/**
 * 自持流程运行时 —— `FlowRuntime` 端口的默认实现(M5-1 切面的甲方)。
 *
 * 确定性状态机 + `sys.node_instance` 持久:按结构调度节点、条件出边选路、
 * 失败走向、审批裁决、状态聚合。**零 LLM、零临场**(编码规范 §5.3;语义出处 OS 03 / 04)。
 *
 * 本文件由 process-service 整体搬迁而来(2026-07-28,行为零变化)——
 * 从此运行时是可替换的:Mastra 编译产物(workflow-compiler)将是同一端口的第二实现,
 * 八例端到端就是两个实现的等价性护栏。定义生命周期(保存/激活/校验)不在此内,
 * 那是「编译哪一份定义」的事,归 usecase。
 */
import type { ProcessNode, ProcessPackage, StaffId, TerminalState, WorkflowState } from '@contracts';
import { PositionVacantError } from '../../contract.ts';
import type {
  ApprovalGateway,
  Clock,
  FlowEventPublisher,
  FlowRuntime,
  OrgDirectory,
  ProcessStore,
  ReceiptNotifier,
  Sfeel,
  TaskGateway,
  WorkflowRecord,
} from '../../port.ts';
import { aggregateWorkflowState, isDigested, nextInstanceNumber, resolveOwner } from '../domain/owner-resolution.ts';
import type { NodeInstance } from '../domain/owner-resolution.ts';
import { assemble, dispatchOf, rejectRouteOf, selectEdges, startNodeOf } from '../domain/routing.ts';

export type SelfHostedRuntimeDeps = {
  readonly store: ProcessStore;
  readonly org: OrgDirectory;
  readonly tasks: TaskGateway;
  readonly approvals: ApprovalGateway;
  readonly sfeel: Sfeel;
  readonly events: FlowEventPublisher;
  readonly receipts: ReceiptNotifier;
  readonly clock: Clock;
};

export function createSelfHostedRuntime(deps: SelfHostedRuntimeDeps): FlowRuntime {
  async function requirePackage(id: string, version?: number): Promise<ProcessPackage> {
    const pkg = await deps.store.getPackage(id, version);
    if (pkg === undefined) throw new Error(`流程包不存在:${id}`);
    return pkg;
  }

  async function requireWorkflow(id: string): Promise<WorkflowRecord> {
    const record = await deps.store.getWorkflow(id);
    if (record === undefined) throw new Error(`工作流不存在:${id}`);
    return record;
  }

  function scopeOf(record: WorkflowRecord) {
    return { ports: record.ports, vars: record.vars, initiation: record.initiation };
  }

  /** 起一个节点:活动 → 起单;审批点 → 卡工位;终点 → 收束 */
  async function enter(
    record: WorkflowRecord,
    pkg: ProcessPackage,
    node: ProcessNode,
    payload: Record<string, unknown>,
  ): Promise<void> {
    const dispatch = dispatchOf(node, payload);

    if (dispatch === undefined) {
      // 只剩起点会走到这(结构件无调度):被指为目标时直通,不建实例
      await advanceFrom(record, pkg, node.id, payload);
      return;
    }

    const instances = await deps.store.listInstances(record.id);
    const instance = nextInstanceNumber(instances, node.id);

    if (dispatch.kind === 'finish') {
      await deps.store.insertInstance(record.id, {
        nodeId: node.id,
        instance,
        running: false,
        waiting: false,
        activated: true,
        terminal: 'released',
      });
      const finished = await deps.store.updateWorkflow(record.id, {
        state: 'completed',
        finishedAt: deps.clock.now().toISOString(),
        ports: { ...record.ports, __output: payload },
      });
      await deps.events.publish({ workflowId: record.id, kind: 'workflow-completed', detail: payload });
      // 凡单必有来源 —— 登记人收消息回执
      if (record.source.by !== undefined) {
        await deps.receipts.notify({
          to: record.source.by as StaffId,
          workflowId: record.id,
          subject: record.subject,
          state: finished.state,
        });
      }
      return;
    }

