import http from 'node:http';
import { readFile } from 'node:fs/promises';
import { fileURLToPath } from 'node:url';
import { dirname, join } from 'node:path';
import { randomUUID } from 'node:crypto';

const __dirname = dirname(fileURLToPath(import.meta.url));
const PORT = parseInt(process.env.PORT || '4003');

// --- Agent Registry: Known worker agents ---
const WORKER_AGENTS = {
  'screenshot': {
    name: 'SnapAPI Screenshot Agent',
    a2aUrl: process.env.SNAPAPI_A2A_URL || 'http://localhost:4002',
    skills: ['screenshot', 'webpage-capture'],
    costPerTask: '$0.01'
  },
  'pdf': {
    name: 'SnapAPI PDF Agent',
    a2aUrl: process.env.SNAPAPI_A2A_URL || 'http://localhost:4002',
    skills: ['markdown-to-pdf', 'document-generation'],
    costPerTask: '$0.005'
  },
  'html': {
    name: 'SnapAPI HTML Agent',
    a2aUrl: process.env.SNAPAPI_A2A_URL || 'http://localhost:4002',
    skills: ['markdown-to-html'],
    costPerTask: 'free'
  }
};

// --- State ---
const swarms = new Map();      // swarmId -> Swarm
const tasks = new Map();        // taskId -> Task
const eventLog = [];            // append-only event log

// --- Agent Card (A2A v0.3 compliant) ---
const agentCard = {
  name: 'OpSpawn Agent Swarm',
  description: 'Multi-agent task decomposition and delegation system. Accepts complex tasks, breaks them into subtasks, delegates to specialized worker agents via A2A, and assembles results.',
  version: '1.0.0',
  url: process.env.PUBLIC_URL || `http://localhost:${PORT}`,
  provider: {
    organization: 'OpSpawn',
    url: 'https://opspawn.com'
  },
  capabilities: {
    streaming: false,
    pushNotifications: false,
    extensions: [
      {
        uri: 'urn:x402:payment:v2',
        description: 'x402 V2 micropayments for inter-agent commerce',
        required: false
      },
      {
        uri: 'urn:opspawn:swarm',
        description: 'Multi-agent task decomposition and delegation',
        required: false
      }
    ]
  },
  skills: [
    {
      id: 'decompose-and-execute',
      name: 'Task Decomposition & Execution',
      description: 'Takes a complex task, decomposes it into subtasks, delegates to specialized worker agents, and assembles the results.',
      tags: ['orchestration', 'multi-agent', 'decomposition'],
      examples: [
        'Create a visual report about opspawn.com including a screenshot and summary',
        'Generate a PDF from this markdown with a screenshot of the rendered page',
        'Capture screenshots of these 3 URLs and compile them into a report'
      ]
    },
    {
      id: 'discover-agents',
      name: 'Agent Discovery',
      description: 'Discover available worker agents and their capabilities.',
      tags: ['discovery', 'registry']
    },
    {
      id: 'swarm-status',
      name: 'Swarm Status',
      description: 'Get the status of a running swarm task, including subtask progress.',
      tags: ['monitoring', 'status']
    }
  ],
  defaultInputModes: ['text/plain'],
  defaultOutputModes: ['application/json', 'text/plain']
};

// --- Task Planner: Decomposes complex tasks into subtasks ---
function planTask(instruction) {
  const lower = instruction.toLowerCase();
  const subtasks = [];

  // URL detection
  const urlMatch = instruction.match(/https?:\/\/[^\s"'<>]+/g);

  // Screenshot requests
  if (lower.includes('screenshot') || lower.includes('capture') || lower.includes('visual')) {
    const urls = urlMatch || ['https://opspawn.com'];
    for (const url of urls) {
      subtasks.push({
        type: 'screenshot',
        agent: 'screenshot',
        params: { url },
        description: `Capture screenshot of ${url}`
      });
    }
  }

  // PDF generation
  if (lower.includes('pdf') || lower.includes('report') || lower.includes('document')) {
    subtasks.push({
      type: 'pdf',
      agent: 'pdf',
      params: { markdown: instruction },
      description: 'Generate PDF report from content'
    });
  }

