# myapp/services/course_service.py
from typing import Dict, List
from flask import current_app
from datetime import datetime
from bson import ObjectId

from ..models.material import Material

# 假设你已有这两个 loader
from db.course import load_course_from_json

def load_course(course_id: str):
    return load_course_from_json(
        course_id, course_data_dir=current_app.config["COURSE_DATA_DIR"]
    )

def user_selected_course_briefs(user_obj):
    """根据用户对象的选课列表，拼装课程简要信息数组"""
    course_list = current_app.extensions["course_list"]
    briefs = []
    for cid in getattr(user_obj, "select_course", []):
        course_obj = load_course(cid)
        brief = course_list.get_course_brief_info(cid, course_obj)
        briefs.append(brief)
    return briefs

def create_material(teacher_id, material_name, description, chapters, image_url):
    material = Material(
        name=material_name,
        description=description,
        teacher_id=teacher_id,
        created_at=datetime.now(),
        updated_at=datetime.now(),
        chapters=chapters,
        image_url=image_url
    )
    mongo = current_app.extensions["mongo"]
    material_id = mongo.db.materials.insert_one(material.model_dump()).inserted_id
    return str(material_id)

def load_material(material_id):
    mongo = current_app.extensions["mongo"]
    material = mongo.db.materials.find_one({"_id": ObjectId(material_id)})
    return Material(**material)

def update_material(material_id, chapters):
    mongo = current_app.extensions["mongo"]
    material = mongo.db.materials.find_one({'_id': ObjectId(material_id)})
    if material:
        mongo.db.materials.update_one(
            {'_id': ObjectId(material_id)},
            {'$set': {'chapters': chapters, 'updated_at': datetime.now()}}
        )
        return True
    return False

def add_material_chapter(material_id, chapter_name, teacher_id):
    mongo = current_app.extensions["mongo"]
    material = mongo.db.materials.find_one({'_id': ObjectId(material_id)})
    if material['teacher_id'] != teacher_id:
        return False
    if material:
        mongo.db.materials.update_one(
            {'_id': ObjectId(material_id)},
            {'$push': {'chapters': {'chapter_name': chapter_name, 'lessons': []}}})
        return True
    
def add_material_chapter_lesson(material_id, chapter_name, lesson_name, teacher_id):
    mongo = current_app.extensions["mongo"]

    lesson_doc = {
        "lesson_name": lesson_name or "",
        "markdown_lesson_file_link": "",
        "markdown_prompt_file_name": "",
        "markdown_score_prompt_file_link": "",
    }

    res = mongo.db.materials.update_one(
        {
            '_id': ObjectId(material_id),
            'teacher_id': teacher_id,
        },
        {
            '$push': {'chapters.$[c].lessons': lesson_doc},
            '$set': {'updated_at': datetime.now()},
        },
        array_filters=[{'c.chapter_name': chapter_name}]  # 命名占位符 c 指向命中的 chapter
    )
    return res.modified_count == 1


def get_materials_by_teacher(teacher_id)->List[Material]:
    mongo = current_app.extensions["mongo"]
    materials = mongo.db.materials.find({'teacher_id': teacher_id})
    return [Material(**material) for material in materials]

def get_materials_by_teacher_dict(teacher_id)->List[Dict]:
    mongo = current_app.extensions["mongo"]
    materials = mongo.db.materials.find({'teacher_id': teacher_id})
    result = []
    for material in materials:
        material['_id'] = str(material['_id'])
        result.append(material)
    return result