import { describe, it, expect, beforeEach, vi } from "vitest";
import { Test, TestingModule } from "@nestjs/testing";
import { ExecutionContext, ForbiddenException, InternalServerErrorException } from "@nestjs/common";
import { Reflector } from "@nestjs/core";
import { Prisma, WorkspaceMemberRole } from "@prisma/client";
import { PermissionGuard } from "./permission.guard";
import { PrismaService } from "../../prisma/prisma.service";
import { Permission } from "../decorators/permissions.decorator";

describe("PermissionGuard", () => {
  let guard: PermissionGuard;
  let reflector: Reflector;
  let prismaService: PrismaService;

  const mockReflector = {
    getAllAndOverride: vi.fn(),
  };

  const mockPrismaService = {
    workspaceMember: {
      findUnique: vi.fn(),
    },
  };

  beforeEach(async () => {
    const module: TestingModule = await Test.createTestingModule({
      providers: [
        PermissionGuard,
        {
          provide: Reflector,
          useValue: mockReflector,
        },
        {
          provide: PrismaService,
          useValue: mockPrismaService,
        },
      ],
    }).compile();

    guard = module.get<PermissionGuard>(PermissionGuard);
    reflector = module.get<Reflector>(Reflector);
    prismaService = module.get<PrismaService>(PrismaService);

    vi.clearAllMocks();
  });

  const createMockExecutionContext = (user: any, workspace: any): ExecutionContext => {
    const mockRequest = {
      user,
      workspace,
    };

    return {
      switchToHttp: () => ({
        getRequest: () => mockRequest,
      }),
      getHandler: vi.fn(),
      getClass: vi.fn(),
    } as any;
  };

  describe("canActivate", () => {
    const userId = "user-123";
    const workspaceId = "workspace-456";

    it("should allow access when no permission is required", async () => {
      const context = createMockExecutionContext({ id: userId }, { id: workspaceId });

      mockReflector.getAllAndOverride.mockReturnValue(undefined);

      const result = await guard.canActivate(context);

      expect(result).toBe(true);
    });

    it("should allow OWNER to access WORKSPACE_OWNER permission", async () => {
      const context = createMockExecutionContext({ id: userId }, { id: workspaceId });

      mockReflector.getAllAndOverride.mockReturnValue(Permission.WORKSPACE_OWNER);
      mockPrismaService.workspaceMember.findUnique.mockResolvedValue({
        role: WorkspaceMemberRole.OWNER,
      });

      const result = await guard.canActivate(context);

      expect(result).toBe(true);
      expect(context.switchToHttp().getRequest().user.workspaceRole).toBe(
        WorkspaceMemberRole.OWNER
      );
    });

    it("should deny ADMIN access to WORKSPACE_OWNER permission", async () => {
      const context = createMockExecutionContext({ id: userId }, { id: workspaceId });

      mockReflector.getAllAndOverride.mockReturnValue(Permission.WORKSPACE_OWNER);
      mockPrismaService.workspaceMember.findUnique.mockResolvedValue({
        role: WorkspaceMemberRole.ADMIN,
      });

      await expect(guard.canActivate(context)).rejects.toThrow(ForbiddenException);
    });

    it("should allow OWNER and ADMIN to access WORKSPACE_ADMIN permission", async () => {
      const context1 = createMockExecutionContext({ id: userId }, { id: workspaceId });
      const context2 = createMockExecutionContext({ id: userId }, { id: workspaceId });

      mockReflector.getAllAndOverride.mockReturnValue(Permission.WORKSPACE_ADMIN);

      // Test OWNER
      mockPrismaService.workspaceMember.findUnique.mockResolvedValue({
        role: WorkspaceMemberRole.OWNER,
      });
      expect(await guard.canActivate(context1)).toBe(true);

      // Test ADMIN
      mockPrismaService.workspaceMember.findUnique.mockResolvedValue({
        role: WorkspaceMemberRole.ADMIN,
      });
      expect(await guard.canActivate(context2)).toBe(true);
    });

    it("should deny MEMBER access to WORKSPACE_ADMIN permission", async () => {
      const context = createMockExecutionContext({ id: userId }, { id: workspaceId });

      mockReflector.getAllAndOverride.mockReturnValue(Permission.WORKSPACE_ADMIN);
      mockPrismaService.workspaceMember.findUnique.mockResolvedValue({
        role: WorkspaceMemberRole.MEMBER,
      });

      await expect(guard.canActivate(context)).rejects.toThrow(ForbiddenException);
    });

    it("should allow OWNER, ADMIN, and MEMBER to access WORKSPACE_MEMBER permission", async () => {
      const context1 = createMockExecutionContext({ id: userId }, { id: workspaceId });
      const context2 = createMockExecutionContext({ id: userId }, { id: workspaceId });
      const context3 = createMockExecutionContext({ id: userId }, { id: workspaceId });

      mockReflector.getAllAndOverride.mockReturnValue(Permission.WORKSPACE_MEMBER);

      // Test OWNER
      mockPrismaService.workspaceMember.findUnique.mockResolvedValue({
        role: WorkspaceMemberRole.OWNER,
      });
      expect(await guard.canActivate(context1)).toBe(true);

