package com.labelsys.backend.service;

import com.labelsys.backend.context.LoginUser;
import com.labelsys.backend.entity.BizDataRecord;
import com.labelsys.backend.enums.UserRole;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Service;

import java.util.List;
import java.util.function.Function;
import java.util.stream.Collectors;

@Slf4j
@Service
@RequiredArgsConstructor
public class DataPermissionService {

    private final JdbcTemplate jdbcTemplate;

    public boolean canAccessCreator(LoginUser currentUser, Long creatorId, UserRole creatorRole) {
        try {
            return switch (currentUser.role()) {
                case EMPLOYEE -> currentUser.userId().equals(creatorId);
                case MANAGER -> creatorRole == UserRole.EMPLOYEE || creatorRole == UserRole.MANAGER;
                case ENGINEER -> true;
            };
        } catch (Exception e) {
            log.error("canAccessCreator failed, companyId={}, userId={}, creatorId={}, error={}",
                    currentUser.companyId(), currentUser.userId(), creatorId, e.getMessage(), e);
            throw e;
        }
    }

    public <T> List<T> filterByRole(
            LoginUser currentUser,
            List<T> allRecords,
            Function<T, UserRole> roleExtractor,
            Function<T, Long> ownerIdExtractor) {
        try {
            if (allRecords == null || allRecords.isEmpty()) {
                return List.of();
            }

            UserRole currentRole = currentUser.role();
            Long currentUserId = currentUser.userId();

            return allRecords.stream()
                    .filter(record -> {
                        UserRole recordRole = roleExtractor.apply(record);
                        Long recordOwnerId = ownerIdExtractor.apply(record);

                        return switch (currentRole) {
                            case EMPLOYEE -> currentUserId.equals(recordOwnerId);
                            case MANAGER -> recordRole == UserRole.EMPLOYEE || recordRole == UserRole.MANAGER;
                            case ENGINEER -> true;
                        };
                    })
                    .collect(Collectors.toList());
        } catch (Exception e) {
            log.error("filterByRole failed, companyId={}, userId={}, error={}",
                    currentUser.companyId(), currentUser.userId(), e.getMessage(), e);
            throw e;
        }
    }

    public List<String> getAllowedRoles(LoginUser currentUser) {
        try {
            return switch (currentUser.role()) {
                case EMPLOYEE -> List.of();
                case MANAGER -> List.of("EMPLOYEE", "MANAGER");
                case ENGINEER -> List.of("EMPLOYEE", "MANAGER", "ENGINEER");
            };
        } catch (Exception e) {
            log.error("getAllowedRoles failed, companyId={}, userId={}, error={}",
                    currentUser.companyId(), currentUser.userId(), e.getMessage(), e);
            throw e;
        }
    }

    public boolean shouldFilterByUserId(LoginUser currentUser) {
        try {
            return currentUser.role() == UserRole.EMPLOYEE;
        } catch (Exception e) {
            log.error("shouldFilterByUserId failed, companyId={}, userId={}, error={}",
                    currentUser.companyId(), currentUser.userId(), e.getMessage(), e);
            throw e;
        }
    }

    public List<BizDataRecord> listVisibleRecords(LoginUser currentUser) {
        try {
            List<BizDataRecord> allRecords = jdbcTemplate.query("""
                            select id, company_id, creator_id, creator_role, record_name, created_at, updated_at
                            from biz_data_record
                            where company_id = ?
                            order by id
                            """,
                    (rs, rowNum) -> BizDataRecord.builder()
                            .id(rs.getLong("id"))
                            .companyId(rs.getLong("company_id"))
                            .creatorId(rs.getLong("creator_id"))
                            .creatorRole(UserRole.valueOf(rs.getString("creator_role")))
                            .recordName(rs.getString("record_name"))
                            .createdAt(rs.getTimestamp("created_at") == null ?
                                    null :
                                    rs.getTimestamp("created_at").toLocalDateTime())
                            .updatedAt(rs.getTimestamp("updated_at") == null ?
                                    null :
                                    rs.getTimestamp("updated_at").toLocalDateTime())
                            .build(),
                    currentUser.companyId());

            return filterByRole(currentUser, allRecords, BizDataRecord::getCreatorRole, BizDataRecord::getCreatorId);
        } catch (Exception e) {
            log.error("listVisibleRecords failed, companyId={}, userId={}, error={}",
                    currentUser.companyId(), currentUser.userId(), e.getMessage(), e);
            throw e;
        }
    }
}