/**
 * Feishu lark client + long-connection event dispatcher.
 *
 * Handles: ws event receiving (im.message.receive_v1 + card.action.trigger),
 * message sending, streaming patch via interactive cards, emoji
 * reactions, file download/upload, and the card action callback.
 */
import * as lark from "@larksuiteoapi/node-sdk";
import { readFile, writeFile, mkdir } from "node:fs/promises";
import { dirname } from "node:path";
import type { FastifyBaseLogger } from "fastify";

export interface FeishuConfig {
  readonly appId: string;
  readonly appSecret: string;
  readonly botOpenId: string;
}

export interface FeishuRuntime {
  readonly client: lark.Client;
  readonly logger: FastifyBaseLogger;
}

export interface OutboundPayload {
  readonly msgType: string;
  readonly content: string;
}

/** Raw `im.message.receive_v1` event payload. */
export interface MessageReceiveEvent {
  /** Feishu's SDK dispatcher flattens v2 headers onto the top-level payload. */
  readonly event_id?: string;
  readonly event_type?: string;
  readonly header?: { readonly event_id?: string; readonly event_type?: string };
  readonly message: {
    readonly message_id: string;
    readonly root_id?: string;
    readonly parent_id?: string;
    readonly thread_id?: string;
    readonly create_time?: string;
    readonly update_time?: string;
    readonly chat_id: string;
    readonly chat_type: string;
    readonly message_type: string;
    readonly content: string;
    readonly mentions?: ReadonlyArray<{
      readonly key: string;
      readonly id: { readonly open_id?: string };
      readonly name: string;
    }>;
  };
  readonly sender: {
    readonly sender_id: { readonly open_id?: string };
    readonly sender_type: string;
  };
}

/** Card action trigger event (button clicks, select changes). */
export interface CardActionEvent {
  readonly operator: { readonly open_id?: string };
  readonly action: {
    readonly value?: unknown;
    readonly tag?: string;
    readonly option?: string;
  };
  readonly context?: { readonly open_message_id?: string; readonly open_chat_id?: string };
  readonly token?: string;
}

// --- Message helpers ---

export function buildOutboundPayload(content: string): OutboundPayload {
  if (containsMarkdownTable(content)) {
    return { msgType: "text", content: JSON.stringify({ text: content }) };
  }
  if (containsMarkdownSyntax(content)) {
    return {
      msgType: "post",
      content: JSON.stringify({ zh_cn: { content: _buildMarkdownPostRows(content) } }),
    };
  }
  return { msgType: "text", content: JSON.stringify({ text: content }) };
}

export function _buildMarkdownPostRows(content: string): unknown[][] {
  if (!content.includes("```")) {
    return [[{ tag: "md", text: content }]];
  }

  const rows: unknown[][] = [];
  const codeBlockPattern = /```[\s\S]*?```/g;
  let cursor = 0;
  let match: RegExpExecArray | null;
  while ((match = codeBlockPattern.exec(content)) !== null) {
    if (match.index > cursor) {
      rows.push([{ tag: "md", text: content.slice(cursor, match.index) }]);
    }
    rows.push([{ tag: "md", text: match[0] }]);
    cursor = match.index + match[0].length;
  }

  if (rows.length === 0) {
    return [[{ tag: "md", text: content }]];
  }
  if (cursor < content.length) {
    rows.push([{ tag: "md", text: content.slice(cursor) }]);
  }
  return rows;
}

export function _stripMarkdownToPlainText(text: string): string {
  return text
    .replace(/```[^\n`]*\n?([\s\S]*?)```/g, "$1")
    .replace(/`([^`\n]+)`/g, "$1")
    .replace(/!\[([^\]\n]*)\]\([^)]+\)/g, "$1")
    .replace(/\[([^\]\n]+)\]\([^)]+\)/g, "$1")
    .replace(/^ {0,3}#{1,6}\s+/gm, "")
    .replace(/^ {0,3}>\s?/gm, "")
    .replace(/^(\s*)[-*+]\s+/gm, "$1")
    .replace(/^(\s*)\d+[.)]\s+/gm, "$1")
    .replace(/\*\*([^*\n]+)\*\*/g, "$1")
    .replace(/__([^_\n]+)__/g, "$1")
    .replace(/~~([^~\n]+)~~/g, "$1")
    .replace(/(^|[^*])\*([^*\n]+)\*/g, "$1$2")
    .replace(/(^|[^_])_([^_\n]+)_/g, "$1$2");
}

