package com.tcm.training.admin.app.system.service;

import com.tcm.training.admin.app.system.vo.AppHelpCenterVO;
import com.tcm.training.admin.common.PageResponse;
import com.tcm.training.admin.system.service.CommonQuestionAppService;
import com.tcm.training.admin.system.service.SystemSettingsAppService;
import com.tcm.training.admin.system.vo.CommonQuestionDetailVO;
import com.tcm.training.admin.system.vo.CommonQuestionListItemVO;
import com.tcm.training.admin.system.vo.SystemSettingsVO;
import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.List;

/**
 * APP 帮助中心服务。
 */
@Service
public class AppHelpCenterService {

    private static final int DEFAULT_PAGE = 1;
    private static final int DEFAULT_PAGE_SIZE = 100;

    private final SystemSettingsAppService systemSettingsAppService;
    private final CommonQuestionAppService commonQuestionAppService;

    /**
     * 注入 APP 帮助中心所需依赖。
     */
    public AppHelpCenterService(SystemSettingsAppService systemSettingsAppService,
                                CommonQuestionAppService commonQuestionAppService) {
        this.systemSettingsAppService = systemSettingsAppService;
        this.commonQuestionAppService = commonQuestionAppService;
    }

    /**
     * 获取帮助中心首页聚合数据。
     */
    public AppHelpCenterVO getHelpCenter() {
        SystemSettingsVO settings = systemSettingsAppService.current();
        PageResponse<CommonQuestionListItemVO> questionPage = commonQuestionAppService.page(DEFAULT_PAGE, DEFAULT_PAGE_SIZE, null);

        AppHelpCenterVO result = new AppHelpCenterVO();
        result.setServicePhone(trimToEmpty(settings == null ? null : settings.getServicePhone()));
        result.setServiceOnlineTime(trimToEmpty(settings == null ? null : settings.getServiceOnlineTime()));
        result.setQuestions(toQuestionItems(questionPage == null ? null : questionPage.getList()));
        return result;
    }

    /**
     * 获取单个常见问题详情。
     */
    public CommonQuestionDetailVO getQuestionDetail(Long id) {
        return commonQuestionAppService.detail(id);
    }

    /**
     * 将常见问题列表裁剪为帮助中心首页需要的字段。
     */
    private List<AppHelpCenterVO.QuestionItemVO> toQuestionItems(List<CommonQuestionListItemVO> questions) {
        List<AppHelpCenterVO.QuestionItemVO> list = new ArrayList<AppHelpCenterVO.QuestionItemVO>();
        if (questions == null) {
            return list;
        }
        for (CommonQuestionListItemVO question : questions) {
            AppHelpCenterVO.QuestionItemVO item = new AppHelpCenterVO.QuestionItemVO();
            item.setId(question.getId());
            item.setTitle(trimToEmpty(question.getTitle()));
            list.add(item);
        }
        return list;
    }

    /**
     * 将可空文本归一化为空字符串。
     */
    private String trimToEmpty(String value) {
        if (value == null) {
            return "";
        }
        return value.trim();
    }
}