import {
  createChannelInboundDebouncer,
  shouldDebounceTextInbound,
} from "openclaw/plugin-sdk/channel-inbound";
import { danger, logVerbose } from "openclaw/plugin-sdk/runtime-env";
import { resolveOpenProviderRuntimeGroupPolicy } from "openclaw/plugin-sdk/runtime-group-policy";
import type { Client } from "../internal/discord.js";
import {
  buildDiscordInboundReplayKey,
  claimDiscordInboundReplay,
  commitDiscordInboundReplay,
  createDiscordInboundReplayGuard,
  DiscordRetryableInboundError,
  releaseDiscordInboundReplay,
} from "./inbound-dedupe.js";
import { buildDiscordInboundJob, resolveDiscordInboundJobQueueKey } from "./inbound-job.js";
import type { DiscordMessageEvent, DiscordMessageHandler } from "./listeners.js";
import { applyImplicitReplyBatchGate } from "./message-handler.batch-gate.js";
import type {
  DiscordMessagePreflightContext,
  DiscordMessagePreflightParams,
} from "./message-handler.preflight.types.js";
import { resolveDiscordAcceptedTypingPrestart } from "./message-handler.reply-typing-policy.js";
import {
  createDiscordMessageRunQueue,
  type DiscordMessageRunQueueTestingHooks,
} from "./message-run-queue.js";
import {
  hasDiscordMessageStickers,
  resolveDiscordMessageChannelId,
  resolveDiscordMessageText,
} from "./message-utils.js";
import {
  createDiscordReplyTypingFeedback,
  type DiscordReplyTypingFeedback,
} from "./reply-typing-feedback.js";
import type { DiscordMonitorStatusSink } from "./status.js";

type PreflightDiscordMessage =
  typeof import("./message-handler.preflight.js").preflightDiscordMessage;
type CreateDiscordReplyTypingFeedback = typeof createDiscordReplyTypingFeedback;

type DiscordMessageHandlerParams = Omit<
  DiscordMessagePreflightParams,
  "ackReactionScope" | "groupPolicy" | "data" | "client"
> & {
  setStatus?: DiscordMonitorStatusSink;
  abortSignal?: AbortSignal;
  testing?: DiscordMessageHandlerTestingHooks;
};

type DiscordMessageHandlerTestingHooks = DiscordMessageRunQueueTestingHooks & {
  preflightDiscordMessage?: PreflightDiscordMessage;
  createReplyTypingFeedback?: CreateDiscordReplyTypingFeedback;
};

type PrestartedTypingFeedbackEntry = {
  channelId: string;
  feedback: DiscordReplyTypingFeedback;
};

let messagePreflightRuntimePromise:
  | Promise<typeof import("./message-handler.preflight.js")>
  | undefined;

async function loadMessagePreflightRuntime() {
  messagePreflightRuntimePromise ??= import("./message-handler.preflight.js");
  return await messagePreflightRuntimePromise;
}

export type DiscordMessageHandlerWithLifecycle = DiscordMessageHandler & {
  deactivate: () => void;
};

function isNonEmptyString(value: string | undefined): value is string {
  return typeof value === "string" && value.length > 0;
}

function startAcceptedTypingFeedback(params: {
  ctx: DiscordMessagePreflightContext;
  createFeedback?: CreateDiscordReplyTypingFeedback;
  dedupeKey: string;
  activeFeedback: Map<string, PrestartedTypingFeedbackEntry>;
}): DiscordReplyTypingFeedback | undefined {
  const { ctx, createFeedback, dedupeKey, activeFeedback } = params;
  if (!resolveDiscordAcceptedTypingPrestart(ctx).shouldPrestart) {
    return undefined;
  }
  const channelId = ctx.messageChannelId.trim();
  const existing = activeFeedback.get(dedupeKey);
  if (existing) {
    // One pre-dispatch keepalive owns each serialized Discord queue key.
    // Later queued jobs get fresh typing when their dispatch turn starts.
    return undefined;
  }
  const replyTypingFeedback =
    ctx.replyTypingFeedback ??
    (createFeedback ?? createDiscordReplyTypingFeedback)({
      cfg: ctx.cfg,
      token: ctx.token,
      accountId: ctx.accountId,
      channelId: ctx.messageChannelId,
      log: logVerbose,
    });
  const cleanup = replyTypingFeedback.onCleanup;
  replyTypingFeedback.onCleanup = () => {
    cleanup?.();
    // Cleanup is the lease release for both normal dispatch and skipped jobs.
    // Without this, a stale queue key would suppress future accepted typing.
    if (activeFeedback.get(dedupeKey)?.feedback === replyTypingFeedback) {
      activeFeedback.delete(dedupeKey);
    }
  };
  activeFeedback.set(dedupeKey, { channelId, feedback: replyTypingFeedback });
  ctx.replyTypingFeedback = replyTypingFeedback;
  void replyTypingFeedback.onReplyStart().catch((err: unknown) => {
    logVerbose(`discord accepted typing feedback failed: ${String(err)}`);
  });
  return replyTypingFeedback;
}

