package cn.seecoder.bok.client;

import cn.seecoder.bok.common.dto.CollectDTO;
import cn.seecoder.bok.common.dto.RateDTO;
import cn.seecoder.bok.common.vo.*;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.json.JsonMapper;
import com.fasterxml.jackson.datatype.jdk8.Jdk8Module;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
import com.fasterxml.jackson.module.paramnames.ParameterNamesModule;
import okhttp3.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.data.domain.*;
import org.springframework.data.util.Streamable;

import javax.validation.constraints.NotBlank;
import javax.validation.constraints.NotNull;
import java.io.IOException;
import java.text.MessageFormat;
import java.util.*;
import java.util.function.Function;

/**
 * @author kunduin
 */
public class SeecoderBokClient
        implements SeecoderBokQuestionApi, SeecoderBokQuestionQueryApi,
        SeecoderBokRecordApi, SeecoderBokUserInteractiveApi,
        SeecoderBokKnowledgeApi {

    private final Logger logger = LoggerFactory.getLogger(getClass());

    private final OkHttpClient client;
    private final ObjectMapper mapper;

    private final int CONFIG_PAGE_START;
    private final String CONFIG_HOST;

    /**
     * 创建client
     *
     * @param host bok地址，示例：{@code "http://bok.seecoder.cn"}
     */
    public SeecoderBokClient(String host) {
        this(host, 0);
    }

    public SeecoderBokClient(String host, int pageStart) {
        this.CONFIG_HOST = host;
        this.CONFIG_PAGE_START = pageStart;
        client = new OkHttpClient();
        mapper = JsonMapper.builder()
                .addModule(new ParameterNamesModule())
                .addModule(new Jdk8Module())
                .addModule(new JavaTimeModule())
                .build();
    }

    @Override
    public List<KnowledgeNodeVO> getKnowledgeNode(String name) {
        HttpUrl httpUrl = createUrlBuilder("/api/knowledge")
                .addQueryParameter("name", name).build();
        Response response = get(httpUrl);
        return getResponseBody(response, new TypeReference<List<KnowledgeNodeVO>>() {})
                .orElse(Collections.emptyList());
    }

    @Override
    public Page<QuestionVO> getQuestionList(
            String stem, String tag, String knowledgeId, Pageable pageable) {
        HttpUrl.Builder urlBuilder = createUrlBuilder("/api/question")
                .addQueryParameter("stem", stem)
                .addQueryParameter("tag", tag)
                .addQueryParameter("knowledgeId", knowledgeId);
        return getQuestionVOS(pageable, urlBuilder);
    }

    @Override
    public QuestionVO createQuestion(@NotNull QuestionVO question) {
        HttpUrl httpUrl = createUrlBuilder("/api/question").build();
        Response response = post(httpUrl, writeRequestBody(question));
        return getResponseBody(response, QuestionVO.class).orElseThrow(() -> SeecoderBokException.UNWRAP_EXCEPTION);
    }

    @Override
    public Optional<QuestionVO> getQuestionById(@NotBlank String questionId) {
        HttpUrl httpUrl = createUrlBuilder(MessageFormat.format("/api/question/{0}", questionId)).build();
        Response response = get(httpUrl);
        return getResponseBody(response, QuestionVO.class);
    }

    @Override
    public QuestionVO updateQuestion(@NotNull QuestionVO question) {
        HttpUrl httpUrl = createUrlBuilder(MessageFormat.format("/api/question/{0}", question.getId())).build();
        Response response = put(httpUrl, writeRequestBody(question));
        return getResponseBody(response, QuestionVO.class).orElseThrow(() -> SeecoderBokException.UNWRAP_EXCEPTION);
    }

    @Override
    public void deleteQuestionById(@NotBlank String questionId) {
        HttpUrl httpUrl = createUrlBuilder(MessageFormat.format("/api/question/{0}", questionId)).build();
        delete(httpUrl);
    }

    @Override
    public List<QuestionVO> getQuestionListByIds(@NotNull List<String> ids) {
        HttpUrl httpUrl = createUrlBuilder("/api/question-query/id")
                .addQueryParameter("id", joinComma(ids))
                .build();
        Response response = get(httpUrl);
        return getResponseBody(response, new TypeReference<List<QuestionVO>>() {})
                .orElse(Collections.emptyList());
    }