  // HTML rendering
  if (lower.includes('html') || lower.includes('render') || lower.includes('preview')) {
    subtasks.push({
      type: 'html',
      agent: 'html',
      params: { markdown: instruction },
      description: 'Render content as HTML'
    });
  }

  // Compound tasks: if "report" is mentioned, include both screenshot + PDF
  if (lower.includes('report') && !subtasks.some(s => s.type === 'screenshot')) {
    const url = urlMatch?.[0] || 'https://opspawn.com';
    subtasks.unshift({
      type: 'screenshot',
      agent: 'screenshot',
      params: { url },
      description: `Capture screenshot for report: ${url}`
    });
  }

  // Default: if no subtasks identified, treat as HTML rendering
  if (subtasks.length === 0) {
    subtasks.push({
      type: 'html',
      agent: 'html',
      params: { markdown: instruction },
      description: 'Process text as HTML content'
    });
  }

  return subtasks;
}

// --- Swarm Execution Engine ---
async function executeSwarm(swarmId) {
  const swarm = swarms.get(swarmId);
  if (!swarm) return;

  swarm.state = 'running';
  swarm.startedAt = new Date().toISOString();
  logEvent('coordinator', 'swarm-started', { swarmId, subtaskCount: swarm.subtasks.length });

  const results = [];
  for (const subtask of swarm.subtasks) {
    subtask.state = 'running';
    subtask.startedAt = new Date().toISOString();
    logEvent('coordinator', 'subtask-started', { swarmId, subtaskId: subtask.id, type: subtask.type });

    try {
      const result = await delegateToWorker(subtask);
      subtask.state = 'completed';
      subtask.result = result;
      subtask.completedAt = new Date().toISOString();
      results.push({ subtaskId: subtask.id, type: subtask.type, result });
      logEvent('coordinator', 'subtask-completed', { swarmId, subtaskId: subtask.id, type: subtask.type });
    } catch (err) {
      subtask.state = 'failed';
      subtask.error = err.message;
      subtask.completedAt = new Date().toISOString();
      results.push({ subtaskId: subtask.id, type: subtask.type, error: err.message });
      logEvent('coordinator', 'subtask-failed', { swarmId, subtaskId: subtask.id, error: err.message });
    }
  }

  // Assemble results
  const completed = swarm.subtasks.filter(s => s.state === 'completed').length;
  const failed = swarm.subtasks.filter(s => s.state === 'failed').length;

  swarm.state = failed === swarm.subtasks.length ? 'failed' : 'completed';
  swarm.completedAt = new Date().toISOString();
  swarm.results = results;
  swarm.summary = `Swarm completed: ${completed}/${swarm.subtasks.length} subtasks succeeded, ${failed} failed.`;

  logEvent('coordinator', 'swarm-completed', { swarmId, completed, failed, total: swarm.subtasks.length });
  return swarm;
}

// --- Worker Delegation via A2A ---
async function delegateToWorker(subtask) {
  const worker = WORKER_AGENTS[subtask.agent];
  if (!worker) throw new Error(`Unknown worker agent: ${subtask.agent}`);

  // Build message text based on subtask type
  let messageText;
  switch (subtask.type) {
    case 'screenshot':
      messageText = `Take a screenshot of ${subtask.params.url}`;
      break;
    case 'pdf':
      messageText = `Convert to PDF:\n\n${subtask.params.markdown}`;
      break;
    case 'html':
      messageText = `Convert to HTML:\n\n${subtask.params.markdown}`;
      break;
    default:
      messageText = subtask.params.markdown || subtask.description;
  }

  // A2A v0.3 JSON-RPC request — POST to root endpoint
  const a2aRequest = {
    jsonrpc: '2.0',
    id: randomUUID(),
    method: 'message/send',
    params: {
      message: {
        messageId: randomUUID(),
        role: 'user',
        kind: 'message',
        parts: [{ kind: 'text', text: messageText }]
      }
    }
  };

  // Send to worker agent root endpoint (A2A uses POST /)
  const url = worker.a2aUrl;
  const response = await fetch(url, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify(a2aRequest)
  });

  if (!response.ok) {
    const text = await response.text();
    throw new Error(`Worker ${subtask.agent} returned ${response.status}: ${text}`);
  }

  const result = await response.json();

