/**
 * interaction 用例 —— 编排 domain,依赖 port.ts(编码规范 §5.3)。
 */
import type { ChatMessage, StaffId, TaskId, ViewBlock } from '@contracts';
import { cardIdSchema } from '@contracts';
import type { InteractionService, PushEnvelope, Subscription } from '../../contract.ts';
import { TemplateRejectedError } from '../../contract.ts';
import type { Audience, Clock, HumanEventPublisher, IdGenerator, InteractionStore, MemoryRecorder } from '../../port.ts';
import type { InteractionPhase } from '../domain/control-handover.ts';
import { checkTemplate, outputControl } from '../domain/control-handover.ts';

export type InteractionServiceDeps = {
  readonly store: InteractionStore;
  readonly events: HumanEventPublisher;
  readonly memory: MemoryRecorder;
  readonly audience: Audience;
  readonly clock: Clock;
  readonly ids: IdGenerator;
};

type Subscriber = { staffId: StaffId; onPush: (envelope: PushEnvelope) => void };

export function createInteractionService(deps: InteractionServiceDeps): InteractionService {
  // SSE 订阅者表是**连接级**状态,不是过程状态:进程内持有,刷新即从投影重建(§9.2)
  const subscribers = new Set<Subscriber>();

  function broadcast(envelope: PushEnvelope): void {
    for (const subscriber of subscribers) {
      try {
        subscriber.onPush(envelope);
      } catch {
        subscribers.delete(subscriber);
      }
    }
  }

  return {
    async timeline(taskId) {
      return deps.store.listMessages(taskId);
    },

    /** 负责人的自由输入 —— 人事件的第二形态;写入任务记忆,不驱动 flow 步 */
    async say(taskId: TaskId, by: StaffId, text: string): Promise<ChatMessage> {
      const message: ChatMessage = {
        k: 'human',
        id: cardIdSchema.parse(deps.ids.next()),
        at: deps.clock.now().toISOString(),
        text,
        by,
      };
      await deps.store.appendMessage(taskId, message);
      await deps.memory.append({ taskId, kind: 'human-input', title: text, detail: { by } });
      await deps.events.publishHumanEvent({ taskId, cardId: message.id, payload: { kind: 'free-input', text } });
      broadcast({ kind: 'chat', taskId, message });
      return message;
    },

    async pushView(taskId: TaskId, blocks: readonly ViewBlock[]) {
      await deps.store.putView(taskId, { blocks });
      broadcast({ kind: 'view', taskId, blocks });
    },

    /** 视图模版过净化门:含脚本 / 事件处理器 / 外部资源一律拒推 */
    async pushViewHtml(taskId, html) {
      const violations = checkTemplate(html);
      if (violations.length > 0) throw new TemplateRejectedError(violations);
      await deps.store.putView(taskId, { html });
      broadcast({ kind: 'view-html', taskId, html });
    },

    async viewOf(taskId) {
      return deps.store.getView(taskId);
    },

    async setPhase(taskId: TaskId, phase: InteractionPhase) {
      await deps.store.setPhase(taskId, phase);
      const output = outputControl(phase);
      broadcast({ kind: 'control', taskId, phase, output });
      return output;
    },

    async phaseOf(taskId) {
      return (await deps.store.phaseOf(taskId)) ?? 'activating';
    },

    subscribe(staffId, onPush) {
      const subscriber: Subscriber = { staffId, onPush };
      subscribers.add(subscriber);
      return { close: () => void subscribers.delete(subscriber) } satisfies Subscription;
    },

    invalidate(target, id) {
      broadcast({ kind: 'invalidate', target, id });
    },
  };
}

/** 供 app 的 SSE 路由复用:按可见性过滤(避免把别人的任务推给不相干的人) */
export async function visibleTo(audience: Audience, staffId: StaffId, taskId: TaskId): Promise<boolean> {
  return audience.canSee(staffId, taskId);
}