/**
 * Worker Session Service
 *
 * Manages the worker session lifecycle:
 * 1. Claim up to 6 tasks for same geo
 * 2. Get Evomi proxy for that geo
 * 3. Check IP availability (not in use, not in cooldown)
 * 4. Lock IP/fingerprint to worker
 * 5. Track task completion
 * 6. Retire session after 6 tasks (8hr cooldown)
 */

import { pool } from '../db/pool';
import { buildEvomiProxyUrl, getEvomiConfig } from './crawl-rotator';

export interface ClaimedTask {
  task_id: number;
  role: string;
  dispensary_id: number;
  dispensary_name: string;
  city: string | null;
  state_code: string;
  platform: string;
  method: string | null;
}

export interface WorkerSession {
  id: number;
  ip_address: string;
  fingerprint_hash: string;
  fingerprint_data: Record<string, unknown> | null;
  state_code: string;
  city: string | null;
  worker_id: string;
  status: 'active' | 'cooldown' | 'available';
  tasks_claimed: number;
  tasks_completed: number;
  tasks_failed: number;
  max_tasks: number;
  locked_at: Date;
}

export interface SessionWithTasks {
  session: WorkerSession;
  tasks: ClaimedTask[];
  proxyUrl: string;
}

const MAX_TASKS_PER_SESSION = 6;
const MAX_IP_ATTEMPTS = 10; // How many IPs to try before giving up
const COOLDOWN_HOURS = 8;

/**
 * Claim tasks and establish a session for a worker.
 * This is the main entry point for the new worker flow.
 *
 * Flow:
 * 1. Claim up to 6 tasks for same geo
 * 2. Get Evomi proxy for that geo
 * 3. Try IPs until we find one that's available
 * 4. Lock IP to this worker
 * 5. Return session + tasks + proxy URL
 */
export async function claimSessionWithTasks(
  workerId: string,
  role?: string
): Promise<SessionWithTasks | null> {
  const client = await pool.connect();

  try {
    await client.query('BEGIN');

    // Step 1: Claim up to 6 tasks for same geo
    const { rows: tasks } = await client.query<ClaimedTask>(
      `SELECT * FROM claim_tasks_batch($1, $2, $3)`,
      [workerId, MAX_TASKS_PER_SESSION, role || null]
    );

    if (tasks.length === 0) {
      await client.query('ROLLBACK');
      console.log(`[WorkerSession] No pending tasks available for ${workerId}`);
      return null;
    }

    // Get geo from first claimed task (all same geo)
    const { state_code, city } = tasks[0];
    console.log(`[WorkerSession] ${workerId} claimed ${tasks.length} tasks for ${city || 'any'}, ${state_code}`);

    // Step 2: Get Evomi proxy for this geo
    const evomiConfig = getEvomiConfig();
    if (!evomiConfig.enabled) {
      await client.query('ROLLBACK');
      throw new Error('Evomi proxy not configured');
    }

    // Step 3: Try to get an available IP
    let session: WorkerSession | null = null;
    let proxyUrl: string | null = null;

    for (let attempt = 0; attempt < MAX_IP_ATTEMPTS; attempt++) {
      // Build proxy URL with unique session ID for each attempt
      const sessionId = `${workerId}-${Date.now()}-${attempt}`;
      const proxyResult = buildEvomiProxyUrl(state_code, sessionId, city || undefined);

      if (!proxyResult) {
        console.warn(`[WorkerSession] Failed to build proxy URL for ${state_code}`);
        continue;
      }

      // TODO: Actually make a request through the proxy to get the real IP
      // For now, we'll use a placeholder - in production, run a quick IP check
      const testIp = await getProxyIp(proxyResult.url);

      if (!testIp) {
        console.warn(`[WorkerSession] Failed to get IP from proxy attempt ${attempt + 1}`);
        continue;
      }

      // Step 4: Try to lock this IP
      const { rows } = await client.query<WorkerSession>(
        `SELECT * FROM lock_worker_session($1, $2, $3, $4)`,
        [workerId, testIp, state_code, city]
      );

      if (rows[0]?.id) {
        session = rows[0];
        proxyUrl = proxyResult.url;
        console.log(`[WorkerSession] ${workerId} locked IP ${testIp} for ${city || 'any'}, ${state_code}`);
        break;
      }

      console.log(`[WorkerSession] IP ${testIp} not available (in use or cooldown), trying next...`);
    }

    if (!session || !proxyUrl) {
      // Release claimed tasks back to pool
      await client.query(`SELECT release_claimed_tasks($1)`, [workerId]);
      await client.query('ROLLBACK');
      console.error(`[WorkerSession] ${workerId} failed to get available IP after ${MAX_IP_ATTEMPTS} attempts`);
      return null;
    }

    // Update session with task count
    await client.query(
      `SELECT session_task_claimed($1, $2)`,
      [workerId, tasks.length]
    );

    await client.query('COMMIT');

    return {
      session,
      tasks,
      proxyUrl,
    };
  } catch (err) {
    await client.query('ROLLBACK');
    throw err;
  } finally {
    client.release();
  }
}

