package eu.eudat.service.remotefetcher;

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.jayway.jsonpath.DocumentContext;
import com.jayway.jsonpath.JsonPath;
import eu.eudat.commons.XmlHandlingService;
import eu.eudat.commons.enums.ReferenceTypeSourceType;
import eu.eudat.commons.exceptions.HugeResultSetException;
import eu.eudat.convention.ConventionService;
import eu.eudat.service.remotefetcher.config.entities.*;
import eu.eudat.service.remotefetcher.models.ExternalDataResult;
import eu.eudat.service.remotefetcher.criteria.ExternalReferenceCriteria;
import eu.eudat.service.remotefetcher.criteria.FetchStrategy;
import gr.cite.tools.exception.MyApplicationException;
import net.minidev.json.JSONArray;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.ParameterizedTypeReference;
import org.springframework.http.*;
import org.springframework.http.client.reactive.ReactorClientHttpConnector;
import org.springframework.http.codec.json.Jackson2JsonDecoder;
import org.springframework.stereotype.Service;
import org.springframework.web.reactive.function.client.WebClient;
import reactor.netty.http.client.HttpClient;

import java.io.File;
import java.nio.file.Paths;
import java.util.*;
import java.util.stream.Collectors;

@Service
public class RemoteFetcherServiceImpl implements RemoteFetcherService {
    private static final Logger logger = LoggerFactory.getLogger(RemoteFetcherServiceImpl.class);

    private WebClient webClient;
    private final ExternalUrlConfigProvider externalUrlConfigProvider;
	private final ConventionService conventionService;
    private final XmlHandlingService xmlHandlingService;
    @Autowired
    public RemoteFetcherServiceImpl(ExternalUrlConfigProvider externalUrlConfigProvider, ConventionService conventionService, XmlHandlingService xmlHandlingService) {
	    this.externalUrlConfigProvider = externalUrlConfigProvider;
	    this.conventionService = conventionService;
	    this.xmlHandlingService = xmlHandlingService;
    }

    private WebClient getWebClient(){
        if (this.webClient == null) {
            this.webClient = WebClient.builder().codecs(clientCodecConfigurer -> {
                        clientCodecConfigurer.defaultCodecs().jackson2JsonDecoder(new Jackson2JsonDecoder(new ObjectMapper(), MediaType.APPLICATION_JSON));
                        clientCodecConfigurer.defaultCodecs().maxInMemorySize(2 * ((int) Math.pow(1024, 3))); //GK: Why here???
                    }
            ).clientConnector(new ReactorClientHttpConnector(HttpClient.create().followRedirect(true))).build();
        }
        return webClient;
    }



    @Override
    public ExternalDataResult getExternalData(List<SourceBaseConfiguration> sources, ExternalReferenceCriteria externalReferenceCriteria, String key, FetchStrategy fetchStrategy)  {
        List<SourceBaseConfiguration> apiSourcesToUse =  sources.stream().map(x -> (SourceBaseConfiguration)x).toList();
        if (!this.conventionService.isNullOrEmpty(key)){
            apiSourcesToUse = sources.stream().filter(x-> x.getKey().equals(key)).map(x -> (SourceBaseConfiguration)x).toList();
        }
        if (this.conventionService.isListNullOrEmpty(apiSourcesToUse)) return new ExternalDataResult();

        apiSourcesToUse.sort(Comparator.comparing(SourceBaseConfiguration::getOrdinal));

        return this.queryExternalData(sources, fetchStrategy, externalReferenceCriteria);
    }

    @Override
    public Integer countExternalData(List<SourceBaseConfiguration> sources, ExternalReferenceCriteria externalReferenceCriteria, String key) {
        return getExternalData(sources, externalReferenceCriteria, key, null).getResults().size();
    }

    private ExternalDataResult queryExternalData(List<SourceBaseConfiguration> sources, FetchStrategy fetchStrategy, ExternalReferenceCriteria externalReferenceCriteria) {

