import { useEffect, useState } from "react";
import { useAuthStore } from "../../../stores/authStore";
import type { Topic } from "../../../types/topic";
import { api } from "../../../utils/api";
import { ChoiceCard } from "../../../components/ChoiceCard";
import { AnimatePresence, motion } from "framer-motion";
import { slideVariants } from "../../../lib/utils";
import { ArrowLeft, Loader2, Search, Zap } from "lucide-react";
import { useExamConfigStore } from "../../../stores/useExamConfigStore";
import { useNavigate } from "react-router-dom";

type Step = "topic" | "review";
const STEPS: Step[] = ["topic", "review"];

const DOTS = [
  { size: 10, color: "#f97316", top: "6%", left: "4%", delay: "0s" },
  { size: 7, color: "#a855f7", top: "28%", left: "2%", delay: "1.2s" },
  { size: 9, color: "#22c55e", top: "62%", left: "3%", delay: "0.6s" },
  { size: 12, color: "#3b82f6", top: "10%", right: "4%", delay: "1.8s" },
  { size: 7, color: "#f43f5e", top: "48%", right: "2%", delay: "0.9s" },
  { size: 9, color: "#eab308", top: "76%", right: "5%", 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');

  :root { --content-max: 1100px; }

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

  .dr-blob { position:fixed;pointer-events:none;z-index:0;filter:blur(48px);opacity:0.35; }
  .dr-blob-1 { width:240px;height:240px;background:#fde68a;top:-80px;left:-80px;border-radius:60% 40% 70% 30%/50% 60% 40% 50%;animation:drWobble1 14s ease-in-out infinite; }
  .dr-blob-2 { width:190px;height:190px;background:#a5f3fc;bottom:-50px;left:6%;border-radius:40% 60% 30% 70%/60% 40% 60% 40%;animation:drWobble2 16s ease-in-out infinite; }
  .dr-blob-3 { width:210px;height:210px;background:#fbcfe8;top:15%;right:-60px;border-radius:70% 30% 50% 50%/40% 60% 40% 60%;animation:drWobble1 18s ease-in-out infinite reverse; }
  .dr-blob-4 { width:150px;height:150px;background:#bfdbfe;bottom:12%;right:2%;border-radius:50% 50% 30% 70%/60% 40% 60% 40%;animation:drWobble2 12s ease-in-out infinite; }

  @keyframes drWobble1 {
    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 drWobble2 {
    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);}
  }

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

  .dr-inner {
    position: relative; z-index: 1;
    max-width: 560px; margin: 0 auto;
    padding: 2rem 1.25rem 8rem;
    display: flex; flex-direction: column; gap: 1.5rem;
  }

  @keyframes drPopIn {
    from { opacity:0; transform:scale(0.92) translateY(12px); }
    to   { opacity:1; transform:scale(1) translateY(0); }
  }
  .dr-anim   { animation: drPopIn 0.4s cubic-bezier(0.34,1.56,0.64,1) both; }
  .dr-anim-1 { animation-delay:0.05s; }
  .dr-anim-2 { animation-delay:0.1s; }

  /* Header */
  .dr-header-row { display:flex;align-items:center;gap:0.75rem; }
  .dr-back-btn {
    width:40px;height:40px;border-radius:50%;
    background:white;border:2.5px solid #f3f4f6;
    display:flex;align-items:center;justify-content:center;
    cursor:pointer;box-shadow:0 3px 10px rgba(0,0,0,0.05);
    transition:all 0.15s ease;flex-shrink:0;
  }
  .dr-back-btn:hover { border-color:#a5f3fc;background:#ecfeff; }
  .dr-back-btn:active { transform:scale(0.9); }
  .dr-back-btn.hidden { opacity:0;pointer-events:none; }

