// models/courses/associations.js

const { Course, CourseProductCategory } = require("./courses.mdl");
const Unit = require("./units.mdl");
const Lesson = require("./lessons.mdl");
const CourseUnit = require("./course_units.mdl");
const UnitLesson = require("./unit_lessons.mdl");
const LessonPage = require("./lesson_page.mdl");
const CourseObjective = require("./course_objective.mdl");
const LessonObjective = require("./lesson_objective.mdl");
const CoursePrerequisite = require("./course_prerequisite.mdl");
const CourseAssessment = require("./course_assessment.mdl");
const UnitQuiz = require("./unit_quiz.mdl");
const QuizQuestion = require("./quiz_question.mdl");
const QuizOption = require("./quiz_option.mdl");
const mdl_Users = require("../users/users.mdl");
const QuizAttempt = require("./quiz_attempt.mdl");
const AssessmentSession       = require("./assessment_session.mdl");
const QuizSession             = require("./quiz_session.mdl");
const mdl_Category            = require("./categories.mdl");
const Certificate             = require("./certificate.mdl");
const CourseInstructor        = require("./course_instructor.mdl");
const CourseReadingProgress   = require("./course_reading_progress.mdl");
const UnitReadingProgress     = require("./unit_reading_progress.mdl");
const LessonReadingProgress   = require("./lesson_reading_progress.mdl");
const CourseAchievement       = require("./course_achievement.mdl");
const CompletionRequirement         = require("./completion_requirement.mdl");
const CompletionRequirementProgress = require("./completion_requirement_progress.mdl");

// ── CourseReadingProgress ─────────────────────────────────────────────────────
CourseReadingProgress.belongsTo(mdl_Users, { foreignKey: 'user_id',   as: 'user'   });
CourseReadingProgress.belongsTo(Course,    { foreignKey: 'course_id', as: 'course' });
mdl_Users.hasMany(CourseReadingProgress,   { foreignKey: 'user_id',   as: 'courseReadingProgress' });
Course.hasMany(CourseReadingProgress,      { foreignKey: 'course_id', as: 'readingProgress'       });

// ── UnitReadingProgress ───────────────────────────────────────────────────────
UnitReadingProgress.belongsTo(mdl_Users, { foreignKey: 'user_id',   as: 'user'   });
UnitReadingProgress.belongsTo(Course,    { foreignKey: 'course_id', as: 'course' });
UnitReadingProgress.belongsTo(Unit,      { foreignKey: 'unit_id',   as: 'unit'   });
mdl_Users.hasMany(UnitReadingProgress,   { foreignKey: 'user_id',   as: 'unitReadingProgress' });
Unit.hasMany(UnitReadingProgress,        { foreignKey: 'unit_id',   as: 'readingProgress'     });

// ── LessonReadingProgress ─────────────────────────────────────────────────────
LessonReadingProgress.belongsTo(mdl_Users, { foreignKey: 'user_id',   as: 'user'   });
LessonReadingProgress.belongsTo(Course,    { foreignKey: 'course_id', as: 'course' });
LessonReadingProgress.belongsTo(Unit,      { foreignKey: 'unit_id',   as: 'unit'   });
LessonReadingProgress.belongsTo(Lesson,    { foreignKey: 'lesson_id', as: 'lesson' });
mdl_Users.hasMany(LessonReadingProgress,   { foreignKey: 'user_id',   as: 'lessonReadingProgress' });
Lesson.hasMany(LessonReadingProgress,      { foreignKey: 'lesson_id', as: 'readingProgress'       });

// ── CompletionRequirement ─────────────────────────────────────────────────────
// Polymorphic across course/unit/lesson via (entity_type, entity_id) — no belongsTo
// to Course/Unit/Lesson here (can't express a 3-way FK); entity resolution happens
// in services/courses/completion.service.js.
CompletionRequirement.hasMany(CompletionRequirementProgress, { foreignKey: 'requirement_id', as: 'progress' });
CompletionRequirementProgress.belongsTo(CompletionRequirement, { foreignKey: 'requirement_id', as: 'requirement' });
CompletionRequirementProgress.belongsTo(mdl_Users, { foreignKey: 'user_id', as: 'user' });

// ── Course ⇄ Unit / Unit ⇄ Lesson (junctions) ─────────────────────────────────
// Units and Lessons are standalone entities. Membership + ordering live on the
// course_units / unit_lessons junction rows (order_index).
Course.belongsToMany(Unit, { through: CourseUnit, foreignKey: "course_id", otherKey: "unit_id", as: "units" });
Unit.belongsToMany(Course, { through: CourseUnit, foreignKey: "unit_id", otherKey: "course_id", as: "courses" });
Unit.belongsToMany(Lesson, { through: UnitLesson, foreignKey: "unit_id", otherKey: "lesson_id", as: "lessons" });
Lesson.belongsToMany(Unit, { through: UnitLesson, foreignKey: "lesson_id", otherKey: "unit_id", as: "units" });

// Direct junction access (attach / detach / reorder / count queries)
Course.hasMany(CourseUnit, { as: "unitLinks", foreignKey: "course_id" });
CourseUnit.belongsTo(Course, { as: "course", foreignKey: "course_id" });
CourseUnit.belongsTo(Unit,   { as: "unit",   foreignKey: "unit_id" });
Unit.hasMany(CourseUnit,     { as: "courseLinks", foreignKey: "unit_id" });
Unit.hasMany(UnitLesson,     { as: "lessonLinks", foreignKey: "unit_id" });
UnitLesson.belongsTo(Unit,   { as: "unit",   foreignKey: "unit_id" });
UnitLesson.belongsTo(Lesson, { as: "lesson", foreignKey: "lesson_id" });
Lesson.hasMany(UnitLesson,   { as: "unitLinks", foreignKey: "lesson_id" });

