package com.mydreamjob.privacy;

import com.mydreamjob.application.CompanyResumeAccessPolicy;
import com.mydreamjob.audit.AuditService;
import com.mydreamjob.auth.User;
import com.mydreamjob.auth.UserRepository;
import com.mydreamjob.common.exception.BusinessException;
import com.mydreamjob.common.exception.ErrorCode;
import com.mydreamjob.privacy.dto.PrivacySettingsResponse;
import com.mydreamjob.privacy.dto.PrivacySettingsUpdateRequest;
import com.mydreamjob.security.UserRoleGuard;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.dao.DataIntegrityViolationException;
import org.springframework.orm.ObjectOptimisticLockingFailureException;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

/**
 * 学生隐私设置服务。
 *
 * <p>身份由调用方从 JWT/SecurityContext 解析后传入 userId，本服务负责校验 STUDENT 角色；
 * 不接受客户端指定的 userId 身份参数。联系方式的可见性策略方法供企业侧脱敏接入使用。
 */
@Slf4j
@Service
@RequiredArgsConstructor
public class PrivacySettingsService {

    private final com.mydreamjob.security.UserRoleGuard userRoleGuard;
    private final StudentPrivacySettingsRepository privacyRepository;
    private final UserRepository userRepository;
    private final AuditService auditService;
    /**
     * S03-B：企业简历可见性统一由失败关闭的授权策略判定。
     * 策略强制校验「投递所属岗位属于该企业」，修复了此前只校验学生与状态、
     * 不校验企业归属的缺陷。
     */
    private final CompanyResumeAccessPolicy companyResumeAccessPolicy;

    /** 校验当前用户必须为 STUDENT，否则抛 FORBIDDEN。 */
    public void assertStudentRole(Long userId) {
        userRoleGuard.requireStudent(userId);
    }

    /**
     * 获取当前学生的隐私设置；无记录时返回默认对象（PRIVATE / contactVisible=false / version=0），
     * 不自动创建数据库记录。
     */
    @Transactional(readOnly = true)
    public PrivacySettingsResponse getCurrentUserSettings(Long userId) {
        assertStudentRole(userId);
        StudentPrivacySettings settings = privacyRepository.findByStudentUserId(userId).orElse(null);
        return toResponse(settings, userId);
    }

    /**
     * 更新当前学生的隐私设置，执行 upsert，确保同一学生至多一行。
     * version 不匹配时抛 PRIVACY_SETTINGS_CONCURRENT_UPDATE（9201 → HTTP 409）。
     */
    @Transactional
    public PrivacySettingsResponse updateCurrentUserSettings(Long userId, PrivacySettingsUpdateRequest req) {
        assertStudentRole(userId);
        validate(req);

        StudentPrivacySettings existing = privacyRepository.findByStudentUserId(userId).orElse(null);
        if (existing != null && req.getVersion() != null) {
            long expected = req.getVersion();
            long current = existing.getVersion() == null ? 0L : existing.getVersion();
            if (current != expected) {
                throw new BusinessException(ErrorCode.PRIVACY_SETTINGS_CONCURRENT_UPDATE);
            }
        }

        try {
            StudentPrivacySettings saved;
            if (existing == null) {
                saved = privacyRepository.saveAndFlush(StudentPrivacySettings.builder()
                        .studentUserId(userId)
                        .resumeVisibility(req.getResumeVisibility())
                        .contactVisible(req.getContactVisible())
                        .version(0L)
                        .build());
            } else {
                existing.setResumeVisibility(req.getResumeVisibility());
                existing.setContactVisible(req.getContactVisible());
                saved = privacyRepository.saveAndFlush(existing);
            }
            // 审计：仅记录事件，不写入 phone/email/password/jwt/resumeUrl 等敏感信息
            auditService.log(userId, "UPDATE_PRIVACY_SETTINGS", "STUDENT_PRIVACY_SETTINGS",
                    saved.getId(), "privacy settings updated", null);
            return toResponse(saved, userId);
        } catch (ObjectOptimisticLockingFailureException | DataIntegrityViolationException e) {
            log.warn("Concurrent privacy settings update conflict for userId={}", userId, e);
            throw new BusinessException(ErrorCode.PRIVACY_SETTINGS_CONCURRENT_UPDATE);
        }
    }

    /**
     * 企业是否可查看某学生的简历（S03-B：委托给失败关闭的授权策略）。
     *
     * <p>判定需要同时满足：投递存在、投递学生与传入 {@code studentUserId} 一致、
     * <strong>投递所属岗位属于 {@code companyId}</strong>，再按隐私设置决定：</p>
     *
     * <ul>
     *   <li>无记录 / null / PRIVATE：不可见</li>
     *   <li>APPLIED_COMPANIES：岗位属于该企业且投递状态为
     *       SUBMITTED/VIEWED/INTERVIEW/HIRED</li>
     *   <li>VERIFIED_COMPANIES：该企业 {@code verified=true} 且拥有该投递岗位</li>
     * </ul>
     */
    public boolean canCompanyViewResume(Long studentUserId, Long companyId, Long applicationId) {
        return companyResumeAccessPolicy.isVisible(studentUserId, companyId, applicationId);
    }

    private void validate(PrivacySettingsUpdateRequest req) {
        if (req.getResumeVisibility() == null || req.getContactVisible() == null) {
            throw new BusinessException(ErrorCode.BAD_REQUEST);
        }
    }

    private PrivacySettingsResponse toResponse(StudentPrivacySettings s, Long userId) {
        if (s == null) {
            return PrivacySettingsResponse.builder()
                    .studentUserId(userId)
                    .resumeVisibility(ResumeVisibility.PRIVATE)
                    .contactVisible(false)
                    .version(0L)
                    .build();
        }
        return PrivacySettingsResponse.builder()
                .id(s.getId())
                .studentUserId(s.getStudentUserId())
                .resumeVisibility(s.getResumeVisibility())
                .contactVisible(s.getContactVisible())
                .version(s.getVersion())
                .createdAt(s.getCreatedAt())
                .updatedAt(s.getUpdatedAt())
                .build();
    }
}