'use client';

import { useEffect, useState, type MouseEvent, type ReactNode } from 'react';
import { ArrowLeft, ArrowRight, RotateCcw } from 'lucide-react';
import type { Lesson, ReviewItem, ReviewLesson } from './lesson-types';
import { getModule } from './module-catalog';
import { courseHref } from './course-navigation';
import {
  emptyReviewState,
  restoreReviewState,
  reviewProgress,
  reviewSignature,
  type ReviewState,
} from './review-state';
import './review.css';

type Navigate = (module: string, lesson?: string) => void;
function ReviewLink({
  module,
  lesson,
  navigate,
  children,
  className,
}: {
  module: string;
  lesson?: string;
  navigate: Navigate;
  children: ReactNode;
  className?: string;
}) {
  return (
    <a
      href={courseHref(module, lesson)}
      className={className}
      onClick={(event: MouseEvent<HTMLAnchorElement>) => {
        if (
          event.button !== 0 ||
          event.metaKey ||
          event.ctrlKey ||
          event.shiftKey ||
          event.altKey
        )
          return;
        event.preventDefault();
        navigate(module, lesson);
      }}
    >
      {children}
    </a>
  );
}

export function ReviewPage({
  lesson,
  lessons,
  navigate,
}: {
  lesson: ReviewLesson;
  lessons: Lesson[];
  navigate: Navigate;
}) {
  const [state, setState] = useState<ReviewState>(emptyReviewState);
  const [loaded, setLoaded] = useState(false);
  const [storageUnavailable, setStorageUnavailable] = useState(false);
  const [attempt, setAttempt] = useState(0);
  const storageKey = `shuhe:module-review:v1:${lesson.sourceModule}`;
  useEffect(() => {
    try {
      // oxlint-disable-next-line react/react-compiler -- Restore this browser's saved answers after hydration; server rendering cannot read localStorage.
      setState(restoreReviewState(localStorage.getItem(storageKey), lesson));
    } catch {
      setStorageUnavailable(true);
    }
    setLoaded(true);
  }, [lesson, storageKey]);
  function update(next: ReviewState) {
    setState(next);
    try {
      localStorage.setItem(
        storageKey,
        JSON.stringify({
          sourceModule: lesson.sourceModule,
          signature: reviewSignature(lesson),
          state: next,
        }),
      );
    } catch {
      setStorageUnavailable(true);
    }
  }
  const progress = reviewProgress(lesson, state);
  const source = getModule(lesson.sourceModule);
  const index = lessons.findIndex((item) => item.id === lesson.id);
  function question(item: ReviewItem, order: number, challenge = false) {
    const prefix = challenge ? '情境' : '问题';
    return (
      <article
        className="review-question"
        id={`review-${item.id}`}
        key={`${item.id}-${attempt}`}
      >
        <div className="review-question-number">
          {prefix} {String(order + 1).padStart(2, '0')}
        </div>
        <h3>{item.title}</h3>
        <p className="review-prompt">{item.prompt}</p>
        <details className="review-notes">
          <summary>记下我的回答（可选）</summary>
          <label htmlFor={`review-note-${item.id}`}>
            先写判断、原因和验证方式，再看参考要点。
          </label>
          <textarea
            id={`review-note-${item.id}`}
            rows={4}
            maxLength={4000}
            disabled={!loaded}
            value={state.notes[item.id] || ''}
            onChange={(event) =>
              update({
                ...state,
                notes: { ...state.notes, [item.id]: event.target.value },
              })
            }
          />
        </details>
        <details className="review-answer">
          <summary>展开参考要点与易错点</summary>
          <div>
            <p>
              对照推理是否完整。表述可以不同；能够解释原因、边界与验证方法，才算独立答出。
            </p>
            <ul>
              {item.checkpoints.map((point) => (
                <li key={point}>{point}</li>
              ))}
            </ul>
            <p className="review-misconception">
              <strong>容易误判：</strong>
              {item.misconception}
            </p>
          </div>
        </details>
        <fieldset className="review-rating" disabled={!loaded}>
