import type { OpenClawPluginApi } from "openclaw/plugin-sdk";
import type { ChannelStore } from "../core/channel-store.js";
import type { IdentityRegistry } from "../core/identity-registry.js";
import { isCurrentSpeaker, setAnchor, hasSpeakers, isDormant, setSpeakerList, markTurnStarted, incrementBlockedPending, getInitializingChannels, type SpeakerEntry } from "../turn-manager.js";
import { getLatestMessageId, sendAndDelete } from "../core/moderator-discord.js";
import { fetchVisibleChannelBotAccountIds } from "../core/channel-members.js";

/** Extract Discord channel ID from sessionKey like "agent:home-developer:discord:channel:1234567890". */
export function parseDiscordChannelId(sessionKey: string): string | undefined {
  const m = sessionKey.match(/:discord:channel:(\d+)$/);
  return m?.[1];
}

type Deps = {
  api: OpenClawPluginApi;
  channelStore: ChannelStore;
  identityRegistry: IdentityRegistry;
  moderatorBotToken: string | undefined;
  noReplyModel: string;
  noReplyProvider: string;
  scheduleIdentifier: string;
};

/**
 * Process-level deduplication for before_model_resolve events.
 * Uses a WeakSet keyed on the event object — works when OpenClaw passes
 * the same event reference to all stacked handlers (hot-reload scenario).
 * Stored on globalThis so it persists across module reloads.
 */
const _BMR_DEDUP_KEY = "_dirigentProcessedBMREvents";
if (!(globalThis as Record<string, unknown>)[_BMR_DEDUP_KEY]) {
  (globalThis as Record<string, unknown>)[_BMR_DEDUP_KEY] = new WeakSet<object>();
}
const processedBeforeModelResolveEvents: WeakSet<object> = (globalThis as Record<string, unknown>)[_BMR_DEDUP_KEY] as WeakSet<object>;

export function registerBeforeModelResolveHook(deps: Deps): void {
  const { api, channelStore, identityRegistry, moderatorBotToken, noReplyModel, noReplyProvider, scheduleIdentifier } = deps;

  const NO_REPLY = { model: noReplyModel, provider: noReplyProvider, noReply: true } as const;

  /** Shared init lock — see turn-manager.ts getInitializingChannels(). */
  const initializingChannels = getInitializingChannels();

  api.on("before_model_resolve", async (event, ctx) => {
    // Deduplicate: if another handler instance already processed this event
    // object, skip. Prevents double-counting from hot-reload stacked handlers.
    const eventObj = event as object;
    if (processedBeforeModelResolveEvents.has(eventObj)) return;
    processedBeforeModelResolveEvents.add(eventObj);

    const sessionKey = ctx.sessionKey;
    if (!sessionKey) return;

    // Only handle Discord group channel sessions
    const channelId = parseDiscordChannelId(sessionKey);
    if (!channelId) return;

    const mode = channelStore.getMode(channelId);

    // dead mode: suppress all responses
    if (mode === "report" || mode === "dead" as string) return NO_REPLY;

    // disabled modes: let agents respond freely
    if (mode === "none" || mode === "work") return;

    // discussion / chat: check turn
    const agentId = ctx.agentId;
    if (!agentId) return;

    // If speaker list not yet loaded, initialize it now
    if (!hasSpeakers(channelId)) {
      // Only one concurrent initializer per channel (Node.js single-threaded: this is safe)
      if (initializingChannels.has(channelId)) {
        api.logger.info(`dirigent: before_model_resolve init in progress, suppressing agentId=${agentId} channel=${channelId}`);
        return NO_REPLY;
      }
      initializingChannels.add(channelId);
      try {
        const agentIds = await fetchVisibleChannelBotAccountIds(api, channelId, identityRegistry);
        const speakers: SpeakerEntry[] = agentIds
          .map((aid) => {
            const entry = identityRegistry.findByAgentId(aid);
            return entry ? { agentId: aid, discordUserId: entry.discordUserId } : null;
          })
          .filter((s): s is SpeakerEntry => s !== null);

        if (speakers.length > 0) {
          setSpeakerList(channelId, speakers);
          const first = speakers[0];
          api.logger.info(`dirigent: initialized speaker list channel=${channelId} first=${first.agentId} all=${speakers.map(s => s.agentId).join(",")}`);

          // If this agent is NOT the first speaker, trigger first speaker and suppress this one
          if (first.agentId !== agentId && moderatorBotToken) {
            await sendAndDelete(moderatorBotToken, channelId, `<@${first.discordUserId}>${scheduleIdentifier}`, api.logger);
            return NO_REPLY;
          }
          // If this agent IS the first speaker, fall through to normal turn logic
        } else {
          // No registered agents visible — let everyone respond freely
          return;
        }
      } catch (err) {
        api.logger.warn(`dirigent: before_model_resolve init failed: ${String(err)}`);
        return;
      } finally {
        initializingChannels.delete(channelId);
      }
    }

    // If channel is dormant: suppress all agents
    if (isDormant(channelId)) return NO_REPLY;

    if (!isCurrentSpeaker(channelId, agentId)) {
      api.logger.info(`dirigent: before_model_resolve blocking non-speaker session=${sessionKey} agentId=${agentId} channel=${channelId}`);
      incrementBlockedPending(channelId, agentId);
      return NO_REPLY;
    }

    // Mark that this is a legitimate turn (guards agent_end against stale NO_REPLY completions)
    markTurnStarted(channelId, agentId);

    // Current speaker: record anchor message ID for tail-match polling
    if (moderatorBotToken) {
      try {
        const anchorId = await getLatestMessageId(moderatorBotToken, channelId);
        if (anchorId) {
          setAnchor(channelId, agentId, anchorId);
          api.logger.info(`dirigent: before_model_resolve anchor set channel=${channelId} agentId=${agentId} anchorId=${anchorId}`);
        }
      } catch (err) {
        api.logger.warn(`dirigent: before_model_resolve failed to get anchor: ${String(err)}`);
      }
    }

    // Verify agent has a known Discord user ID (needed for tail-match later)
    const identity = identityRegistry.findByAgentId(agentId);
    if (!identity) {
      api.logger.warn(`dirigent: before_model_resolve no identity for agentId=${agentId} — proceeding without tail-match capability`);
    }
  });
}