package com.dms.service;

import com.dms.common.DmsException;
import com.dms.common.Page;
import com.dms.common.Payloads;
import com.dms.common.TimeRanges;
import com.dms.mapper.AttachmentBindingMapper;
import com.dms.mapper.DocumentMapper;
import com.dms.model.AttachmentBindingEntity;
import com.dms.model.DocumentEntity;
import com.dms.security.AuthContext;
import com.dms.service.AuthorizationService.AttachmentAccess;
import com.dms.service.AuthorizationService.PlanAccess;
import jakarta.servlet.http.HttpServletRequest;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import org.springframework.stereotype.Service;

/**
 * 共享附件及其有效挂载关系只读查询，
 * 对齐 backend/dms/services/attachment_query_service.py。
 *
 * <p>附件无 ACL（固定 PUBLIC / ALL_AUTHENTICATED / PUBLISHED），
 * 普通用户仅能通过至少一个有权有效主案访问附件；
 * 主案挂载列表全量可见（allowedActions 为空集、正文片段抑制）。</p>
 */
@Service
public class AttachmentQueryService {

    /** 对齐 AttachmentType 枚举全集（阶段11新增 ACCOMPANYING_PLAN 配套方案）。 */
    public static final Set<String> ATTACHMENT_TYPES = Set.of(
            "SUPPORT_ACHIEVEMENT", "TRAINING_MATERIAL", "TYPICAL_CASE",
            "ACCOMPANYING_PLAN");

    private final AttachmentBindingMapper attachmentBindingMapper;
    private final DocumentMapper documentMapper;
    private final AuthorizationService authorizationService;
    private final DocumentQueryService documentQueryService;

    public AttachmentQueryService(AttachmentBindingMapper attachmentBindingMapper,
                                  DocumentMapper documentMapper,
                                  AuthorizationService authorizationService,
                                  DocumentQueryService documentQueryService) {
        this.attachmentBindingMapper = attachmentBindingMapper;
        this.documentMapper = documentMapper;
        this.authorizationService = authorizationService;
        this.documentQueryService = documentQueryService;
    }

    // ------------------------------------------------------------ 序列化

    /** 对齐 mounted_plan_count。 */
    public long mountedPlanCount(long attachmentId) {
        return attachmentBindingMapper.countActiveByAttachment(attachmentId);
    }

    /** 对齐 attachment_summary。 */
    public Map<String, Object> attachmentSummary(DocumentEntity attachment, AuthContext context,
                                                 PlanAccess planAccess, String keyword) {
        Map<String, Object> result = Payloads.orderedMap();
        result.put("id", String.valueOf(attachment.getId()));
        result.put("documentName", attachment.getDocumentName());
        result.put("summary", attachment.getSummary());
        result.put("description", attachment.getDescription());
        result.put("documentType", attachment.getDocumentType());
        result.put("status", attachment.getDocumentStatus());
        result.put("securityLevel", attachment.getSecurityLevel());
        // 附件不可授权（AttachmentHasNoAcl），借阅摘要固定占位
        result.put("borrowSummary", "未配置");
        result.put("attachmentType", attachment.getAttachmentType());
        result.put("categoryId", null);
        result.put("categoryName", null);
        result.put("categoryPath", null);
        result.put("organizationId", attachment.getOrganizationId() == null
                ? null : String.valueOf(attachment.getOrganizationId()));
        result.put("organizationName", attachment.getOrganizationName());
        result.put("parentDocumentId", null);
        result.put("rootDocumentId", null);
        result.put("tags", documentQueryService.tagsOf(attachment.getTags()));
        result.put("fileExtension", attachment.getFileExtension());
        result.put("childCount", attachment.getChildCount());
        result.put("attachmentCount", attachment.getAttachmentCount());
        result.put("viewCount", attachment.getViewCount());
        result.put("downloadCount", attachment.getDownloadCount());
        result.put("createdByName", attachment.getCreatedByName());
        result.put("createdAt", DocumentQueryService.iso(attachment.getCreatedAt()));
        result.put("updatedAt", DocumentQueryService.iso(attachment.getUpdatedAt()));
        result.put("rowVersion", attachment.getRowVersion());
        result.put("allowedActions",
                authorizationService.attachmentAllowedActions(context, attachment, planAccess));
        result.put("mountedPlanCount", mountedPlanCount(attachment.getId()));
        String snippet = DocumentQueryService.contentSnippet(attachment.getContentText(), keyword);
        if (snippet != null) {
            result.put("contentSnippet", snippet);
        }
        return result;
    }