    /*
     * 谁来干:**编排不带岗位**(2026-07-28 第五轮,活动点与审批点同一口径)——
     * 负责人是**运营时分配**的:工作流绑了员工组就按组轮值(组员并集里最闲者先),
     * 没绑组就全员轮值;staffId 稳定排序保证同输入必同结果。
     * 分派结果记在节点实例上(assignee)—— 审批箱、链条、治理列表都按它认人。
     */
    const seen = new Map<string, { staffId: string; name: string; openTasks: number }>();
    for (const position of await deps.org.positions()) {
      for (const c of await deps.org.candidates(position)) if (!seen.has(c.staffId)) seen.set(c.staffId, c);
    }
    const everyone = [...seen.values()];
    const group = new Set(Object.values(record.workGroup ?? {}));
    const groupPool = everyone.filter((c) => group.has(c.staffId));
    // 组员全不在岗时退回全员 —— 单不能没人接
    const pool = groupPool.length > 0 ? groupPool : everyone;
    const spec = { position: groupPool.length > 0 ? '(员工组轮值)' : '(全员轮值)', strategy: 'sole' as const };
    const resolution = resolveOwner(spec, { candidates: pool });
    if (resolution.kind === 'vacant') throw new PositionVacantError(spec.position);

    await deps.events.publish({
      workflowId: record.id,
      kind: 'owner-resolved',
      detail: { nodeId: node.id, position: spec.position, staffId: resolution.staffId, by: resolution.by, rationale: resolution.rationale },
    });

    if (dispatch.kind === 'start-task') {
      const task = await deps.tasks.start({
        activityId: dispatch.node.activityId,
        ownerId: resolution.staffId as StaffId,
        title: dispatch.node.label,
        workflowId: record.id,
        nodeId: node.id,
        data: payload,
        ...(dispatch.node.message === undefined ? {} : { message: dispatch.node.message }),
      });
      await deps.store.insertInstance(record.id, {
        nodeId: node.id,
        instance,
        running: true,
        waiting: false,
        activated: true,
        taskId: task.id,
        assigneeId: resolution.staffId,
      });
      await deps.events.publish({ workflowId: record.id, kind: 'task-started', detail: { nodeId: node.id, taskId: task.id } });
      return;
    }

    const approval = await deps.approvals.raise({
      workflowId: record.id,
      nodeId: node.id,
      approverId: resolution.staffId as StaffId,
      subject: dispatch.node.label,
      basis: Object.entries(payload).map(([k, v]) => ({ k, v: String(v) })),
    });
    await deps.store.insertInstance(record.id, {
      nodeId: node.id,
      instance,
      running: false,
      waiting: true,
      activated: true,
      approvalId: approval.id,
      assigneeId: resolution.staffId,
    });
    await deps.events.publish({ workflowId: record.id, kind: 'approval-raised', detail: { nodeId: node.id, approvalId: approval.id } });
  }

  /**
   * 从某节点继续流转:选边 → 装配 → 进下一节点。
   *
   * 返回**有没有真的推出去**。审批点的驳回要用它:图上显式画了驳回出边就走边,
   * 没画的包才退回 `reject` 声明 —— 调用方据此判断,不必自己再选一遍边。
   *
   * `quiet` 为真时不发 `route-dead-end`:那种「先试边、不成再退回声明」的探路
   * 一条边都没中是**正常分支**,不是死路,报出来就是假警。
   */
  async function advanceFrom(
    record: WorkflowRecord,
    pkg: ProcessPackage,
    fromNodeId: string,
    payload: Record<string, unknown>,
    quiet = false,
  ): Promise<boolean> {
    const scope = scopeOf(record);
    const flat = { ...scope.initiation, ...scope.vars, ...payload };
    const edges = selectEdges(pkg, fromNodeId, flat, deps.sfeel.condition);

    /*
     * 一条边都没选中,而这个节点确实有出边 —— 流到此为止,再没有谁会来推它。
     * 这是**死路**,不是终点。条件全不成立最容易碰上(实测:A1 的出口少了两枚去向旗,
     * 两条条件出边一条都选不中,流无声停在 A1)。
     *
     * 状态聚合已经会把它报成 `abnormal`(没到终点就不算完成),但那只说「有问题」、
     * 不说「哪儿有问题」。这里留一条可诊断的痕:哪个节点、出边各自的条件、判据里到底有哪些键。
     * 只记键名不记值 —— 诊断够用,载荷不进事件明文。
     */
    if (edges.length === 0) {
      const outgoing = pkg.edges.filter((e) => e.from === fromNodeId);
      if (outgoing.length > 0 && !quiet) {
        await deps.events.publish({
          workflowId: record.id,
          kind: 'route-dead-end',
          detail: {
            nodeId: fromNodeId,
            edges: outgoing.map((e) => ({ id: e.id, to: e.to, condition: e.condition ?? '(无条件)' })),
            availableKeys: Object.keys(flat).sort(),
          },
        });
      }
    }

    for (const edge of edges) {
      const target = pkg.nodes.find((n) => n.id === edge.to);
      if (target === undefined) continue;