export function createDiscordMessageHandler(
  params: DiscordMessageHandlerParams,
): DiscordMessageHandlerWithLifecycle {
  const { groupPolicy } = resolveOpenProviderRuntimeGroupPolicy({
    providerConfigPresent: params.cfg.channels?.discord !== undefined,
    groupPolicy: params.discordConfig?.groupPolicy,
    defaultGroupPolicy: params.cfg.channels?.defaults?.groupPolicy,
  });
  const ackReactionScope =
    params.discordConfig?.ackReactionScope ??
    params.cfg.messages?.ackReactionScope ??
    "group-mentions";
  const preflightDiscordMessageImpl = params.testing?.preflightDiscordMessage;
  const replayGuard = createDiscordInboundReplayGuard();
  // The map owns pre-dispatch typing leases, not queued work itself.
  // Each lease is released by the feedback cleanup hook installed below.
  const prestartedTypingFeedback = new Map<string, PrestartedTypingFeedbackEntry>();
  const messageRunQueue = createDiscordMessageRunQueue({
    runtime: params.runtime,
    setStatus: params.setStatus,
    abortSignal: params.abortSignal,
    replayGuard,
    testing: params.testing,
  });

  const { debouncer } = createChannelInboundDebouncer<{
    data: DiscordMessageEvent;
    client: Client;
    abortSignal?: AbortSignal;
    replayKey?: string;
  }>({
    cfg: params.cfg,
    channel: "discord",
    buildKey: (entry) => {
      const message = entry.data.message;
      const authorId = entry.data.author?.id;
      if (!message || !authorId) {
        return null;
      }
      const channelId = resolveDiscordMessageChannelId({
        message,
        eventChannelId: entry.data.channel_id,
      });
      if (!channelId) {
        return null;
      }
      return `discord:${params.accountId}:${channelId}:${authorId}`;
    },
    shouldDebounce: (entry) => {
      const message = entry.data.message;
      if (!message) {
        return false;
      }
      const baseText = resolveDiscordMessageText(message, { includeForwarded: false });
      return shouldDebounceTextInbound({
        text: baseText,
        cfg: params.cfg,
        hasMedia:
          (message.attachments && message.attachments.length > 0) ||
          hasDiscordMessageStickers(message),
      });
    },
    onFlush: async (entries) => {
      const last = entries.at(-1);
      if (!last) {
        return;
      }
      const replayKeys = entries.map((entry) => entry.replayKey).filter(isNonEmptyString);
      const abortSignal = last.abortSignal;
      if (abortSignal?.aborted) {
        releaseDiscordInboundReplay({
          replayKeys,
          error: abortSignal.reason,
          replayGuard,
        });
        return;
      }
      try {
        if (entries.length === 1) {
          const preflight =
            preflightDiscordMessageImpl ??
            (await loadMessagePreflightRuntime()).preflightDiscordMessage;
          const ctx = await preflight({
            ...params,
            ackReactionScope,
            groupPolicy,
            abortSignal,
            data: last.data,
            client: last.client,
          });
          if (!ctx) {
            await commitDiscordInboundReplay({ replayKeys, replayGuard });
            return;
          }
          const queueKey = resolveDiscordInboundJobQueueKey(ctx);
          startAcceptedTypingFeedback({
            ctx,
            createFeedback: params.testing?.createReplyTypingFeedback,
            dedupeKey: queueKey,
            activeFeedback: prestartedTypingFeedback,
          });
          applyImplicitReplyBatchGate(ctx, params.replyToMode, false);
          messageRunQueue.enqueue(buildDiscordInboundJob(ctx, { replayKeys }));
          return;
        }
        const combinedBaseText = entries
          .map((entry) =>
            resolveDiscordMessageText(entry.data.message, { includeForwarded: false }),
          )
          .filter(Boolean)
          .join("\n");
        const syntheticMessage = Object.create(Object.getPrototypeOf(last.data.message), {
          ...Object.getOwnPropertyDescriptors(last.data.message),
