import type { IncomingMessage, ServerResponse } from "node:http";
import SlackBolt from "@slack/bolt";
import { resolveTextChunkLimit } from "../../auto-reply/chunk.js";
import { DEFAULT_GROUP_HISTORY_LIMIT } from "../../auto-reply/reply/history.js";
import {
  addAllowlistUserEntriesFromConfigEntry,
  buildAllowlistResolutionSummary,
  mergeAllowlist,
  patchAllowlistUsersInConfigEntries,
  summarizeMapping,
} from "../../channels/allowlists/resolve-utils.js";
import { loadConfig } from "../../config/config.js";
import { isDangerousNameMatchingEnabled } from "../../config/dangerous-name-matching.js";
import {
  resolveOpenProviderRuntimeGroupPolicy,
  resolveDefaultGroupPolicy,
  warnMissingProviderGroupPolicyFallbackOnce,
} from "../../config/runtime-group-policy.js";
import type { SessionScope } from "../../config/sessions.js";
import { warn } from "../../globals.js";
import { computeBackoff, sleepWithAbort } from "../../infra/backoff.js";
import { installRequestBodyLimitGuard } from "../../infra/http-body.js";
import { normalizeMainKey } from "../../routing/session-key.js";
import { createNonExitingRuntime, type RuntimeEnv } from "../../runtime.js";
import { resolveSlackAccount } from "../accounts.js";
import { resolveSlackWebClientOptions } from "../client.js";
import { normalizeSlackWebhookPath, registerSlackHttpHandler } from "../http/index.js";
import { resolveSlackChannelAllowlist } from "../resolve-channels.js";
import { resolveSlackUserAllowlist } from "../resolve-users.js";
import { resolveSlackAppToken, resolveSlackBotToken } from "../token.js";
import { normalizeAllowList } from "./allow-list.js";
import { resolveSlackSlashCommandConfig } from "./commands.js";
import { createSlackMonitorContext } from "./context.js";
import { registerSlackMonitorEvents } from "./events.js";
import { createSlackMessageHandler } from "./message-handler.js";
import { registerSlackMonitorSlashCommands } from "./slash.js";
import type { MonitorSlackOpts } from "./types.js";

const slackBoltModule = SlackBolt as typeof import("@slack/bolt") & {
  default?: typeof import("@slack/bolt");
};
// Bun allows named imports from CJS; Node ESM doesn't. Use default+fallback for compatibility.
// Fix: Check if module has App property directly (Node 25.x ESM/CJS compat issue)
const slackBolt =
  (slackBoltModule.App ? slackBoltModule : slackBoltModule.default) ?? slackBoltModule;
const { App, HTTPReceiver } = slackBolt;

const SLACK_WEBHOOK_MAX_BODY_BYTES = 1024 * 1024;
const SLACK_WEBHOOK_BODY_TIMEOUT_MS = 30_000;
const SLACK_SOCKET_RECONNECT_POLICY = {
  initialMs: 2_000,
  maxMs: 30_000,
  factor: 1.8,
  jitter: 0.25,
  maxAttempts: 12,
} as const;

type SlackSocketDisconnectEvent = "disconnect" | "unable_to_socket_mode_start" | "error";

type EmitterLike = {
  on: (event: string, listener: (...args: unknown[]) => void) => unknown;
  off: (event: string, listener: (...args: unknown[]) => void) => unknown;
};

function getSocketEmitter(app: unknown): EmitterLike | null {
  const receiver = (app as { receiver?: unknown }).receiver;
  const client =
    receiver && typeof receiver === "object"
      ? (receiver as { client?: unknown }).client
      : undefined;
  if (!client || typeof client !== "object") {
    return null;
  }
  const on = (client as { on?: unknown }).on;
  const off = (client as { off?: unknown }).off;
  if (typeof on !== "function" || typeof off !== "function") {
    return null;
  }
  return {
    on: (event, listener) =>
      (
        on as (this: unknown, event: string, listener: (...args: unknown[]) => void) => unknown
      ).call(client, event, listener),
    off: (event, listener) =>
      (
        off as (this: unknown, event: string, listener: (...args: unknown[]) => void) => unknown
      ).call(client, event, listener),
  };
}