/** Send a text message using the best Feishu message type for the content. */
export async function sendTextMessage(rt: FeishuRuntime, chatId: string, text: string): Promise<string | null> {
  const payload = buildOutboundPayload(text);
  const client = rt.client as unknown as {
    im: { v1: { message: { create: (p: unknown) => Promise<MessageCreateResponse> } } };
  };
  try {
    const res = await client.im.v1.message.create({
      params: { receive_id_type: "chat_id" },
      data: { receive_id: chatId, msg_type: payload.msgType, content: payload.content },
    });
    return messageIdFromResponse(res);
  } catch (e) {
    if (payload.msgType === "post" && isPostContentFormatError(e)) {
      try {
        const res = await client.im.v1.message.create({
          params: { receive_id_type: "chat_id" },
          data: {
            receive_id: chatId,
            msg_type: "text",
            content: JSON.stringify({ text: _stripMarkdownToPlainText(text) }),
          },
        });
        return messageIdFromResponse(res);
      } catch {
        return null;
      }
    }
    return null;
  }
}

/** Send a plain text message (fire-and-forget). */
export async function sendText(rt: FeishuRuntime, chatId: string, text: string): Promise<void> {
  await sendTextMessage(rt, chatId, text);
}

/** Patch a text-as-card message in-place (streaming updates). */
export async function patchTextMessage(rt: FeishuRuntime, messageId: string, text: string): Promise<void> {
  const payload = buildOutboundPayload(text);
  const card = buildInteractiveCardFromOutboundPayload(payload);
  const client = rt.client as unknown as {
    im: { v1: { message: { patch: (p: unknown) => Promise<unknown> } } };
  };
  try {
    await client.im.v1.message.patch({
      path: { message_id: messageId },
      params: { msg_type: "interactive" },
      data: { content: JSON.stringify(card) },
    });
  } catch (e) {
    rt.logger.warn({ messageId, err: e instanceof Error ? e.message : String(e) }, "patchTextMessage failed");
  }
}

/** Send an approval card with buttons. Returns message_id on success. */
export async function sendApprovalCard(
  rt: FeishuRuntime,
  chatId: string,
  title: string,
  body: string,
  buttons: ReadonlyArray<{ label: string; value: string; style?: "primary" | "default" | "danger" }>,
): Promise<string | null> {
  const card = {
    config: { wide_screen_mode: true },
    header: { title: { content: title, tag: "plain_text" }, template: "orange" },
    elements: [
      { tag: "markdown", content: body },
      {
        tag: "action",
        actions: buttons.map((button) => ({
          tag: "button",
          text: { tag: "plain_text", content: button.label },
          type: button.style ?? "default",
          value: { approval_action: button.value },
        })),
      },
    ],
  };
  const client = rt.client as unknown as {
    im: { v1: { message: { create: (p: unknown) => Promise<MessageCreateResponse> } } };
  };
  try {
    const res = await client.im.v1.message.create({
      params: { receive_id_type: "chat_id" },
      data: { receive_id: chatId, msg_type: "interactive", content: JSON.stringify(card) },
    });
    return messageIdFromResponse(res);
  } catch (e) {
    rt.logger.warn({ chatId, err: e instanceof Error ? e.message : String(e) }, "sendApprovalCard failed");
    return null;
  }
}

/** Update a card to show it has been resolved. */
export async function resolveCard(
  rt: FeishuRuntime,
  messageId: string,
  icon: string,
  label: string,
  template: "green" | "red",
  resolvedBy: string,
): Promise<void> {
  const card = {
    config: { wide_screen_mode: true },
    header: { title: { content: `${icon} ${label}`, tag: "plain_text" }, template },
    elements: [{ tag: "markdown", content: `${icon} **${label}** by ${resolvedBy}` }],
  };
  const client = rt.client as unknown as {
    im: { v1: { message: { patch: (p: unknown) => Promise<unknown> } } };
  };
  try {
    await client.im.v1.message.patch({
      path: { message_id: messageId },
      params: { msg_type: "interactive" },
      data: { content: JSON.stringify(card) },
    });
  } catch (e) {
    rt.logger.warn({ messageId, err: e instanceof Error ? e.message : String(e) }, "resolveCard failed");
  }
}

/** React to a message with an emoji. */
export async function reactToMessage(rt: FeishuRuntime, messageId: string, emoji: string): Promise<void> {
  try {
    await rt.client.request({
      method: "POST",
      url: `/open-apis/im/v1/messages/${messageId}/reactions`,
      data: { reaction_type: { emoji_type: emoji } },
    });
  } catch (e) {
    rt.logger.warn({ messageId, err: e instanceof Error ? e.message : String(e) }, "reactToMessage failed");
  }
}

/** Add a reaction to a message, returning the reaction_id (needed for later removal). */
export async function addReaction(rt: FeishuRuntime, messageId: string, emojiType: string): Promise<string | null> {
  try {
    const res = await rt.client.request({
      method: "POST",
      url: `/open-apis/im/v1/messages/${messageId}/reactions`,
      data: { reaction_type: { emoji_type: emojiType } },
    }) as ReactionCreateResponse;
    const reactionId = reactionIdFromResponse(res);
    if (reactionId === null) {
      rt.logger.warn({ messageId, emojiType }, "addReaction failed: response missing reaction_id");
    }
    return reactionId;
  } catch (e) {
    rt.logger.warn({ messageId, emojiType, err: e instanceof Error ? e.message : String(e) }, "addReaction failed");
    return null;
  }
}