/**
 * Get the real IP address from a proxy by making a test request
 */
async function getProxyIp(proxyUrl: string): Promise<string | null> {
  try {
    // Use a simple IP check service
    const { default: axios } = await import('axios');
    const { HttpsProxyAgent } = await import('https-proxy-agent');

    const agent = new HttpsProxyAgent(proxyUrl);
    const response = await axios.get('https://api.ipify.org?format=json', {
      httpAgent: agent,
      httpsAgent: agent,
      timeout: 10000,
    });

    return response.data?.ip || null;
  } catch (err: any) {
    console.warn(`[WorkerSession] IP check failed: ${err.message}`);
    return null;
  }
}

/**
 * Mark a task as started (running)
 */
export async function startTask(taskId: number, workerId: string): Promise<boolean> {
  const { rows } = await pool.query(
    `SELECT start_task($1, $2) as success`,
    [taskId, workerId]
  );
  return rows[0]?.success || false;
}

/**
 * Mark a task as completed
 */
export async function completeTask(
  taskId: number,
  workerId: string,
  result?: Record<string, unknown>
): Promise<boolean> {
  const client = await pool.connect();
  try {
    await client.query('BEGIN');

    // Complete the task
    const { rows } = await client.query(
      `SELECT complete_task($1, $2, $3) as success`,
      [taskId, workerId, result ? JSON.stringify(result) : null]
    );

    if (rows[0]?.success) {
      // Update session counter
      await client.query(`SELECT session_task_completed($1)`, [workerId]);
    }

    await client.query('COMMIT');
    return rows[0]?.success || false;
  } catch (err) {
    await client.query('ROLLBACK');
    throw err;
  } finally {
    client.release();
  }
}

/**
 * Mark a task as failed (returns to pending for retry)
 */
export async function failTask(
  taskId: number,
  workerId: string,
  error?: string
): Promise<boolean> {
  const client = await pool.connect();
  try {
    await client.query('BEGIN');

    // Fail the task (may return to pending or mark as permanently failed)
    const { rows } = await client.query(
      `SELECT fail_task($1, $2, $3) as success`,
      [taskId, workerId, error || null]
    );

    if (rows[0]?.success) {
      // Update session counter
      await client.query(`SELECT session_task_failed($1)`, [workerId]);
    }

    await client.query('COMMIT');
    return rows[0]?.success || false;
  } catch (err) {
    await client.query('ROLLBACK');
    throw err;
  } finally {
    client.release();
  }
}

/**
 * Get current session for a worker
 */
export async function getWorkerSession(workerId: string): Promise<WorkerSession | null> {
  const { rows } = await pool.query(
    `SELECT * FROM get_worker_session($1)`,
    [workerId]
  );
  return rows[0] as WorkerSession || null;
}

/**
 * Check if worker session is complete (all 6 tasks done)
 */
export async function isSessionComplete(workerId: string): Promise<boolean> {
  const session = await getWorkerSession(workerId);
  if (!session) return true; // No session = complete

  const totalDone = session.tasks_completed + session.tasks_failed;
  return totalDone >= session.tasks_claimed;
}

/**
 * Retire a worker's session (start 8hr cooldown)
 */
export async function retireSession(workerId: string): Promise<boolean> {
  const { rows } = await pool.query(
    `SELECT retire_worker_session($1) as success`,
    [workerId]
  );
  console.log(`[WorkerSession] ${workerId} session retired, IP in ${COOLDOWN_HOURS}hr cooldown`);
  return rows[0]?.success || false;
}

/**
 * Release any claimed tasks back to pool (for worker shutdown)
 */
export async function releaseClaimedTasks(workerId: string): Promise<number> {
  const { rows } = await pool.query(
    `SELECT release_claimed_tasks($1) as count`,
    [workerId]
  );
  const count = rows[0]?.count || 0;
  if (count > 0) {
    console.log(`[WorkerSession] Released ${count} claimed tasks for ${workerId}`);
  }
  return count;
}

/**
 * Cleanup: release expired sessions from cooldown
 */
export async function releaseExpiredSessions(): Promise<number> {
  const { rows } = await pool.query(
    `SELECT release_expired_sessions() as count`
  );
  return rows[0]?.count || 0;
}

/**
 * Get session stats for monitoring
 */
export async function getSessionStats(): Promise<{
  active: number;
  cooldown: number;
  available: number;
  uniqueIps: number;
}> {
  const { rows } = await pool.query(`
    SELECT
      COUNT(*) FILTER (WHERE status = 'active') as active,
      COUNT(*) FILTER (WHERE status = 'cooldown') as cooldown,
      COUNT(*) FILTER (WHERE status = 'available') as available,
      COUNT(DISTINCT ip_address) as unique_ips
    FROM worker_sessions
  `);

  return {
    active: parseInt(rows[0]?.active || '0'),
    cooldown: parseInt(rows[0]?.cooldown || '0'),
    available: parseInt(rows[0]?.available || '0'),
    uniqueIps: parseInt(rows[0]?.unique_ips || '0'),
  };
}