          <legend>
            {challenge
              ? '合上要点后，我能独立推演这个变化吗？'
              : '合上要点后，我能用自己的话解释吗？'}
          </legend>
          <label>
            <input
              type="radio"
              name={`review-rating-${item.id}`}
              value="revisit"
              checked={state.answers[item.id] === 'revisit'}
              onChange={() =>
                update({
                  ...state,
                  answers: { ...state.answers, [item.id]: 'revisit' },
                })
              }
            />
            还需要回学
          </label>
          <label>
            <input
              type="radio"
              name={`review-rating-${item.id}`}
              value="ready"
              checked={state.answers[item.id] === 'ready'}
              onChange={() =>
                update({
                  ...state,
                  answers: { ...state.answers, [item.id]: 'ready' },
                })
              }
            />
            {challenge ? '能独立推演并说明取舍' : '能独立解释并举例'}
          </label>
        </fieldset>
        <div className="review-revisit">
          <span>需要时回学：</span>
          {item.revisit.map((link) => (
            <ReviewLink
              key={link.lessonId}
              module={lesson.sourceModule}
              lesson={link.lessonId}
              navigate={navigate}
            >
              {link.lessonId} · {link.label}
              <ArrowRight size={13} />
            </ReviewLink>
          ))}
        </div>
      </article>
    );
  }
  return (
    <article className="lesson-article review-page">
      <ReviewLink module="review" navigate={navigate} className="back-link">
        <ArrowLeft size={14} />
        复盘与自测 · 全部单元
      </ReviewLink>
      <div className="eyebrow">
        REVIEW {lesson.id} / {lessons.length}
        <span />
        {lesson.group}
      </div>
      <h1 className="lesson-title" tabIndex={-1}>
        {lesson.title}
      </h1>
      <p className="lead">{lesson.summary}</p>
      <div className="meta-row">
        <span>{source?.name}</span>
        <span>{lesson.questions.length} 个理解问题</span>
        <span>{lesson.challenges.length} 个情境推演</span>
      </div>
      <section id="review-start" className="lesson-start">
        <div className="section-heading">
          <h2>先独立回答，再对照</h2>
        </div>
        <p className="lesson-scenario">{lesson.intro.scenario}</p>
        <ul>
          {lesson.intro.startingPoint.map((item) => (
            <li key={item}>{item}</li>
          ))}
        </ul>
        <p className="lesson-outcome">
          <strong>本轮目标</strong>
          {lesson.intro.outcome}
        </p>
        <ol className="review-method">
          <li>先合上原课件，用自己的话回答；需要时记下思路。</li>
          <li>
            展开要点找遗漏，再合上要点重述；依赖提示才能答出的题标为“还需要回学”。
          </li>
          <li>
            完成情境推演，并核对四项掌握标准的实际证据。阅读过答案本身不作为掌握依据。
          </li>
        </ol>
        {state.contentChanged && (
          <p className="learning-section-note">
            问题或掌握标准已有更新，旧笔记已保留供参考；旧自评已清除，请按本轮内容重新回答和核对证据。
          </p>
        )}
        <p className="learning-section-note">
          {storageUnavailable
            ? '当前浏览器无法保存记录，回答暂留在本页；离开前请自行保存。'
            : '回答与自评自动保存在当前浏览器，可下次继续。更换浏览器或清除浏览数据后需要重新记录。'}
        </p>
      </section>
      <section id="review-questions">
        <div className="section-heading">
          <h2>核心理解问题</h2>
          <span>说清发生了什么，以及为什么</span>
        </div>
        {lesson.questions.map((item, i) => question(item, i))}
      </section>
      <section id="review-challenges">
        <div className="section-heading">
          <h2>换个情况，再想一步</h2>
          <span>条件变化后，判断还成立吗</span>
        </div>
        {lesson.challenges.map((item, i) => question(item, i, true))}
      </section>
      <section id="review-mastery">
        <div className="section-heading">
          <h2>达到什么程度，算掌握这个模块</h2>
        </div>
        <p>
          每项都需要能拿出下面的证据。操作类证据在自己的练习环境验证；设计类证据用图、推演或文字说明。
        </p>
        <fieldset className="review-evidence" disabled={!loaded}>
          <legend className="sr-only">掌握标准与证据</legend>