function waitForSlackSocketDisconnect(
  app: unknown,
  abortSignal?: AbortSignal,
): Promise<{
  event: SlackSocketDisconnectEvent;
  error?: unknown;
}> {
  return new Promise((resolve) => {
    const emitter = getSocketEmitter(app);
    if (!emitter) {
      abortSignal?.addEventListener("abort", () => resolve({ event: "disconnect" }), {
        once: true,
      });
      return;
    }

    const disconnectListener = () => resolveOnce({ event: "disconnect" });
    const startFailListener = () => resolveOnce({ event: "unable_to_socket_mode_start" });
    const errorListener = (error: unknown) => resolveOnce({ event: "error", error });
    const abortListener = () => resolveOnce({ event: "disconnect" });

    const cleanup = () => {
      emitter.off("disconnected", disconnectListener);
      emitter.off("unable_to_socket_mode_start", startFailListener);
      emitter.off("error", errorListener);
      abortSignal?.removeEventListener("abort", abortListener);
    };

    const resolveOnce = (value: { event: SlackSocketDisconnectEvent; error?: unknown }) => {
      cleanup();
      resolve(value);
    };

    emitter.on("disconnected", disconnectListener);
    emitter.on("unable_to_socket_mode_start", startFailListener);
    emitter.on("error", errorListener);
    abortSignal?.addEventListener("abort", abortListener, { once: true });
  });
}

function formatUnknownError(error: unknown): string {
  if (error instanceof Error) {
    return error.message;
  }
  if (typeof error === "string") {
    return error;
  }
  try {
    return JSON.stringify(error);
  } catch {
    return "unknown error";
  }
}

function parseApiAppIdFromAppToken(raw?: string) {
  const token = raw?.trim();
  if (!token) {
    return undefined;
  }
  const match = /^xapp-\d-([a-z0-9]+)-/i.exec(token);
  return match?.[1]?.toUpperCase();
}

export async function monitorSlackProvider(opts: MonitorSlackOpts = {}) {
  const cfg = opts.config ?? loadConfig();
  const runtime: RuntimeEnv = opts.runtime ?? createNonExitingRuntime();

  let account = resolveSlackAccount({
    cfg,
    accountId: opts.accountId,
  });

  if (!account.enabled) {
    runtime.log?.(`[${account.accountId}] slack account disabled; monitor startup skipped`);
    if (opts.abortSignal?.aborted) {
      return;
    }
    await new Promise<void>((resolve) => {
      opts.abortSignal?.addEventListener("abort", () => resolve(), {
        once: true,
      });
    });
    return;
  }

  const historyLimit = Math.max(
    0,
    account.config.historyLimit ??
      cfg.messages?.groupChat?.historyLimit ??
      DEFAULT_GROUP_HISTORY_LIMIT,
  );

  const sessionCfg = cfg.session;
  const sessionScope: SessionScope = sessionCfg?.scope ?? "per-sender";
  const mainKey = normalizeMainKey(sessionCfg?.mainKey);

  const slackMode = opts.mode ?? account.config.mode ?? "socket";
  const slackWebhookPath = normalizeSlackWebhookPath(account.config.webhookPath);
  const signingSecret = account.config.signingSecret?.trim();
  const botToken = resolveSlackBotToken(opts.botToken ?? account.botToken);
  const appToken = resolveSlackAppToken(opts.appToken ?? account.appToken);
  if (!botToken || (slackMode !== "http" && !appToken)) {
    const missing =
      slackMode === "http"
        ? `Slack bot token missing for account "${account.accountId}" (set channels.slack.accounts.${account.accountId}.botToken or SLACK_BOT_TOKEN for default).`
        : `Slack bot + app tokens missing for account "${account.accountId}" (set channels.slack.accounts.${account.accountId}.botToken/appToken or SLACK_BOT_TOKEN/SLACK_APP_TOKEN for default).`;
    throw new Error(missing);
  }
  if (slackMode === "http" && !signingSecret) {
    throw new Error(
      `Slack signing secret missing for account "${account.accountId}" (set channels.slack.signingSecret or channels.slack.accounts.${account.accountId}.signingSecret).`,
    );
  }

