/**
 * ChatbotSDK 入口文件
 * 单例模式，IIFE 挂载 window.ChatbotSDK
 *
 * 参数映射：
 *   integrateId → roleId（客服角色 ID）
 *   userId → accountId（客户账号 ID）
 *   chatId → 自动管理（从 /conversation/list 获取或自动生成）
 */
import { SDKConfig, ResolvedConfig, ChatbotSDKInstance } from './types';
import { parseConfig } from './config';
import { setDebug, logger } from './logger';
import { setApiConfig } from './api';
import { injectStyles, removeStyles } from './styles';
import { createLauncher, createChatWindow, enableDrag } from './dom';
import { initChat, initChatHistory, getMessages, setCategory, loadHistoryConversations, sendQuickReply, retryFromMessage, handleFeedback } from './chat';
import { clearMessages } from './storage';
import { setLocale } from './i18n';

// ==================== 单例状态 ====================

let config: ResolvedConfig | null = null;
let isInitialized = false;
let launcherEl: HTMLElement | null = null;
let windowEl: HTMLElement | null = null;
let messagesContainer: HTMLElement | null = null;
let inputEl: HTMLTextAreaElement | null = null;
let sendBtn: HTMLElement | null = null;
let clearBtn: HTMLElement | null = null;
let categorySelect: HTMLSelectElement | null = null;
let historyPanel: HTMLElement | null = null;
let showLoadingFn: (() => HTMLElement) | null = null;
let hideLoadingFn: (() => void) | null = null;
let dragCleanup: (() => void) | null = null;

/** 提示气泡元素 */
let teaserEl: HTMLElement | null = null;
/** 提示气泡定时器 */
let teaserTimer: ReturnType<typeof setTimeout> | null = null;
/** 未读徽章元素（挂在 launcher 内部） */
let badgeEl: HTMLElement | null = null;

// ==================== 公开 API ====================

/** 初始化 SDK */
function init(rawConfig: SDKConfig): void {
  if (isInitialized) {
    logger.warn('SDK 已初始化，请先调用 destroy() 再重新初始化');
    return;
  }

  // 1. 配置解析与校验
  const parsed = parseConfig(rawConfig);
  if (!parsed) return;
  config = parsed;

  // 2. 设置国际化语言
  setLocale(config.locale);

  // 3. 设置日志级别
  setDebug(config.debug);

  // 4. 设置 API 配置
  setApiConfig(config);

  // 5. 注入样式
  injectStyles(config);

  // 6. 创建悬浮按钮
  launcherEl = createLauncher(config, toggle);
  document.body.appendChild(launcherEl);

  // 获取未读徽章引用（由 createLauncher 创建）
  badgeEl = launcherEl.querySelector('.csk-launcher__badge');

  // 7. 创建聊天弹窗
  const dom = createChatWindow(config);
  windowEl = dom.window;
  messagesContainer = dom.messagesContainer;
  inputEl = dom.inputEl;
  sendBtn = dom.sendBtn;
  clearBtn = dom.clearBtn;
  categorySelect = dom.categorySelect;
  historyPanel = dom.historyPanel;
  showLoadingFn = dom.showLoading;
  hideLoadingFn = dom.hideLoading;
  document.body.appendChild(windowEl);

  // 8. 安置提示气泡（挂在 launcher 同层，由配置控制显示）
  teaserEl = dom.teaserEl;
  document.body.appendChild(teaserEl);
  positionTeaser();

  // 9. 启用拖拽
  const headerEl = windowEl.querySelector('.csk-header') as HTMLElement;
  if (headerEl) {
    dragCleanup = enableDrag(headerEl, windowEl);
  }

  // 10. 初始化对话模块
  initChat(config, {
    messagesContainer,
    inputEl,
    sendBtn,
    clearBtn,
    categorySelect,
    historyPanel,
    welcomeEl: dom.welcomeEl,
    newMsgBtn: dom.newMsgBtn,
    searchInput: dom.searchInput,
    ariaLiveEl: dom.ariaLiveEl,
    showLoading: showLoadingFn,
    hideLoading: hideLoadingFn,
  });

