/**
 * MSW Handlers - P7 扩展（组卷 + 题库 + 教材 + 考试分析）
 *
 * 维护者：ai13（teacher-portal）
 * 关联：graphql-p7-exams.ts、workline.md §3 P7 交付物
 *
 * 设计：本文件独立于 handlers.ts，不修改共享文件，最后统一合并。
 * - 拦截 POST /api/v1/teacher/graphql，按 operationName 分发 P7-exams 操作。
 * - 未覆盖的 operation（P2/P3/P4/P5/P7-grades）返回 undefined → MSW fallthrough 至下游 handler。
 *
 * 注册顺序：p7ExamsHandlers 必须在 handlers 之前注册（见 browser.ts / server.ts）。
 *
 * 覆盖 operationName（对应 graphql-p7-exams.ts）：
 * - ExamBuild → 试卷结构 + 题库候选分页
 * - SaveExamBuild → 保存组卷
 * - ExamAnalytics → 考后分析
 * - QuestionsLibrary → 题库列表（六维筛选 + 分页）
 * - QuestionCreate / QuestionUpdate / QuestionDelete → 题目 CRUD
 * - QuestionBatchImport → 批量导入
 * - QuestionBatchExport → 批量导出
 * - Textbooks → 教材列表
 * - TextbookDetail → 教材详情
 * - TextbookCreate → 创建教材
 */

import { http, HttpResponse } from "msw";
import {
  filterQuestions,
  findQuestion,
  createMockQuestion,
  updateMockQuestion,
  deleteMockQuestion,
  batchImportQuestions,
  batchExportQuestions,
} from "./fixtures/questions";
import {
  filterTextbooks,
  findTextbookDetail,
  createMockTextbook,
} from "./fixtures/textbooks";
import {
  generateExamAnalytics,
  generateExamBuildStructure,
} from "./fixtures/exam-analytics";
import { findMockExamDetail } from "./fixtures/exams";
import type {
  QuestionsLibraryFilter,
  QuestionCreateInput,
  QuestionUpdateInput,
  QuestionBatchImportInput,
  SaveExamBuildInput,
  TextbooksFilter,
  TextbookCreateInput,
} from "@/lib/graphql-p7-exams";

/** GraphQL 响应体（urql 期望 { data: ... }） */
function graphqlData<T>(data: T) {
  return HttpResponse.json({ data });
}

function extractOperationName(query?: string): string {
  if (!query) return "Unknown";
  const match = query.match(/(?:query|mutation)\s+(\w+)/);
  return match?.[1] ?? "Unknown";
}

export const p7ExamsHandlers = [
  // POST /api/v1/teacher/graphql → P7-exams operations（未覆盖的 fallthrough 至 handlers.ts）
  http.post("*/api/v1/teacher/graphql", async ({ request }) => {
    const body = (await request.json()) as {
      operationName?: string;
      query?: string;
      variables?: Record<string, unknown>;
    };

    const operationName =
      body.operationName ?? extractOperationName(body.query);
    const variables = body.variables ?? {};

    switch (operationName) {
      case "ExamBuild": {
        const examId = (variables.examId as string) ?? "";
        const candidatePage = (variables.candidatePage as number) ?? 1;
        const candidatePageSize = (variables.candidatePageSize as number) ?? 10;
        const filter =
          (variables.filter as QuestionsLibraryFilter | undefined) ?? undefined;
        // 调用 exams.ts 的 findMockExamDetail 拿基础信息
        const examDetail = examId ? findMockExamDetail(examId) : null;
        // 同时叠加题库筛选（filter 影响 candidates）
        const structure = generateExamBuildStructure(
          examId,
          examDetail,
          candidatePage,
          candidatePageSize,
        );
        if (!structure) {
          return HttpResponse.json(
            {
              errors: [
                {
                  message: `试卷结构不存在: ${examId}`,
                  extensions: { code: "BFF_TEACHER_NOT_FOUND" },
                },
              ],
            },
            { status: 200 },
          );
        }
        // 叠加 filter 到 candidates
        if (filter) {
          const filtered = filterQuestions({
            ...filter,
            page: candidatePage,
            pageSize: candidatePageSize,
          });
          return graphqlData({
            examBuild: {
              ...structure,
              candidates: filtered,
            },
          });
        }
        return graphqlData({ examBuild: structure });
      }

