import { createContext, useCallback, useContext, useState } from "react";
import api from "@/utils/api.util";
import { toast } from "sonner";

// ─── Context ──────────────────────────────────────────────────────────────────

const ClientCoursesContext = createContext(null);

// ─── Provider ─────────────────────────────────────────────────────────────────

export function ClientCoursesProvider({ children }) {
  // ── List state
  const [courses, setCourses] = useState([]);
  const [coursesLoading, setCoursesLoading] = useState(false);

  // ── Detail state
  const [course, setCourse] = useState(null);
  const [courseLoading, setCourseLoading] = useState(false);
  const [courseBlocked, setCourseBlocked] = useState(false); // true = 403, prompt upgrade

  // ── Unit state
  const [unit, setUnit] = useState(null);
  const [unitLoading, setUnitLoading] = useState(false);

  // ── Lesson state
  const [lesson, setLesson] = useState(null);
  const [lessonLoading, setLessonLoading] = useState(false);

  // ── Quiz state
  const [quiz, setQuiz] = useState(null);
  const [quizLoading, setQuizLoading] = useState(false);

  // ── Assessment state
  const [assessment, setAssessment] = useState(null);
  const [assessmentLoading, setAssessmentLoading] = useState(false);

  // ─── Actions ────────────────────────────────────────────────────────────────

  const getCourses = useCallback(async () => {
    setCoursesLoading(true);
    try {
      const { data } = await api.get("/client/courses");
      setCourses(data.data ?? []);
    } catch (err) {
      toast.error(err?.response?.data?.message ?? "Could not load courses.");
    } finally {
      setCoursesLoading(false);
    }
  }, []);

  const getCourse = useCallback(async (courseId) => {
    setCourseLoading(true);
    setCourseBlocked(false);
    try {
      const { data } = await api.get(`/client/courses/${courseId}`);
      setCourse(data.data ?? null);
    } catch (err) {
      if (err?.response?.status === 403) {
        setCourseBlocked(true); // let the UI show an upgrade prompt
      } else {
        toast.error(err?.response?.data?.message ?? "Could not load course.");
      }
    } finally {
      setCourseLoading(false);
    }
  }, []);

  const getUnit = useCallback(async (courseId, unitId) => {
    setUnitLoading(true);
    try {
      const { data } = await api.get(`/client/courses/${courseId}/units/${unitId}`);
      setUnit(data.data ?? null);
    } catch (err) {
      toast.error(err?.response?.data?.message ?? "Could not load unit.");
    } finally {
      setUnitLoading(false);
    }
  }, []);

  const getLesson = useCallback(async (courseId, unitId, lessonId) => {
    setLessonLoading(true);
    try {
      const { data } = await api.get(
        `/client/courses/${courseId}/units/${unitId}/lessons/${lessonId}`
      );
      setLesson(data.data ?? null);
    } catch (err) {
      toast.error(err?.response?.data?.message ?? "Could not load lesson.");
    } finally {
      setLessonLoading(false);
    }
  }, []);

  const getUnitQuiz = useCallback(async (courseId, unitId) => {
    setQuizLoading(true);
    try {
      const { data } = await api.get(
        `/client/courses/${courseId}/units/${unitId}/quiz`
      );
      setQuiz(data.data ?? null);
    } catch (err) {
      toast.error(err?.response?.data?.message ?? "Could not load quiz.");
    } finally {
      setQuizLoading(false);
    }
  }, []);

  const getCourseAssessment = useCallback(async (courseId) => {
    setAssessmentLoading(true);
    try {
      const { data } = await api.get(`/client/courses/${courseId}/assessment`);
      setAssessment(data.data ?? null);
    } catch (err) {
      toast.error(err?.response?.data?.message ?? "Could not load assessment.");
    } finally {
      setAssessmentLoading(false);
    }
  }, []);

