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.dto.FeatureConversionStepTwoValidationRequest;
import com.sztzjy.linkCommerce.entity.dto.FeatureConversionStepTwoValidationResult;
import com.sztzjy.linkCommerce.service.FeatureConversionStepTwoService;
import org.apache.commons.lang3.StringUtils;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Service;

import java.math.BigDecimal;
import java.math.RoundingMode;
import java.util.Arrays;
import java.util.List;

@Service
public class FeatureConversionStepTwoServiceImpl implements FeatureConversionStepTwoService {
    private static final int MIN_ROWS = 8;
    private static final int MAX_ROWS = 12;
    private static final List<String> KANO_TYPES = Arrays.asList("基本型", "期望型", "兴奋型", "无差异型", "反向型");

    @Override
    public FeatureConversionStepTwoValidationResult validate(FeatureConversionStepTwoValidationRequest request, JwtUser user) {
        requireStudent(user);
        List<String> sourceDefinitions = request == null ? null : request.getSourceDefinitions();
        List<FeatureConversionStepTwoValidationRequest.RiceScoreRow> rows = request == null ? null : request.getRows();
        if (sourceDefinitions == null || rows == null || rows.size() < MIN_ROWS || rows.size() > MAX_ROWS || sourceDefinitions.size() != rows.size()) {
            throw badRequest("RICE 评分行数必须与第一步需求转化表一致，且为 8 至 12 行");
        }
        for (int index = 0; index < rows.size(); index++) {
            String expectedId = String.format("F%02d", index + 1);
            String expectedName = sourceDefinitions.get(index);
            FeatureConversionStepTwoValidationRequest.RiceScoreRow row = rows.get(index);
            if (row == null || StringUtils.isBlank(expectedName) || !expectedId.equals(row.getRequirementId()) || !expectedName.equals(row.getName())) {
                throw badRequest("需求 ID 与功能名称必须与第一步的功能定义保持一致");
            }
            if (!KANO_TYPES.contains(row.getKano()) || !isScore(row.getReach()) || !isScore(row.getImpact())
                    || !isConfidence(row.getConfidence()) || row.getEffort() == null || row.getEffort() <= 0 || !isRiceScoreValid(row)) {
                throw badRequest("请完整填写 KANO、Reach、Impact、Confidence、Effort，并确认 RICE 得分正确");
            }
        }
        FeatureConversionStepTwoValidationResult result = new FeatureConversionStepTwoValidationResult();
        result.setValid(true);
        result.setMessage("RICE 评分填写完整。");
        return result;
    }

    private boolean isScore(Double value) {
        return value != null && value >= 1 && value <= 5 && value == Math.rint(value);
    }

    private boolean isConfidence(Double value) {
        return value != null && value >= 1 && value <= 100 && value == Math.rint(value);
    }

    private boolean isRiceScoreValid(FeatureConversionStepTwoValidationRequest.RiceScoreRow row) {
        if (StringUtils.isBlank(row.getRiceScore())) return false;
        try {
            BigDecimal expected = BigDecimal.valueOf(row.getReach())
                    .multiply(BigDecimal.valueOf(row.getImpact()))
                    .multiply(BigDecimal.valueOf(row.getConfidence()).movePointLeft(2))
                    .divide(BigDecimal.valueOf(row.getEffort()), 2, RoundingMode.HALF_UP);
            return expected.compareTo(new BigDecimal(row.getRiceScore())) == 0;
        } catch (NumberFormatException error) {
            return false;
        }
    }

    private void requireStudent(JwtUser user) {
        if (user == null || StringUtils.isBlank(user.getUserId())) {
            throw new ServiceException(HttpStatus.UNAUTHORIZED, "请先登录后再提交");
        }
        if (user.getRoleId() != 4) {
            throw new ServiceException(HttpStatus.FORBIDDEN, "仅学生可以提交实训答案");
        }
    }

    private ServiceException badRequest(String message) {
        return new ServiceException(HttpStatus.BAD_REQUEST, message);
    }
}