/**
 * Contract test for POST /api/v1/hedging/sessions/{id}/start
 * Tests the API contract for starting hedging sessions
 */

import { describe, it, expect, beforeAll, afterAll } from '@jest/globals';
import axios, { AxiosInstance } from 'axios';

describe('POST /api/v1/hedging/sessions/{id}/start', () => {
  let client: AxiosInstance;
  const baseURL = 'http://localhost:3000/api/v1/hedging';

  beforeAll(() => {
    client = axios.create({
      baseURL,
      headers: {
        'Content-Type': 'application/json',
        'Authorization': 'Bearer test-api-key'
      },
      timeout: 5000
    });
  });

  afterAll(() => {
    // Cleanup if needed
  });

  describe('Basic Functionality', () => {
    it('should start a pending hedging session', async () => {
      const sessionId = 'test-session-1';
      
      try {
        const response = await client.post(`/sessions/${sessionId}/start`);
        
        // Should return 200 OK
        expect(response.status).toBe(200);
        
        // Response should match schema
        expect(response.data.success).toBe(true);
        expect(response.data.session).toBeDefined();
        expect(response.data.session.id).toBe(sessionId);
        expect(response.data.session.status).toBe('active');
        expect(response.data.session.startTime).toBeDefined();
        expect(new Date(response.data.session.startTime)).toBeInstanceOf(Date);
      } catch (error) {
        // This test should fail initially since the endpoint doesn't exist yet
        expect(error.response?.status).toBe(404);
      }
    });

    it('should return appropriate success message', async () => {
      const sessionId = 'test-session-2';
      
      try {
        const response = await client.post(`/sessions/${sessionId}/start`);
        
        expect(response.status).toBe(200);
        expect(response.data.success).toBe(true);
        expect(response.data.message).toBeDefined();
        expect(typeof response.data.message).toBe('string');
      } catch (error) {
        // This test should fail initially since the endpoint doesn't exist yet
        expect(error.response?.status).toBe(404);
      }
    });
  });

  describe('Session Status Validation', () => {
    it('should reject starting a session that is not in pending status', async () => {
      const activeSessionId = 'active-session-1';
      
      try {
        await client.post(`/sessions/${activeSessionId}/start`);
        fail('Should have rejected starting an active session');
      } catch (error) {
        expect(error.response?.status).toBe(400);
        expect(error.response?.data.success).toBe(false);
        expect(error.response?.data.error.code).toBe('INVALID_SESSION_STATUS');
        expect(error.response?.data.error.message).toContain('pending');
      }
    });

    it('should reject starting a completed session', async () => {
      const completedSessionId = 'completed-session-1';
      
      try {
        await client.post(`/sessions/${completedSessionId}/start`);
        fail('Should have rejected starting a completed session');
      } catch (error) {
        expect(error.response?.status).toBe(400);
        expect(error.response?.data.success).toBe(false);
        expect(error.response?.data.error.code).toBe('INVALID_SESSION_STATUS');
      }
    });

    it('should reject starting a failed session', async () => {
      const failedSessionId = 'failed-session-1';
      
      try {
        await client.post(`/sessions/${failedSessionId}/start`);
        fail('Should have rejected starting a failed session');
      } catch (error) {
        expect(error.response?.status).toBe(400);
        expect(error.response?.data.success).toBe(false);
        expect(error.response?.data.error.code).toBe('INVALID_SESSION_STATUS');
      }
    });
  });

  describe('Account Validation', () => {
    it('should reject starting session with inactive accounts', async () => {
      const sessionWithInactiveAccount = 'session-inactive-account';
      
      try {
        await client.post(`/sessions/${sessionWithInactiveAccount}/start`);
        fail('Should have rejected starting session with inactive account');
      } catch (error) {
        expect(error.response?.status).toBe(400);
        expect(error.response?.data.success).toBe(false);
        expect(error.response?.data.error.code).toBe('ACCOUNT_NOT_ACTIVE');
      }
    });

    it('should reject starting session with insufficient balance', async () => {
      const sessionInsufficientBalance = 'session-insufficient-balance';
      
      try {
        await client.post(`/sessions/${sessionInsufficientBalance}/start`);
        fail('Should have rejected starting session with insufficient balance');
      } catch (error) {
        expect(error.response?.status).toBe(400);
        expect(error.response?.data.success).toBe(false);
        expect(error.response?.data.error.code).toBe('INSUFFICIENT_BALANCE');
      }
    });
  });

