"use client";

import { useState, useEffect } from "react";
import Link from "next/link";
import { getTopicCurriculum } from "../config";
import { canWatchLesson } from "@/app/cloudphone/lib/payment";
import { isBookmarked, toggleBookmark, getBookmarks, getCompletedLessons } from "@/app/cloudphone/lib/learning";

type TopicCurriculumProps = {
  topicId: string;
};

export function TopicCurriculum({ topicId }: TopicCurriculumProps) {
  const [expanded, setExpanded] = useState<Record<number, boolean>>({});
  const [bookmarks, setBookmarks] = useState<Set<string>>(new Set());
  const [completed, setCompleted] = useState<Set<string>>(new Set());

  const curriculum = getTopicCurriculum(topicId);

  useEffect(() => {
    setBookmarks(getBookmarks());
    setCompleted(getCompletedLessons());
    const onB = () => setBookmarks(getBookmarks());
    const onP = () => setCompleted(getCompletedLessons());
    window.addEventListener("learning:bookmarks", onB);
    window.addEventListener("learning:progress", onP);
    return () => {
      window.removeEventListener("learning:bookmarks", onB);
      window.removeEventListener("learning:progress", onP);
    };
  }, []);

  useEffect(() => {
    const curr = getTopicCurriculum(topicId);
    if (curr?.modules?.length) {
      setExpanded((prev) => {
        const next = { ...prev };
        curr.modules.forEach((_, i) => {
          if (next[i] === undefined) next[i] = i === 0;
        });
        return next;
      });
    }
  }, [topicId]);

  const toggle = (i: number) => {
    setExpanded((prev) => ({ ...prev, [i]: !prev[i] }));
  };

  if (!curriculum?.hasContent || !curriculum.modules.length) return null;

  const modules = curriculum.modules;

  return (
    <section className="border-t border-[var(--border)] py-12 md:py-16 lg:py-20">
      <div className="mx-auto max-w-6xl px-4 sm:px-6">
        <h2 className="mb-4 text-center text-xl font-bold sm:text-2xl md:text-3xl">实战课程</h2>
        <p className="mb-6 text-center text-[var(--muted-foreground)] sm:mb-8 md:mb-10">
          从入门到进阶，完整学习路径
        </p>
        <div className="space-y-2 md:space-y-3">
          {modules.map((module, i) => {
            const isOpen = expanded[i] ?? true;
            return (
              <div
                key={module.title}
                className="animate__animated animate__fadeInUp overflow-hidden rounded-xl border border-[var(--border)] bg-[var(--card)] shadow-sm transition-all duration-200 hover:border-[var(--accent)]/30 hover:shadow-md md:rounded-2xl"
                style={{ animationDelay: `${i * 0.06}s`, animationFillMode: "both" }}
              >
                <button
                  type="button"
                  onClick={() => toggle(i)}
                  className="flex w-full items-center justify-between gap-3 px-4 py-3 text-left transition hover:bg-[var(--muted)]/50 sm:px-5 sm:py-4"
                >
                  <span className="flex items-center gap-2 text-base font-semibold sm:text-lg">
                    <span
                      className={`inline-block transition-transform duration-200 ${isOpen ? "rotate-90" : ""}`}
                    >
                      ▶
                    </span>
                    <span>{module.emoji}</span>
                    {module.title}
                  </span>
                  <span className="text-sm text-[var(--muted-foreground)]">{module.lessons.length} 节</span>
                </button>
                {isOpen && (
                  <ul className="border-t border-[var(--border)]">
                    {module.lessons.map((lesson, li) => {
                      const origMod = module.originalModuleIndex;
                      const free = origMod === 0 && li < 2;
                      const unlocked = canWatchLesson(origMod, li);
                      const key = `${origMod}-${li}`;
                      const bookmarked = isBookmarked(origMod, li);
                      const isCompleted = completed.has(key);
                      return (
                        <li key={key}>
                          <Link
                            href={`/cloudphone/course/${origMod}/${li}`}
                            className="flex flex-col gap-1 px-4 py-3 transition hover:bg-[var(--muted)]/50 sm:flex-row sm:items-center sm:justify-between sm:px-5 sm:py-3"
                          >
                            <span className="flex items-center gap-2 truncate sm:gap-3">
                              <button
                                type="button"
                                onClick={(e) => {
                                  e.preventDefault();
                                  e.stopPropagation();
                                  toggleBookmark(origMod, li);
                                }}
                                className="shrink-0 text-xs"
                                aria-label={bookmarked ? "取消收藏" : "收藏"}
                              >
                                {bookmarked ? "⭐" : "☆"}
                              </button>
                              <span
                                className={
                                  unlocked ? "text-[var(--foreground)]" : "text-[var(--muted-foreground)]"
                                }
                              >
                                {lesson.name}
                              </span>
                              {free && (
                                <span className="shrink-0 rounded bg-[var(--accent)]/20 px-1.5 py-0.5 text-xs text-[var(--accent)]">
                                  试看
                                </span>
                              )}
                              {isCompleted && (
                                <span className="shrink-0 rounded bg-green-500/20 px-1.5 py-0.5 text-xs text-green-600 dark:text-green-400">
                                  ✓
                                </span>
                              )}
                              {!unlocked && (
                                <span className="shrink-0 text-xs text-[var(--muted-foreground)]">🔒</span>
                              )}
                            </span>
                            <span className="flex shrink-0 items-center gap-2 text-xs text-[var(--muted-foreground)] sm:text-sm">
                              {lesson.duration}
                              <span className="text-[var(--accent)]">→</span>
                            </span>
                          </Link>
                        </li>
                      );
                    })}
                  </ul>
                )}
              </div>
            );
          })}
        </div>
      </div>
    </section>
  );
}