# views/lesson.py
from flask import Blueprint, jsonify, request, render_template, session, current_app
from werkzeug.exceptions import BadRequest
from bson import ObjectId
from datetime import datetime
from ..auth.decorators import require_role
from ..services.course_service import load_material,save_materials_markdown_cos
from ..services.cos_service import upload_file
import uuid

bp = Blueprint('lesson', __name__)

@bp.route("/api/upload", methods=["POST"])
def upload():
    f = request.files['file']
    url = upload_file(f, "image_" + str(uuid.uuid4()))
    return jsonify({"url": url})


# 返回课时元信息（含三份 markdown 的可访问链接或直接内容）
@bp.route('/api/materials/<material_id>/chapters/<chapter_name>/lessons/<lesson_name>', methods=['GET'])
@require_role(roles="teacher")
def edit_lesson_detail(material_id, chapter_name, lesson_name):
    teacher_uuid = session.get("user_uuid")
    teacher_id = current_app.extensions["uuid2username"][teacher_uuid]
    material = load_material(material_id)
    for chapter in material.chapters:
        if chapter.chapter_name == chapter_name:
            for lesson in chapter.lessons:
                if lesson.lesson_name == lesson_name:
                    return render_template('lesson.html', lesson=lesson.model_dump(), role="teacher", material={**material.model_dump(), "material_id": material_id}, chapter=chapter.model_dump())
    return jsonify({"message": "课时不存在"}), 404

# 返回某份 markdown 文件内容（你也可以直接返回 S3/OSS 的直链）
@bp.route('/api/lesson_file/<material_id>/<chapter_name>/<lesson_name>/<filename>', methods=['GET'])
def get_markdown_file(material_id, chapter_name, lesson_name, filename):
    # TODO: 真实环境从存储读取
    demo_map = {
        "lesson.md": "# 主题\n## 阶段一\n### 步骤A\n内容A...\n### 步骤B\n内容B...\n",
        "prompt.md": "# 主题\n## 阶段一\n### 步骤A\n提示A...\n### 步骤B\n提示B...\n",
        "score_prompt.md": "# 主题\n## 阶段一\n### 步骤A\n评分A...\n### 步骤B\n评分B...\n"
    }
    return demo_map.get(filename, ""), 200

@bp.route("/api/materials/save/<material_id>/<chapter_name>/<lesson_name>", methods=['POST'])
@require_role(roles='teacher')
def save_materials_markdown(material_id, chapter_name, lesson_name):
    payload = request.get_json(silent=True, force=True)
    if not payload:
        raise BadRequest("缺少 JSON payload")

    # 基础校验
    required_keys = ("lesson", "prompt", "score")
    for k in required_keys:
        if k not in payload or not isinstance(payload[k], dict):
            raise BadRequest(f"缺少或非法字段: {k}")
        if "cdn_link" not in payload[k] or "content" not in payload[k]:
            raise BadRequest(f"{k} 需要包含 cdn_link 与 content 字段")
        if not isinstance(payload[k]["cdn_link"], str) or not isinstance(payload[k]["content"], str):
            raise BadRequest(f"{k}.cdn_link 与 {k}.content 必须为字符串")

    # 可选：版本/并发控制（若你前端传了）
    version = payload.get("version")

    docs = {
        "lesson": {
            "cdn_link": payload["lesson"]["cdn_link"].strip(),
            "content" : payload["lesson"]["content"]
        },
        "prompt": {
            "cdn_link": payload["prompt"]["cdn_link"].strip(),
            "content" : payload["prompt"]["content"]
        },
        "score": {
            "cdn_link": payload["score"]["cdn_link"].strip(),
            "content" : payload["score"]["content"]
        }
    }

    # 轻量防御：限制单次大小（自行按需调整）
    max_size = 4 * 1024 * 1024  # 2MB/份
    for name, doc in docs.items():
        if len(doc["content"].encode("utf-8")) > max_size:
            raise BadRequest(f"{name} 文档过大，超过 {max_size} 字节限制")

    # 调用服务层保存：写源站、刷新/回写 CDN、更新索引等
    # 建议服务层返回新版本/新链接等元信息
    result = save_materials_markdown_cos(
        material_id=material_id,
        chapter_name=chapter_name,
        lesson_name=lesson_name,
        docs=docs,
        version=version,         # 可选，用于并发检测
        actor=getattr(request, "user", None)  # 若你的鉴权中注入了当前教师
    )

    # 统一响应
    return jsonify({
        "ok": True,
        "material_id": material_id,
        "chapter_name": chapter_name,
        "lesson_name": lesson_name,
        "result": result  # e.g. {"lesson":{"cdn_link": "...", "version":"..."}, ...}
    }), 200