// ── Course ────────────────────────────────────────────────────────────────────
Course.belongsTo(mdl_Users, { as: "creator", foreignKey: "createdBy" });
Course.belongsTo(mdl_Users, { as: "updater", foreignKey: "updatedBy" });
Course.hasMany(CourseObjective, { as: "objectives", foreignKey: "course_id" });
Course.hasMany(CoursePrerequisite, { as: "prerequisites", foreignKey: "course_id" });
Course.hasOne(CourseAssessment, { as: "assessment",    foreignKey: "course_id" });
Course.hasMany(Certificate,      { as: "certificates",  foreignKey: "course_id" });
Course.hasMany(CourseInstructor,  { as: "instructors",   foreignKey: "course_id" });
CourseInstructor.belongsTo(Course,    { as: "course", foreignKey: "course_id" });
CourseInstructor.belongsTo(mdl_Users, { as: "user",   foreignKey: "user_id"   });
Course.hasMany(CourseAchievement, { as: "courseAchievements", foreignKey: "course_id" });
CourseAchievement.belongsTo(Course, { as: "course", foreignKey: "course_id" });
Course.belongsToMany(mdl_Category, { through: CourseProductCategory, foreignKey: 'course_id',   otherKey: 'category_id', as: 'categories' });
mdl_Category.belongsToMany(Course,        { through: CourseProductCategory, foreignKey: 'category_id', otherKey: 'course_id',   as: 'courses'    });

// ── Unit ──────────────────────────────────────────────────────────────────────
Unit.belongsTo(mdl_Users, { as: "creator", foreignKey: "createdBy" });
Unit.belongsTo(mdl_Users, { as: "updater", foreignKey: "updatedBy" });
Unit.hasOne(UnitQuiz, { as: "quiz", foreignKey: "unit_id" });

// ── Lesson ────────────────────────────────────────────────────────────────────
Lesson.belongsTo(mdl_Users, { as: "creator", foreignKey: "createdBy" });
Lesson.belongsTo(mdl_Users, { as: "updater", foreignKey: "updatedBy" });
Lesson.hasOne(LessonPage, { as: "page", foreignKey: "lesson_id" });
Lesson.hasMany(LessonObjective, { as: "objectives", foreignKey: "lesson_id" });

// ── UnitQuiz ──────────────────────────────────────────────────────────────────
UnitQuiz.belongsTo(Unit, { as: "unit", foreignKey: "unit_id" });
UnitQuiz.belongsTo(mdl_Users, { as: "creator", foreignKey: "createdBy" });
UnitQuiz.belongsTo(mdl_Users, { as: "updater", foreignKey: "updatedBy" });
UnitQuiz.hasMany(QuizQuestion, { as: "questions", foreignKey: "quiz_id" });

// ── CourseAssessment ──────────────────────────────────────────────────────────
CourseAssessment.belongsTo(Course, { as: "course", foreignKey: "course_id" });
CourseAssessment.belongsTo(mdl_Users, { as: "creator", foreignKey: "createdBy" });
CourseAssessment.belongsTo(mdl_Users, { as: "updater", foreignKey: "updatedBy" });
CourseAssessment.hasMany(QuizQuestion, { as: "questions", foreignKey: "assessment_id" });

// ── QuizQuestion ──────────────────────────────────────────────────────────────
QuizQuestion.belongsTo(UnitQuiz, { as: "quiz", foreignKey: "quiz_id" });
QuizQuestion.belongsTo(CourseAssessment, { as: "assessment", foreignKey: "assessment_id" });
QuizQuestion.hasMany(QuizOption, { as: "options", foreignKey: "question_id" });

// ── QuizOption ────────────────────────────────────────────────────────────────
QuizOption.belongsTo(QuizQuestion, { as: "question", foreignKey: "question_id" });

// ── QuizAttempt ───────────────────────────────────────────────────────────────
QuizAttempt.belongsTo(UnitQuiz, { as: "quiz", foreignKey: "quiz_id" });
QuizAttempt.belongsTo(CourseAssessment, { as: "assessment", foreignKey: "assessment_id" });
QuizAttempt.belongsTo(mdl_Users, { as: "user", foreignKey: "user_id" });
UnitQuiz.hasMany(QuizAttempt, { as: "attempts", foreignKey: "quiz_id" });
CourseAssessment.hasMany(QuizAttempt, { as: "attempts", foreignKey: "assessment_id" });

// ── AssessmentSession ─────────────────────────────────────────────────────────
AssessmentSession.belongsTo(CourseAssessment, { as: "assessment", foreignKey: "assessment_id" });
AssessmentSession.belongsTo(mdl_Users,        { as: "user",       foreignKey: "user_id" });
CourseAssessment.hasMany(AssessmentSession,   { as: "sessions",   foreignKey: "assessment_id" });

// ── QuizSession ───────────────────────────────────────────────────────────────
QuizSession.belongsTo(UnitQuiz,    { as: "quiz", foreignKey: "quiz_id" });
QuizSession.belongsTo(mdl_Users,   { as: "user", foreignKey: "user_id" });
UnitQuiz.hasMany(QuizSession,      { as: "sessions", foreignKey: "quiz_id" });

module.exports = {
    Course, CourseProductCategory,
    Unit, Lesson, LessonPage,
    CourseUnit, UnitLesson,
    CourseObjective, LessonObjective,
    CoursePrerequisite, CourseAssessment,
    UnitQuiz, QuizQuestion, QuizOption, QuizAttempt,
    AssessmentSession, QuizSession,
    mdl_Category, Certificate, CourseInstructor,
    CourseReadingProgress, UnitReadingProgress, LessonReadingProgress,
    CourseAchievement,
    CompletionRequirement, CompletionRequirementProgress,
};