      case "SaveExamBuild": {
        const input = variables.input as SaveExamBuildInput;
        const totalScore = input.questions.reduce(
          (acc, q) => acc + (q.score || 0),
          0,
        );
        const now = new Date().toISOString();
        return graphqlData({
          saveExamBuild: {
            examId: input.examId,
            totalScore,
            questionCount: input.questions.length,
            savedAt: now,
          },
        });
      }

      case "ExamAnalytics": {
        const examId = (variables.examId as string) ?? "";
        const analytics = generateExamAnalytics(examId);
        if (!analytics) {
          // 兜底：未匹配到 EXAM_DEFS 时按 examId 生成（使用第一场考试的 totalScore）
          return HttpResponse.json(
            {
              errors: [
                {
                  message: `考试分析不存在: ${examId}`,
                  extensions: { code: "BFF_TEACHER_NOT_FOUND" },
                },
              ],
            },
            { status: 200 },
          );
        }
        return graphqlData({ examAnalytics: analytics });
      }

      case "QuestionsLibrary": {
        const filter =
          (variables.filter as QuestionsLibraryFilter | undefined) ?? {};
        return graphqlData({
          questionsLibrary: filterQuestions(filter),
        });
      }

      case "QuestionCreate": {
        const input = variables.input as QuestionCreateInput;
        const created = createMockQuestion(input);
        return graphqlData({ questionCreate: created });
      }

      case "QuestionUpdate": {
        const input = variables.input as QuestionUpdateInput;
        const updated = updateMockQuestion(input);
        if (!updated) {
          return HttpResponse.json(
            {
              errors: [
                {
                  message: `题目不存在: ${input.questionId}`,
                  extensions: { code: "BFF_TEACHER_NOT_FOUND" },
                },
              ],
            },
            { status: 200 },
          );
        }
        return graphqlData({ questionUpdate: updated });
      }

      case "QuestionDelete": {
        const questionId = variables.questionId as string;
        // 删除前确认存在
        const existed = findQuestion(questionId);
        if (!existed) {
          return HttpResponse.json(
            {
              errors: [
                {
                  message: `题目不存在: ${questionId}`,
                  extensions: { code: "BFF_TEACHER_NOT_FOUND" },
                },
              ],
            },
            { status: 200 },
          );
        }
        deleteMockQuestion(questionId);
        return graphqlData({
          questionDelete: { questionId, deleted: true },
        });
      }

      case "QuestionBatchImport": {
        const input = variables.input as QuestionBatchImportInput;
        const result = batchImportQuestions(input);
        return graphqlData({ questionBatchImport: result });
      }

      case "QuestionBatchExport": {
        const filter =
          (variables.filter as QuestionsLibraryFilter | undefined) ?? {};
        const result = batchExportQuestions(filter);
        return graphqlData({ questionBatchExport: result });
      }

      case "Textbooks": {
        const filter =
          (variables.filter as TextbooksFilter | undefined) ?? {};
        return graphqlData({ textbooks: filterTextbooks(filter) });
      }

      case "TextbookDetail": {
        const id = (variables.id as string) ?? "";
        const detail = findTextbookDetail(id);
        if (!detail) {
          return HttpResponse.json(
            {
              errors: [
                {
                  message: `教材不存在: ${id}`,
                  extensions: { code: "BFF_TEACHER_NOT_FOUND" },
                },
              ],
            },
            { status: 200 },
          );
        }
        return graphqlData({ textbookDetail: detail });
      }

      case "TextbookCreate": {
        const input = variables.input as TextbookCreateInput;
        const created = createMockTextbook(input);
        return graphqlData({ textbookCreate: created });
      }

      default:
        // 未覆盖的 P2/P3/P4/P5/P7-grades operation：返回 undefined → fallthrough 至 handlers.ts
        return undefined;
    }
  }),
];