package com.mydreamjob.feedback;

import com.mydreamjob.application.Application;
import com.mydreamjob.application.ApplicationRepository;
import com.mydreamjob.common.exception.BusinessException;
import com.mydreamjob.common.exception.ErrorCode;
import com.mydreamjob.company.Company;
import com.mydreamjob.company.CompanyRepository;
import com.mydreamjob.feedback.dto.CandidateFeedbackRequest;
import com.mydreamjob.feedback.dto.CandidateFeedbackResponse;
import com.mydreamjob.job.Job;
import com.mydreamjob.job.JobService;
import com.mydreamjob.candidatescore.refresh.CandidateScoringRefreshRequestService;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.*;

@Slf4j
@Service
@RequiredArgsConstructor
public class CandidateFeedbackService {

    private final CandidateFeedbackRepository feedbackRepository;
    private final ApplicationRepository applicationRepository;
    private final JobService jobService;
    /** R01-D4-1：候选人反馈创建后登记评分快照刷新（INTEGRITY 维度）。 */
    private final CandidateScoringRefreshRequestService scoringRefreshRequestService;
    private final CompanyRepository companyRepository;
    private static final ObjectMapper mapper = new ObjectMapper();

    private Application findApplication(Long appId) {
        return applicationRepository.findById(appId)
                .orElseThrow(() -> new BusinessException(ErrorCode.APPLICATION_NOT_FOUND));
    }

    private Job findJob(Application app) {
        return jobService.getJob(app.getJobId());
    }

    /**
     * 企业归属校验：先按当前登录 userId 解析其拥有的企业，
     * 再将企业 id 与 job.companyId 比较（userId 与 companyId 属不同命名空间，不可直接比较）。
     */
    private void assertCompanyOwner(Long userId, Job job) {
        Company company = companyRepository.findByOwnerUserId(userId)
                .orElseThrow(() -> new BusinessException(ErrorCode.FORBIDDEN));
        if (!company.getId().equals(job.getCompanyId()))
            throw new BusinessException(ErrorCode.FORBIDDEN);
    }

    private void assertStudentOwner(Long studentUserId, Application app) {
        if (!app.getStudentUserId().equals(studentUserId))
            throw new BusinessException(ErrorCode.FORBIDDEN);
    }

    // ── 创建 ──────────────────────────────────────────────────

    @Transactional
    public CandidateFeedbackResponse createFeedback(Long userId, Long applicationId, CandidateFeedbackRequest req) {
        Application app = findApplication(applicationId);
        Job job = findJob(app);
        assertCompanyOwner(userId, job);

        if (feedbackRepository.existsByApplicationId(applicationId))
            throw new BusinessException(ErrorCode.DUPLICATE_FEEDBACK);

        CandidateFeedback fb = CandidateFeedback.builder()
                .applicationId(applicationId)
                .companyUserId(userId)
                .studentUserId(app.getStudentUserId())
                .rating(req.getRating()).content(req.getContent())
                .tags(toJson(req.getTags()))
                .build();
        CandidateFeedback saved = feedbackRepository.save(fb);
        // R01-D4-1：候选人反馈计数/均值影响 INTEGRITY 维度 → 登记当前周期刷新。
        scoringRefreshRequestService.requestRefresh(app.getStudentUserId(), java.time.LocalDateTime.now());
        return toResponse(saved);
    }

    // ── 查询 ──────────────────────────────────────────────────

    public CandidateFeedbackResponse getFeedback(Long userId, Long applicationId) {
        Application app = findApplication(applicationId);
        Job job = findJob(app);

        // 企业（按 userId 解析归属企业后比较企业 id）或学生任一匹配即可查看
        boolean isStudent = app.getStudentUserId().equals(userId);
        boolean isCompany = companyRepository.findByOwnerUserId(userId)
                .map(c -> c.getId().equals(job.getCompanyId()))
                .orElse(false);
        if (!isCompany && !isStudent)
            throw new BusinessException(ErrorCode.FORBIDDEN);

        CandidateFeedback fb = feedbackRepository.findByApplicationId(applicationId)
                .orElseThrow(() -> new BusinessException(ErrorCode.FEEDBACK_NOT_FOUND));
        return toResponse(fb);
    }

    // ── 修改 ──────────────────────────────────────────────────

    @Transactional
    public CandidateFeedbackResponse updateFeedback(Long userId, Long applicationId, CandidateFeedbackRequest req) {
        Application app = findApplication(applicationId);
        Job job = findJob(app);
        assertCompanyOwner(userId, job);

        CandidateFeedback fb = feedbackRepository.findByApplicationId(applicationId)
                .orElseThrow(() -> new BusinessException(ErrorCode.FEEDBACK_NOT_FOUND));

        if (req.getRating() != null) fb.setRating(req.getRating());
        if (req.getContent() != null) fb.setContent(req.getContent());
        if (req.getTags() != null) fb.setTags(toJson(req.getTags()));
        CandidateFeedback updated = feedbackRepository.save(fb);
        // R01-D4-2 F2：修改 rating 会改变 AVG(rating) → 与写操作同事务登记刷新。
        scoringRefreshRequestService.requestRefresh(app.getStudentUserId(), java.time.LocalDateTime.now());
        return toResponse(updated);
    }

    // ── 删除 ──────────────────────────────────────────────────

    @Transactional
    public void deleteFeedback(Long userId, Long applicationId) {
        Application app = findApplication(applicationId);
        Job job = findJob(app);
        assertCompanyOwner(userId, job);

        CandidateFeedback fb = feedbackRepository.findByApplicationId(applicationId)
                .orElseThrow(() -> new BusinessException(ErrorCode.FEEDBACK_NOT_FOUND));
        // R01-D4-2 F2：删除前先固定候选人标识，删除后仍能正确登记。
        Long studentUserId = app.getStudentUserId();
        feedbackRepository.delete(fb);
        // COUNT(*) 与 AVG(rating) 同时变化 → 与删除操作同事务登记刷新。
        scoringRefreshRequestService.requestRefresh(studentUserId, java.time.LocalDateTime.now());
    }

    // ── 视图 ──────────────────────────────────────────────────

    public CandidateFeedbackResponse toResponse(CandidateFeedback fb) {
        if (fb == null) return null;
        return CandidateFeedbackResponse.builder()
                .id(fb.getId())
                .applicationId(fb.getApplicationId())
                .rating(fb.getRating())
                .content(fb.getContent())
                .tags(fromJson(fb.getTags()))
                .createdAt(fb.getCreatedAt())
                .updatedAt(fb.getUpdatedAt())
                .build();
    }

    private String toJson(List<String> list) {
        if (list == null) return null;
        try { return mapper.writeValueAsString(list); }
        catch (JsonProcessingException e) { throw new RuntimeException("JSON error", e); }
    }

    private List<String> fromJson(String json) {
        if (json == null || json.isBlank()) return List.of();
        try { return mapper.readValue(json, new TypeReference<List<String>>() {}); }
        catch (JsonProcessingException e) { return List.of(); }
    }
}