from flask import Blueprint, request, jsonify
from app.models import db, StudentGoal, Goal
from app.routes.auth import login_required_json
from datetime import datetime, timedelta

student_goals_bp = Blueprint("student_goals", __name__)

def compute_status(start_date, assessment_date):
    """根据日期计算状态"""
    now = datetime.now()
    if start_date and now < start_date:
        return "未开始"
    elif assessment_date and now > assessment_date:
        return "已结束"
    else:
        return "进行中"

@student_goals_bp.route("/api/students/<int:student_id>/goals", methods=["GET"])
@login_required_json
def get_student_goals(student_id):
    records = StudentGoal.query.filter_by(student_id=student_id).all()

    # 计算状态并排序
    def sort_key(r):
        status_order = {"进行中": 1, "未开始": 2, "已结束": 3}
        status = compute_status(r.start_date, r.assessment_date)
        order = status_order.get(status, 4)
        assessment = r.assessment_date if r.assessment_date else datetime.min
        return (order, -assessment.timestamp() if assessment else 0)

    records.sort(key=sort_key)
    return jsonify([r.to_dict() for r in records])

@student_goals_bp.route("/api/students/<int:student_id>/goals", methods=["POST"])
@login_required_json
def assign_goal(student_id):
    data = request.get_json()

    # 检查目标是否存在
    goal = Goal.query.get(data["goal_id"])
    if not goal:
        return jsonify({"error": "目标不存在"}), 404

    # 检查是否已分配
    existing = StudentGoal.query.filter_by(student_id=student_id, goal_id=data["goal_id"]).first()
    if existing:
        return jsonify({"error": "目标已分配"}), 400

    # 处理评估日期
    assessment_date = None
    if data.get("assessment_date"):
        # 直接指定日期
        assessment_date = datetime.fromisoformat(data["assessment_date"])
    elif data.get("assessment_days"):
        # 指定天数后
        assessment_date = datetime.now() + timedelta(days=int(data["assessment_days"]))

    # 处理开始日期
    start_date = None
    if data.get("start_date"):
        start_date = datetime.fromisoformat(data["start_date"])
    # 如果没有指定开始日期，默认为当前时间
    elif data.get("start_now"):
        start_date = datetime.now()

    record = StudentGoal(
        student_id=student_id,
        goal_id=data["goal_id"],
        start_date=start_date,
        assessment_date=assessment_date
    )
    db.session.add(record)
    db.session.commit()
    return jsonify(record.to_dict()), 201

@student_goals_bp.route("/api/students/<int:student_id>/goals/<int:goal_id>", methods=["PUT"])
@login_required_json
def update_student_goal(student_id, goal_id):
    record = StudentGoal.query.filter_by(student_id=student_id, goal_id=goal_id).first_or_404()
    data = request.get_json()

    if "start_date" in data:
        if data["start_date"]:
            record.start_date = datetime.fromisoformat(data["start_date"])
        else:
            record.start_date = None
    if "assessment_date" in data:
        if data["assessment_date"]:
            record.assessment_date = datetime.fromisoformat(data["assessment_date"])
        else:
            record.assessment_date = None
    if "mastery_level" in data:
        record.mastery_level = data["mastery_level"]
    if "achievement_date" in data:
        if data["achievement_date"]:
            record.achievement_date = datetime.fromisoformat(data["achievement_date"])
        else:
            record.achievement_date = None
    if "comment" in data:
        record.comment = data["comment"]

    db.session.commit()
    return jsonify(record.to_dict())

@student_goals_bp.route("/api/students/<int:student_id>/goals/<int:goal_id>", methods=["DELETE"])
@login_required_json
def remove_student_goal(student_id, goal_id):
    record = StudentGoal.query.filter_by(student_id=student_id, goal_id=goal_id).first_or_404()
    db.session.delete(record)
    db.session.commit()
    return jsonify({"message": "移除成功"})