/**
 * Revocation Service
 * Based on: docs/foundation/Agent_Governance_Protocol_v1.md
 * 
 * Handles agent revocation, suspension, and reinstatement
 */

import { db } from '../../infra/db/client';
import { logger } from '../../infra/logger/logger';
import { v4 as uuidv4 } from 'uuid';
import {
  RevokeAgentRequest,
  RevocationType,
  RevocationEffect,
  AgentRevocation,
  GovernanceScope,
} from '../../domain/governance/types';
import { permissionEngine, buildContext } from './permissions';
import { governanceService } from './governance.service';

export class RevocationService {
  /**
   * Revoke an agent
   */
  async revokeAgent(request: RevokeAgentRequest): Promise<{
    success: boolean;
    revocationId?: string;
    error?: string;
  }> {
    const context = await buildContext(request.actorId, request.scope);
    
    // Check permission
    const canRevoke = await permissionEngine.canRevokeAgent(context, request.targetId);
    
    if (!canRevoke.allowed) {
      logger.warn(`Revocation denied: ${request.actorId} → ${request.targetId}`, {
        reason: canRevoke.reason,
      });
      return { success: false, error: canRevoke.reason };
    }
    
    try {
      const revocationId = uuidv4();
      
      // Get target agent DAIS ID
      const agent = await db.query<{ dais_identity_id: string }>(
        `SELECT dais_identity_id FROM agents WHERE id = $1`,
        [request.targetId]
      );
      
      const daisId = agent.rows[0]?.dais_identity_id;
      
      // Determine what to revoke based on type
      const effect = this.getRevocationEffect(request.revocationType);
      
      // Start transaction
      await db.query('BEGIN');
      
      try {
        // Update agent status
        const status = request.revocationType === 'shadow' ? 'active' : 'revoked';
        
        await db.query(
          `UPDATE agents 
           SET status = $1, 
               revoked_at = now(), 
               revoked_by = $2, 
               revocation_reason = $3,
               revocation_type = $4,
               updated_at = now()
           WHERE id = $5`,
          [status, request.actorId, request.reason, request.revocationType, request.targetId]
        );
        
        // Invalidate DAIS keys if applicable
        if (effect.daisKeysInvalidated && daisId) {
          await db.query(
            `UPDATE dais_keys 
             SET revoked = true, 
                 revoked_at = now(), 
                 revoked_by = $1,
                 revoked_reason = $2
             WHERE dais_id = $3 AND revoked = false`,
            [request.actorId, request.reason, daisId]
          );
        }
        
        // Terminate assignments if applicable
        if (effect.assignmentsTerminated) {
          await db.query(
            `UPDATE agent_assignments 
             SET end_ts = now()
             WHERE agent_id = $1 AND end_ts IS NULL`,
            [request.targetId]
          );
        }
        
        // Create revocation record
        await db.query(
          `INSERT INTO agent_revocations (
            id, agent_id, dais_id, revoked_by, revocation_type, reason, scope,
            keys_invalidated, wallet_disabled, room_access_revoked,
            node_privileges_removed, assignments_terminated, reversible
          ) VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13)`,
          [
            revocationId,
            request.targetId,
            daisId,
            request.actorId,
            request.revocationType,
            request.reason,
            request.scope,
            effect.daisKeysInvalidated,
            effect.walletSigningDisabled,
            effect.roomAccessRevoked,
            effect.nodePrivilegesRemoved,
            effect.assignmentsTerminated,
            request.revocationType !== 'hard',
          ]
        );
        
        await db.query('COMMIT');
        
        // Log governance event
        await governanceService.logEvent('agent.revoked', request.actorId, request.targetId, request.scope, {
          revocationId,
          revocationType: request.revocationType,
          reason: request.reason,
          effect,
        });
        
        logger.info(`Agent revoked: ${request.targetId}`, {
          actorId: request.actorId,
          revocationType: request.revocationType,
        });
        
        return { success: true, revocationId };
      } catch (error) {
        await db.query('ROLLBACK');
        throw error;
      }
    } catch (error) {
      logger.error('Failed to revoke agent', error);
      throw error;
    }
  }

  /**
   * Suspend an agent temporarily
   */
  async suspendAgent(
    actorId: string,
    targetId: string,
    reason: string,
    scope: GovernanceScope,
    durationHours?: number
  ): Promise<{ success: boolean; error?: string }> {
    const context = await buildContext(actorId, scope);
    
    // Check permission
    const canRevoke = await permissionEngine.canRevokeAgent(context, targetId);
    if (!canRevoke.allowed) {
      return { success: false, error: canRevoke.reason };
    }
    
    try {
      await db.query(
        `UPDATE agents 
         SET status = 'suspended', 
             revoked_at = now(),
             revoked_by = $1,
             revocation_reason = $2,
             revocation_type = 'soft',
             updated_at = now()
         WHERE id = $3`,
        [actorId, reason, targetId]
      );
      
      await governanceService.logEvent('agent.revoked', actorId, targetId, scope, {
        action: 'suspended',
        reason,
        durationHours,
      });
      
      logger.info(`Agent suspended: ${targetId}`, { actorId, durationHours });
      
      return { success: true };
    } catch (error) {
      logger.error('Failed to suspend agent', error);
      throw error;
    }
  }

