import { useEffect, useState } from "react";
import { useParams, useNavigate } from "react-router-dom";
import { api } from "../../../utils/api";
import { useAuthStore } from "../../../stores/authStore";
import type { PracticeSheet } from "../../../types/sheet";
import { CircleQuestionMark, Clock, Layers, Loader, Tag } from "lucide-react";
import {
  Carousel,
  CarouselContent,
  CarouselItem,
  type CarouselApi,
} from "../../../components/ui/carousel";
import { useExamConfigStore } from "../../../stores/useExamConfigStore";

// ─── Shared background dots (same subtle config as rest of app) ───────────────
const DOTS = [
  { size: 10, color: "#f97316", top: "8%", left: "5%", delay: "0s" },
  { size: 7, color: "#a855f7", top: "28%", left: "2%", delay: "1.2s" },
  { size: 9, color: "#22c55e", top: "60%", left: "4%", delay: "0.6s" },
  { size: 12, color: "#3b82f6", top: "12%", right: "4%", delay: "1.8s" },
  { size: 7, color: "#f43f5e", top: "45%", right: "3%", delay: "0.9s" },
  { size: 9, color: "#eab308", top: "75%", right: "6%", delay: "0.4s" },
];

const STYLES = `
  @import url('https://fonts.googleapis.com/css2?family=Nunito:wght@400;700;800;900&family=Nunito+Sans:wght@400;600;700&display=swap');

  .pt-screen {
    min-height: 100vh;
    background: #fffbf4;
    font-family: 'Nunito', sans-serif;
    position: relative;
    overflow-x: hidden;
  }

  /* ── Blobs ── */
  .pt-blob { position: fixed; pointer-events: none; z-index: 0; filter: blur(48px); opacity: 0.35; }
  .pt-blob-1 { width:240px;height:240px;background:#fde68a;top:-80px;left:-80px;border-radius:60% 40% 70% 30%/50% 60% 40% 50%;animation:ptWobble1 14s ease-in-out infinite; }
  .pt-blob-2 { width:190px;height:190px;background:#a5f3c0;bottom:-50px;left:6%;border-radius:40% 60% 30% 70%/60% 40% 60% 40%;animation:ptWobble2 16s ease-in-out infinite; }
  .pt-blob-3 { width:210px;height:210px;background:#fbcfe8;top:15%;right:-60px;border-radius:70% 30% 50% 50%/40% 60% 40% 60%;animation:ptWobble1 18s ease-in-out infinite reverse; }
  .pt-blob-4 { width:150px;height:150px;background:#bfdbfe;bottom:12%;right:2%;border-radius:50% 50% 30% 70%/60% 40% 60% 40%;animation:ptWobble2 12s ease-in-out infinite; }

  @keyframes ptWobble1 {
    0%,100%{border-radius:60% 40% 70% 30%/50% 60% 40% 50%;transform:translate(0,0) rotate(0deg);}
    50%{border-radius:40% 60% 30% 70%/60% 40% 60% 40%;transform:translate(12px,16px) rotate(8deg);}
  }
  @keyframes ptWobble2 {
    0%,100%{border-radius:40% 60% 30% 70%/60% 40% 60% 40%;transform:translate(0,0) rotate(0deg);}
    50%{border-radius:60% 40% 70% 30%/40% 60% 40% 60%;transform:translate(-10px,12px) rotate(-6deg);}
  }

  /* ── Floating dots ── */
  .pt-dot { position:fixed;border-radius:50%;pointer-events:none;z-index:0;opacity:0.3;animation:ptFloat 7s ease-in-out infinite; }
  @keyframes ptFloat {
    0%,100%{transform:translateY(0) rotate(0deg);}
    50%{transform:translateY(-12px) rotate(180deg);}
  }

  /* ── Inner scroll container ── */
  .pt-inner {
    position: relative; z-index: 1;
    max-width: 580px; margin: 0 auto;
    padding: 2rem 1.25rem 4rem;
    display: flex; flex-direction: column; gap: 1.25rem;
  }

  /* ── Pop-in animation ── */
  @keyframes ptPopIn {
    from { opacity:0; transform: scale(0.92) translateY(12px); }
    to   { opacity:1; transform: scale(1) translateY(0); }
  }
  .pt-anim   { animation: ptPopIn 0.4s cubic-bezier(0.34,1.56,0.64,1) both; }
  .pt-anim-1 { animation-delay: 0.05s; }
  .pt-anim-2 { animation-delay: 0.1s; }
  .pt-anim-3 { animation-delay: 0.15s; }
  .pt-anim-4 { animation-delay: 0.2s; }
  .pt-anim-5 { animation-delay: 0.25s; }