        ExternalDataResult results = new ExternalDataResult();

	    if (this.conventionService.isListNullOrEmpty(sources)) return new ExternalDataResult();

	    for (SourceBaseConfiguration source : sources) {
		    if (source.getType() == null || source.getType().equals(ReferenceTypeSourceType.API)) {
			    try {
                    SourceExternalApiConfiguration<ResultsConfiguration<ResultFieldsMappingConfiguration>, AuthenticationConfiguration, QueryConfig> apiSource = (SourceExternalApiConfiguration)source;
                    this.applyFunderToQuery(apiSource, externalReferenceCriteria);

                    String auth = null;
				    if (apiSource.getAuth() != null) {
					    auth = this.buildAuthentication(apiSource.getAuth());
				    }
				    results.addAll(this.queryExternalData(fetchStrategy, apiSource, externalReferenceCriteria, auth));
			    } catch (Exception e) {
				    logger.error(e.getLocalizedMessage(), e);
			    }
		    } else if (source.getType() != null &&  source.getType().equals(ReferenceTypeSourceType.STATIC)) {
                SourceStaticOptionConfiguration<StaticOption> staticSource = (SourceStaticOptionConfiguration)source;
			    results.addAll(getAllResultsFromMockUpJson(staticSource.getKey(), externalReferenceCriteria.getLike())); //TODO:
		    }
	    }
        return results;
    }

    private String buildAuthentication(AuthenticationConfiguration authenticationConfiguration) {
        HttpMethod method;
        switch (authenticationConfiguration.getAuthMethod()) {
            case GET -> method = HttpMethod.GET;
            case POST -> method =HttpMethod.POST;
            default -> throw new MyApplicationException("unrecognized type " + authenticationConfiguration.getAuthMethod());
        }
        
        Map<String, Object> response = this.getWebClient().method(method).uri(authenticationConfiguration.getAuthUrl())
                .contentType(MediaType.APPLICATION_JSON)
                .bodyValue(this.parseBodyString(authenticationConfiguration.getAuthRequestBody()))
                .exchangeToMono(mono -> mono.bodyToMono(new ParameterizedTypeReference<Map<String, Object>>() {
                })).block();
        if (response == null) throw new MyApplicationException("Authentication " + authenticationConfiguration.getAuthUrl() + " failed");

        return authenticationConfiguration.getType() + " " + response.getOrDefault(authenticationConfiguration.getAuthTokenPath(), null);
    }


    private void applyFunderToQuery(SourceExternalApiConfiguration<ResultsConfiguration<ResultFieldsMappingConfiguration>, AuthenticationConfiguration, QueryConfig> apiSource, ExternalReferenceCriteria externalReferenceCriteria) {
        //TODO new reference logic
//	    if (apiSource.getFunderQuery() != null) {
//		    if (externalReferenceCriteria.getFunderId() != null && !apiSource.getFunderQuery().startsWith("dmp:")) {
//			    apiSource.setUrl(apiSource.getUrl().replace("{funderQuery}", apiSource.getFunderQuery()));
//		    }
//		    else {
//			    apiSource.setUrl(apiSource.getUrl().replace("{funderQuery}", ""));
//		    }
//	    }
    }

    private String replaceLookupFieldQuery(ExternalReferenceCriteria externalReferenceCriteria, List<QueryConfig> queryConfigs) {
        String finalQuery = "";
        if (this.conventionService.isNullOrEmpty(externalReferenceCriteria.getLike())) return finalQuery;
        QueryConfig queryConfig = queryConfigs.stream().filter(x -> !this.conventionService.isNullOrEmpty(x.getCondition()) && externalReferenceCriteria.getLike().matches(x.getCondition()))
                .min((Comparator.comparing(QueryConfig::getOrdinal))).orElse(null);
        if (queryConfig != null) {
            if (queryConfig.getSeparator() != null) {
                String[] likes = externalReferenceCriteria.getLike().split(queryConfig.getSeparator());
                finalQuery = queryConfig.getValue();
                for (int i = 0; i < likes.length; i++) {
                    finalQuery = finalQuery.replaceAll("\\{like" + (i + 1) + "}", likes[i]);
                }
            } else {
                finalQuery = queryConfig.getValue().replaceAll("\\{like}", externalReferenceCriteria.getLike());
            }

