package ru.soune.nocopy.handler;

import com.fasterxml.jackson.databind.ObjectMapper;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.data.jpa.domain.Specification;
import org.springframework.stereotype.Component;
import ru.soune.nocopy.dto.BaseRequest;
import ru.soune.nocopy.dto.BaseResponse;

import ru.soune.nocopy.dto.MessageCode;
import ru.soune.nocopy.dto.user.UserAdditionalInfoBody;

import ru.soune.nocopy.dto.user.UserDTO;
import ru.soune.nocopy.entity.tarif.TariffInfo;
import ru.soune.nocopy.entity.user.User;
import ru.soune.nocopy.entity.user.UserAdditionalInfo;
import ru.soune.nocopy.entity.user.UserAdditionalInfoAnswer;
import ru.soune.nocopy.entity.user.UserAdditionalInfoListAnswer;
import ru.soune.nocopy.exception.UserAdditionalInfoNotFound;
import ru.soune.nocopy.repository.UserRepository;
import ru.soune.nocopy.service.user.AdditionalInfoService;
import ru.soune.nocopy.service.user.UserService;
import ru.soune.nocopy.service.user.UserSpecifications;


import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.stream.Collectors;

@Component
@Slf4j
@RequiredArgsConstructor
public class UserInfoHandler implements RequestHandler {

    private final AdditionalInfoService additionalInfoService;

    private final ObjectMapper objectMapper;

    private final UserRepository userRepository;

    private final UserService userService;

    @Override
    public BaseResponse handle(BaseRequest request) throws Exception {
        try {
            UserAdditionalInfoBody body = objectMapper.convertValue(request.getMessageBody(),
                    UserAdditionalInfoBody.class);

            log.info("Processing UserInfoHandler with action: {}", body.getAction());

            return switch (body.getAction()) {
                case "getAll" -> getAllAdditionalInfos(request);
                case "getAllWithPagination" -> getAllAdditionalInfoWithPagination(request, body);
                case "getById" -> getAdditionalInfoById(request, body.getUserId());
                case "getIngoById" -> getInfoById(request, body.getUserId());
                case "update" -> updateAdditionalInfo(request, body);
                case "delete" -> deleteAdditionalInfo(request, body.getUserId());
                default -> new BaseResponse(
                        request.getMsgId(),
                        MessageCode.INVALID_ACTION.getCode(),
                        "Invalid action: " + body.getAction(),
                        null
                );
            };
        } catch (IllegalArgumentException e) {
            log.error("Validation error in UserInfoHandler", e);
            return new BaseResponse(
                    request.getMsgId(),
                    MessageCode.VALIDATION_ERROR.getCode(),
                    e.getMessage(),
                    null);
        } catch (UserAdditionalInfoNotFound e) {
            log.error("User additional info not found", e);
            return new BaseResponse(
                    request.getMsgId(),
                    MessageCode.NOT_FOUND.getCode(),
                    e.getMessage(),
                    null);
        } catch (Exception e) {
            log.error("Unexpected error in UserInfoHandler", e);
            return new BaseResponse(
                    request.getMsgId(),
                    MessageCode.INTERNAL_ERROR.getCode(),
                    "Internal server error: " + e.getMessage(),
                    null);
        }
    }

    private BaseResponse getAllAdditionalInfos(BaseRequest request) {
        log.info("Getting all additional infos");

        List<UserAdditionalInfo> infos = additionalInfoService.getAllAdditionalInfos();

        List<UserAdditionalInfoAnswer> answerItems = infos.stream()
                .map(this::convertToAnswer)
                .collect(Collectors.toList());

        UserAdditionalInfoListAnswer listAnswer = UserAdditionalInfoListAnswer.builder()
                .items(answerItems)
                .count(answerItems.size())
                .build();

        return new BaseResponse(
                request.getMsgId(),
                MessageCode.SUCCESS.getCode(),
                MessageCode.SUCCESS.getDescription(),
                listAnswer
        );
    }

    private BaseResponse getAllAdditionalInfoWithPagination(BaseRequest request, UserAdditionalInfoBody req) {
        Sort.Direction direction =
                Sort.Direction.fromString(req.getSortDirection() != null ? req.getSortDirection() : "desc");
        String sortBy = req.getSortBy() != null ? req.getSortBy() : "createdAt";

        String sortField = switch (sortBy) {
            case "fullName" -> "fullName";
            case "email" -> "email";
            case "createdAt" -> "createdAt";
            case "verificationStatus" -> "verificationStatus";
            case "tariff" -> "personalTariffInfo.status";
            case "tokens" -> "personalTariffInfo.tokens";
            default -> "createdAt";
        };

        Pageable pageable = PageRequest.of(req.getPage(), req.getSize(), Sort.by(direction, sortField));

        Specification<User> spec = (root, query, cb) -> cb.conjunction();

        if (req.getFullName() != null) {
            spec = spec.and(UserSpecifications.byFullName(req.getFullName()));
        }
        if (req.getEmail() != null) {
            spec = spec.and(UserSpecifications.byEmail(req.getEmail()));
        }
        if (req.getIsActive() != null) {
            spec = spec.and(UserSpecifications.byIsActive(req.getIsActive()));
        }
        if (req.getEmailVerified() != null) {
            spec = spec.and(UserSpecifications.byEmailVerified(req.getEmailVerified()));
        }
        if (req.getSubscriptionType() != null) {
            spec = spec.and(UserSpecifications.bySubscriptionType(req.getSubscriptionType()));
        }
        if (req.getDateFrom() != null || req.getDateTo() != null) {
            spec = spec.and(UserSpecifications.byCreatedAtRange(req.getDateFrom(), req.getDateTo()));
        }