  /* ── Header ── */
  .pt-header { animation: ptPopIn 0.4s cubic-bezier(0.34,1.56,0.64,1) both; }
  .pt-eyebrow {
    font-size: 0.65rem; font-weight: 800; letter-spacing: 0.16em;
    text-transform: uppercase; color: #a855f7; margin-bottom: 0.3rem;
  }
  .pt-title {
    font-size: clamp(1.6rem, 5vw, 2.2rem); font-weight: 900;
    color: #1e1b4b; letter-spacing: -0.02em; line-height: 1.15;
  }
  .pt-desc {
    font-family: 'Nunito Sans', sans-serif;
    font-size: 0.9rem; font-weight: 600; color: #9ca3af; margin-top: 0.3rem;
  }

  /* ── White card base ── */
  .pt-card {
    background: white; border: 2.5px solid #f3f4f6; border-radius: 24px;
    padding: 1.25rem 1.5rem;
    box-shadow: 0 6px 20px rgba(0,0,0,0.04);
    box-sizing: border-box;
  }

  /* ── Stats row ── */
  .pt-stats-row {
    display: grid; grid-template-columns: repeat(3, 1fr); gap: 0.75rem;
  }
  .pt-stat {
    display: flex; flex-direction: column; align-items: center;
    gap: 0.5rem; padding: 0.85rem 0.5rem;
    background: white; border: 2.5px solid #f3f4f6; border-radius: 20px;
    box-shadow: 0 3px 10px rgba(0,0,0,0.04);
  }
  .pt-stat-icon {
    width: 44px; height: 44px; border-radius: 50%;
    display: flex; align-items: center; justify-content: center;
  }
  .pt-stat-icon.cyan   { background: #cffafe; }
  .pt-stat-icon.purple { background: #f3e8ff; }
  .pt-stat-icon.amber  { background: #fef3c7; }
  .pt-stat-value { font-size: 1.4rem; font-weight: 900; color: #1e1b4b; line-height: 1; }
  .pt-stat-label { font-size: 0.65rem; font-weight: 700; letter-spacing: 0.1em; text-transform: uppercase; color: #9ca3af; }

  /* ── Loading skeleton ── */
  .pt-loading {
    display: flex; flex-direction: column; align-items: center;
    gap: 0.75rem; padding: 2rem;
    background: white; border: 2.5px solid #f3f4f6; border-radius: 24px;
    box-shadow: 0 6px 20px rgba(0,0,0,0.04);
  }
  .pt-spinner { animation: ptSpin 0.8s linear infinite; }
  @keyframes ptSpin { to { transform: rotate(360deg); } }
  .pt-loading-text {
    font-size: 0.85rem; font-weight: 700; color: #9ca3af;
  }

  /* ── Module carousel card ── */
  .pt-module-card {
    background: white; border: 2.5px solid #f3f4f6; border-radius: 24px;
    padding: 1.25rem 1.5rem;
    box-shadow: 0 6px 20px rgba(0,0,0,0.04);
    display: flex; flex-direction: column; gap: 1rem;
  }
  .pt-module-header {
    display: flex; align-items: center; gap: 0.6rem;
  }
  .pt-section-badge {
    font-size: 0.65rem; font-weight: 800; letter-spacing: 0.12em;
    text-transform: uppercase; color: #a855f7;
    background: #f3e8ff; border-radius: 100px; padding: 0.25rem 0.7rem;
  }
  .pt-module-title {
    font-size: 0.95rem; font-weight: 900; color: #1e1b4b; line-height: 1.3;
  }
  .pt-module-stats {
    display: grid; grid-template-columns: repeat(3, 1fr); gap: 0.6rem;
  }
  .pt-module-stat {
    display: flex; flex-direction: column; align-items: center; gap: 0.4rem;
    padding: 0.7rem 0.4rem;
    border: 2px solid #f3f4f6; border-radius: 16px;
    background: #fafafa;
  }
  .pt-module-stat-icon {
    width: 36px; height: 36px; border-radius: 50%;
    display: flex; align-items: center; justify-content: center;
  }
  .pt-module-stat-icon.cyan   { background: #cffafe; }
  .pt-module-stat-icon.lime   { background: #d9f99d; }
  .pt-module-stat-icon.amber  { background: #fef3c7; }
  .pt-module-stat-value { font-size: 1rem; font-weight: 900; color: #1e1b4b; line-height: 1; }
  .pt-module-stat-label { font-size: 0.6rem; font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase; color: #9ca3af; }

