import { describe, it, expect, beforeAll, afterAll } from 'vitest';
import { buildApp } from '@/app';
import { prismaClient } from '@/infrastructure/database';
import { FastifyInstance } from 'fastify';
import { loginAs, authHeader } from '../helpers/auth';
import {
  encryptCredential,
  generateCredentialSecret,
  issueIntegrationToken,
} from '@/modules/catalog/products';

/** Covers specs/007-orchestration-assignment/quickstart.md Scenario 2 (LEAST_LOADED,
 * SKILL_BASED, and the empty-eligible-set outcome) against a real Postgres/Redis. */
describe('Orchestration and assignment — strategies (User Story 2)', () => {
  let app: FastifyInstance;
  let authToken: string;
  let secret: string;
  let teamId: string;

  beforeAll(async () => {
    app = await buildApp();
    authToken = await loginAs(app, 'ADMIN');
    const team = await app.inject({
      method: 'POST',
      url: '/admin/teams',
      headers: authHeader(authToken),
      payload: { name: `Strategy Team ${Date.now()}` },
    });
    teamId = team.json().data.id;
  });

  afterAll(async () => {
    await app.close();
  });

  async function createProductAndEscalate(problem = 'Needs a human.') {
    const externalProductId = `TEST_STRAT_PROD_${Date.now()}_${Math.random().toString(36).slice(2)}`;
    const product = await prismaClient.product.create({
      data: { externalProductId, name: 'Strategy Test Product', status: 'active' },
    });
    secret = generateCredentialSecret();
    await prismaClient.productIntegration.create({
      data: {
        productId: product.id,
        credentialRef: encryptCredential(secret),
        authMechanism: 'signed_token',
        allowedScope: { tenantIds: ['tenant-1'] },
        status: 'active',
        rateLimitPerMinute: 1000,
        rateLimitPerUserPerMinute: 1000,
      },
    });
    const token = issueIntegrationToken(secret, {
      externalProductId,
      tenantId: 'tenant-1',
      userId: 'user-1',
    });
    const created = await app.inject({
      method: 'POST',
      url: '/v1/support/requests',
      headers: { authorization: `Bearer ${token}` },
      payload: {
        productId: externalProductId,
        tenantId: 'tenant-1',
        userId: 'user-1',
        source: 'test',
        problem,
      },
    });
    return { externalProductId, productId: product.id, ticketId: created.json().data.ticketId };
  }

  async function escalate(ticketId: string) {
    const ticket = await prismaClient.ticket.findUniqueOrThrow({ where: { id: ticketId } });
    return app.inject({
      method: 'PATCH',
      url: `/tickets/${ticketId}/status`,
      headers: authHeader(authToken),
      payload: { status: 'HUMAN_ESCALATION', expectedVersion: ticket.version },
    });
  }

  it('LEAST_LOADED picks the eligible agent with the lowest current workload', async () => {
    const skillTag = `least_loaded_skill_${Date.now()}`;
    const agentLow = await app.inject({
      method: 'POST',
      url: `/admin/teams/${teamId}/agents`,
      headers: authHeader(authToken),
      payload: { name: 'Low Load Agent' },
    });
    const agentHigh = await app.inject({
      method: 'POST',
      url: `/admin/teams/${teamId}/agents`,
      headers: authHeader(authToken),
      payload: { name: 'High Load Agent' },
    });
    for (const id of [agentLow.json().data.id, agentHigh.json().data.id]) {
      await app.inject({
        method: 'PUT',
        url: `/admin/agents/${id}/skills/${skillTag}`,
        headers: authHeader(authToken),
        payload: { level: 1 },
      });
    }
    await app.inject({
      method: 'PUT',
      url: `/admin/agents/${agentLow.json().data.id}/availability`,
      headers: authHeader(authToken),
      payload: { status: 'available', workingHours: {}, currentLoad: 1 },
    });
    await app.inject({
      method: 'PUT',
      url: `/admin/agents/${agentHigh.json().data.id}/availability`,
      headers: authHeader(authToken),
      payload: { status: 'available', workingHours: {}, currentLoad: 9 },
    });

    const { externalProductId, ticketId } = await createProductAndEscalate();
    await app.inject({
      method: 'POST',
      url: '/admin/hierarchy-nodes',
      headers: authHeader(authToken),
      payload: {
        name: `LL Node ${Date.now()}`,
        order: 0,
        productScope: [externalProductId],
        skills: [skillTag],
        assignmentStrategy: 'LEAST_LOADED',
      },
    });

    await escalate(ticketId);
    const current = await app.inject({ method: 'GET', url: `/tickets/${ticketId}/assignment` });
    expect(current.json().data.agentId).toBe(agentLow.json().data.id);
  });

  it('SKILL_BASED prefers the eligible agent with the higher proficiency level', async () => {
    const skillTag = `skill_based_skill_${Date.now()}`;
    const agentExpert = await app.inject({
      method: 'POST',
      url: `/admin/teams/${teamId}/agents`,
      headers: authHeader(authToken),
      payload: { name: 'Expert Agent' },
    });
    const agentNovice = await app.inject({
      method: 'POST',
      url: `/admin/teams/${teamId}/agents`,
      headers: authHeader(authToken),
      payload: { name: 'Novice Agent' },
    });
    await app.inject({
      method: 'PUT',
      url: `/admin/agents/${agentExpert.json().data.id}/skills/${skillTag}`,
      headers: authHeader(authToken),
      payload: { level: 9 },
    });
    await app.inject({
      method: 'PUT',
      url: `/admin/agents/${agentNovice.json().data.id}/skills/${skillTag}`,
      headers: authHeader(authToken),
      payload: { level: 1 },
    });

    const { externalProductId, ticketId } = await createProductAndEscalate();
    await app.inject({
      method: 'POST',
      url: '/admin/hierarchy-nodes',
      headers: authHeader(authToken),
      payload: {
        name: `SB Node ${Date.now()}`,
        order: 0,
        productScope: [externalProductId],
        skills: [skillTag],
        assignmentStrategy: 'SKILL_BASED',
      },
    });

    await escalate(ticketId);
    const current = await app.inject({ method: 'GET', url: `/tickets/${ticketId}/assignment` });
    expect(current.json().data.agentId).toBe(agentExpert.json().data.id);
  });

  it('an empty eligible set assigns nobody, leaves the ticket escalated, and records the outcome', async () => {
    const skillTag = `nobody_has_this_skill_${Date.now()}`;
    const { externalProductId, ticketId } = await createProductAndEscalate();
    await app.inject({
      method: 'POST',
      url: '/admin/hierarchy-nodes',
      headers: authHeader(authToken),
      payload: {
        name: `Empty Node ${Date.now()}`,
        order: 0,
        productScope: [externalProductId],
        skills: [skillTag],
        assignmentStrategy: 'ROUND_ROBIN',
      },
    });

    await escalate(ticketId);

    const current = await app.inject({ method: 'GET', url: `/tickets/${ticketId}/assignment` });
    expect(current.statusCode).toBe(404);

    const ticket = await prismaClient.ticket.findUniqueOrThrow({ where: { id: ticketId } });
    expect(ticket.status).toBe('HUMAN_ESCALATION');

    const history = await app.inject({
      method: 'GET',
      url: `/tickets/${ticketId}/assignment-history`,
    });
    const rows: { agentId: string | null; action: string }[] = history.json().data;
    expect(rows.some((r) => r.agentId === null && r.action === 'unassigned')).toBe(true);
  });
});