          content: { value: combinedBaseText, enumerable: true, configurable: true },
          attachments: { value: [], enumerable: true, configurable: true },
          message_snapshots: {
            value: (last.data.message as { message_snapshots?: unknown }).message_snapshots,
            enumerable: true,
            configurable: true,
          },
          messageSnapshots: {
            value: (last.data.message as { messageSnapshots?: unknown }).messageSnapshots,
            enumerable: true,
            configurable: true,
          },
          rawData: {
            value: { ...(last.data.message as { rawData?: Record<string, unknown> }).rawData },
            enumerable: true,
            configurable: true,
          },
        }) as DiscordMessageEvent["message"];
        const syntheticData: DiscordMessageEvent = {
          ...last.data,
          message: syntheticMessage,
        };
        const preflight =
          preflightDiscordMessageImpl ??
          (await loadMessagePreflightRuntime()).preflightDiscordMessage;
        const ctx = await preflight({
          ...params,
          ackReactionScope,
          groupPolicy,
          abortSignal,
          data: syntheticData,
          client: last.client,
        });
        if (!ctx) {
          await commitDiscordInboundReplay({ replayKeys, replayGuard });
          return;
        }
        const queueKey = resolveDiscordInboundJobQueueKey(ctx);
        startAcceptedTypingFeedback({
          ctx,
          createFeedback: params.testing?.createReplyTypingFeedback,
          dedupeKey: queueKey,
          activeFeedback: prestartedTypingFeedback,
        });
        applyImplicitReplyBatchGate(ctx, params.replyToMode, true);
        if (entries.length > 1) {
          const ids = entries.map((entry) => entry.data.message?.id).filter(isNonEmptyString);
          if (ids.length > 0) {
            const ctxBatch = ctx as typeof ctx & {
              MessageSids?: string[];
              MessageSidFirst?: string;
              MessageSidLast?: string;
            };
            ctxBatch.MessageSids = ids;
            ctxBatch.MessageSidFirst = ids[0];
            ctxBatch.MessageSidLast = ids[ids.length - 1];
          }
        }
        messageRunQueue.enqueue(buildDiscordInboundJob(ctx, { replayKeys }));
      } catch (error) {
        if (error instanceof DiscordRetryableInboundError) {
          releaseDiscordInboundReplay({ replayKeys, error, replayGuard });
        } else {
          await commitDiscordInboundReplay({ replayKeys, replayGuard });
        }
        throw error;
      }
    },
    onError: (err) => {
      params.runtime.error(danger(`discord debounce flush failed: ${String(err)}`));
    },
  });

  const handler: DiscordMessageHandlerWithLifecycle = async (data, client, options) => {
    try {
      if (options?.abortSignal?.aborted) {
        return;
      }
      // Filter bot-own messages before they enter the debounce queue.
      // The same check exists in preflightDiscordMessage(), but by that point
      // the message has already consumed debounce capacity and blocked
      // legitimate user messages. On active servers this causes cumulative
      // slowdown (see #15874).
      const msgAuthorId = data.message?.author?.id ?? data.author?.id;
      if (params.botUserId && msgAuthorId === params.botUserId) {
        return;
      }
      const replayKey = buildDiscordInboundReplayKey({
        accountId: params.accountId,
        data,
      });
      if (
        !(await claimDiscordInboundReplay({
          replayKey,
          replayGuard,
        }))
      ) {
        return;
      }

      await debouncer.enqueue({
        data,
        client,
        abortSignal: options?.abortSignal,
        replayKey: replayKey ?? undefined,
      });
    } catch (err) {
      params.runtime.error(danger(`handler failed: ${String(err)}`));
    }
  };

  handler.deactivate = messageRunQueue.deactivate;

  return handler;
}