  .dr-eyebrow {
    font-size:0.62rem;font-weight:800;letter-spacing:0.16em;
    text-transform:uppercase;color:#0891b2;
    display:flex;align-items:center;gap:0.35rem;
  }
  .dr-title {
    font-size:1.75rem;font-weight:900;color:#1e1b4b;
    letter-spacing:-0.02em;line-height:1.15;
  }
  .dr-sub {
    font-family:'Nunito Sans',sans-serif;
    font-size:0.82rem;font-weight:600;color:#9ca3af;
    margin-top:0.2rem;line-height:1.5;
  }

  /* Progress */
  .dr-progress-wrap {
    background:white;border:2.5px solid #f3f4f6;
    border-radius:100px;overflow:hidden;height:8px;
    box-shadow:0 2px 8px rgba(0,0,0,0.04);
  }
  .dr-progress-fill {
    height:100%;
    background:linear-gradient(90deg,#22d3ee,#0891b2);
    border-radius:100px;
    transition:width 0.5s cubic-bezier(0.34,1.56,0.64,1);
  }
  .dr-progress-labels {
    display:flex;justify-content:space-between;
    font-size:0.6rem;font-weight:800;letter-spacing:0.1em;
    text-transform:uppercase;color:#d1d5db;
    margin-top:0.35rem;padding:0 0.1rem;
  }
  .dr-progress-labels span.done { color:#0891b2; }

  /* Step card */
  .dr-step-card {
    background:white;border:2.5px solid #f3f4f6;
    border-radius:24px;padding:1.25rem;
    box-shadow:0 4px 20px rgba(0,0,0,0.05);
    display:flex;flex-direction:column;gap:1rem;
  }
  .dr-step-title {
    font-size:1rem;font-weight:900;color:#1e1b4b;
    display:flex;align-items:center;gap:0.5rem;
  }
  .dr-step-badge {
    font-size:0.58rem;font-weight:800;letter-spacing:0.1em;
    text-transform:uppercase;padding:0.2rem 0.55rem;
    border-radius:100px;background:#ecfeff;
    border:2px solid #a5f3fc;color:#0891b2;
  }

  /* Search */
  .dr-search-wrap { position:relative; }
  .dr-search-icon {
    position:absolute;left:0.85rem;top:50%;
    transform:translateY(-50%);pointer-events:none;color:#9ca3af;
  }
  .dr-search-input {
    width:100%;padding:0.7rem 1rem 0.7rem 2.5rem;
    background:#f9fafb;border:2.5px solid #f3f4f6;
    border-radius:14px;
    font-family:'Nunito Sans',sans-serif;
    font-size:0.85rem;font-weight:600;color:#1e1b4b;
    outline:none;transition:all 0.2s ease;
    box-sizing:border-box;
  }
  .dr-search-input:focus {
    border-color:#67e8f9;background:white;
    box-shadow:0 0 0 3px rgba(8,145,178,0.1);
  }
  .dr-search-input::placeholder { color:#9ca3af; }

  /* Topic grid */
  .dr-topic-grid {
    display:grid;grid-template-columns:1fr;
    gap:0.6rem;max-height:380px;overflow-y:auto;
    padding-right:0.25rem;
  }
  @media(min-width:480px){ .dr-topic-grid { grid-template-columns:1fr 1fr; } }

  /* Loading / empty */
  .dr-loading {
    display:flex;align-items:center;justify-content:center;
    gap:0.6rem;padding:2rem;
    font-size:0.85rem;font-weight:700;color:#9ca3af;
  }
  .dr-spinner { animation:drSpin 0.8s linear infinite; }
  @keyframes drSpin { to { transform:rotate(360deg); } }
  .dr-empty { text-align:center;padding:2rem;color:#9ca3af;font-size:0.85rem;font-weight:700; }