  /* ── Dot indicator ── */
  .pt-dots {
    display: flex; align-items: center; justify-content: center; gap: 0.4rem;
    margin-top: 0.75rem;
  }
  .pt-dot-ind {
    border-radius: 100px; height: 7px;
    transition: width 0.3s ease, background 0.3s ease;
  }
  .pt-dot-ind.active { width: 20px; background: #a855f7; }
  .pt-dot-ind.inactive { width: 7px; background: #e5e7eb; }

  /* ── Tip card ── */
  .pt-tip {
    display: flex; align-items: flex-start; gap: 0.75rem;
  }
  .pt-tip-emoji { font-size: 1.4rem; flex-shrink: 0; margin-top: 2px; }
  .pt-tip-text { font-size: 0.88rem; font-weight: 700; color: #374151; line-height: 1.5; }

  /* ── Start button ── */
  .pt-start-btn {
    width: 100%;
    background: #f97316; color: white; border: none; border-radius: 100px;
    padding: 1.1rem; font-family: 'Nunito', sans-serif;
    font-size: 1rem; font-weight: 800; cursor: pointer;
    box-shadow: 0 6px 0 #c2560e, 0 8px 20px rgba(249,115,22,0.25);
    transition: transform 0.1s ease, box-shadow 0.1s ease;
    display: flex; align-items: center; justify-content: center; gap: 0.5rem;
  }
  .pt-start-btn:hover:not(:disabled) { transform:translateY(-2px); box-shadow:0 8px 0 #c2560e,0 12px 24px rgba(249,115,22,0.3); }
  .pt-start-btn:active:not(:disabled) { transform:translateY(3px); box-shadow:0 3px 0 #c2560e,0 4px 12px rgba(249,115,22,0.2); }
  .pt-start-btn:disabled { opacity:0.6; cursor:not-allowed; box-shadow:none; }

  /* ── Error card ── */
  .pt-error {
    background: #fff5f5; border: 2.5px solid #fecaca; border-radius: 24px;
    padding: 1.5rem; text-align: center;
    font-size: 0.9rem; font-weight: 700; color: #ef4444;
  }
`;

export const Pretest = () => {
  const { setSheetId, setMode, storeDuration, setQuestionCount } =
    useExamConfigStore();
  const user = useAuthStore((state) => state.user);
  const { sheetId } = useParams<{ sheetId: string }>();
  const navigate = useNavigate();

  const [carouselApi, setCarouselApi] = useState<CarouselApi>();
  const [current, setCurrent] = useState(0);
  const [practiceSheet, setPracticeSheet] = useState<PracticeSheet | null>(
    null,
  );

  function handleStartTest(id: string) {
    if (!id) return;
    setSheetId(id);
    setMode("SIMULATION");
    storeDuration(practiceSheet?.time_limit ?? 0);
    setQuestionCount(2);
    navigate(`/student/practice/${id}/test`, { replace: true });
  }

  useEffect(() => {
    if (!user) return;
    async function fetchSheet(id: string) {
      const authStorage = localStorage.getItem("auth-storage");
      if (!authStorage) return;
      const {
        state: { token },
      } = JSON.parse(authStorage);
      if (!token) return;
      const data = await api.getPracticeSheetById(token, id);
      setPracticeSheet(data);
    }
    fetchSheet(sheetId!);
  }, [sheetId, user]);

  useEffect(() => {
    if (!carouselApi) return;
    setCurrent(carouselApi.selectedScrollSnap() + 1);
    carouselApi.on("select", () =>
      setCurrent(carouselApi.selectedScrollSnap() + 1),
    );
  }, [carouselApi]);

  return (
    <div className="pt-screen">
      <style>{STYLES}</style>

      {/* Blobs */}
      <div className="pt-blob pt-blob-1" />
      <div className="pt-blob pt-blob-2" />
      <div className="pt-blob pt-blob-3" />
      <div className="pt-blob pt-blob-4" />

      {/* Floating dots */}
      {DOTS.map((d, i) => (
        <div
          key={i}
          className="pt-dot"
          style={
            {
              width: d.size,
              height: d.size,
              background: d.color,
              top: d.top,
              left: d.left,
              right: d.right,
              animationDelay: d.delay,
              animationDuration: `${5 + i * 0.5}s`,
            } as React.CSSProperties
          }
        />
      ))}

      <div className="pt-inner">
        {/* ── Header ── */}
        <header className="pt-header">
          <p className="pt-eyebrow">📋 Practice Sheet</p>
          {practiceSheet ? (
            <>
              <h1 className="pt-title">{practiceSheet.title}</h1>
              <p className="pt-desc">{practiceSheet.description}</p>
            </>
          ) : (
            <>
              <div
                style={{
                  height: "2rem",
                  width: "70%",
                  background: "#f3f4f6",
                  borderRadius: 8,
                  marginBottom: "0.5rem",
                }}
              />
              <div
                style={{
                  height: "1rem",
                  width: "50%",
                  background: "#f3f4f6",
                  borderRadius: 8,
                }}
              />
            </>
          )}
        </header>

