package id.iptek.utms.preference.service;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import id.iptek.utms.auth.security.UserPrincipal;
import id.iptek.utms.core.exception.AppException;
import id.iptek.utms.core.i18n.MessageResolver;
import id.iptek.utms.preference.domain.UserUiPreference;
import id.iptek.utms.preference.dto.TablePreferenceProfile;
import id.iptek.utms.preference.dto.TablePreferenceRequest;
import id.iptek.utms.preference.dto.TablePreferenceSavedProfile;
import id.iptek.utms.preference.dto.UserUiPreferencesResponse;
import id.iptek.utms.preference.repository.UserUiPreferenceRepository;
import id.iptek.utms.tenant.TenantContext;
import org.springframework.security.core.Authentication;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.time.Instant;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.UUID;
import java.util.regex.Pattern;

@Service
public class UserPreferenceService {

    private static final String VALUE_JSON_FIELD = "visibleColumns";
    private static final Pattern PREFERENCE_KEY_PATTERN =
            Pattern.compile("^(users|roles|workflow|audit|modules):[A-Za-z0-9_./-]+$");
    private static final Map<String, List<String>> DEFAULT_COLUMNS_BY_KEY = Map.of(
            "users:workflow-requests", List.of("id", "resourceType", "resourceId", "makerUsername", "status", "requiredSteps", "currentStep", "createdAt", "updatedAt", "actions"),
            "workflow:requests", List.of("id", "resourceType", "resourceId", "makerUsername", "status", "updatedAt")
    );

    private final UserUiPreferenceRepository repository;
    private final ObjectMapper objectMapper;
    private final MessageResolver messageResolver;

    public UserPreferenceService(UserUiPreferenceRepository repository,
                                ObjectMapper objectMapper,
                                MessageResolver messageResolver) {
        this.repository = repository;
        this.objectMapper = objectMapper;
        this.messageResolver = messageResolver;
    }

    public UserUiPreferencesResponse getAll(Authentication authentication) {
        UUID userId = getUserId(authentication);
        TenantContext.getRequiredTenantId();

        List<UserUiPreference> preferences = repository.findByUserId(userId);
        preferences.sort(Comparator.comparing(UserUiPreference::getUpdatedAt, Comparator.nullsLast(Comparator.reverseOrder())));

        List<TablePreferenceProfile> columns = preferences.stream()
                .map(this::toProfile)
                .toList();
        Instant latestUpdatedAt = preferences.stream()
                .map(UserUiPreference::getUpdatedAt)
                .filter(Objects::nonNull)
                .max(Instant::compareTo)
                .orElse(null);

        return new UserUiPreferencesResponse(columns, latestUpdatedAt);
    }

    @Transactional
    public TablePreferenceSavedProfile upsert(Authentication authentication, TablePreferenceRequest request) {
        UUID userId = getUserId(authentication);
        String tenantId = TenantContext.getRequiredTenantId();
        String normalizedKey = normalizePreferenceKey(request.preferenceKey());
        List<String> normalizedColumns = normalizeVisibleColumns(request.visibleColumns());

        UserUiPreference preference = repository.findByUserIdAndPreferenceKey(userId, normalizedKey)
                .orElseGet(() -> {
                    UserUiPreference created = new UserUiPreference();
                    created.setUserId(userId);
                    created.setTenantId(tenantId);
                    created.setPreferenceKey(normalizedKey);
                    return created;
                });
        preference.setValueJson(serializePreferenceValue(normalizedColumns));
        UserUiPreference saved = repository.save(preference);
        return new TablePreferenceSavedProfile(
                saved.getPreferenceKey(),
                normalizedColumns,
                saved.getUpdatedAt()
        );
    }

    @Transactional
    public TablePreferenceProfile resetTablePreference(Authentication authentication, String preferenceKey) {
        UUID userId = getUserId(authentication);
        String normalizedKey = normalizePreferenceKey(preferenceKey);

        repository.deleteByUserIdAndPreferenceKey(userId, normalizedKey);
        return new TablePreferenceProfile(normalizedKey, getDefaultColumns(normalizedKey));
    }

    @Transactional
    public void resetAll(Authentication authentication) {
        UUID userId = getUserId(authentication);
        repository.deleteByUserId(userId);
    }

    private TablePreferenceProfile toProfile(UserUiPreference preference) {
        return new TablePreferenceProfile(
                preference.getPreferenceKey(),
                parseVisibleColumns(preference.getValueJson())
        );
    }

    private UUID getUserId(Authentication authentication) {
        Object principal = authentication != null ? authentication.getPrincipal() : null;
        if (principal instanceof UserPrincipal userPrincipal) {
            return userPrincipal.getId();
        }
        throw new AppException(messageResolver.get("auth.invalid.credentials"));
    }

    private String normalizePreferenceKey(String preferenceKey) {
        if (preferenceKey == null || preferenceKey.isBlank()) {
            throw new AppException(messageResolver.get("user.preferences.invalid.key"));
        }
        String normalized = preferenceKey.trim();
        if (!PREFERENCE_KEY_PATTERN.matcher(normalized).matches()) {
            throw new AppException(messageResolver.get("user.preferences.invalid.key"));
        }
        return normalized;
    }

    private List<String> normalizeVisibleColumns(List<String> visibleColumns) {
        if (visibleColumns == null || visibleColumns.isEmpty()) {
            throw new AppException(messageResolver.get("user.preferences.invalid.columns"));
        }
        List<String> normalized = visibleColumns.stream()
                .map(column -> column == null ? null : column.trim())
                .filter(Objects::nonNull)
                .toList();
        if (normalized.isEmpty() || normalized.stream().anyMatch(String::isBlank)) {
            throw new AppException(messageResolver.get("user.preferences.invalid.columns"));
        }
        return List.copyOf(normalized);
    }

    private String serializePreferenceValue(List<String> visibleColumns) {
        try {
            Map<String, List<String>> value = new LinkedHashMap<>();
            value.put(VALUE_JSON_FIELD, visibleColumns);
            return objectMapper.writeValueAsString(value);
        } catch (Exception ex) {
            throw new AppException(messageResolver.get("user.preferences.serialize.failed"));
        }
    }

    private List<String> parseVisibleColumns(String valueJson) {
        try {
            JsonNode root = objectMapper.readTree(valueJson);
            JsonNode columns = root.get(VALUE_JSON_FIELD);
            if (columns == null || !columns.isArray()) {
                throw new AppException(messageResolver.get("user.preferences.invalid.value"));
            }
            List<String> visibleColumns = new ArrayList<>();
            for (JsonNode value : columns) {
                String column = value != null ? value.asText() : null;
                if (column == null || column.isBlank()) {
                    throw new AppException(messageResolver.get("user.preferences.invalid.value"));
                }
                visibleColumns.add(column);
            }
            return visibleColumns;
        } catch (AppException ex) {
            throw ex;
        } catch (Exception ex) {
            throw new AppException(messageResolver.get("user.preferences.invalid.value"));
        }
    }

    private List<String> getDefaultColumns(String preferenceKey) {
        return DEFAULT_COLUMNS_BY_KEY.getOrDefault(preferenceKey, List.of("id", "createdAt", "updatedAt", "actions"));
    }
}