/** Remove a previously added reaction by its reaction_id. */
export async function removeReaction(rt: FeishuRuntime, messageId: string, reactionId: string): Promise<boolean> {
  try {
    await rt.client.request({
      method: "DELETE",
      url: `/open-apis/im/v1/messages/${messageId}/reactions/${reactionId}`,
    });
    return true;
  } catch (e) {
    rt.logger.warn({ messageId, reactionId, err: e instanceof Error ? e.message : String(e) }, "removeReaction failed");
    return false;
  }
}

// --- File helpers ---

/** Download a file/image from a Feishu message to a local path. */
export async function downloadMessageFile(
  rt: FeishuRuntime,
  messageId: string,
  fileKey: string,
  savePath: string,
): Promise<void> {
  await mkdir(dirname(savePath), { recursive: true });
  try {
    const res = await rt.client.request({
      method: "GET",
      url: `/open-apis/im/v1/messages/${messageId}/resources/${fileKey}`,
      params: { type: "file" },
      responseType: "arraybuffer",
    }) as { data: Buffer };
    await writeFile(savePath, res.data);
  } catch (e) {
    rt.logger.warn({ messageId, fileKey, err: e instanceof Error ? e.message : String(e) }, "downloadMessageFile failed");
  }
}

/** Upload and send a file to a chat. */
export async function sendFile(rt: FeishuRuntime, chatId: string, filePath: string, fileName: string): Promise<string | null> {
  const client = rt.client as unknown as {
    im: { v1: {
      file: { create: (p: unknown) => Promise<FileCreateResponse> }
      message: { create: (p: unknown) => Promise<MessageCreateResponse> }
    } };
  };
  try {
    const buf = await readFile(filePath);
    const ext = fileName.split(".").pop() ?? "";
    const fileType = ext === "pdf" ? "pdf" : ext === "doc" ? "doc" : ext === "xls" ? "xls" : ext === "ppt" ? "ppt" : "stream";
    const uploadRes = await client.im.v1.file.create({ data: { file_type: fileType, file_name: fileName, file: buf } });
    const fileKey = fileKeyFromResponse(uploadRes);
    if (fileKey === undefined) {
      rt.logger.warn({ chatId, filePath }, "sendFile failed: upload response missing file_key");
      return null;
    }
    const msgRes = await client.im.v1.message.create({
      params: { receive_id_type: "chat_id" },
      data: { receive_id: chatId, msg_type: "file", content: JSON.stringify({ file_key: fileKey }) },
    });
    const messageId = messageIdFromResponse(msgRes);
    if (messageId === null) {
      rt.logger.warn({ chatId, filePath }, "sendFile failed: message response missing message_id");
    }
    return messageId;
  } catch (e) {
    rt.logger.warn({ chatId, filePath, err: e instanceof Error ? e.message : String(e) }, "sendFile failed");
    return null;
  }
}

type MessageCreateResponse = {
  readonly message_id?: string | undefined;
  readonly data?: { readonly message_id?: string | undefined } | undefined;
} | null;

type FileCreateResponse = {
  readonly file_key?: string | undefined;
  readonly data?: { readonly file_key?: string | undefined } | undefined;
} | null;

type ReactionCreateResponse = {
  readonly reaction_id?: string | undefined;
  readonly data?: { readonly reaction_id?: string | undefined } | undefined;
} | null;

function messageIdFromResponse(res: MessageCreateResponse): string | null {
  return res?.data?.message_id ?? res?.message_id ?? null;
}

function fileKeyFromResponse(res: FileCreateResponse): string | undefined {
  return res?.file_key ?? res?.data?.file_key;
}

function reactionIdFromResponse(res: ReactionCreateResponse): string | null {
  return res?.data?.reaction_id ?? res?.reaction_id ?? null;
}

function containsMarkdownSyntax(content: string): boolean {
  const patterns = [
    /^ {0,3}#{1,6}\s+\S/m,
    /^ {0,3}>\s+\S/m,
    /^ {0,3}(?:[-*+]\s+\S|\d+[.)]\s+\S)/m,
    /```/,
    /`[^`\n]+`/,
    /\*\*[^*\n]+\*\*/,
    /__[^_\n]+__/,
    /~~[^~\n]+~~/,
    /(^|[^*])\*[^*\s][^*\n]*\*(?!\*)/,
    /(^|[^_])_[^_\s][^_\n]*_(?!_)/,
    /\[[^\]\n]+\]\([^)]+\)/,
  ];
  return patterns.some((pattern) => pattern.test(content));
}