  describe('Risk Validation', () => {
    it('should reject starting session with active risk breaches', async () => {
      const sessionWithRiskBreach = 'session-risk-breach';
      
      try {
        await client.post(`/sessions/${sessionWithRiskBreach}/start`);
        fail('Should have rejected starting session with active risk breaches');
      } catch (error) {
        expect(error.response?.status).toBe(400);
        expect(error.response?.data.success).toBe(false);
        expect(error.response?.data.error.code).toBe('RISK_LIMIT_EXCEEDED');
      }
    });

    it('should reject starting session that would exceed risk limits', async () => {
      const sessionExceedsRisk = 'session-exceeds-risk';
      
      try {
        await client.post(`/sessions/${sessionExceedsRisk}/start`);
        fail('Should have rejected starting session that exceeds risk limits');
      } catch (error) {
        expect(error.response?.status).toBe(400);
        expect(error.response?.data.success).toBe(false);
        expect(error.response?.data.error.code).toBe('RISK_LIMIT_EXCEEDED');
      }
    });
  });

  describe('Session Not Found', () => {
    it('should return 404 for non-existent session', async () => {
      const nonExistentSessionId = 'non-existent-session';
      
      try {
        await client.post(`/sessions/${nonExistentSessionId}/start`);
        fail('Should have returned 404 for non-existent session');
      } catch (error) {
        expect(error.response?.status).toBe(404);
        expect(error.response?.data.success).toBe(false);
        expect(error.response?.data.error.code).toBe('SESSION_NOT_FOUND');
      }
    });

    it('should return 404 for invalid session ID format', async () => {
      const invalidSessionId = 'invalid-session-id-format!@#';
      
      try {
        await client.post(`/sessions/${invalidSessionId}/start`);
        fail('Should have returned 404 for invalid session ID');
      } catch (error) {
        expect(error.response?.status).toBe(404);
        expect(error.response?.data.success).toBe(false);
        expect(error.response?.data.error.code).toBe('SESSION_NOT_FOUND');
      }
    });
  });

  describe('Authentication', () => {
    it('should reject request without authorization header', async () => {
      const clientWithoutAuth = axios.create({
        baseURL,
        headers: {
          'Content-Type': 'application/json'
        }
      });

      try {
        await clientWithoutAuth.post('/sessions/test-session/start');
        fail('Should have rejected unauthorized request');
      } catch (error) {
        expect(error.response?.status).toBe(401);
      }
    });

    it('should reject request with invalid authorization token', async () => {
      const clientWithInvalidAuth = axios.create({
        baseURL,
        headers: {
          'Content-Type': 'application/json',
          'Authorization': 'Bearer invalid-token'
        }
      });

      try {
        await clientWithInvalidAuth.post('/sessions/test-session/start');
        fail('Should have rejected request with invalid token');
      } catch (error) {
        expect(error.response?.status).toBe(401);
      }
    });
  });

  describe('Concurrent Operations', () => {
    it('should handle concurrent start requests for same session', async () => {
      const sessionId = 'concurrent-session';
      
      try {
        // Make multiple concurrent start requests
        const requests = Array(3).fill(null).map(() => 
          client.post(`/sessions/${sessionId}/start`)
        );
        
        const responses = await Promise.all(requests);
        
        // Only one should succeed, others should fail with appropriate error
        const successfulResponses = responses.filter(r => r.status === 200);
        const failedResponses = responses.filter(r => r.status !== 200);
        
        expect(successfulResponses.length).toBe(1);
        expect(failedResponses.length).toBe(2);
        
        failedResponses.forEach(response => {
          expect(response.data.success).toBe(false);
          expect(response.data.error.code).toBe('INVALID_SESSION_STATUS');
        });
      } catch (error) {
        // This test should fail initially since the endpoint doesn't exist yet
        expect(error.response?.status).toBe(404);
      }
    });
  });

  describe('Market Data Validation', () => {
    it('should reject starting session when market data is unavailable', async () => {
      const sessionNoMarketData = 'session-no-market-data';
      
      try {
        await client.post(`/sessions/${sessionNoMarketData}/start`);
        fail('Should have rejected starting session without market data');
      } catch (error) {
        expect(error.response?.status).toBe(503);
        expect(error.response?.data.success).toBe(false);
        expect(error.response?.data.error.code).toBe('MARKET_DATA_UNAVAILABLE');
      }
    });
  });
});