import { type Editor, Extension, type Range } from '@tiptap/core';
import { PluginKey } from '@tiptap/pm/state';
import { Suggestion, type SuggestionKeyDownProps, type SuggestionProps } from '@tiptap/suggestion';

interface CommandItem {
  title: string;
  description: string;
  icon: string;
  command: (props: { editor: Editor; range: Range }) => void;
}

/**
 * 斜杠命令扩展的选项。
 *
 * `onImageUpload` 由宿主注入（参见 index.ts），用于把用户选择的图片文件
 * 上传到服务端并返回可访问的 URL。未提供时"上传图片"命令会被隐藏，
 * 只保留"图片链接"（手动填 URL）。
 */
export interface SlashCommandOptions {
  onImageUpload?: (file: File) => Promise<string>;
  /** 由 index.ts 注入：直接调 coordinator.insertUploading（走占位符 + 上传）。 */
  onInsertUploading?: (file: File) => void;
}

const SlashCommandPluginKey = new PluginKey('slashCommand');

/**
 * 斜杠命令扩展。
 *
 * `onImageUpload` 通过 `addOptions` 注入，"上传图片"命令据此决定是否出现。
 */
export const SlashCommand = Extension.create<SlashCommandOptions>({
  name: 'slashCommand',

  addOptions() {
    return {
      onImageUpload: undefined,
      onInsertUploading: undefined,
    };
  },

  addProseMirrorPlugins() {
    // 依据是否提供上传回调，决定可用命令集。
    const uploadFn = this.options.onImageUpload;
    const COMMANDS: CommandItem[] = [
      {
        title: '标题 1',
        description: '大标题',
        icon: 'H1',
        command: ({ editor, range }) => {
          editor.chain().focus().deleteRange(range).setHeading({ level: 1 }).run();
        },
      },
      {
        title: '标题 2',
        description: '中标题',
        icon: 'H2',
        command: ({ editor, range }) => {
          editor.chain().focus().deleteRange(range).setHeading({ level: 2 }).run();
        },
      },
      {
        title: '标题 3',
        description: '小标题',
        icon: 'H3',
        command: ({ editor, range }) => {
          editor.chain().focus().deleteRange(range).setHeading({ level: 3 }).run();
        },
      },
      {
        title: '无序列表',
        description: '创建无序列表',
        icon: '•',
        command: ({ editor, range }) => {
          editor.chain().focus().deleteRange(range).toggleBulletList().run();
        },
      },
      {
        title: '有序列表',
        description: '创建有序列表',
        icon: '1.',
        command: ({ editor, range }) => {
          editor.chain().focus().deleteRange(range).toggleOrderedList().run();
        },
      },
      {
        title: '任务列表',
        description: '创建任务列表',
        icon: '☑',
        command: ({ editor, range }) => {
          editor.chain().focus().deleteRange(range).toggleTaskList().run();
        },
      },
      {
        title: '引用',
        description: '插入引用块',
        icon: '❝',
        command: ({ editor, range }) => {
          editor.chain().focus().deleteRange(range).toggleBlockquote().run();
        },
      },
      {
        title: '代码块',
        description: '插入代码块',
        icon: '<>',
        command: ({ editor, range }) => {
          editor.chain().focus().deleteRange(range).toggleCodeBlock().run();
        },
      },
      {
        title: '分割线',
        description: '插入水平分割线',
        icon: '—',
        command: ({ editor, range }) => {
          editor.chain().focus().deleteRange(range).setHorizontalRule().run();
        },
      },
      {
        title: '表格',
        description: '插入 3×3 表格',
        icon: '▦',
        command: ({ editor, range }) => {
          editor
            .chain()
            .focus()
            .deleteRange(range)
            .insertTable({ rows: 3, cols: 3, withHeaderRow: true })
            .run();
        },
      },
    ];

    // 图片相关命令：上传命令仅在上传回调可用时才出现。
    if (uploadFn) {
      COMMANDS.push({
        title: '上传图片',
        description: '从本地选择并上传图片',
        icon: '📤',
        command: ({ editor, range }) => {
          // 必须先删掉 /命令 文本，文件选择对话框会阻塞，关闭后 range 可能失效。
          editor.chain().focus().deleteRange(range).run();
          const input = document.createElement('input');
          input.type = 'file';
          input.accept = 'image/jpeg,image/png,image/gif,image/webp';
          input.addEventListener('change', () => {
            const file = input.files?.[0];
            if (!file) return;
            // 优先走 coordinator（占位符 + 上传），否则退回直接上传（无占位符）
            if (this.options.onInsertUploading) {
              this.options.onInsertUploading(file);
            } else if (uploadFn) {
              uploadFn(file)
                .then((url) => {
                  editor.chain().focus().setImage({ src: url }).run();
                })
                .catch((err) => {
                  const msg = err instanceof Error ? err.message : String(err);
                  console.error('[SlashCommand] Upload failed:', msg);
                });
            }
          });
          // click() 会立即触发原生文件选择器；回调在用户选择文件后异步执行。
          input.click();
        },
      });
    }