    /** 对齐 attachment_detail：summary 之上补充文件字段与固定权限摘要。 */
    public Map<String, Object> attachmentDetail(DocumentEntity attachment, AuthContext context) {
        Map<String, Object> result = attachmentSummary(attachment, context, null, null);
        result.put("originalFileName", attachment.getOriginalFileName());
        result.put("mimeType", attachment.getMimeType());
        result.put("fileSize", attachment.getFileSize());
        result.put("fileHash", attachment.getFileHash());
        Map<String, Object> permissionSummary = Payloads.orderedMap();
        permissionSummary.put("borrowerCount", 0);
        permissionSummary.put("inheritedFromMainPlan", false);
        result.put("permissionSummary", permissionSummary);
        result.put("contentText", attachment.getContentText());
        // 提取状态/失败原因仅供管理员排障（"编辑"界面提示与重新解析）
        if ("ADMIN".equals(context.roleCode())) {
            result.put("contentExtractStatus", attachment.getContentExtractStatus());
            result.put("contentExtractError", attachment.getContentExtractError());
            result.put("contentExtractedAt", attachment.getContentExtractedAt() == null
                    ? null : DocumentQueryService.iso(attachment.getContentExtractedAt()));
        }
        return result;
    }

    // ------------------------------------------------------------ 查询入口

    /**
     * 对齐 list_attachments：列表全量可见（全局检索需要）——
     * 普通用户同样返回全部附件标题，但 allowedActions 为空集，
     * 且不返回详细说明与正文片段；内容访问由详情/预览/下载接口
     * 按挂载主案权限独立拦截。
     */
    public Map<String, Object> listAttachments(Map<String, String> params) {
        AuthContext context = AuthContext.get();
        boolean isAdmin = "ADMIN".equals(context.roleCode());
        Page.Params page = Page.of(
                DocumentQueryService.positiveIntParam(params, "page", 1),
                DocumentQueryService.positiveIntParam(params, "pageSize", 20));
        Map<String, Object> filters = Payloads.orderedMap();
        filters.put("types", List.of("ATTACHMENT"));
        // 高级检索·数据内容/提供单位（契约1.55）：附件列表与方案列表同口径
        // （keywordScope 缺省 TITLE，与原 keyword→titlePattern 行为一致）
        String keyword = params.get("keyword");
        DocumentQueryService.applyKeywordScope(filters, keyword,
                params.get("keywordScope"), false);
        DocumentQueryService.applyAdvancedFilters(filters, params);
        documentQueryService.applyOrganizationFilter(filters, params.get("organizationId"));
        // 高级检索·数据密级（契约1.55）：单选过滤（securityLevels 多选保留兼容），
        // 修复漏接线导致的密级筛选不生效
        String securityLevel = DocumentQueryService.enumParam(
                params.get("securityLevel"), DocumentQueryService.SECURITY_LEVELS,
                "securityLevel");
        if (securityLevel != null) {
            filters.put("securityLevel", securityLevel);
        }
        String attachmentType = DocumentQueryService.enumParam(
                params.get("attachmentType"), ATTACHMENT_TYPES, "attachmentType");
        if (attachmentType != null) {
            filters.put("attachmentType", attachmentType);
        }
        String extension = params.get("fileExtension");
        if (extension != null && !extension.isEmpty()) {
            // 对齐 Python：truthy 即过滤（含纯空白），归一 strip/lower/lstrip('.')
            String normalized = extension.strip().toLowerCase(Locale.ROOT);
            while (normalized.startsWith(".")) {
                normalized = normalized.substring(1);
            }
            filters.put("fileExtension", normalized);
        }
        TimeRanges.UpdatedRange range = TimeRanges.parseUpdatedRange(params);
        if (range.from() != null) {
            filters.put("updatedFrom", range.from());
        }
        if (range.to() != null) {
            filters.put("updatedTo", range.to());
        }
        filters.put("orderBy", DocumentQueryService.orderByParam(params));