  // Handle JSON-RPC error
  if (result.error) {
    throw new Error(`Worker ${subtask.agent} error: ${result.error.message}`);
  }

  const taskResult = result.result;
  const state = taskResult?.status?.state;
  const message = taskResult?.status?.message;

  // Check if payment is required (x402 flow)
  if (state === 'input-required') {
    // Look for x402 payment info in message parts or metadata
    const dataPart = message?.parts?.find(p => p.kind === 'data' && p.data?.['x402.payment.required']);
    const accepts = dataPart?.data?.['x402.accepts'] || taskResult?.metadata?.['x402.accepts'];
    if (accepts || dataPart) {
      return {
        state: 'payment-required',
        worker: worker.name,
        cost: worker.costPerTask,
        paymentInfo: accepts,
        skill: dataPart?.data?.skill || subtask.type,
        message: `Worker ${worker.name} requires payment of ${worker.costPerTask} to complete this task.`
      };
    }
  }

  // Task completed successfully
  if (state === 'completed') {
    const parts = message?.parts || [];
    return {
      state: 'completed',
      worker: worker.name,
      output: parts.map(p => p.text || (p.data ? JSON.stringify(p.data) : '[binary]')).join('\n')
    };
  }

  return { state: state || 'unknown', raw: result };
}

// --- Event Logging ---
function logEvent(agentId, action, data = {}) {
  const event = {
    timestamp: new Date().toISOString(),
    agentId,
    action,
    ...data
  };
  eventLog.push(event);
  // Keep last 1000 events
  if (eventLog.length > 1000) eventLog.shift();
}

// --- HTTP Request Helpers ---
function parseBody(req) {
  return new Promise((resolve, reject) => {
    const chunks = [];
    req.on('data', c => chunks.push(c));
    req.on('end', () => {
      try { resolve(JSON.parse(Buffer.concat(chunks).toString())); }
      catch { resolve(null); }
    });
    req.on('error', reject);
  });
}

function json(res, data, status = 200) {
  res.writeHead(status, {
    'Content-Type': 'application/json',
    'Access-Control-Allow-Origin': '*',
    'Access-Control-Allow-Methods': 'GET, POST, OPTIONS',
    'Access-Control-Allow-Headers': 'Content-Type, Authorization'
  });
  res.end(JSON.stringify(data, null, 2));
}

function cors(res) {
  res.writeHead(204, {
    'Access-Control-Allow-Origin': '*',
    'Access-Control-Allow-Methods': 'GET, POST, DELETE, OPTIONS',
    'Access-Control-Allow-Headers': 'Content-Type, Authorization'
  });
  res.end();
}

// --- HTTP Server ---
const server = http.createServer(async (req, res) => {
  const url = new URL(req.url, `http://localhost:${PORT}`);
  const path = url.pathname;

  if (req.method === 'OPTIONS') return cors(res);

  // --- A2A: Agent Card ---
  if (path === '/.well-known/agent-card.json' && req.method === 'GET') {
    return json(res, agentCard);
  }

  // --- Health ---
  if (path === '/health' && req.method === 'GET') {
    return json(res, {
      status: 'ok',
      service: 'agent-swarm',
      version: '1.0.0',
      uptime: process.uptime(),
      activeSwarms: [...swarms.values()].filter(s => s.state === 'running').length,
      totalSwarms: swarms.size,
      totalEvents: eventLog.length,
      workerAgents: Object.keys(WORKER_AGENTS).length
    });
  }

  // --- A2A: message/send (create and execute swarm) ---
  if (path.match(/^\/tasks\/[^/]+\/send$/) && req.method === 'POST') {
    const contextId = path.split('/')[2];
    const body = await parseBody(req);

    if (!body?.params?.message?.parts?.[0]?.text) {
      return json(res, {
        jsonrpc: '2.0',
        id: body?.id || null,
        error: { code: -32600, message: 'Invalid request: missing message text' }
      }, 400);
    }

    const instruction = body.params.message.parts[0].text;
    const subtaskPlans = planTask(instruction);