    COMMANDS.push(
      {
        title: '图片链接',
        description: '通过 URL 插入图片',
        icon: '🖼',
        command: ({ editor, range }) => {
          const url = window.prompt('输入图片 URL');
          if (url && isValidUrl(url)) {
            editor.chain().focus().deleteRange(range).setImage({ src: url }).run();
          }
        },
      },
      {
        title: '链接',
        description: '插入链接',
        icon: '🔗',
        command: ({ editor, range }) => {
          const url = window.prompt('输入链接 URL');
          if (!url || !isValidUrl(url)) return;
          // deleteRange 后光标停在 range.to；先插入 URL 文本，再选中刚插入的范围设 link
          // （setLink 需要非空选区才生效，原顺序 setLink 在空选区无效）。
          const insertFrom = range.to;
          editor
            .chain()
            .focus()
            .deleteRange(range)
            .insertContent(url)
            .setTextSelection({ from: insertFrom, to: insertFrom + url.length })
            .setLink({ href: url })
            .run();
        },
      },
    );

    return [
      Suggestion<CommandItem>({
        pluginKey: SlashCommandPluginKey,
        editor: this.editor,
        char: '/',
        items: ({ query }) => {
          return COMMANDS.filter(
            (item) =>
              item.title.toLowerCase().includes(query.toLowerCase()) ||
              item.description.toLowerCase().includes(query.toLowerCase()),
          );
        },
        render() {
          let popup: SlashPopup | null = null;

          return {
            onStart(props) {
              popup = createPopup(props);
            },
            onUpdate(props) {
              if (!popup) return;
              popup.updateItems(props.items);
              popup.updatePosition();
            },
            onKeyDown(props) {
              if (!popup) return false;
              return popup.onKeyDown(props);
            },
            onExit() {
              if (popup) {
                popup.destroy();
                popup = null;
              }
            },
          };
        },
        command: ({ editor, range, props: item }) => {
          item.command({ editor, range });
        },
      }),
    ];
  },
});

/** 斜杠命令浮层实例:供 Suggestion render 生命周期驱动。 */
interface SlashPopup {
  component: HTMLElement;
  updateItems(items: CommandItem[]): void;
  updatePosition(): void;
  onKeyDown(props: SuggestionKeyDownProps): boolean;
  destroy(): void;
}

/** 校验图片/链接 URL:只允许 http(s) 和 data:image。拒绝 javascript: 等。 */
export function isValidUrl(url: string): boolean {
  return /^https?:\/\//i.test(url) || /^data:image\//i.test(url);
}

function createPopup(props: SuggestionProps<CommandItem>): SlashPopup {
  const component = document.createElement('div');
  component.classList.add('slash-command');

  const list = document.createElement('div');
  list.classList.add('slash-command-list');
  component.appendChild(list);

  let selectedIndex = 0;
  let currentItems: CommandItem[] = [];

  function renderItems(items: CommandItem[]) {
    currentItems = items;
    list.innerHTML = '';
    selectedIndex = 0;

    items.forEach((item, index) => {
      const el = document.createElement('div');
      el.classList.add('slash-command-item');
      if (index === 0) el.classList.add('is-selected');

      el.innerHTML = `
        <div class="slash-command-item-icon">${item.icon}</div>
        <div class="slash-command-item-text">
          <div class="slash-command-item-title">${item.title}</div>
          <div class="slash-command-item-desc">${item.description}</div>
        </div>
      `;

      el.addEventListener('click', () => {
        props.command(item);
      });

      el.addEventListener('mouseenter', () => {
        selectedIndex = index;
        updateSelection();
      });

      list.appendChild(el);
    });
  }

  function updateSelection() {
    const children = list.children;
    for (let i = 0; i < children.length; i++) {
      if (i === selectedIndex) {
        children[i].classList.add('is-selected');
      } else {
        children[i].classList.remove('is-selected');
      }
    }
    children[selectedIndex]?.scrollIntoView({ block: 'nearest' });
  }

  function selectItem() {
    if (currentItems[selectedIndex]) {
      props.command(currentItems[selectedIndex]);
    }
  }

  function updatePosition() {
    const rect = props.clientRect?.();
    if (!rect) return;
    component.style.left = `${rect.left}px`;
    component.style.top = `${rect.bottom + 4}px`;
  }

  renderItems(props.items);
  document.body.appendChild(component);
  updatePosition();

  return {
    component,
    updateItems(items: CommandItem[]) {
      renderItems(items);
    },
    updatePosition,
    onKeyDown({ event }: SuggestionKeyDownProps): boolean {
      if (event.key === 'ArrowUp') {
        event.preventDefault();
        selectedIndex = (selectedIndex - 1 + currentItems.length) % currentItems.length;
        updateSelection();
        return true;
      }
      if (event.key === 'ArrowDown') {
        event.preventDefault();
        selectedIndex = (selectedIndex + 1) % currentItems.length;
        updateSelection();
        return true;
      }
      if (event.key === 'Enter') {
        event.preventDefault();
        selectItem();
        return true;
      }
      if (event.key === 'Escape') {
        event.preventDefault();
        return true;
      }
      return false;
    },
    destroy() {
      component.remove();
    },
  };
}