      /*
       * 多入边即异或汇合:上游互斥,只会来一条 —— **没有「等回齐」这回事**。
       * (等待逻辑随网关一起摘除;AND 并行待「并行组」声明时再带自己的汇合语义。)
       * 节点只收**装配后的**载荷:活动与审批点都有契约,不被上游多余字段污染;
       * 判据要用的隐性上下文(审批 verdict、放行选口 outcome)由系统注入判据作用域,不走映射。
       */
      const arriving = assemble(edge, { ...scope, ports: { ...scope.ports, [fromNodeId]: payload } }, deps.sfeel.expression);
      try {
        await enter(record, pkg, target, arriving);
      } catch (error) {
        /*
         * 一条分支起不来,不该把整条终态上报连坐掀翻 —— 那会让**上游任务的终态也报不上去**,
         * 流停在原地且一行日志都没有。这里把它记成工作流事件并落一个未激活的实例:
         * 其余分支照走,这一支在治理台「需处置」里现形,等人处置。
         */
        const detail = error instanceof Error ? error.message : String(error);
        await deps.events.publish({
          workflowId: record.id,
          kind: 'node-start-failed',
          detail: { nodeId: target.id, from: fromNodeId, error: detail },
        });
        const instances = await deps.store.listInstances(record.id);
        await deps.store.insertInstance(record.id, {
          nodeId: target.id,
          instance: nextInstanceNumber(instances, target.id),
          running: false,
          waiting: true,
          activated: true,
          terminal: 'blocked',
        });
      }
    }
    return edges.length > 0;
  }

  /** 工作流状态是聚合投影 —— 每次变动后重算 */
  async function refreshState(workflowId: string): Promise<WorkflowState> {
    const record = await requireWorkflow(workflowId);
    if (record.state === 'terminated') return 'terminated';
    const instances = await deps.store.listInstances(workflowId);
    // 「完成」凭到过终点,不凭没有在跑的了 —— 所以要把包的终点节点交给聚合
    const pkg = await deps.store.getPackage(record.packageId, record.packageVersion);
    const endNodeIds = (pkg?.nodes ?? []).filter((n) => n.kind === 'end').map((n) => n.id);
    const state = aggregateWorkflowState(instances as NodeInstance[], false, endNodeIds);
    if (state !== record.state) {
      await deps.store.updateWorkflow(workflowId, {
        state,
        ...(state === 'completed' ? { finishedAt: deps.clock.now().toISOString() } : {}),
      });
    }
    return state;
  }

  /** 失败走向四选一:终止流(默认)/ 改道 / 升审批 / 容忍 */
  async function applyFailure(
    workflowId: string,
    nodeId: string,
    instance: number,
    node: Extract<ProcessNode, { kind: 'activity' }>,
    terminal: TerminalState,
  ): Promise<WorkflowState> {
    const record = await requireWorkflow(workflowId);
    const pkg = await requirePackage(record.packageId, record.packageVersion);
    const disposition = node.failure;
    const digested = isDigested(disposition.kind);

    await deps.store.updateInstance(workflowId, nodeId, instance, { failureDigested: digested });
    await deps.events.publish({
      workflowId,
      kind: 'failure-disposition',
      detail: { nodeId, terminal, disposition: disposition.kind },
    });

    if (disposition.kind === 'reroute') {
      const edge = pkg.edges.find((e) => e.id === disposition.edgeId);
      const target = edge === undefined ? undefined : pkg.nodes.find((n) => n.id === edge.to);
      if (edge !== undefined && target !== undefined) {
        // 失败载荷 = 终态、原因码与说明
        const payload = assemble(edge, scopeOf(record), deps.sfeel.expression);
        await enter(record, pkg, target, { ...payload, __terminal: terminal });
      }
    }

    if (disposition.kind === 'escalate') {
      const target = pkg.nodes.find((n) => n.id === disposition.approvalNodeId);
      if (target !== undefined) await enter(record, pkg, target, { __terminal: terminal, __from: nodeId });
    }

    if (disposition.kind === 'tolerate') {
      /*
       * 容忍 = 这条支线的失败被吸收,**流继续往下走**。
       * 光把实例标成「已消化」而不往下推,这条线就断在这儿 —— 下游谁也不会再被叫起。
       * 载荷为空 —— 容忍分支本就没有产出,下游的必填映射不得依赖它(闭合校验已拦)。
       */
      await advanceFrom(record, pkg, nodeId, {});
    }

    return refreshState(workflowId);
  }

  return {
    /** 起单后进入起点:调用方(usecase)负责起单前置(校验/建单/留痕),这里只管走 */
    async begin(record, pkg) {
      const start = startNodeOf(pkg);
      if (start !== undefined) await advanceFrom(record, pkg, start.id, record.initiation);
    },