        }
        return finalQuery;
    }

    protected String replaceLookupFields(String path, ExternalReferenceCriteria externalReferenceCriteria, String firstPage, List<QueryConfig> queries) {
        if (!this.conventionService.isNullOrEmpty(path)) return path;
        String completedPath = path;
        
        if (externalReferenceCriteria.getLike() != null) {
            if ((path.contains("openaire") || path.contains("orcid") || path.contains("ror") || path.contains("fairsharing")) && externalReferenceCriteria.getLike().isEmpty()) {
                completedPath = completedPath.replaceAll("\\{like}", "*");
                completedPath = completedPath.replaceAll("\\{query}", "*");
            } else {
                if (completedPath.contains("{query}")) {
                    completedPath = completedPath.replaceAll("\\{query}", this.replaceLookupFieldQuery(externalReferenceCriteria, queries));
                } else {
                    completedPath = completedPath.replaceAll("\\{like}", externalReferenceCriteria.getLike());
                }
            }
        } else {
            completedPath = completedPath.replace("{like}", "");
        }
        if (!this.conventionService.isNullOrEmpty(externalReferenceCriteria.getFunderId())) {
            String[] founderParts = externalReferenceCriteria.getFunderId().split(":");
            String funderPrefix = founderParts.length > 0 ? founderParts[0] : "";
            String funderId = externalReferenceCriteria.getFunderId().replace(funderPrefix + ":", "");
            if (!funderId.isEmpty() && funderId.toCharArray()[0] == ':') {
                funderId = externalReferenceCriteria.getFunderId();
            }
            completedPath = completedPath.replace("{funderId}", funderId);
        } else if(completedPath.contains("{funderId}")){
            logger.warn("FunderId is null.");
            completedPath = completedPath.replace("{funderId}", " ");
        }
        
        if (!this.conventionService.isNullOrEmpty(externalReferenceCriteria.getPage()))  completedPath = completedPath.replace("{page}", externalReferenceCriteria.getPage());
        else  if (!this.conventionService.isNullOrEmpty(firstPage))  completedPath = completedPath.replace("{page}", firstPage);
        else completedPath = completedPath.replace("{page}", "1");

        completedPath = completedPath.replace("{pageSize}", !this.conventionService.isNullOrEmpty(externalReferenceCriteria.getPageSize()) ? externalReferenceCriteria.getPageSize() : "60");
        completedPath = completedPath.replace("{host}", !this.conventionService.isNullOrEmpty(externalReferenceCriteria.getHost()) ? externalReferenceCriteria.getHost() : "");
        completedPath = completedPath.replace("{path}", !this.conventionService.isNullOrEmpty(externalReferenceCriteria.getPath()) ? externalReferenceCriteria.getPath() : "");
        
        
        return completedPath;
    }

    private ExternalDataResult queryExternalData(FetchStrategy fetchStrategy, final SourceExternalApiConfiguration<ResultsConfiguration<ResultFieldsMappingConfiguration>, AuthenticationConfiguration, QueryConfig> apiSource, ExternalReferenceCriteria externalReferenceCriteria, String auth) throws Exception {
        String replacedPath = replaceLookupFields(apiSource.getUrl(), externalReferenceCriteria, apiSource.getFirstPage(), apiSource.getQueries());
        String replacedBody = replaceLookupFields(apiSource.getRequestBody(), externalReferenceCriteria, apiSource.getFirstPage(), apiSource.getQueries());