  const slackCfg = account.config;
  const dmConfig = slackCfg.dm;

  const dmEnabled = dmConfig?.enabled ?? true;
  const dmPolicy = slackCfg.dmPolicy ?? dmConfig?.policy ?? "pairing";
  let allowFrom = slackCfg.allowFrom ?? dmConfig?.allowFrom;
  const groupDmEnabled = dmConfig?.groupEnabled ?? false;
  const groupDmChannels = dmConfig?.groupChannels;
  let channelsConfig = slackCfg.channels;
  const defaultGroupPolicy = resolveDefaultGroupPolicy(cfg);
  const providerConfigPresent = cfg.channels?.slack !== undefined;
  const { groupPolicy, providerMissingFallbackApplied } = resolveOpenProviderRuntimeGroupPolicy({
    providerConfigPresent,
    groupPolicy: slackCfg.groupPolicy,
    defaultGroupPolicy,
  });
  warnMissingProviderGroupPolicyFallbackOnce({
    providerMissingFallbackApplied,
    providerKey: "slack",
    accountId: account.accountId,
    log: (message) => runtime.log?.(warn(message)),
  });

  const resolveToken = account.userToken || botToken;
  const useAccessGroups = cfg.commands?.useAccessGroups !== false;
  const reactionMode = slackCfg.reactionNotifications ?? "own";
  const reactionAllowlist = slackCfg.reactionAllowlist ?? [];
  const replyToMode = slackCfg.replyToMode ?? "off";
  const threadHistoryScope = slackCfg.thread?.historyScope ?? "thread";
  const threadInheritParent = slackCfg.thread?.inheritParent ?? false;
  const slashCommand = resolveSlackSlashCommandConfig(opts.slashCommand ?? slackCfg.slashCommand);
  const textLimit = resolveTextChunkLimit(cfg, "slack", account.accountId);
  const ackReactionScope = cfg.messages?.ackReactionScope ?? "group-mentions";
  const mediaMaxBytes = (opts.mediaMaxMb ?? slackCfg.mediaMaxMb ?? 20) * 1024 * 1024;
  const removeAckAfterReply = cfg.messages?.removeAckAfterReply ?? false;

  const receiver =
    slackMode === "http"
      ? new HTTPReceiver({
          signingSecret: signingSecret ?? "",
          endpoints: slackWebhookPath,
        })
      : null;
  const clientOptions = resolveSlackWebClientOptions();
  const app = new App(
    slackMode === "socket"
      ? {
          token: botToken,
          appToken,
          socketMode: true,
          clientOptions,
        }
      : {
          token: botToken,
          receiver: receiver ?? undefined,
          clientOptions,
        },
  );
  const slackHttpHandler =
    slackMode === "http" && receiver
      ? async (req: IncomingMessage, res: ServerResponse) => {
          const guard = installRequestBodyLimitGuard(req, res, {
            maxBytes: SLACK_WEBHOOK_MAX_BODY_BYTES,
            timeoutMs: SLACK_WEBHOOK_BODY_TIMEOUT_MS,
            responseFormat: "text",
          });
          if (guard.isTripped()) {
            return;
          }
          try {
            await Promise.resolve(receiver.requestListener(req, res));
          } catch (err) {
            if (!guard.isTripped()) {
              throw err;
            }
          } finally {
            guard.dispose();
          }
        }
      : null;
  let unregisterHttpHandler: (() => void) | null = null;

  let botUserId = "";
  let teamId = "";
  let apiAppId = "";
  const expectedApiAppIdFromAppToken = parseApiAppIdFromAppToken(appToken);
  try {
    const auth = await app.client.auth.test({ token: botToken });
    botUserId = auth.user_id ?? "";
    teamId = auth.team_id ?? "";
    apiAppId = (auth as { api_app_id?: string }).api_app_id ?? "";
  } catch {
    // auth test failing is non-fatal; message handler falls back to regex mentions.
  }

  if (apiAppId && expectedApiAppIdFromAppToken && apiAppId !== expectedApiAppIdFromAppToken) {
    runtime.error?.(
      `slack token mismatch: bot token api_app_id=${apiAppId} but app token looks like api_app_id=${expectedApiAppIdFromAppToken}`,
    );
  }