    @Override
    public List<RecordVO> createUserRecord(@NotNull List<RecordVO> records) {
        HttpUrl httpUrl = createUrlBuilder("/api/record").build();
        Response response = post(httpUrl, writeRequestBody(records));
        return getResponseBody(response, new TypeReference<List<RecordVO>>() {})
                .orElse(Collections.emptyList());
    }

    @Override
    public Page<RecordVO> getUserRecord(
            List<String> userIdList,
            List<String> questionIdList,
            List<String> recordIdList,
            Pageable pageable) {
        HttpUrl.Builder urlBuilder = createUrlBuilder("/api/record")
                .addQueryParameter("userId", joinComma(userIdList))
                .addQueryParameter("questionId", joinComma(questionIdList))
                .addQueryParameter("recordId", joinComma(recordIdList));
        HttpUrl httpUrl = addPageableToParams(urlBuilder, pageable).build();
        Response response = get(httpUrl);
        return getResponseBody(response, new TypeReference<Page<RecordVO>>() {})
                .map(recordVOS -> new PageImpl<>(
                        recordVOS.getContent(),
                        parseBokToPageable(recordVOS.getNumber(), recordVOS.getSize(), pageable),
                        recordVOS.getTotalElements()))
                .orElse(new PageImpl<>(Collections.emptyList()));
    }

    @Override
    public PageableRecordQuestionVO getUserRecordQuestions(
            @NotNull String userId, Pageable pageable) {
        HttpUrl.Builder urlBuilder = createUrlBuilder(MessageFormat.format("/api/record/{0}/question", userId));
        HttpUrl httpUrl = addPageableToParams(urlBuilder, pageable).build();
        Response response = get(httpUrl);
        return getResponseBody(response, PageableRecordQuestionVO.class)
                .map(pageableRecordQuestionVO -> {
                    PageVO page = pageableRecordQuestionVO.getPage();
                    page.setNumber(parseBokToPageableNumber(page.getNumber()));
                    pageableRecordQuestionVO.setPage(page);
                    return pageableRecordQuestionVO;
                })
                .orElse(PageableRecordQuestionVO.ofEmpty());
    }

    @Override
    public void collectQuestion(
            @NotBlank String userId, @NotBlank String questionId, @NotNull CollectDTO collectDTO) {
        HttpUrl httpUrl = createUrlBuilder(
                MessageFormat.format("/api/user/{0}/question/{1}/collection", userId, questionId)).build();
        post(httpUrl, writeRequestBody(collectDTO));
    }

    @Override
    public void rateQuestion(
            @NotBlank String userId, @NotBlank String questionId, @NotNull RateDTO rateDTO) {
        HttpUrl httpUrl = createUrlBuilder(
                MessageFormat.format("/api/user/{0}/question/{1}/rate", userId, questionId)).build();
        post(httpUrl, writeRequestBody(rateDTO));
    }

    @Override
    public Page<QuestionVO> getUserInteractiveQuestions(
            @NotBlank String userId, Boolean collect, Boolean rate, Pageable pageable) {
        HttpUrl.Builder urlBuilder = createUrlBuilder(MessageFormat.format("/api/user/{0}/question", userId))
                .addQueryParameter("collection", String.valueOf(collect))
                .addQueryParameter("rate", String.valueOf(rate));
        return getQuestionVOS(pageable, urlBuilder);
    }

    @Override
    public Optional<InteractiveVO> getUserInteractiveQuestion(
            @NotBlank String userId, @NotBlank String questionId) {
        HttpUrl httpUrl = createUrlBuilder(
                MessageFormat.format("/api/user/{0}/question/{1}", userId, questionId)).build();
        Response response = get(httpUrl);
        return getResponseBody(response, InteractiveVO.class);
    }

    @Override
    public List<InteractiveVO> getUserInteractiveQuestionIn(
            @NotBlank String userId, List<String> questionIdList) {
        HttpUrl httpUrl = createUrlBuilder(
                MessageFormat.format("/api/user/{0}/questionInList", userId)).build();
        Response response = get(httpUrl);
        return getResponseBody(response, new TypeReference<List<InteractiveVO>>() {})
                .orElse(Collections.emptyList());
    }

    private Page<QuestionVO> getQuestionVOS(Pageable pageable, HttpUrl.Builder urlBuilder) {
        HttpUrl httpUrl = addPageableToParams(urlBuilder, pageable).build();
        Response response = get(httpUrl);
        return getResponseBody(response, PageableQuestionListVO.class)
                .map(pageableQuestionListVO ->
                        new PageImpl<>(
                                pageableQuestionListVO.getQuestions(),
                                parseBokToPageable(pageableQuestionListVO.getPage(), pageable),
                                pageableQuestionListVO.getPage().getTotalElements()))
                .orElse(new PageImpl<>(Collections.emptyList()));
    }