        ExternalDataResult externalDataResult = this.getExternalDataResults(replacedPath, apiSource, replacedBody, auth);
        if(externalDataResult != null) {
            if (apiSource.getFilterType() != null && apiSource.getFilterType().equals("local") && (externalReferenceCriteria.getLike() != null && !externalReferenceCriteria.getLike().isEmpty())) {
                externalDataResult.setResults(externalDataResult.getResults().stream()
                        .filter(r -> r.get("name").toLowerCase().contains(externalReferenceCriteria.getLike().toLowerCase()))
                        .collect(Collectors.toList()));
            }
            externalDataResult.setResults(externalDataResult.getResults().stream().peek(x -> x.put("tag", apiSource.getLabel())).peek(x -> x.put("key", apiSource.getKey())).toList());
            if (fetchStrategy == FetchStrategy.FIRST) return externalDataResult;

            Long maxResults = this.externalUrlConfigProvider.getExternalUrls().getMaxresults();
            if (externalDataResult.getResults().size() > maxResults)
                throw new HugeResultSetException("The submitted search query " + externalReferenceCriteria.getLike() + " is about to return " + externalDataResult.getResults().size() + " results... Please submit a more detailed search query");

            return externalDataResult;
        }
        else {
            return new ExternalDataResult();
        }
    }

    protected ExternalDataResult getExternalDataResults(String urlString, final SourceExternalApiConfiguration<ResultsConfiguration<ResultFieldsMappingConfiguration>, AuthenticationConfiguration, QueryConfig>  apiSource, String requestBody, String auth) {

        try {
            JsonNode jsonBody = new ObjectMapper().readTree(requestBody);
            HttpMethod method;
            switch (apiSource.getHttpMethod()) {
                case GET -> method = HttpMethod.GET;
                case POST -> method =HttpMethod.POST;
                default -> throw new MyApplicationException("unrecognized type " + apiSource.getHttpMethod());
            }
            
            ResponseEntity<String> response = this.getWebClient().method(method).uri(urlString).headers(httpHeaders -> {
                if (this.conventionService.isNullOrEmpty(apiSource.getContentType())) {
                    httpHeaders.setAccept(Collections.singletonList(MediaType.valueOf(apiSource.getContentType())));
                    httpHeaders.setContentType(MediaType.valueOf(apiSource.getContentType()));
                }
                if (auth != null) {
                    httpHeaders.set("Authorization", auth);
                }
            }).bodyValue(jsonBody).retrieve().toEntity(String.class).block();
            if (response == null || !response.getStatusCode().isSameCodeAs(HttpStatus.OK) || !response.hasBody() || response.getBody()  == null) return null;
            
            //do here all the parsing
            List<String> responseContentTypeHeader = response.getHeaders().getOrDefault("Content-Type", null);
            String responseContentType =  !this.conventionService.isListNullOrEmpty(responseContentTypeHeader)  && responseContentTypeHeader.getFirst() != null ? responseContentTypeHeader.getFirst() : "";
            
            if (responseContentType.contains("json") ) {
                DocumentContext jsonContext = JsonPath.parse(response.getBody());
                return this.parseData(jsonContext, apiSource.getResults());
            } else {
                throw new MyApplicationException("Unsupported response type" + responseContentType);
            }

        } catch (Exception exception) {
            logger.error(exception.getMessage(), exception);
        } 

        return null;
    }

    private ExternalDataResult parseData (DocumentContext jsonContext, ResultsConfiguration<ResultFieldsMappingConfiguration> resultsConfigurationEntity) {
        ExternalDataResult result = new ExternalDataResult();
        if (this.conventionService.isNullOrEmpty(resultsConfigurationEntity.getResultsArrayPath())) return new ExternalDataResult();
        List<Map<String, Object>> rawData = jsonContext.read(resultsConfigurationEntity.getResultsArrayPath());

        result.setRawData(rawData);
        
        if (this.conventionService.isListNullOrEmpty(rawData) || this.conventionService.isListNullOrEmpty(resultsConfigurationEntity.getFieldsMapping())) return new ExternalDataResult();
        