  /* Review rows */
  .dr-review-row {
    display:flex;align-items:flex-start;gap:0.75rem;
    padding:0.85rem 0;border-bottom:2px solid #f9fafb;
  }
  .dr-review-row:last-child { border-bottom:none;padding-bottom:0; }
  .dr-review-icon {
    width:34px;height:34px;border-radius:10px;flex-shrink:0;
    display:flex;align-items:center;justify-content:center;font-size:0.95rem;
  }
  .dr-review-label {
    font-size:0.62rem;font-weight:800;letter-spacing:0.12em;
    text-transform:uppercase;color:#9ca3af;
  }
  .dr-review-value {
    font-size:0.9rem;font-weight:800;color:#1e1b4b;
    margin-top:0.1rem;line-height:1.4;
  }
  .dr-chip-wrap { display:flex;flex-wrap:wrap;gap:0.35rem;margin-top:0.35rem; }
  .dr-chip {
    background:#ecfeff;border:2px solid #a5f3fc;
    border-radius:100px;padding:0.2rem 0.65rem;
    font-size:0.72rem;font-weight:800;color:#0891b2;
  }

  /* Stat chips in review */
  .dr-stat-row { display:flex;gap:0.6rem;margin-top:0.25rem; }
  .dr-stat {
    display:flex;flex-direction:column;align-items:center;
    background:#f0fdff;border:2px solid #a5f3fc;
    border-radius:14px;padding:0.5rem 0.85rem;flex:1;
  }
  .dr-stat-val { font-size:1rem;font-weight:900;color:#0891b2; }
  .dr-stat-label {
    font-size:0.58rem;font-weight:800;letter-spacing:0.1em;
    text-transform:uppercase;color:#67e8f9;margin-top:0.1rem;
  }

  /* CTA bar */
  .dr-cta-bar {
    position: fixed;
    bottom: 96px;
    left: 0;
    right: 0;
    z-index: 5;
    padding: 0.85rem 1.25rem calc(0.85rem + env(safe-area-inset-bottom));
  }
  .dr-cta-inner {
    max-width: 560px;
    margin: 0 auto;
    display: flex;
    gap: 0.75rem;
    align-items: center;
  }

  @media (min-width: 900px) {
    .dr-inner { max-width: var(--content-max); padding: 3rem 1.5rem 10rem; }
    .dr-topic-grid { grid-template-columns: repeat(3, 1fr); gap: 0.75rem; }
    .dr-cta-bar { left: var(--sidebar-width); right: 0; }

    /* Align decorative blobs relative to the centered content container */
    .dr-blob-3 { right: calc((100vw - var(--content-max)) / 2 - 48px); }
    .dr-blob-1 { left: calc((100vw - var(--content-max)) / 2 - 56px); }
    .dr-blob-2 { left: calc((100vw - var(--content-max)) / 2 + 12px); }
    .dr-blob-4 { right: calc((100vw - var(--content-max)) / 2 + 12px); }
  }

  .dr-next-btn {
    flex:1;padding:0.9rem 1.5rem;
    background:#0891b2;color:white;border:none;
    border-radius:100px;cursor:pointer;
    font-family:'Nunito',sans-serif;font-size:0.92rem;font-weight:900;
    display:flex;align-items:center;justify-content:center;gap:0.4rem;
    box-shadow:0 6px 0 #0e7490,0 8px 20px rgba(8,145,178,0.28);
    transition:transform 0.1s ease,box-shadow 0.1s ease;
  }
  .dr-next-btn:hover  { transform:translateY(-2px);box-shadow:0 8px 0 #0e7490,0 12px 24px rgba(8,145,178,0.32); }
  .dr-next-btn:active { transform:translateY(3px); box-shadow:0 3px 0 #0e7490; }
  .dr-next-btn:disabled {
    background:#e5e7eb;color:#9ca3af;cursor:not-allowed;
    box-shadow:0 4px 0 #d1d5db;
  }
  .dr-next-btn:disabled:hover { transform:none;box-shadow:0 4px 0 #d1d5db; }

