/**
 * E2E Tests: Chat Streaming, Tool Events, and Approval Gate
 *
 * Scenarios covered:
 *   4. Chat message sent and response received (with mock agentRunner)
 *   9. Tool execution — mock runner calls onToolUse, SSE includes tool event
 *  10. External mutation gate — eventBus-based approval flow
 */
import { describe, it, expect, afterEach } from 'vitest';
import fs from 'node:fs';
import os from 'node:os';
import path from 'node:path';
import type { FastifyInstance } from 'fastify';
import { startService } from '@waggle/server/local/service';
import type { AgentRunner } from '@waggle/server/local/routes/chat';
import { injectWithAuth } from './test-utils.js';

function makeTmpDir(): string {
  return fs.mkdtempSync(path.join(os.tmpdir(), 'waggle-e2e-'));
}

// Port 0 lets the OS assign a free port; inject() bypasses the network anyway
const TEST_PORT = 0;

/**
 * Parse SSE text into structured events.
 * Each event is: "event: <type>\ndata: <json>\n\n"
 */
function parseSSE(raw: string): Array<{ event: string; data: unknown }> {
  const events: Array<{ event: string; data: unknown }> = [];
  const blocks = raw.split('\n\n').filter(b => b.trim());

  for (const block of blocks) {
    const lines = block.split('\n');
    let event = '';
    let data = '';
    for (const line of lines) {
      if (line.startsWith('event: ')) {
        event = line.slice(7);
      } else if (line.startsWith('data: ')) {
        data = line.slice(6);
      }
    }
    if (event && data) {
      try {
        events.push({ event, data: JSON.parse(data) });
      } catch {
        events.push({ event, data });
      }
    }
  }
  return events;
}

describe('Chat E2E', () => {
  const servers: FastifyInstance[] = [];
  const tmpDirs: string[] = [];

  afterEach(async () => {
    for (const s of servers) {
      try { await s.close(); } catch { /* ignore */ }
    }
    servers.length = 0;
    for (const d of tmpDirs) {
      try { fs.rmSync(d, { recursive: true, force: true }); } catch { /* ignore */ }
    }
    tmpDirs.length = 0;
  });

  // Scenario 4: Chat message sent and response received via SSE
  it('sends chat message and receives SSE token + done events', async () => {
    const dataDir = makeTmpDir();
    tmpDirs.push(dataDir);
    const port = TEST_PORT;

    const { server } = await startService({ dataDir, port, skipLiteLLM: true });
    servers.push(server);

    // Inject mock agentRunner
    const mockRunner: AgentRunner = async (config) => {
      if (config.onToken) {
        config.onToken('Hello ');
        config.onToken('world');
      }
      return {
        content: 'Hello world',
        usage: { inputTokens: 10, outputTokens: 5 },
        toolsUsed: [],
      };
    };
    server.agentRunner = mockRunner;

    const res = await injectWithAuth(server, {
      method: 'POST',
      url: '/api/chat',
      payload: { message: 'Hi there' },
    });

    // SSE hijacks the response — status comes from raw writeHead
    // inject() returns the raw body as payload
    const events = parseSSE(res.payload);

    // Should have token events
    const tokenEvents = events.filter(e => e.event === 'token');
    expect(tokenEvents.length).toBe(2);
    expect((tokenEvents[0].data as { content: string }).content).toBe('Hello ');
    expect((tokenEvents[1].data as { content: string }).content).toBe('world');

    // Should have done event
    const doneEvents = events.filter(e => e.event === 'done');
    expect(doneEvents.length).toBe(1);
    const doneData = doneEvents[0].data as { content: string; usage: unknown; toolsUsed: string[] };
    expect(doneData.content).toBe('Hello world');
    expect(doneData.toolsUsed).toEqual([]);
  });

  // Scenario 9: Tool execution events in SSE stream
  it('includes tool events in SSE when agentRunner calls onToolUse', async () => {
    const dataDir = makeTmpDir();
    tmpDirs.push(dataDir);
    const port = TEST_PORT;

    const { server } = await startService({ dataDir, port, skipLiteLLM: true });
    servers.push(server);

    const mockRunner: AgentRunner = async (config) => {
      if (config.onToken) {
        config.onToken('Reading file...');
      }
      if (config.onToolUse) {
        config.onToolUse('read_file', { path: '/src/index.ts' });
      }
      if (config.onToken) {
        config.onToken(' Done.');
      }
      if (config.onToolUse) {
        config.onToolUse('write_file', { path: '/src/output.ts', content: 'export {}' });
      }
      return {
        content: 'Reading file... Done.',
        usage: { inputTokens: 20, outputTokens: 10 },
        toolsUsed: ['read_file', 'write_file'],
      };
    };
    server.agentRunner = mockRunner;

    const res = await injectWithAuth(server, {
      method: 'POST',
      url: '/api/chat',
      payload: { message: 'Read the index file' },
    });

    const events = parseSSE(res.payload);

    // Should have tool events
    const toolEvents = events.filter(e => e.event === 'tool');
    expect(toolEvents.length).toBe(2);

    const tool1 = toolEvents[0].data as { name: string; input: Record<string, unknown> };
    expect(tool1.name).toBe('read_file');
    expect(tool1.input.path).toBe('/src/index.ts');

    const tool2 = toolEvents[1].data as { name: string; input: Record<string, unknown> };
    expect(tool2.name).toBe('write_file');