    private Response get(HttpUrl httpUrl) {
        return requestWithMethod("GET", httpUrl, null);
    }

    private void delete(HttpUrl httpUrl) {
        requestWithMethod("DELETE", httpUrl, null);
    }

    private Response post(HttpUrl httpUrl, RequestBody requestBody) {
        return requestWithMethod("POST", httpUrl, requestBody);
    }

    private Response put(HttpUrl httpUrl, RequestBody requestBody) {
        return requestWithMethod("PUT", httpUrl, requestBody);
    }

    private Response requestWithMethod(String method, HttpUrl httpUrl, RequestBody requestBody) {
        Request request = new Request.Builder().url(httpUrl).method(method, requestBody).build();
        try {
            return client.newCall(request).execute();
        } catch (IOException e) {
            logger.error("IOException.", e);
            throw SeecoderBokException.IO_EXCEPTION;
        }
    }

    private HttpUrl.Builder createUrlBuilder(final String path) {
        return Objects.requireNonNull(HttpUrl.parse(CONFIG_HOST + path)).newBuilder();
    }

    private <T> Optional<T> getResponseBody(Response response, Class<T> tClass) {
        return getResponseBody(
                response,
                bodyString -> {
                    try {
                        return mapper.readValue(bodyString, tClass);
                    } catch (JsonProcessingException e) {
                        logger.error("JsonProcessingException.", e);
                        throw SeecoderBokException.JSON_EXCEPTION;
                    }
                });
    }

    private <T> Optional<T> getResponseBody(Response response, TypeReference<T> typeReference) {
        return getResponseBody(
                response,
                bodyString -> {
                    try {
                        return mapper.readValue(bodyString, typeReference);
                    } catch (JsonProcessingException e) {
                        logger.error("JsonProcessingException.", e);
                        throw SeecoderBokException.JSON_EXCEPTION;
                    }
                });
    }

    private <T> Optional<T> getResponseBody(Response response, Function<String, T> mapType) {
        return Optional.ofNullable(response.body())
                .map(body -> {
                    try {
                        String bodyString = body.string();
                        return mapType.apply(bodyString);
                    } catch (IOException e) {
                        logger.error("IOException.", e);
                        throw SeecoderBokException.IO_EXCEPTION;
                    }
                });
    }

    private <T> RequestBody writeRequestBody(T obj) {
        if (obj == null) {
            return null;
        }

        try {
            return RequestBody.create(mapper.writeValueAsString(obj), SeecoderBokConstants.JSON);
        } catch (JsonProcessingException e) {
            logger.error("JsonProcessingException.", e);
            throw SeecoderBokException.JSON_EXCEPTION;
        }
    }

    private int parsePageableNumberToBok(int pageNumber) {
        return pageNumber - CONFIG_PAGE_START + SeecoderBokConstants.PAGE_START;
    }

    private int parseBokToPageableNumber(int bokPageNumber) {
        return bokPageNumber - SeecoderBokConstants.PAGE_START + CONFIG_PAGE_START;
    }

    private Pageable parseBokToPageable(PageVO pageVO, Pageable pageable) {
        return parseBokToPageable(pageVO.getNumber(), pageVO.getSize(), pageable);
    }

    private Pageable parseBokToPageable(int page, int size, Pageable pageable) {
        if (pageable == null) {
            return PageRequest.of(parseBokToPageableNumber(page), size);
        }
        return pageable;
    }

    private HttpUrl.Builder addPageableToParams(HttpUrl.Builder builder, Pageable pageable) {
        return Optional.ofNullable(pageable)
                .map(notNullPageable ->
                        // TODO: not accept error
                        builder.addQueryParameter("page", String.valueOf(parsePageableNumberToBok(notNullPageable.getPageNumber()) + 1))
                                .addQueryParameter("sort", parseSort(notNullPageable.getSort()))
                                .addQueryParameter("size", String.valueOf(notNullPageable.getPageSize()))
                )
                .orElse(builder);
    }

    private String joinComma(Iterable<String> list) {
        return Optional.ofNullable(list)
                .map(notNullList -> String.join(",", notNullList))
                .orElse("");
    }

    private String parseSort(Sort sort) {
        return String.join("|",
                sort.map(order -> order.getProperty() + "," + order.getDirection()));
    }
}