        List<Map<String, String>> parsedData = new ArrayList<>();
        for (Map<String, Object> stringObjectMap: rawData){
            Map<String, String> map = new HashMap<>();
            for(ResultFieldsMappingConfiguration field : resultsConfigurationEntity.getFieldsMapping()){
                String pathValue = field.getResponsePath();
                if (!pathValue.contains(".")){
                    if (stringObjectMap.containsKey(pathValue)) {
                        map.put(field.getCode(), normalizeValue(stringObjectMap.get(pathValue)));
                    }
                }else {
                    if (stringObjectMap.containsKey(pathValue.split("\\.")[0])){
                        String value = null;
                        Object fieldObj = stringObjectMap.get(pathValue.split("\\.")[0]);
                        if (fieldObj != null){
                            if (fieldObj instanceof Map){
                                Object o = ((Map<String, Object>) fieldObj).get(pathValue.split("\\.")[1]);
                                if(o instanceof String){
                                    value = (String)o;
                                }
                                else if(o instanceof Integer){
                                    value = String.valueOf(o);
                                }
                            } else if (fieldObj instanceof List) {
                                Object o = ((List<Map<String,?>>) fieldObj).get(0).get(pathValue.split("\\.")[1]);
                                if(o instanceof String){
                                    value = (String)o;
                                }
                                else if(o instanceof Integer){
                                    value = String.valueOf(o);
                                }
                            }
                        }
                        if (value != null){
                            map.put(field.getCode(), value);
                        }
                    }
                }
            }
            parsedData.add(map);
        }
        result.setResults(parsedData);
        return result;
    }

    private static String normalizeValue(Object value) {
        if (value instanceof JSONArray jsonArray) {
            
	        if (!jsonArray.isEmpty() && jsonArray.getFirst() instanceof String) {
                return jsonArray.getFirst().toString();
            } else {
                for (Object o : jsonArray) {
                    if ((o instanceof Map) && ((Map<?, ?>) o).containsKey("content")) {
                        try {
                            return ((Map<String, String>) o).get("content");
                        }
                        catch (ClassCastException e){
                            if(((Map<?, ?>) o).get("content") instanceof Integer) {
                                return String.valueOf(((Map<?, ?>) o).get("content"));
                            }
                            return null;
                        }
                    }
                }
            }
        } else if (value instanceof Map) {
            String key = ((Map<String, String>)value).containsKey("$") ? "$" : "content";
            return ((Map<String, String>)value).get(key);
        }
        return value != null ? value.toString() : null;
    }
    
    private ExternalDataResult getAllResultsFromMockUpJson(String path, String query) {
        List<Map<String, String>> internalResults;
        try {
            String filePath = Paths.get(path).toUri().toURL().toString();
            ObjectMapper mapper = new ObjectMapper();
            internalResults = mapper.readValue(new File(filePath), new TypeReference<List<Map<String, String>>>(){});
            return new ExternalDataResult(searchListMap(internalResults, query));
        } catch (Exception e) {
            logger.error(e.getMessage(), e);
            return new ExternalDataResult();
        }
    }

    private List<Map<String, String>> searchListMap(List<Map<String, String>> internalResults, String query) {
        List<Map<String, String>> list = new LinkedList<>();
        for (Map<String, String> map : internalResults)
        {
            if (map.get("name") != null && map.get("name").toUpperCase().contains(query.toUpperCase())) {
                list.add(map);
            }
            if (map.get("label") != null && map.get("label").toUpperCase().contains(query.toUpperCase())) {
                list.add(map);
            }
        }
        return list;
    }

    private String parseBodyString(String bodyString) {
        String finalBodyString = bodyString;
        if (bodyString.contains("{env:")) {
            int index = bodyString.indexOf("{env: ");
            while (index >= 0) {
                int endIndex = bodyString.indexOf("}", index + 6);
                String envName = bodyString.substring(index + 6, endIndex);
                finalBodyString = finalBodyString.replace("{env: " + envName + "}", System.getenv(envName));
                index = bodyString.indexOf("{env: ", index + 6);
            }
        }
        return finalBodyString;
    }

}