        List<DocumentEntity> attachments = documentMapper.listOverviewByFilters(filters);
        long total = attachments.size();
        int fromIndex = Math.min(page.offset(), attachments.size());
        int toIndex = Math.min(page.offset() + page.pageSize(), attachments.size());
        List<DocumentEntity> selected = attachments.subList(fromIndex, toIndex);
        // 列表主体查询不携带 content_text 大字段；仅管理员 contentKeyword
        // 检索生成当前页摘要时批量补查。契约1.55：数据内容为 CONTENT/ALL
        // 时摘要关键词回落到检索关键词（正文命中需展示片段）。
        String snippetKeyword = params.get("contentKeyword");
        if ((snippetKeyword == null || snippetKeyword.strip().isEmpty())
                && DocumentQueryService.keywordScopeContentLike(params)
                && keyword != null && !keyword.strip().isEmpty()) {
            snippetKeyword = keyword.strip();
        }
        if (isAdmin
                && snippetKeyword != null && !snippetKeyword.strip().isEmpty()) {
            documentQueryService.fillContentText(selected);
        }
        List<Map<String, Object>> items = new ArrayList<>();
        for (DocumentEntity item : selected) {
            Map<String, Object> summary = attachmentSummary(item, context, null,
                    isAdmin ? snippetKeyword : null);
            if (!isAdmin) {
                summary.put("description", null);
            }
            items.add(summary);
        }
        return Page.result(items, page, total);
    }

    /** 对齐 get_attachment：访问前置 + 详情 + 独立事务查看计数。 */
    public Map<String, Object> getAttachment(long attachmentId, HttpServletRequest request) {
        AuthContext context = AuthContext.get();
        DocumentEntity attachment = activeAttachment(attachmentId);
        AttachmentAccess access;
        try {
            access = authorizationService.requireAttachmentAccess(attachment, context, false);
        } catch (DmsException e) {
            // 操作位隔离补全：查看位不足但具备附件操作位（编辑/删除等）时放行
            // "编辑视图"——详情仅元数据（查看计数与审计不记录）；密级不足维持拒绝
            if (!"DOCUMENT_VIEW_FORBIDDEN".equals(e.code())
                    || authorizationService.attachmentAllowedActions(context, attachment, null)
                            .isEmpty()) {
                throw e;
            }
            access = authorizationService.evaluateAttachmentAccess(attachment, context);
        }
        Map<String, Object> result = attachmentDetail(attachment, context);
        if ("USER".equals(context.roleCode())) {
            List<String> actions = new ArrayList<>();
            // 编辑视图（无查看权）不下发 VIEW 位
            if (access.canView()) {
                actions.add("VIEW");
            }
            if (access.canDownload()) {
                actions.add("DOWNLOAD");
            }
            // 契约1.41：矩阵附件编辑位独立下发（详情访问已含挂载聚合查看）
            if (authorizationService.attachmentEditAllowed(attachment, context)) {
                actions.add("EDIT");
            }
            result.put("allowedActions", actions);
        }
        if (access.canView()) {
            result.put("viewCount", documentQueryService.recordView(attachment, request));
        } else {
            // 编辑视图：回显库中当前计数（查询未携带时按 0），不增计不审计
            result.put("viewCount",
                    attachment.getViewCount() == null ? 0L : attachment.getViewCount());
        }
        return result;
    }

    /** 对齐 list_attachment_main_plans：附件可达且有权主案清单。 */
    public Map<String, Object> listAttachmentMainPlans(long attachmentId) {
        AuthContext context = AuthContext.get();
        activeAttachment(attachmentId);
        AccessMemo memo = new AccessMemo();
        List<Map<String, Object>> items = new ArrayList<>();
        for (DocumentEntity main : attachmentBindingMapper
                .listActiveMainsByAttachmentOrdered(attachmentId)) {
            if (!authorizationService.evaluatePlanAccess(main, context, memo).allowed()) {
                continue;
            }
            Map<String, Object> item = Payloads.orderedMap();
            item.put("id", String.valueOf(main.getId()));
            item.put("documentName", main.getDocumentName());
            item.put("categoryName", main.getCategoryName());
            item.put("securityLevel", main.getSecurityLevel());
            items.add(item);
        }
        Map<String, Object> result = Payloads.orderedMap();
        result.put("items", items);
        result.put("total", items.size());
        return result;
    }