  .dr-start-btn {
    flex:1;padding:0.9rem 1.5rem;
    background:linear-gradient(135deg,#22d3ee,#0891b2);color:white;border:none;
    border-radius:100px;cursor:pointer;
    font-family:'Nunito',sans-serif;font-size:0.92rem;font-weight:900;
    display:flex;align-items:center;justify-content:center;gap:0.4rem;
    box-shadow:0 6px 0 #0e7490,0 8px 20px rgba(8,145,178,0.3);
    transition:transform 0.1s ease,box-shadow 0.1s ease;
  }
  .dr-start-btn:hover  { transform:translateY(-2px);box-shadow:0 8px 0 #0e7490,0 12px 24px rgba(8,145,178,0.35); }
  .dr-start-btn:active { transform:translateY(3px); box-shadow:0 3px 0 #0e7490; }
`;

export const Drills = () => {
  const user = useAuthStore((state) => state.user);
  const navigate = useNavigate();

  const [direction, setDirection] = useState<1 | -1>(1);
  const [step, setStep] = useState<Step>("topic");
  const [topics, setTopics] = useState<Topic[]>([]);
  const [loading, setLoading] = useState(false);
  const [selectedTopics, setSelectedTopics] = useState<Topic[]>([]);
  const [search, setSearch] = useState("");

  const { storeTopics, setMode, setQuestionCount } = useExamConfigStore();

  const stepIndex = STEPS.indexOf(step);
  const progressPct = ((stepIndex + 1) / STEPS.length) * 100;

  const toggleTopic = (topic: Topic) => {
    setSelectedTopics((prev) =>
      prev.some((t) => t.id === topic.id)
        ? prev.filter((t) => t.id !== topic.id)
        : [...prev, topic],
    );
  };

  const goNext = () => {
    setDirection(1);
    setStep("review");
  };
  const goBack = () => {
    setDirection(-1);
    setStep("topic");
  };

  function handleStartDrill() {
    if (!user || !topics) return;
    navigate(`/student/practice/${topics[0].id}/test`, { replace: true });
  }

  useEffect(() => {
    const fetchAllTopics = async () => {
      if (!user) return;
      try {
        setLoading(true);
        const authStorage = localStorage.getItem("auth-storage");
        if (!authStorage) return;
        const {
          state: { token },
        } = JSON.parse(authStorage) as { state?: { token?: string } };
        if (!token) return;
        const response = await api.fetchAllTopics(token);
        setTopics(response);
      } catch (e) {
        console.error("Failed to load topics:", e);
      } finally {
        setLoading(false);
      }
    };
    fetchAllTopics();
  }, [user]);

  const filteredTopics = topics.filter((t) =>
    t.name.toLowerCase().includes(search.toLowerCase()),
  );

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

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

      {/* Dots */}
      {DOTS.map((d, i) => (
        <div
          key={i}
          className="dr-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="dr-inner">
        {/* Header */}
        <div className="dr-header-row dr-anim">
          <button
            className={`dr-back-btn${step === "topic" ? " hidden" : ""}`}
            onClick={goBack}
          >
            <ArrowLeft size={17} color="#6b7280" />
          </button>
          <div style={{ flex: 1 }}>
            <p className="dr-eyebrow">
              <Zap size={11} /> Drills
            </p>
            <h1 className="dr-title">
              {step === "topic" ? "Pick your topics" : "Review & launch"}
            </h1>
            <p className="dr-sub">
              {step === "topic"
                ? "Choose what you want to drill. Speed and accuracy await."
                : "Everything look good? Time to drill."}
            </p>
          </div>
        </div>

        {/* Progress */}
        <div className="dr-anim dr-anim-1">
          <div className="dr-progress-wrap">
            <div
              className="dr-progress-fill"
              style={{ width: `${progressPct}%` }}
            />
          </div>
          <div className="dr-progress-labels">
            {STEPS.map((s, i) => (
              <span key={s} className={i <= stepIndex ? "done" : ""}>
                {s === "topic" ? "Topics" : "Review"}
              </span>
            ))}
          </div>
        </div>