    /** 任务终态到达:按终态决定继续流转还是走失败走向 */
    async onTaskTerminal(taskId, terminal, ports) {
      const located = await deps.store.findInstanceByTask(taskId);
      if (located === undefined) return undefined;

      const record = await requireWorkflow(located.workflowId);
      const pkg = await requirePackage(record.packageId, record.packageVersion);
      const node = pkg.nodes.find((n) => n.id === located.nodeId);

      await deps.store.updateInstance(record.id, located.nodeId, located.instance, {
        running: false,
        waiting: false,
        terminal,
      });
      await deps.events.publish({ workflowId: record.id, kind: 'task-terminal', detail: { taskId, terminal } });

      const merged = await deps.store.updateWorkflow(record.id, { ports: { ...record.ports, ...ports } });

      if (terminal === 'released') {
        // 落地收敛后才发射输出口 —— 下游只见落地完成的任务。
        // 各口载荷合并成一份路由作用域:只取第一口,活动没有必交付口时就什么都拿不到。
        const payload: Record<string, unknown> = Object.assign({}, ...Object.values(ports));
        await advanceFrom(merged, pkg, located.nodeId, payload);
      } else if (node?.kind === 'activity') {
        // 非完成终态触发**声明的失败走向**;流程层不自动重试
        await applyFailure(record.id, located.nodeId, located.instance, node, terminal);
      }

      return refreshState(record.id);
    },

    applyFailure,

    /** 审批裁决:通过继续流转;驳回按**声明的走向**回指定节点重开新实例 */
    async onApprovalVerdict(workflowId, nodeId, verdict, payload) {
      const record = await requireWorkflow(workflowId);
      const pkg = await requirePackage(record.packageId, record.packageVersion);
      const node = pkg.nodes.find((n) => n.id === nodeId);
      if (node?.kind !== 'approval') throw new Error(`节点不是审批点:${nodeId}`);

      const instances = await deps.store.listInstances(workflowId);
      const current = instances.filter((i) => i.nodeId === nodeId).at(-1);
      if (current !== undefined) {
        await deps.store.updateInstance(workflowId, nodeId, current.instance, {
          waiting: false,
          terminal: 'released',
        });
      }
      await deps.events.publish({ workflowId, kind: 'approval-verdict', detail: { nodeId, verdict } });

      /*
       * **裁决进载荷**:审批点的两个去向就是它自己的两条条件出边,
       * 条件判的正是这个字段(`verdict = "pass"` / `verdict = "reject"`)。
       * 系统注入判据作用域,不走映射、不进设计者编排面。
       */
      const carried = { ...payload, verdict };

      if (verdict === 'pass') {
        await advanceFrom(record, pkg, nodeId, carried);
      } else {
        /*
         * 驳回:**先看图**。图上显式画了驳回出边就走边 —— 编排即定契约,图是真相。
         * 没画的包才退回 `reject` 声明:它是 schema 必填的通用机制,
         * 不是所有流程包都会把驳回画成边。
         *
         * `quiet` 传真:这一步「试边不成」是正常分支,不是死路,不该报 route-dead-end。
         */
        const routedByEdge = await advanceFrom(record, pkg, nodeId, carried, true);
        if (!routedByEdge) {
          const route = rejectRouteOf(node, scopeOf(record), deps.sfeel.expression);
          if (route.kind === 'terminate') {
            await deps.store.updateWorkflow(workflowId, { state: 'terminated', finishedAt: deps.clock.now().toISOString() });
          } else {
            // 回指定节点**重开新实例**(同节点、新任务 ID、留痕关联),不复活旧任务
            const target = pkg.nodes.find((n) => n.id === route.nodeId);
            if (target !== undefined) await enter(record, pkg, target, { ...route.payload, ...payload });
          }
        }
      }
      return refreshState(workflowId);
    },

    refreshState,

    async terminate(workflowId, reason) {
      await deps.store.updateWorkflow(workflowId, {
        state: 'terminated',
        finishedAt: deps.clock.now().toISOString(),
      });
      // 工作流终止级联:在途任务终止、待答卡与征答消息作废、审批点撤卡
      await deps.events.publish({ workflowId, kind: 'workflow-terminated', detail: { reason } });
      return 'terminated';
    },
  };
}