    // Done event should list tools used
    const doneEvents = events.filter(e => e.event === 'done');
    expect(doneEvents.length).toBe(1);
    const doneData = doneEvents[0].data as { toolsUsed: string[] };
    expect(doneData.toolsUsed).toEqual(['read_file', 'write_file']);
  });

  // Scenario 10: External mutation gate — eventBus approval flow
  // The approval gate is driven by the eventBus: the agent emits a
  // 'gate:request' event and waits for 'gate:response'. This test
  // verifies the eventBus-based flow without needing an HTTP endpoint.
  it('external mutation gate: eventBus blocks and resumes on approval', async () => {
    const dataDir = makeTmpDir();
    tmpDirs.push(dataDir);
    const port = TEST_PORT;

    const { server } = await startService({ dataDir, port, skipLiteLLM: true });
    servers.push(server);

    // Simulate the approval gate pattern used by the desktop app:
    // agentRunner emits 'gate:request' on the eventBus, waits for 'gate:response'
    const gateLog: string[] = [];

    const mockRunner: AgentRunner = async (config) => {
      // Simulate a tool that triggers an approval gate
      if (config.onToolUse) {
        config.onToolUse('bash', { command: 'rm -rf /important' });
      }

      // Emit gate request and wait for response
      const approved = await new Promise<boolean>((resolve) => {
        server.eventBus.once('gate:response', (response: { approved: boolean }) => {
          gateLog.push(response.approved ? 'approved' : 'denied');
          resolve(response.approved);
        });
        server.eventBus.emit('gate:request', {
          tool: 'bash',
          input: { command: 'rm -rf /important' },
          requestId: 'gate-001',
        });
      });

      if (config.onToken) {
        config.onToken(approved ? 'Executed.' : 'Blocked.');
      }

      return {
        content: approved ? 'Executed.' : 'Blocked.',
        usage: { inputTokens: 15, outputTokens: 3 },
        toolsUsed: approved ? ['bash'] : [],
      };
    };
    server.agentRunner = mockRunner;

    // Listen for gate requests and auto-approve
    server.eventBus.on('gate:request', (req: { requestId: string }) => {
      gateLog.push('request-received');
      // Simulate user clicking "Approve" in the UI
      server.eventBus.emit('gate:response', { requestId: req.requestId, approved: true });
    });

    const res = await injectWithAuth(server, {
      method: 'POST',
      url: '/api/chat',
      payload: { message: 'Delete the folder' },
    });

    const events = parseSSE(res.payload);
    const doneEvents = events.filter(e => e.event === 'done');
    expect(doneEvents.length).toBe(1);

    const doneData = doneEvents[0].data as { content: string; toolsUsed: string[] };
    expect(doneData.content).toBe('Executed.');
    expect(doneData.toolsUsed).toEqual(['bash']);

    // Verify gate flow happened in correct order
    expect(gateLog.length).toBe(2);
    expect(gateLog[0]).toBe('request-received');
    expect(gateLog[1]).toBe('approved');
  });

  // Scenario 10b: External mutation gate — denial path
  it('external mutation gate: eventBus blocks and returns denial', async () => {
    const dataDir = makeTmpDir();
    tmpDirs.push(dataDir);
    const port = TEST_PORT;

    const { server } = await startService({ dataDir, port, skipLiteLLM: true });
    servers.push(server);

    const gateLog: string[] = [];

    const mockRunner: AgentRunner = async (config) => {
      if (config.onToolUse) {
        config.onToolUse('bash', { command: 'rm -rf /important' });
      }

      // Emit gate request and wait for response
      const approved = await new Promise<boolean>((resolve) => {
        server.eventBus.once('gate:response', (response: { approved: boolean }) => {
          gateLog.push(response.approved ? 'approved' : 'denied');
          resolve(response.approved);
        });
        server.eventBus.emit('gate:request', {
          tool: 'bash',
          input: { command: 'rm -rf /important' },
          requestId: 'gate-002',
        });
      });

      if (config.onToken) {
        config.onToken(approved ? 'Executed.' : 'Blocked.');
      }

      return {
        content: approved ? 'Executed.' : 'Blocked.',
        usage: { inputTokens: 15, outputTokens: 3 },
        toolsUsed: approved ? ['bash'] : [],
      };
    };
    server.agentRunner = mockRunner;

    // Listen for gate requests and auto-DENY
    server.eventBus.on('gate:request', (req: { requestId: string }) => {
      gateLog.push('request-received');
      // Simulate user clicking "Deny" in the UI
      server.eventBus.emit('gate:response', { requestId: req.requestId, approved: false });
    });

    const res = await injectWithAuth(server, {
      method: 'POST',
      url: '/api/chat',
      payload: { message: 'Delete the folder' },
    });

    const events = parseSSE(res.payload);
    const doneEvents = events.filter(e => e.event === 'done');
    expect(doneEvents.length).toBe(1);

    const doneData = doneEvents[0].data as { content: string; toolsUsed: string[] };
    expect(doneData.content).toBe('Blocked.');
    expect(doneData.toolsUsed).toEqual([]);

    // Verify gate flow happened in correct order with denial
    expect(gateLog.length).toBe(2);
    expect(gateLog[0]).toBe('request-received');
    expect(gateLog[1]).toBe('denied');
  });
});