package com.sztzjy.linkCommerce.service.impl;

import com.sztzjy.linkCommerce.config.exception.handler.ServiceException;
import com.sztzjy.linkCommerce.config.security.JwtUser;
import com.sztzjy.linkCommerce.entity.SchoolClass;
import com.sztzjy.linkCommerce.entity.TeachingClassStudent;
import com.sztzjy.linkCommerce.mapper.SchoolClassMapper;
import com.sztzjy.linkCommerce.mapper.TeachingClassStudentMapper;
import com.sztzjy.linkCommerce.service.StudentTeachingClassResolver;
import org.apache.commons.lang3.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Service;

@Service
public class StudentTeachingClassResolverImpl implements StudentTeachingClassResolver {
    @Autowired
    public SchoolClassMapper schoolClassMapper;
    @Autowired
    public TeachingClassStudentMapper teachingClassStudentMapper;

    @Override
    public String resolveRequired(JwtUser user) {
        requireStudent(user);
        String teachingClassId;
        if (user.isDemoMode()) {
            teachingClassId = StringUtils.trimToNull(user.getDemoTeachingClassId());
            if (teachingClassId == null) {
                throw new ServiceException(HttpStatus.FORBIDDEN, "Demo teaching class is required");
            }
        } else {
            TeachingClassStudent membership = teachingClassStudentMapper.selectActiveByStudentUserId(user.getUserId());
            teachingClassId = membership == null ? null : StringUtils.trimToNull(membership.getTeachingClassId());
            if (teachingClassId == null) {
                throw new ServiceException(HttpStatus.BAD_REQUEST, "Student has no active teaching class");
            }
        }
        validateTeachingClass(user, teachingClassId);
        return teachingClassId;
    }

    @Override
    public String resolveRequested(JwtUser user, String requestedTeachingClassId) {
        String resolved = resolveRequired(user);
        String requested = StringUtils.trimToNull(requestedTeachingClassId);
        if (requested != null && !StringUtils.equals(resolved, requested)) {
            throw new ServiceException(HttpStatus.FORBIDDEN, "Teaching class does not match current student context");
        }
        return resolved;
    }

    private void validateTeachingClass(JwtUser user, String teachingClassId) {
        SchoolClass schoolClass = schoolClassMapper.selectByPrimaryKey(teachingClassId);
        if (schoolClass == null || !"TEACHING".equals(schoolClass.getClassType())
                || !StringUtils.equals(user.getSchoolId(), schoolClass.getSchoolId())) {
            throw new ServiceException(HttpStatus.FORBIDDEN, "Teaching class is unavailable");
        }
    }

    private void requireStudent(JwtUser user) {
        if (user == null || user.getRoleId() != 4 || StringUtils.isBlank(user.getUserId())) {
            throw new ServiceException(HttpStatus.FORBIDDEN, "Student only");
        }
    }
}