import { App } from "@slack/bolt";

import { resolveTextChunkLimit } from "../../auto-reply/chunk.js";
import { DEFAULT_GROUP_HISTORY_LIMIT } from "../../auto-reply/reply/history.js";
import { loadConfig } from "../../config/config.js";
import type { SessionScope } from "../../config/sessions.js";
import type { DmPolicy, GroupPolicy } from "../../config/types.js";
import { normalizeMainKey } from "../../routing/session-key.js";
import type { RuntimeEnv } from "../../runtime.js";

import { resolveSlackAccount } from "../accounts.js";
import { resolveSlackAppToken, resolveSlackBotToken } from "../token.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";

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

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

  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 botToken = resolveSlackBotToken(opts.botToken ?? account.botToken);
  const appToken = resolveSlackAppToken(opts.appToken ?? account.appToken);
  if (!botToken || !appToken) {
    throw new Error(
      `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).`,
    );
  }

  const runtime: RuntimeEnv = opts.runtime ?? {
    log: console.log,
    error: console.error,
    exit: (code: number): never => {
      throw new Error(`exit ${code}`);
    },
  };

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

  const dmEnabled = dmConfig?.enabled ?? true;
  const dmPolicy = (dmConfig?.policy ?? "pairing") as DmPolicy;
  const allowFrom = dmConfig?.allowFrom;
  const groupDmEnabled = dmConfig?.groupEnabled ?? false;
  const groupDmChannels = dmConfig?.groupChannels;
  const channelsConfig = slackCfg.channels;
  const groupPolicy = (slackCfg.groupPolicy ?? "open") as GroupPolicy;
  const useAccessGroups = cfg.commands?.useAccessGroups !== false;
  const reactionMode = slackCfg.reactionNotifications ?? "own";
  const reactionAllowlist = slackCfg.reactionAllowlist ?? [];
  const replyToMode = slackCfg.replyToMode ?? "off";
  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 app = new App({
    token: botToken,
    appToken,
    socketMode: true,
  });

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

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

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

  registerSlackMonitorEvents({ ctx, account, handleSlackMessage });
  registerSlackMonitorSlashCommands({ ctx, account });

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

  try {
    await app.start();
    runtime.log?.("slack socket mode connected");
    if (opts.abortSignal?.aborted) return;
    await new Promise<void>((resolve) => {
      opts.abortSignal?.addEventListener("abort", () => resolve(), {
        once: true,
      });
    });
  } finally {
    opts.abortSignal?.removeEventListener("abort", stopOnAbort);
    await app.stop().catch(() => undefined);
  }
}