        {/* ── At-a-glance stats ── */}
        {practiceSheet ? (
          <div className="pt-stats-row pt-anim pt-anim-1">
            <div className="pt-stat">
              <div className="pt-stat-icon cyan">
                <Clock size={22} color="#0891b2" />
              </div>
              <span className="pt-stat-value">{practiceSheet.time_limit}</span>
              <span className="pt-stat-label">Minutes</span>
            </div>
            <div className="pt-stat">
              <div className="pt-stat-icon purple">
                <Layers size={22} color="#9333ea" />
              </div>
              <span className="pt-stat-value">
                {practiceSheet.modules.length}
              </span>
              <span className="pt-stat-label">Modules</span>
            </div>
            <div className="pt-stat">
              <div className="pt-stat-icon amber">
                <CircleQuestionMark size={22} color="#d97706" />
              </div>
              <span className="pt-stat-value">
                {practiceSheet.questions_count}
              </span>
              <span className="pt-stat-label">Questions</span>
            </div>
          </div>
        ) : (
          <div className="pt-loading pt-anim pt-anim-1">
            <Loader size={26} className="pt-spinner" color="#a855f7" />
            <p className="pt-loading-text">Loading sheet details...</p>
          </div>
        )}

        {/* ── Module carousel ── */}
        <div className="pt-anim pt-anim-2">
          <Carousel setApi={setCarouselApi}>
            <CarouselContent>
              {practiceSheet ? (
                practiceSheet.modules.length > 0 ? (
                  practiceSheet.modules.map((module, index) => (
                    <CarouselItem key={index}>
                      <div className="pt-module-card">
                        <div className="pt-module-header">
                          <span className="pt-section-badge">
                            Section {Math.floor(index / 2) + 1}
                          </span>
                        </div>
                        <p className="pt-module-title">{module.title}</p>
                        <div className="pt-module-stats">
                          <div className="pt-module-stat">
                            <div className="pt-module-stat-icon cyan">
                              <Clock size={18} color="#0891b2" />
                            </div>
                            <span className="pt-module-stat-value">
                              {module.duration}
                            </span>
                            <span className="pt-module-stat-label">Min</span>
                          </div>
                          <div className="pt-module-stat">
                            <div className="pt-module-stat-icon lime">
                              <CircleQuestionMark size={18} color="#65a30d" />
                            </div>
                            <span className="pt-module-stat-value">
                              {module.questions.length}
                            </span>
                            <span className="pt-module-stat-label">
                              Questions
                            </span>
                          </div>
                          <div className="pt-module-stat">
                            <div className="pt-module-stat-icon amber">
                              <Tag size={18} color="#d97706" />
                            </div>
                            <span
                              className="pt-module-stat-value"
                              style={{ fontSize: "0.85rem" }}
                            >
                              {module.section}
                            </span>
                            <span className="pt-module-stat-label">Type</span>
                          </div>
                        </div>
                      </div>
                    </CarouselItem>
                  ))
                ) : (
                  <CarouselItem>
                    <div className="pt-error">
                      😕 No modules available for this sheet.
                    </div>
                  </CarouselItem>
                )
              ) : (
                <CarouselItem>
                  <div className="pt-loading">
                    <Loader size={26} className="pt-spinner" color="#a855f7" />
                    <p className="pt-loading-text">Loading modules...</p>
                  </div>
                </CarouselItem>
              )}
            </CarouselContent>

            {/* Dot indicator */}
            {practiceSheet && practiceSheet.modules.length > 1 && (
              <div className="pt-dots">
                {practiceSheet.modules.map((_, i) => (
                  <div
                    key={i}
                    className={`pt-dot-ind ${i + 1 === current ? "active" : "inactive"}`}
                  />
                ))}
              </div>
            )}
          </Carousel>
        </div>

        {/* ── Encouragement tip ── */}
        <div className="pt-card pt-anim pt-anim-3">
          <div className="pt-tip">
            <span className="pt-tip-emoji">💪</span>
            <p className="pt-tip-text">
              Take your time, read each question carefully, and do your best.
              Every practice run brings you closer to your goal!
            </p>
          </div>
        </div>

        {/* ── Start button ── */}
        <button
          className="pt-start-btn pt-anim pt-anim-4"
          onClick={() => handleStartTest(practiceSheet?.id!)}
          disabled={!practiceSheet}
        >
          {practiceSheet ? (
            <>Start Test →</>
          ) : (
            <Loader size={20} className="pt-spinner" />
          )}
        </button>
      </div>
    </div>
  );
};