    /**
     * 对齐 list_main_plan_attachments：主案挂载列表全量可见
     * （主案无权限时 allowedActions 为空集、正文片段同步抑制）。
     */
    public Map<String, Object> listMainPlanAttachments(long mainDocumentId,
                                                       Map<String, String> params) {
        AuthContext context = AuthContext.get();
        DocumentEntity main = documentMapper.findActiveMainById(mainDocumentId);
        if (main == null) {
            throw new DmsException("MAIN_PLAN_NOT_FOUND", 404, "主案不存在", null);
        }
        PlanAccess mainAccess = authorizationService.evaluatePlanAccess(main, context);
        Page.Params page = Page.of(
                DocumentQueryService.positiveIntParam(params, "page", 1),
                DocumentQueryService.positiveIntParam(params, "pageSize", 20));
        List<AttachmentBindingEntity> bindings =
                attachmentBindingMapper.listActiveByMain(main.getId());
        if (bindings.isEmpty()) {
            return Page.result(List.of(), page, 0);
        }
        List<Long> attachmentIds = new ArrayList<>();
        for (AttachmentBindingEntity binding : bindings) {
            attachmentIds.add(binding.getAttachmentDocumentId());
        }
        Map<String, Object> filters = Payloads.orderedMap();
        filters.put("types", List.of("ATTACHMENT"));
        filters.put("ids", attachmentIds);
        String keyword = params.get("keyword");
        if (keyword != null && !keyword.strip().isEmpty()) {
            filters.put("titlePattern",
                    "%" + DocumentQueryService.escapeLike(keyword) + "%");
        }
        DocumentQueryService.applyAdvancedFilters(filters, params);
        String attachmentType = DocumentQueryService.enumParam(
                params.get("attachmentType"), ATTACHMENT_TYPES, "attachmentType");
        if (attachmentType != null) {
            filters.put("attachmentType", attachmentType);
        }
        TimeRanges.UpdatedRange range = TimeRanges.parseUpdatedRange(params);
        if (range.from() != null) {
            filters.put("updatedFrom", range.from());
        }
        if (range.to() != null) {
            filters.put("updatedTo", range.to());
        }

        Map<Long, DocumentEntity> kept = new HashMap<>();
        for (DocumentEntity document : documentMapper.listOverviewByFilters(filters)) {
            kept.put(document.getId(), document);
        }
        // 列表主体查询不携带 content_text 大字段；仅主案有权限且
        // contentKeyword 检索生成摘要时，对涉及的挂载附件批量补查。
        String contentKeyword = params.get("contentKeyword");
        if (mainAccess.allowed() && contentKeyword != null
                && !contentKeyword.strip().isEmpty()) {
            List<DocumentEntity> pageAttachments = new ArrayList<>();
            for (AttachmentBindingEntity binding : bindings) {
                DocumentEntity attachment = kept.get(binding.getAttachmentDocumentId());
                if (attachment != null) {
                    pageAttachments.add(attachment);
                }
            }
            documentQueryService.fillContentText(pageAttachments);
        }
        List<Map<String, Object>> items = new ArrayList<>();
        for (AttachmentBindingEntity binding : bindings) {
            DocumentEntity attachment = kept.get(binding.getAttachmentDocumentId());
            if (attachment == null) {
                continue;
            }
            Map<String, Object> item = attachmentSummary(attachment, context, mainAccess,
                    mainAccess.allowed() ? params.get("contentKeyword") : null);
            item.put("bindingId", String.valueOf(binding.getId()));
            item.put("bindingSortNo", binding.getSortNo());
            items.add(item);
        }
        long total = items.size();
        int fromIndex = Math.min(page.offset(), items.size());
        int toIndex = Math.min(page.offset() + page.pageSize(), items.size());
        return Page.result(items.subList(fromIndex, toIndex), page, total);
    }

    // ------------------------------------------------------------ 内部实现

    /** 对齐 _attachment。 */
    private DocumentEntity activeAttachment(long attachmentId) {
        DocumentEntity attachment = documentMapper.findActiveAttachmentById(attachmentId);
        if (attachment == null) {
            throw new DmsException("RESOURCE_NOT_FOUND", 404, "共享附件不存在", null);
        }
        return attachment;
    }
}