  /**
   * Reinstate a revoked/suspended agent
   */
  async reinstateAgent(
    actorId: string,
    targetId: string,
    scope: GovernanceScope,
    reason?: string
  ): Promise<{ success: boolean; error?: string }> {
    const context = await buildContext(actorId, scope);
    
    // Check actor has sufficient level
    if (context.actorLevel !== 'city_governance' && context.actorLevel !== 'district_lead') {
      return { success: false, error: 'Only City Governance or District Lead can reinstate agents' };
    }
    
    try {
      // Check if revocation is reversible
      const revocation = await db.query<{ reversible: boolean; revocation_type: RevocationType }>(
        `SELECT reversible, revocation_type FROM agent_revocations 
         WHERE agent_id = $1 AND reversed_at IS NULL
         ORDER BY created_at DESC LIMIT 1`,
        [targetId]
      );
      
      if (revocation.rows.length === 0) {
        return { success: false, error: 'No active revocation found' };
      }
      
      if (!revocation.rows[0].reversible) {
        return { success: false, error: 'This revocation is not reversible (hard revocation)' };
      }
      
      await db.query('BEGIN');
      
      try {
        // Restore agent status
        await db.query(
          `UPDATE agents 
           SET status = 'active',
               revoked_at = NULL,
               revoked_by = NULL,
               revocation_reason = NULL,
               revocation_type = NULL,
               updated_at = now()
           WHERE id = $1`,
          [targetId]
        );
        
        // Mark revocation as reversed
        await db.query(
          `UPDATE agent_revocations 
           SET reversed_at = now(), reversed_by = $1
           WHERE agent_id = $2 AND reversed_at IS NULL`,
          [actorId, targetId]
        );
        
        await db.query('COMMIT');
        
        await governanceService.logEvent('agent.reinstated', actorId, targetId, scope, {
          reason,
        });
        
        logger.info(`Agent reinstated: ${targetId}`, { actorId });
        
        return { success: true };
      } catch (error) {
        await db.query('ROLLBACK');
        throw error;
      }
    } catch (error) {
      logger.error('Failed to reinstate agent', error);
      throw error;
    }
  }

  /**
   * Revoke DAIS keys
   */
  async revokeDaisKeys(
    actorId: string,
    daisId: string,
    reason: string
  ): Promise<{ success: boolean; keysRevoked: number; error?: string }> {
    try {
      // Get actor level
      const actorLevel = await permissionEngine.getAgentLevel(actorId);
      
      // Only City Governance, District Lead, or Orchestrator can revoke keys
      if (!['city_governance', 'district_lead', 'orchestrator'].includes(actorLevel)) {
        return { success: false, keysRevoked: 0, error: 'Insufficient permissions to revoke keys' };
      }
      
      const result = await db.query(
        `UPDATE dais_keys 
         SET revoked = true, revoked_at = now(), revoked_by = $1, revoked_reason = $2
         WHERE dais_id = $3 AND revoked = false
         RETURNING id`,
        [actorId, reason, daisId]
      );
      
      logger.info(`DAIS keys revoked: ${daisId}`, { actorId, count: result.rowCount });
      
      return { success: true, keysRevoked: result.rowCount || 0 };
    } catch (error) {
      logger.error('Failed to revoke DAIS keys', error);
      throw error;
    }
  }

  /**
   * Get revocation history for an agent
   */
  async getRevocationHistory(agentId: string): Promise<AgentRevocation[]> {
    const result = await db.query<AgentRevocation>(
      `SELECT * FROM agent_revocations WHERE agent_id = $1 ORDER BY created_at DESC`,
      [agentId]
    );
    
    return result.rows;
  }

  /**
   * Get revocation effect based on type
   */
  private getRevocationEffect(type: RevocationType): RevocationEffect {
    switch (type) {
      case 'hard':
        return {
          daisKeysInvalidated: true,
          walletSigningDisabled: true,
          roomAccessRevoked: true,
          nodePrivilegesRemoved: true,
          assignmentsTerminated: true,
        };
      case 'soft':
        return {
          daisKeysInvalidated: false,
          walletSigningDisabled: true,
          roomAccessRevoked: true,
          nodePrivilegesRemoved: true,
          assignmentsTerminated: true,
        };
      case 'shadow':
        return {
          daisKeysInvalidated: false,
          walletSigningDisabled: false,
          roomAccessRevoked: false,
          nodePrivilegesRemoved: false,
          assignmentsTerminated: false,
        };
    }
  }
}

export const revocationService = new RevocationService();