"use client";

import type { ReactElement } from "react";
import type {
  BlockData,
  BlockType,
} from "../types";
import {
  isBlackboardBlockData,
  isExerciseBlockData,
  isHomeworkBlockData,
  isImportBlockData,
  isKeyPointBlockData,
  isNewTeachingBlockData,
  isObjectiveBlockData,
  isReflectionBlockData,
  isRichTextBlockData,
  isSummaryBlockData,
  isTextStudyBlockData,
} from "../lib/type-guards";
import { RichTextBlock } from "../components/blocks/rich-text-block";
import { ExerciseBlock } from "../components/blocks/exercise-block";
import { TextStudyBlock } from "../components/blocks/text-study-block";
import { ObjectiveBlock } from "../components/blocks/objective-block";
import { KeyPointBlock } from "../components/blocks/key-point-block";
import { ImportBlock } from "../components/blocks/import-block";
import { NewTeachingBlock } from "../components/blocks/new-teaching-block";
import { SummaryBlock } from "../components/blocks/summary-block";
import { HomeworkBlock } from "../components/blocks/homework-block";
import { BlackboardBlock } from "../components/blocks/blackboard-block";
import { ReflectionBlock } from "../components/blocks/reflection-block";

/**
 * Block 注册表：配置驱动渲染。
 * 新增 Block 类型只需在此注册，无需修改 NodeEditPanel。
 */

export interface BlockRenderProps {
  blockId: string;
  data: BlockData;
  textbookId?: string;
  chapterId?: string;
  classes?: { id: string; name: string }[];
  /** V5-5：当前课案 ID（仅 RichTextBlock 用于素材库 picker 关联） */
  planId?: string;
  onUpdate: (data: BlockData) => void;
}

export interface BlockRegistryEntry {
  /** 是否为富文本类（共享 RichTextBlock 编辑器） */
  isRichText?: boolean;
}

/**
 * Block 注册表元数据（单一数据源，P0-9 修复）。
 * isRichText 属性是判断富文本 block 的唯一权威来源。
 * 组件渲染由 BlockRenderer 统一处理，避免在 render 中动态获取组件引用。
 */
export const BLOCK_REGISTRY: Record<BlockType, BlockRegistryEntry> = {
  objective: {},
  key_point: {},
  import: {},
  new_teaching: {},
  consolidation: { isRichText: true },
  summary: {},
  homework: {},
  blackboard: {},
  text_study: {},
  exercise: {},
  rich_text: { isRichText: true },
  reflection: {},
};

/**
 * 判断某 BlockType 是否为富文本类。
 * P0-9 修复：统一以 BLOCK_REGISTRY.isRichText 为唯一数据源，
 * 删除 constants.ts 中的 RICH_TEXT_BLOCK_TYPES 和此处的 RICH_TEXT_TYPES 冗余定义。
 */
export function isRichTextBlock(type: BlockType): boolean {
  return BLOCK_REGISTRY[type]?.isRichText === true;
}

/**
 * 静态 Block 渲染组件。
 * 根据 type 从注册表查找并渲染对应 Block，所有组件引用均为模块顶层静态声明，
 * 满足 react-hooks/static-components 规则。
 * 新增 Block 类型时，在此 switch 中添加对应 case 即可。
 *
 * V3 修复：使用类型守卫替代 `as` 断言，安全收窄 BlockData 联合类型。
 * 类型守卫失败时返回 null（理论上不会发生，因为 type 与 data 由调用方保证一致）。
 */
export function BlockRenderer(props: BlockRenderProps & { type: BlockType }): ReactElement | null {
  const { type, ...rest } = props;
  switch (type) {
    case "objective": {
      if (!isObjectiveBlockData(rest.data)) return null;
      return (
        <ObjectiveBlock
          data={rest.data}
          onUpdate={(d) => rest.onUpdate(d)}
        />
      );
    }
    case "key_point": {
      if (!isKeyPointBlockData(rest.data)) return null;
      return (
        <KeyPointBlock
          data={rest.data}
          onUpdate={(d) => rest.onUpdate(d)}
        />
      );
    }
    case "import": {
      if (!isImportBlockData(rest.data)) return null;
      return (
        <ImportBlock
          data={rest.data}
          onUpdate={(d) => rest.onUpdate(d)}
        />
      );
    }
    case "new_teaching": {
      if (!isNewTeachingBlockData(rest.data)) return null;
      return (
        <NewTeachingBlock
          data={rest.data}
          textbookId={rest.textbookId}
          chapterId={rest.chapterId}
          onUpdate={(d) => rest.onUpdate(d)}
        />
      );
    }
    case "summary": {
      if (!isSummaryBlockData(rest.data)) return null;
      return (
        <SummaryBlock
          data={rest.data}
          onUpdate={(d) => rest.onUpdate(d)}
        />
      );
    }
    case "homework": {
      if (!isHomeworkBlockData(rest.data)) return null;
      return (
        <HomeworkBlock
          data={rest.data}
          onUpdate={(d) => rest.onUpdate(d)}
        />
      );
    }
    case "blackboard": {
      if (!isBlackboardBlockData(rest.data)) return null;
      return (
        <BlackboardBlock
          data={rest.data}
          textbookId={rest.textbookId}
          chapterId={rest.chapterId}
          onUpdate={(d) => rest.onUpdate(d)}
        />
      );
    }
    case "reflection": {
      if (!isReflectionBlockData(rest.data)) return null;
      return (
        <ReflectionBlock
          data={rest.data}
          onUpdate={(d) => rest.onUpdate(d)}
        />
      );
    }
    case "exercise": {
      if (!isExerciseBlockData(rest.data)) return null;
      return (
        <ExerciseBlock
          blockId={rest.blockId}
          data={rest.data}
          classes={rest.classes ?? []}
          textbookId={rest.textbookId}
          chapterId={rest.chapterId}
        />
      );
    }
    case "text_study": {
      if (!isTextStudyBlockData(rest.data)) return null;
      return <TextStudyBlock blockId={rest.blockId} data={rest.data} />;
    }
    case "rich_text":
    case "consolidation": {
      if (!isRichTextBlockData(rest.data)) return null;
      return (
        <RichTextBlock
          data={rest.data}
          textbookId={rest.textbookId}
          chapterId={rest.chapterId}
          planId={rest.planId}
          blockId={rest.blockId}
          onUpdate={(d) => rest.onUpdate(d)}
        />
      );
    }
    default:
      return null;
  }
}