  // 11. 监听知识库分类切换事件
  windowEl.addEventListener('csk:categoryChange', ((e: CustomEvent) => {
    setCategory(e.detail.categoryId);
  }) as EventListener);

  // 12. 监听会话管理面板加载事件
  windowEl.addEventListener('csk:loadHistory', () => {
    loadHistoryConversations();
  });

  // 13. 监听快捷问题芯片点击
  windowEl.addEventListener('csk:quickReply', ((e: CustomEvent) => {
    sendQuickReply(e.detail.text);
  }) as EventListener);

  // 14. 监听 AI 消息重试事件
  windowEl.addEventListener('csk:retry', ((e: CustomEvent) => {
    retryFromMessage(e.detail.msgId);
  }) as EventListener);

  // 15. 监听消息反馈事件（👍 / 👎）
  windowEl.addEventListener('csk:feedback', ((e: CustomEvent) => {
    handleFeedback(e.detail.msgId, e.detail.value);
  }) as EventListener);

  // 16. 新消息到达通知（用于未读徽章）
  windowEl.addEventListener('csk:newMessage', () => {
    notifyNewMessage();
  });

  // 17. ESC 键关闭弹窗
  document.addEventListener('keydown', onKeyDown);

  // 17. 窗口 resize 时重新定位 teaser
  window.addEventListener('resize', onResize);

  isInitialized = true;
  logger.lifecycleInit(config.integrateId, config.requestDomain);

  // 18. 首访提示气泡（延迟显示，弹窗未打开时生效）
  if (config.showTeaser) {
    teaserTimer = setTimeout(() => {
      // 弹窗关闭时才显示
      if (windowEl && windowEl.classList.contains('csk-window--hidden')) {
        showTeaser();
      }
    }, 1500);
  }

  // 19. 异步初始化 chatId 和对话历史（不阻塞 UI）
  initChatHistory().catch(err => {
    logger.warn('chatId 初始化失败，将在发送消息时重试', err);
  });
}

// ==================== 提示气泡控制 ====================

/** 根据 launcher 位置定位 teaser 气泡 */
function positionTeaser(): void {
  if (!teaserEl || !launcherEl) return;
  const rect = launcherEl.getBoundingClientRect();
  const isLeft = config?.position === 'left-bottom';
  if (isLeft) {
    teaserEl.style.left = `${rect.left}px`;
  } else {
    teaserEl.style.right = `${window.innerWidth - rect.right}px`;
  }
  teaserEl.style.bottom = `${window.innerHeight - rect.top + 8}px`;
}

function showTeaser(): void {
  if (!teaserEl) return;
  positionTeaser();
  teaserEl.classList.remove('csk-teaser--hidden');
  // 点击气泡本身 → 打开弹窗
  teaserEl.addEventListener('click', onTeaserClick);
  // 关闭按钮（阻止冒泡，不打开弹窗）
  const closeBtn = teaserEl.querySelector('.csk-teaser__close');
  if (closeBtn) {
    closeBtn.addEventListener('click', onTeaserClose);
  }
}

function hideTeaser(): void {
  if (!teaserEl) return;
  teaserEl.classList.add('csk-teaser--hidden');
  teaserEl.removeEventListener('click', onTeaserClick);
  const closeBtn = teaserEl.querySelector('.csk-teaser__close');
  if (closeBtn) closeBtn.removeEventListener('click', onTeaserClose);
}

function onTeaserClick(e: Event): void {
  // 关闭按钮点击不打开弹窗
  if ((e.target as HTMLElement).closest('.csk-teaser__close')) return;
  hideTeaser();
  open();
}

function onTeaserClose(e: Event): void {
  e.stopPropagation();
  hideTeaser();
}

function onResize(): void {
  if (teaserEl && !teaserEl.classList.contains('csk-teaser--hidden')) {
    positionTeaser();
  }
}