        {/* Step content */}
        <div style={{ position: "relative", overflow: "hidden" }}>
          <AnimatePresence mode="wait" custom={direction}>
            {/* Step 1 — Topic */}
            {step === "topic" && (
              <motion.div
                key="topic"
                custom={direction}
                variants={slideVariants}
                initial="initial"
                animate="animate"
                exit="exit"
              >
                <div className="dr-step-card">
                  <div className="dr-step-title">
                    Choose topics
                    {selectedTopics.length > 0 && (
                      <span className="dr-step-badge">
                        {selectedTopics.length} selected
                      </span>
                    )}
                  </div>

                  <div className="dr-search-wrap">
                    <Search size={15} className="dr-search-icon" />
                    <input
                      className="dr-search-input"
                      placeholder="Search topics..."
                      value={search}
                      onChange={(e) => setSearch(e.target.value)}
                    />
                  </div>

                  {loading ? (
                    <div className="dr-loading">
                      <Loader2
                        size={22}
                        color="#0891b2"
                        className="dr-spinner"
                      />
                      Loading topics...
                    </div>
                  ) : filteredTopics.length === 0 ? (
                    <p className="dr-empty">No topics match "{search}"</p>
                  ) : (
                    <div className="dr-topic-grid">
                      {filteredTopics.map((t) => (
                        <ChoiceCard
                          key={t.id}
                          label={t.name}
                          subLabel={t.parent_name}
                          section={t.section}
                          selected={selectedTopics.some((st) => st.id === t.id)}
                          onClick={() => toggleTopic(t)}
                        />
                      ))}
                    </div>
                  )}
                </div>
              </motion.div>
            )}

            {/* Step 2 — Review */}
            {step === "review" && (
              <motion.div
                key="review"
                custom={direction}
                variants={slideVariants}
                initial="initial"
                animate="animate"
                exit="exit"
              >
                <div className="dr-step-card">
                  <p className="dr-step-title">Your drill setup</p>

                  {/* Topics */}
                  <div className="dr-review-row">
                    <div
                      className="dr-review-icon"
                      style={{
                        background: "#ecfeff",
                        border: "2px solid #a5f3fc",
                      }}
                    >
                      📚
                    </div>
                    <div>
                      <p className="dr-review-label">Topics</p>
                      <div className="dr-chip-wrap">
                        {selectedTopics.map((t) => (
                          <span key={t.id} className="dr-chip">
                            {t.name}
                          </span>
                        ))}
                      </div>
                    </div>
                  </div>

                  {/* Stats */}
                  <div className="dr-review-row">
                    <div
                      className="dr-review-icon"
                      style={{
                        background: "#ecfeff",
                        border: "2px solid #a5f3fc",
                      }}
                    >
                      ⚡
                    </div>
                    <div style={{ flex: 1 }}>
                      <p className="dr-review-label">Session</p>
                      <div className="dr-stat-row">
                        <div className="dr-stat">
                          <span className="dr-stat-val">7</span>
                          <span className="dr-stat-label">Questions</span>
                        </div>
                        <div className="dr-stat">
                          <span className="dr-stat-val">~5</span>
                          <span className="dr-stat-label">Minutes</span>
                        </div>
                        <div className="dr-stat">
                          <span className="dr-stat-val">⏱️</span>
                          <span className="dr-stat-label">Timed</span>
                        </div>
                      </div>
                    </div>
                  </div>
                </div>
              </motion.div>
            )}
          </AnimatePresence>
        </div>
      </div>

      {/* CTA bar */}
      <div className="dr-cta-bar">
        <div className="dr-cta-inner">
          {step === "topic" && (
            <button
              className="dr-next-btn"
              disabled={selectedTopics.length === 0}
              onClick={() => {
                storeTopics(selectedTopics.map((t) => t.id));
                setMode("DRILL");
                setQuestionCount(7);
                goNext();
              }}
            >
              Next — Review ⚡
            </button>
          )}
          {step === "review" && (
            <button className="dr-start-btn" onClick={handleStartDrill}>
              ⚡ Start Drill
            </button>
          )}
        </div>
      </div>
    </div>
  );
};