function containsMarkdownTable(content: string): boolean {
  const lines = content.split(/\r?\n/);
  for (let i = 0; i < lines.length - 1; i += 1) {
    const current = lines[i];
    const next = lines[i + 1];
    if (current !== undefined && next !== undefined && isTableHeaderLine(current) && isTableSeparatorLine(next)) {
      return true;
    }
  }
  return false;
}

function isTableHeaderLine(line: string): boolean {
  const trimmed = line.trim();
  return trimmed.startsWith("|") && trimmed.includes("|", 1);
}

function isTableSeparatorLine(line: string): boolean {
  const trimmed = line.trim();
  if (!trimmed.startsWith("|")) return false;
  const cells = trimmed.replace(/^\|/, "").replace(/\|$/, "").split("|");
  return cells.length > 0 && cells.every((cell) => /^:?-{3,}:?$/.test(cell.trim()));
}

function buildInteractiveCardFromOutboundPayload(payload: OutboundPayload): { elements: Array<{ tag: "div"; text: { tag: "lark_md"; content: string } }> } {
  return {
    elements: rowsFromOutboundPayload(payload).map((row) => ({
      tag: "div",
      text: { tag: "lark_md", content: row.map(markdownTextFromPostElement).join("") },
    })),
  };
}

function rowsFromOutboundPayload(payload: OutboundPayload): unknown[][] {
  if (payload.msgType !== "post") {
    return [[{ tag: "md", text: textFromTextPayload(payload.content) }]];
  }
  try {
    const parsed = JSON.parse(payload.content) as { zh_cn?: { content?: unknown } };
    return Array.isArray(parsed.zh_cn?.content) ? parsed.zh_cn.content as unknown[][] : [[{ tag: "md", text: "" }]];
  } catch {
    return [[{ tag: "md", text: "" }]];
  }
}

function textFromTextPayload(content: string): string {
  try {
    const parsed = JSON.parse(content) as { text?: unknown };
    return typeof parsed.text === "string" ? parsed.text : content;
  } catch {
    return content;
  }
}

function markdownTextFromPostElement(element: unknown): string {
  if (typeof element !== "object" || element === null) return "";
  const text = (element as { text?: unknown }).text;
  return typeof text === "string" ? text : "";
}

function isPostContentFormatError(error: unknown): boolean {
  return errorText(error).includes("content format of the post type is incorrect");
}

function errorText(error: unknown): string {
  if (error instanceof Error) {
    return `${error.message} ${errorText((error as { response?: unknown }).response)}`;
  }
  if (typeof error === "string") return error;
  if (typeof error === "object" && error !== null) {
    try {
      return JSON.stringify(error);
    } catch {
      return String(error);
    }
  }
  return String(error);
}

// --- Lark client + ws listener ---

export function createLarkClient(config: FeishuConfig): lark.Client {
  return new lark.Client({
    appId: config.appId,
    appSecret: config.appSecret,
    appType: lark.AppType.SelfBuild,
  });
}

export function startFeishuListenerWithClient(
  config: FeishuConfig,
  client: lark.Client,
  logger: FastifyBaseLogger,
  onMessage: (event: MessageReceiveEvent, rt: FeishuRuntime) => Promise<void>,
  onCardAction?: (event: CardActionEvent, rt: FeishuRuntime) => Promise<void>,
): FeishuRuntime {
  const wsClient = new lark.WSClient({
    appId: config.appId,
    appSecret: config.appSecret,
    domain: lark.Domain.Feishu,
    loggerLevel: lark.LoggerLevel.info,
  });
  const rt: FeishuRuntime = { client, logger };
  const handlers: Record<string, (data: unknown) => Promise<void>> = {
    "im.message.receive_v1": async (data) => {
      try { await onMessage(data as MessageReceiveEvent, rt); }
      catch (e) { logger.error({ err: e }, "feishu message handler threw"); }
    },
  };
  if (onCardAction !== undefined) {
    handlers["card.action.trigger"] = async (data) => {
      try { await onCardAction(data as CardActionEvent, rt); }
      catch (e) { logger.error({ err: e }, "feishu card action handler threw"); }
    };
  }
  void wsClient.start({ eventDispatcher: new lark.EventDispatcher({}).register(handlers) });
  return rt;
}

export function startFeishuListener(
  config: FeishuConfig,
  logger: FastifyBaseLogger,
  onMessage: (event: MessageReceiveEvent, rt: FeishuRuntime) => Promise<void>,
  onCardAction?: (event: CardActionEvent, rt: FeishuRuntime) => Promise<void>,
): FeishuRuntime {
  return startFeishuListenerWithClient(config, createLarkClient(config), logger, onMessage, onCardAction);
}