    // Create swarm
    const swarmId = randomUUID();
    const swarm = {
      id: swarmId,
      contextId,
      instruction,
      state: 'planned',
      createdAt: new Date().toISOString(),
      subtasks: subtaskPlans.map((plan, i) => ({
        id: `${swarmId}-sub-${i}`,
        ...plan,
        state: 'pending',
        result: null
      }))
    };
    swarms.set(swarmId, swarm);

    logEvent('coordinator', 'swarm-created', {
      swarmId,
      instruction: instruction.substring(0, 200),
      subtaskCount: subtaskPlans.length,
      subtaskTypes: subtaskPlans.map(s => s.type)
    });

    // Execute asynchronously
    executeSwarm(swarmId).catch(err => {
      logEvent('coordinator', 'swarm-error', { swarmId, error: err.message });
    });

    // Return immediately with task status
    return json(res, {
      jsonrpc: '2.0',
      id: body.id || null,
      result: {
        id: swarmId,
        contextId,
        status: {
          state: 'working',
          message: {
            role: 'agent',
            parts: [{
              type: 'text',
              text: `Swarm created with ${subtaskPlans.length} subtask(s): ${subtaskPlans.map(s => s.description).join(', ')}`
            }],
            metadata: {
              'swarm.id': swarmId,
              'swarm.subtaskCount': subtaskPlans.length,
              'swarm.subtasks': subtaskPlans.map(s => ({
                type: s.type,
                agent: s.agent,
                description: s.description
              }))
            }
          },
          timestamp: new Date().toISOString()
        }
      }
    });
  }

  // --- Get swarm status ---
  if (path.match(/^\/swarms\/[^/]+$/) && req.method === 'GET') {
    const swarmId = path.split('/')[2];
    const swarm = swarms.get(swarmId);
    if (!swarm) return json(res, { error: 'Swarm not found' }, 404);
    return json(res, swarm);
  }

  // --- List all swarms ---
  if (path === '/swarms' && req.method === 'GET') {
    const list = [...swarms.values()].map(s => ({
      id: s.id,
      state: s.state,
      instruction: s.instruction.substring(0, 100),
      subtaskCount: s.subtasks.length,
      createdAt: s.createdAt,
      completedAt: s.completedAt
    }));
    return json(res, { swarms: list, total: list.length });
  }

  // --- Discover worker agents ---
  if (path === '/agents' && req.method === 'GET') {
    return json(res, {
      coordinator: {
        name: agentCard.name,
        version: agentCard.version,
        skills: agentCard.skills.map(s => s.id)
      },
      workers: Object.entries(WORKER_AGENTS).map(([id, w]) => ({
        id,
        name: w.name,
        skills: w.skills,
        costPerTask: w.costPerTask,
        a2aUrl: w.a2aUrl
      }))
    });
  }

  // --- Event log ---
  if (path === '/events' && req.method === 'GET') {
    const last = parseInt(url.searchParams.get('last') || '50');
    return json(res, {
      events: eventLog.slice(-last),
      total: eventLog.length
    });
  }

  // --- Dashboard ---
  if (path === '/' && req.method === 'GET') {
    try {
      const html = await readFile(join(__dirname, 'dashboard.html'), 'utf8');
      res.writeHead(200, { 'Content-Type': 'text/html' });
      res.end(html);
    } catch {
      res.writeHead(200, { 'Content-Type': 'text/html' });
      res.end('<html><body><h1>Agent Swarm</h1><p>Dashboard loading...</p></body></html>');
    }
    return;
  }

  // --- Favicon ---
  if (path === '/favicon.ico') {
    res.writeHead(204);
    return res.end();
  }

  // --- 404 ---
  json(res, { error: 'Not found' }, 404);
});

server.listen(PORT, () => {
  console.log(`Agent Swarm coordinator running on port ${PORT}`);
  console.log(`Agent card: http://localhost:${PORT}/.well-known/agent-card.json`);
  console.log(`Dashboard: http://localhost:${PORT}/`);
  console.log(`Workers: ${Object.keys(WORKER_AGENTS).length} registered`);
});

export { agentCard, WORKER_AGENTS, planTask };