        Page<User> allUsers = userRepository.findAll(spec, pageable);

        Page<Map<String, Object>> dtoPage = allUsers.map(user -> {
            Map<String, Object> map = new LinkedHashMap<>();
            map.put("id", user.getId());
            map.put("fullName", user.getFullName());
            map.put("email", user.getEmail());
            map.put("verificationStatus", user.getVerificationStatus() != null ? user.getVerificationStatus().name() : null);
            map.put("createdAt", user.getCreatedAt() != null ? user.getCreatedAt().toString() : null);

            TariffInfo tariff = user.getActiveTariffInfo();
            if (tariff != null) {
                map.put("tariff", tariff.getStatus() != null ? tariff.getStatus().name() : null);
                map.put("tokens", tariff.getTokens() != null ? tariff.getTokens() : 0);
            } else {
                map.put("tariff", null);
                map.put("tokens", 0);
            }

            return map;
        });

        Map<String, Object> response = new LinkedHashMap<>();
        response.put("content", dtoPage.getContent());
        response.put("totalElements", allUsers.getTotalElements());
        response.put("totalPages", allUsers.getTotalPages());
        response.put("number", allUsers.getNumber());
        response.put("size", allUsers.getSize());

        return new BaseResponse(
                request.getMsgId(),
                MessageCode.SUCCESS.getCode(),
                MessageCode.SUCCESS.getDescription(),
                response);
    }


    private BaseResponse getAdditionalInfoById(BaseRequest request, Long userId) {
        log.info("Getting additional info for user: {}", userId);

        if (userId == null) {
            throw new IllegalArgumentException("User ID is required for getById action");
        }

        UserAdditionalInfo info = additionalInfoService.getAdditionalInfoByUser(userId);

        if (info == null) {
            throw new UserAdditionalInfoNotFound(
                    String.format("User additional info not found for userId: %d", userId)
            );
        }

        UserAdditionalInfoAnswer answer = convertToAnswer(info);

        return new BaseResponse(
                request.getMsgId(),
                MessageCode.SUCCESS.getCode(),
                MessageCode.SUCCESS.getDescription(),
                answer
        );
    }

    private BaseResponse getInfoById(BaseRequest request, Long userId) {
        log.info("Getting info for user: {}", userId);

        if (userId == null) {
            throw new IllegalArgumentException("User Id is required for getById action");
        }

        UserDTO userInfo = userService.getUserInfo(userId);

        return new BaseResponse(
                request.getMsgId(),
                MessageCode.SUCCESS.getCode(),
                MessageCode.SUCCESS.getDescription(),
                userInfo);
    }

    private BaseResponse updateAdditionalInfo(BaseRequest request, UserAdditionalInfoBody body) {
        log.info("Updating additional info for user: {}", body.getUserId());

        if (body.getUserId() == null) {
            throw new IllegalArgumentException("User ID is required for update action");
        }

        validateIpAddress(body.getIpAddress());
        validateUserAgent(body.getUserAgent());

        Optional<UserAdditionalInfo> updatedInfo = additionalInfoService.updateAdditionalInfo(
                body.getUserId(),
                body.getIpAddress(),
                body.getUserAgent()
        );

        if (updatedInfo.isEmpty()) {
            throw new UserAdditionalInfoNotFound(
                    String.format("User additional info not found for userId: %d", body.getUserId())
            );
        }

        UserAdditionalInfoAnswer answer = convertToAnswer(updatedInfo.get());

        return new BaseResponse(
                request.getMsgId(),
                MessageCode.SUCCESS.getCode(),
                MessageCode.SUCCESS.getDescription(),
                answer
        );
    }

    private BaseResponse deleteAdditionalInfo(BaseRequest request, Long userId) {
        log.info("Deleting additional info for user: {}", userId);

        if (userId == null) {
            throw new IllegalArgumentException("User ID is required for delete action");
        }

        UserAdditionalInfo existingInfo = additionalInfoService.getAdditionalInfoByUser(userId);

        if (existingInfo == null) {
            throw new UserAdditionalInfoNotFound(
                    String.format("User additional info not found for userId: %d", userId)
            );
        }

        additionalInfoService.deleteAdditionalInfo(userId);

        return new BaseResponse(
                request.getMsgId(),
                MessageCode.SUCCESS.getCode(),
                MessageCode.SUCCESS.getDescription(),
                Map.of("deleted", true, "user_id", userId)
        );
    }

    private UserAdditionalInfoAnswer convertToAnswer(UserAdditionalInfo info) {
        return UserAdditionalInfoAnswer.builder()
                .id(info.getId())
                .userId(info.getUser() != null ? info.getUser().getId() : null)
                .ipAddress(info.getIpAddress())
                .userAgent(info.getUserAgent())
                .registrationDate(info.getRegistrationDate())
                .build();
    }

    private void validateIpAddress(String ip) {
        if (ip == null || ip.trim().isEmpty()) {
            throw new IllegalArgumentException("IP address is required for update action");
        }

        String ipv4Pattern =
                "^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$";

        if (!ip.trim().matches(ipv4Pattern)) {
            log.warn("Invalid IP address format: {}", ip);
            throw new IllegalArgumentException("Invalid IP address format");
        }
    }

    private void validateUserAgent(String userAgent) {
        if (userAgent == null || userAgent.trim().isEmpty()) {
            throw new IllegalArgumentException("User agent is required for update action");
        }

        if (userAgent.length() > 500) {
            throw new IllegalArgumentException("User agent must not exceed 500 characters");
        }
    }
}