  const ctx = createSlackMonitorContext({
    cfg,
    accountId: account.accountId,
    botToken,
    app,
    runtime,
    botUserId,
    teamId,
    apiAppId,
    historyLimit,
    sessionScope,
    mainKey,
    dmEnabled,
    dmPolicy,
    allowFrom,
    allowNameMatching: isDangerousNameMatchingEnabled(slackCfg),
    groupDmEnabled,
    groupDmChannels,
    defaultRequireMention: slackCfg.requireMention,
    channelsConfig,
    groupPolicy,
    useAccessGroups,
    reactionMode,
    reactionAllowlist,
    replyToMode,
    threadHistoryScope,
    threadInheritParent,
    slashCommand,
    textLimit,
    ackReactionScope,
    mediaMaxBytes,
    removeAckAfterReply,
  });

  // Wire up event liveness tracking: update lastEventAt on every inbound event
  // so the health monitor can detect "half-dead" sockets that pass health checks
  // but silently stop delivering events.
  const trackEvent = opts.setStatus
    ? () => {
        opts.setStatus!({ lastEventAt: Date.now(), lastInboundAt: Date.now() });
      }
    : undefined;

  const handleSlackMessage = createSlackMessageHandler({ ctx, account, trackEvent });

  registerSlackMonitorEvents({ ctx, account, handleSlackMessage, trackEvent });
  await registerSlackMonitorSlashCommands({ ctx, account });
  if (slackMode === "http" && slackHttpHandler) {
    unregisterHttpHandler = registerSlackHttpHandler({
      path: slackWebhookPath,
      handler: slackHttpHandler,
      log: runtime.log,
      accountId: account.accountId,
    });
  }

  if (resolveToken) {
    void (async () => {
      if (opts.abortSignal?.aborted) {
        return;
      }

      if (channelsConfig && Object.keys(channelsConfig).length > 0) {
        try {
          const entries = Object.keys(channelsConfig).filter((key) => key !== "*");
          if (entries.length > 0) {
            const resolved = await resolveSlackChannelAllowlist({
              token: resolveToken,
              entries,
            });
            const nextChannels = { ...channelsConfig };
            const mapping: string[] = [];
            const unresolved: string[] = [];
            for (const entry of resolved) {
              const source = channelsConfig?.[entry.input];
              if (!source) {
                continue;
              }
              if (!entry.resolved || !entry.id) {
                unresolved.push(entry.input);
                continue;
              }
              mapping.push(`${entry.input}→${entry.id}${entry.archived ? " (archived)" : ""}`);
              const existing = nextChannels[entry.id] ?? {};
              nextChannels[entry.id] = { ...source, ...existing };
            }
            channelsConfig = nextChannels;
            ctx.channelsConfig = nextChannels;
            summarizeMapping("slack channels", mapping, unresolved, runtime);
          }
        } catch (err) {
          runtime.log?.(`slack channel resolve failed; using config entries. ${String(err)}`);
        }
      }

      const allowEntries =
        allowFrom?.filter((entry) => String(entry).trim() && String(entry).trim() !== "*") ?? [];
      if (allowEntries.length > 0) {
        try {
          const resolvedUsers = await resolveSlackUserAllowlist({
            token: resolveToken,
            entries: allowEntries.map((entry) => String(entry)),
          });
          const { mapping, unresolved, additions } = buildAllowlistResolutionSummary(
            resolvedUsers,
            {
              formatResolved: (entry) => {
                const note = (entry as { note?: string }).note
                  ? ` (${(entry as { note?: string }).note})`
                  : "";
                return `${entry.input}→${entry.id}${note}`;
              },
            },
          );
          allowFrom = mergeAllowlist({ existing: allowFrom, additions });
          ctx.allowFrom = normalizeAllowList(allowFrom);
          summarizeMapping("slack users", mapping, unresolved, runtime);
        } catch (err) {
          runtime.log?.(`slack user resolve failed; using config entries. ${String(err)}`);
        }
      }

      if (channelsConfig && Object.keys(channelsConfig).length > 0) {
        const userEntries = new Set<string>();
        for (const channel of Object.values(channelsConfig)) {
          addAllowlistUserEntriesFromConfigEntry(userEntries, channel);
        }

