps.publishTouchedFiles,
        // Single source of truth (KTD-6): prefer the caller-threaded run id so the
        // executor's persistence deps probe/flip rows under the SAME id; fall back
        // to the canonical derivation when unthreaded.
        runId: this.deps.runId ?? `${task.id}:${definition.id}`,
        onBranchProgress: (progress) => {
          this.branchProgress.set(progress.branchId, progress);
          try {
            this.deps.onBranchProgress?.(progress);
          } catch {
            // Progress reporting must never affect the run.
          }
        },
      });
      const result = await executor.run(task, settings, validatedIr);
      if (!result.executed) {
        return this.fallBack(task.id, "not-executed");
      }
      const disposition: WorkflowGraphRunDisposition = result.outcome === "success" ? "completed" : "failed";
      this.emit("terminal", task.id, `${definition.id}:${disposition}`);
      const interruptedNodeId = typeof result.context[WORKFLOW_INTERRUPTED_NODE_ID_CONTEXT_KEY] === "string"
        ? result.context[WORKFLOW_INTERRUPTED_NODE_ID_CONTEXT_KEY]
        : undefined;
      const interruptedAbortKind = result.context[WORKFLOW_INTERRUPTED_NODE_ABORT_KIND_CONTEXT_KEY] === WORKFLOW_NODE_ENGINE_PAUSE_ABORT_KIND
        ? WORKFLOW_NODE_ENGINE_PAUSE_ABORT_KIND
        : undefined;
      return {
        disposition,
        outcome: result.outcome,
        visitedNodeIds: result.visitedNodeIds,
        context: result.context,
        interruptedNodeId,
        interruptedAbortKind,
      };
    } catch (err) {
      const reason = `interpreter-error: ${err instanceof Error ? err.message : String(err)}`;
      if (sideEffectsRan) {
        // Too late to fall back — the caller parks the task for human review.
        this.emit("terminal", task.id, `${definition.id}:failed (${reason})`);
        return { disposition: "failed", outcome: "failure", reason, visitedNodeIds: invoked };
      }
      this.emit("fallback", task.id, reason);
      return { disposition: "fell-back", reason, visitedNodeIds: invoked };
    }
  }
}