      // Test ADMIN
      mockPrismaService.workspaceMember.findUnique.mockResolvedValue({
        role: WorkspaceMemberRole.ADMIN,
      });
      expect(await guard.canActivate(context2)).toBe(true);

      // Test MEMBER
      mockPrismaService.workspaceMember.findUnique.mockResolvedValue({
        role: WorkspaceMemberRole.MEMBER,
      });
      expect(await guard.canActivate(context3)).toBe(true);
    });

    it("should deny GUEST access to WORKSPACE_MEMBER permission", async () => {
      const context = createMockExecutionContext({ id: userId }, { id: workspaceId });

      mockReflector.getAllAndOverride.mockReturnValue(Permission.WORKSPACE_MEMBER);
      mockPrismaService.workspaceMember.findUnique.mockResolvedValue({
        role: WorkspaceMemberRole.GUEST,
      });

      await expect(guard.canActivate(context)).rejects.toThrow(ForbiddenException);
    });

    it("should allow any role (including GUEST) to access WORKSPACE_ANY permission", async () => {
      const context = createMockExecutionContext({ id: userId }, { id: workspaceId });

      mockReflector.getAllAndOverride.mockReturnValue(Permission.WORKSPACE_ANY);
      mockPrismaService.workspaceMember.findUnique.mockResolvedValue({
        role: WorkspaceMemberRole.GUEST,
      });

      const result = await guard.canActivate(context);

      expect(result).toBe(true);
    });

    it("should throw ForbiddenException when user context is missing", async () => {
      const context = createMockExecutionContext(null, { id: workspaceId });

      mockReflector.getAllAndOverride.mockReturnValue(Permission.WORKSPACE_MEMBER);

      await expect(guard.canActivate(context)).rejects.toThrow(ForbiddenException);
    });

    it("should throw ForbiddenException when workspace context is missing", async () => {
      const context = createMockExecutionContext({ id: userId }, null);

      mockReflector.getAllAndOverride.mockReturnValue(Permission.WORKSPACE_MEMBER);

      await expect(guard.canActivate(context)).rejects.toThrow(ForbiddenException);
    });

    it("should throw ForbiddenException when user is not a workspace member", async () => {
      const context = createMockExecutionContext({ id: userId }, { id: workspaceId });

      mockReflector.getAllAndOverride.mockReturnValue(Permission.WORKSPACE_MEMBER);
      mockPrismaService.workspaceMember.findUnique.mockResolvedValue(null);

      await expect(guard.canActivate(context)).rejects.toThrow(ForbiddenException);
      await expect(guard.canActivate(context)).rejects.toThrow(
        "You are not a member of this workspace"
      );
    });

    it("should throw InternalServerErrorException on database connection errors", async () => {
      const context = createMockExecutionContext({ id: userId }, { id: workspaceId });

      mockReflector.getAllAndOverride.mockReturnValue(Permission.WORKSPACE_MEMBER);
      mockPrismaService.workspaceMember.findUnique.mockRejectedValue(
        new Error("Database connection failed")
      );

      await expect(guard.canActivate(context)).rejects.toThrow(InternalServerErrorException);
      await expect(guard.canActivate(context)).rejects.toThrow("Failed to verify permissions");
    });

    it("should throw InternalServerErrorException on Prisma connection timeout", async () => {
      const context = createMockExecutionContext({ id: userId }, { id: workspaceId });

      mockReflector.getAllAndOverride.mockReturnValue(Permission.WORKSPACE_MEMBER);

      const prismaError = new Prisma.PrismaClientKnownRequestError("Connection timed out", {
        code: "P1001", // Authentication failed (connection error)
        clientVersion: "5.0.0",
      });

      mockPrismaService.workspaceMember.findUnique.mockRejectedValue(prismaError);

      await expect(guard.canActivate(context)).rejects.toThrow(InternalServerErrorException);
    });

    it("should return null role for Prisma not found error (P2025)", async () => {
      const context = createMockExecutionContext({ id: userId }, { id: workspaceId });

      mockReflector.getAllAndOverride.mockReturnValue(Permission.WORKSPACE_MEMBER);

      const prismaError = new Prisma.PrismaClientKnownRequestError("Record not found", {
        code: "P2025", // Record not found
        clientVersion: "5.0.0",
      });

      mockPrismaService.workspaceMember.findUnique.mockRejectedValue(prismaError);

      // P2025 should be treated as "not a member" -> ForbiddenException
      await expect(guard.canActivate(context)).rejects.toThrow(ForbiddenException);
      await expect(guard.canActivate(context)).rejects.toThrow(
        "You are not a member of this workspace"
      );
    });

    it("should NOT mask database pool exhaustion as permission denied", async () => {
      const context = createMockExecutionContext({ id: userId }, { id: workspaceId });

      mockReflector.getAllAndOverride.mockReturnValue(Permission.WORKSPACE_MEMBER);

      const prismaError = new Prisma.PrismaClientKnownRequestError("Connection pool exhausted", {
        code: "P2024", // Connection pool timeout
        clientVersion: "5.0.0",
      });

      mockPrismaService.workspaceMember.findUnique.mockRejectedValue(prismaError);

      // Should NOT throw ForbiddenException for DB errors
      await expect(guard.canActivate(context)).rejects.toThrow(InternalServerErrorException);
      await expect(guard.canActivate(context)).rejects.not.toThrow(ForbiddenException);
    });
  });
});