          {lesson.mastery.map((item) => (
            <label key={item.id} aria-label={item.text}>
              <input
                type="checkbox"
                checked={!!state.evidence[item.id]}
                onChange={(event) =>
                  update({
                    ...state,
                    evidence: {
                      ...state.evidence,
                      [item.id]: event.target.checked,
                    },
                  })
                }
              />
              <span>
                <strong>{item.text}</strong>
                <span>{item.evidence}</span>
              </span>
            </label>
          ))}
        </fieldset>
      </section>
      <section id="review-result">
        <div className="section-heading">
          <h2>本轮自测结果与回学计划</h2>
        </div>
        <div
          className={`review-result${progress.mastered ? ' review-result-ready' : ''}`}
          aria-live="polite"
        >
          <strong>
            {progress.mastered
              ? '按你的自评，已达到本模块的掌握标准'
              : '本轮还有待验证的部分'}
          </strong>
          <p>
            独立回答 {progress.ready} / {progress.total} 项 · 掌握证据{' '}
            {progress.evidence} / {progress.evidenceTotal} 项
          </p>
          <p>
            {progress.mastered
              ? '请隔一天换一个商品或故障条件，再闭卷推演一次，确认能够复用。这里记录的是你的自评，不对文字答案自动判分。'
              : '理解问题和情境推演都能独立完成，且四项证据均已核对，才达到本轮标准。先补齐下面的缺口，再回来自测。'}
          </p>
        </div>
        {progress.revisit.length > 0 && (
          <ul className="review-gaps">
            {progress.revisit.map((item) => (
              <li key={item.id}>
                <a href={`#review-${item.id}`}>{item.title}</a>
                <span>
                  {state.answers[item.id] === 'revisit'
                    ? '已标记需回学'
                    : '尚未自评'}
                </span>
              </li>
            ))}
          </ul>
        )}
        {lesson.mastery.filter((item) => !state.evidence[item.id]).length >
          0 && (
          <div className="review-pending-evidence">
            <h3>还需要补齐的掌握证据</h3>
            <ul>
              {lesson.mastery
                .filter((item) => !state.evidence[item.id])
                .map((item) => (
                  <li key={item.id}>
                    <a href="#review-mastery">{item.text}</a>
                  </li>
                ))}
            </ul>
          </div>
        )}
        <div className="review-result-actions">
          <ReviewLink
            module={lesson.sourceModule}
            navigate={navigate}
            className="secondary-link"
          >
            回到{source?.name}
            <ArrowRight size={15} />
          </ReviewLink>
          <button
            type="button"
            className="review-reset"
            disabled={!loaded}
            onClick={() => {
              update(emptyReviewState());
              setAttempt((value) => value + 1);
            }}
          >
            <RotateCcw size={14} />
            清除本单元回答与自评，重新开始
          </button>
        </div>
      </section>
      <div className="lesson-pagination">
        <ReviewLink
          module="review"
          lesson={index > 0 ? lessons[index - 1].id : undefined}
          navigate={navigate}
        >
          <span>
            <ArrowLeft size={13} />
            {index > 0 ? '上一单元' : '复盘概览'}
          </span>
          <strong>
            {index > 0 ? lessons[index - 1].title : '选择要自测的模块'}
          </strong>
        </ReviewLink>
        <ReviewLink
          module="review"
          lesson={
            index < lessons.length - 1 ? lessons[index + 1].id : undefined
          }
          navigate={navigate}
          className="next"
        >
          <span>
            {index < lessons.length - 1 ? '下一单元' : '回到复盘概览'}
            <ArrowRight size={13} />
          </span>
          <strong>
            {index < lessons.length - 1
              ? lessons[index + 1].title
              : '选择下一轮要巩固的模块'}
          </strong>
        </ReviewLink>
      </div>
    </article>
  );
}