  const submitUnitQuiz = useCallback(async (courseId, unitId, quizId, answers) => {
    try {
      const { data } = await api.post(
        `/client/courses/${courseId}/units/${unitId}/quiz/${quizId}/submit`,
        { answers }
      );
      return data.data ?? null;
    } catch (err) {
      toast.error(err?.response?.data?.message ?? "Could not submit quiz.");
      return null;
    }
  }, []);

  const submitCourseAssessment = useCallback(async (courseId, assessmentId, answers) => {
    try {
      const { data } = await api.post(
        `/client/courses/${courseId}/assessment/${assessmentId}/submit`,
        { answers }
      );
      return data.data ?? null;
    } catch (err) {
      toast.error(err?.response?.data?.message ?? "Could not submit assessment.");
      return null;
    }
  }, []);

  // ─── Course Purchases ───────────────────────────────────────────────────────

  const [purchases,        setPurchases]        = useState([]);
  const [purchasesLoading, setPurchasesLoading] = useState(false);
  const [purchaseLoading,  setPurchaseLoading]  = useState(false);

  const getMyPurchases = useCallback(async () => {
    setPurchasesLoading(true);
    try {
      const { data } = await api.get("/client/course-purchases");
      setPurchases(data.data ?? []);
    } catch (err) {
      toast.error(err?.response?.data?.message ?? "Could not load purchases.");
    } finally { setPurchasesLoading(false); }
  }, []);

  const createCourseOrder = useCallback(async (productId) => {
    setPurchaseLoading(true);
    try {
      const { data } = await api.post("/client/course-purchases/order", { product_id: productId });
      return data.data ?? null;
    } catch (err) {
      toast.error(err?.response?.data?.message ?? "Could not create order.");
      return null;
    } finally { setPurchaseLoading(false); }
  }, []);

  const captureCourseOrder = useCallback(async (orderId) => {
    setPurchaseLoading(true);
    try {
      const { data } = await api.post("/client/course-purchases/capture", { order_id: orderId });
      toast.success("Purchase confirmed! You now have access to this course.");
      return data.data ?? null;
    } catch (err) {
      toast.error(err?.response?.data?.message ?? "Could not capture payment.");
      return null;
    } finally { setPurchaseLoading(false); }
  }, []);

  const cancelCourseOrder = useCallback(async (orderId) => {
    try {
      await api.post("/client/course-purchases/cancel", { order_id: orderId });
    } catch { /* silent */ }
  }, []);

  // ─── Reset helpers ──────────────────────────────────────────────────────────

  const resetCourse = useCallback(() => { setCourse(null); setCourseBlocked(false); }, []);
  const resetUnit = useCallback(() => setUnit(null), []);
  const resetLesson = useCallback(() => setLesson(null), []);
  const resetQuiz = useCallback(() => setQuiz(null), []);
  const resetAssessment = useCallback(() => setAssessment(null), []);

  // ─── Value ──────────────────────────────────────────────────────────────────

  const value = {
    // state
    courses, coursesLoading,
    course, courseLoading, courseBlocked,
    unit, unitLoading,
    lesson, lessonLoading,
    quiz, quizLoading,
    assessment, assessmentLoading,

    // actions
    getCourses,
    getCourse,
    getUnit,
    getLesson,
    getUnitQuiz,
    getCourseAssessment,
    submitUnitQuiz,
    submitCourseAssessment,

    // purchases
    purchases, purchasesLoading, purchaseLoading,
    getMyPurchases,
    createCourseOrder,
    captureCourseOrder,
    cancelCourseOrder,

    // resets
    resetCourse,
    resetUnit,
    resetLesson,
    resetQuiz,
    resetAssessment,
  };

  return (
    <ClientCoursesContext.Provider value={value}>
      {children}
    </ClientCoursesContext.Provider>
  );
}

// ─── Hook ─────────────────────────────────────────────────────────────────────

export function useClientCourses() {
  const ctx = useContext(ClientCoursesContext);
  if (!ctx) throw new Error("useClientCourses must be used within ClientCoursesProvider");
  return ctx;
}

export default ClientCoursesContext;