        if (userEntries.size > 0) {
          try {
            const resolvedUsers = await resolveSlackUserAllowlist({
              token: resolveToken,
              entries: Array.from(userEntries),
            });
            const { resolvedMap, mapping, unresolved } =
              buildAllowlistResolutionSummary(resolvedUsers);

            const nextChannels = patchAllowlistUsersInConfigEntries({
              entries: channelsConfig,
              resolvedMap,
            });
            channelsConfig = nextChannels;
            ctx.channelsConfig = nextChannels;
            summarizeMapping("slack channel users", mapping, unresolved, runtime);
          } catch (err) {
            runtime.log?.(
              `slack channel user resolve failed; using config entries. ${String(err)}`,
            );
          }
        }
      }
    })();
  }

  const stopOnAbort = () => {
    if (opts.abortSignal?.aborted && slackMode === "socket") {
      void app.stop();
    }
  };
  opts.abortSignal?.addEventListener("abort", stopOnAbort, { once: true });

  try {
    if (slackMode === "socket") {
      let reconnectAttempts = 0;
      while (!opts.abortSignal?.aborted) {
        try {
          await app.start();
          reconnectAttempts = 0;
          runtime.log?.("slack socket mode connected");
        } catch (err) {
          reconnectAttempts += 1;
          if (
            SLACK_SOCKET_RECONNECT_POLICY.maxAttempts > 0 &&
            reconnectAttempts >= SLACK_SOCKET_RECONNECT_POLICY.maxAttempts
          ) {
            throw err;
          }
          const delayMs = computeBackoff(SLACK_SOCKET_RECONNECT_POLICY, reconnectAttempts);
          runtime.error?.(
            `slack socket mode failed to start. retry ${reconnectAttempts}/${SLACK_SOCKET_RECONNECT_POLICY.maxAttempts || "∞"} in ${Math.round(delayMs / 1000)}s (${formatUnknownError(err)})`,
          );
          try {
            await sleepWithAbort(delayMs, opts.abortSignal);
          } catch {
            break;
          }
          continue;
        }

        if (opts.abortSignal?.aborted) {
          break;
        }

        const disconnect = await waitForSlackSocketDisconnect(app, opts.abortSignal);
        if (opts.abortSignal?.aborted) {
          break;
        }

        reconnectAttempts += 1;
        if (
          SLACK_SOCKET_RECONNECT_POLICY.maxAttempts > 0 &&
          reconnectAttempts >= SLACK_SOCKET_RECONNECT_POLICY.maxAttempts
        ) {
          throw new Error(
            `Slack socket mode reconnect max attempts reached (${reconnectAttempts}/${SLACK_SOCKET_RECONNECT_POLICY.maxAttempts}) after ${disconnect.event}`,
          );
        }

        const delayMs = computeBackoff(SLACK_SOCKET_RECONNECT_POLICY, reconnectAttempts);
        runtime.error?.(
          `slack socket disconnected (${disconnect.event}). retry ${reconnectAttempts}/${SLACK_SOCKET_RECONNECT_POLICY.maxAttempts || "∞"} in ${Math.round(delayMs / 1000)}s${
            disconnect.error ? ` (${formatUnknownError(disconnect.error)})` : ""
          }`,
        );
        await app.stop().catch(() => undefined);
        try {
          await sleepWithAbort(delayMs, opts.abortSignal);
        } catch {
          break;
        }
      }
    } else {
      runtime.log?.(`slack http mode listening at ${slackWebhookPath}`);
      if (!opts.abortSignal?.aborted) {
        await new Promise<void>((resolve) => {
          opts.abortSignal?.addEventListener("abort", () => resolve(), {
            once: true,
          });
        });
      }
    }
  } finally {
    opts.abortSignal?.removeEventListener("abort", stopOnAbort);
    unregisterHttpHandler?.();
    await app.stop().catch(() => undefined);
  }
}

export const __testing = {
  resolveSlackRuntimeGroupPolicy: resolveOpenProviderRuntimeGroupPolicy,
  resolveDefaultGroupPolicy,
  getSocketEmitter,
  waitForSlackSocketDisconnect,
};