// ==================== 未读徽章 ====================

function showBadge(): void {
  if (badgeEl) badgeEl.classList.remove('csk-launcher__badge--hidden');
}

function hideBadge(): void {
  if (badgeEl) badgeEl.classList.add('csk-launcher__badge--hidden');
}

/** 新消息到达时弹窗关闭，则显示徽章 */
function notifyNewMessage(): void {
  if (windowEl && windowEl.classList.contains('csk-window--hidden')) {
    showBadge();
  }
}

// ==================== a11y 焦点陷阱 ====================

/** 弹窗内可聚焦元素选择器 */
const FOCUSABLE = 'button, [href], input, select, textarea, [tabindex]:not([tabindex="-1"])';

function trapFocus(e: KeyboardEvent): void {
  if (!windowEl || windowEl.classList.contains('csk-window--hidden')) return;
  if (e.key !== 'Tab') return;

  const focusables = Array.from(windowEl.querySelectorAll(FOCUSABLE)) as HTMLElement[];
  if (focusables.length === 0) return;

  const first = focusables[0];
  const last = focusables[focusables.length - 1];

  if (e.shiftKey) {
    // Shift+Tab：在第一个元素上按 → 跳到最后一个
    if (document.activeElement === first) {
      e.preventDefault();
      last.focus();
    }
  } else {
    // Tab：在最后一个元素上按 → 跳到第一个
    if (document.activeElement === last) {
      e.preventDefault();
      first.focus();
    }
  }
}

// ==================== 全局键盘事件 ====================

function onKeyDown(e: KeyboardEvent): void {
  if (e.key === 'Escape' && windowEl && !windowEl.classList.contains('csk-window--hidden')) {
    close();
  }
  trapFocus(e);
}

/** 销毁 SDK 实例 */
function destroy(): void {
  if (!isInitialized) return;

  if (teaserTimer) { clearTimeout(teaserTimer); teaserTimer = null; }
  hideTeaser();
  if (teaserEl && teaserEl.parentNode) { teaserEl.parentNode.removeChild(teaserEl); teaserEl = null; }

  if (launcherEl && launcherEl.parentNode) { launcherEl.parentNode.removeChild(launcherEl); launcherEl = null; }
  if (windowEl && windowEl.parentNode) { windowEl.parentNode.removeChild(windowEl); windowEl = null; }
  if (dragCleanup) { dragCleanup(); dragCleanup = null; }

  removeStyles();
  document.removeEventListener('keydown', onKeyDown);
  window.removeEventListener('resize', onResize);

  const oldIntegrateId = config?.integrateId;
  config = null;
  isInitialized = false;
  messagesContainer = null;
  inputEl = null;
  sendBtn = null;
  clearBtn = null;
  categorySelect = null;
  historyPanel = null;
  showLoadingFn = null;
  hideLoadingFn = null;
  badgeEl = null;

  logger.lifecycleDestroy(oldIntegrateId || '');
}

function open(): void {
  if (!windowEl) return;
  windowEl.classList.remove('csk-window--hidden');
  hideTeaser();
  hideBadge();
  setTimeout(() => { if (inputEl) inputEl.focus(); }, 80);
}

function close(): void {
  if (!windowEl) return;
  windowEl.classList.add('csk-window--hidden');
}

function toggle(): void {
  if (!windowEl) return;
  if (windowEl.classList.contains('csk-window--hidden')) {
    open();
  } else {
    close();
  }
}

function clearHistory(): void {
  if (!config) return;
  if (clearBtn) { clearBtn.click(); }
  else if (confirm('确定清空所有对话记录？')) { clearMessages(config.integrateId); }
}

// ==================== 挂载到全局 ====================

const ChatbotSDK: ChatbotSDKInstance = {
  init,
  destroy,
  open,
  close,
  toggle,
  clearHistory,
};

if (typeof window !== 'undefined') {
  (window as unknown as Record<string, unknown>).ChatbotSDK = ChatbotSDK;
}

export default ChatbotSDK;