// Edge Functions
// Deploy and run functions at the edge (Vercel Edge, Cloudflare Workers)

import { EventEmitter } from 'events';

type EdgeRuntime = 'edge' | 'nodejs';
type EdgeRegion = 'auto' | 'iad1' | 'sfo1' | 'gru1' | 'fra1' | 'hkg1' | 'hnd1' | 'lhr1' | 'sin1' | 'syd1';

interface EdgeFunction {
  id: string;
  tenantId: string;
  name: string;
  slug: string;
  runtime: EdgeRuntime;
  entrypoint: string;
  code: string;
  envVars: Record<string, string>;
  regions: EdgeRegion[];
  status: 'building' | 'ready' | 'error' | 'disabled';
  deployment: {
    url?: string;
    deployedAt?: Date;
    version: string;
  };
  performance: {
    coldStart: number;
    avgDuration: number;
    invocations: number;
    errors: number;
  };
  createdAt: Date;
  updatedAt: Date;
}

interface EdgeExecution {
  id: string;
  functionId: string;
  region: string;
  status: 'success' | 'error' | 'timeout';
  duration: number;
  memory: number;
  input: Record<string, unknown>;
  output?: unknown;
  error?: string;
  logs: string[];
  timestamp: Date;
}

// Edge Functions Manager
export class EdgeFunctionsManager extends EventEmitter {
  private functions: Map<string, EdgeFunction> = new Map();
  private executions: Map<string, EdgeExecution[]> = new Map();

  // Create edge function
  create(config: Omit<EdgeFunction, 'id' | 'status' | 'deployment' | 'performance' | 'createdAt' | 'updatedAt'>): EdgeFunction {
    const fn: EdgeFunction = {
      ...config,
      id: crypto.randomUUID(),
      status: 'building',
      deployment: { version: '1.0.0' },
      performance: {
        coldStart: 0,
        avgDuration: 0,
        invocations: 0,
        errors: 0,
      },
      createdAt: new Date(),
      updatedAt: new Date(),
    };

    this.functions.set(fn.id, fn);
    this.emit('functionCreated', fn);
    
    // Auto-deploy
    this.deploy(fn.id);
    
    return fn;
  }

  // Deploy to edge
  async deploy(functionId: string): Promise<void> {
    const fn = this.functions.get(functionId);
    if (!fn) throw new Error('Function not found');

    fn.status = 'building';
    this.emit('deployStarted', fn);

    try {
      // Simulate build & deploy
      await new Promise(resolve => setTimeout(resolve, 3000));

      fn.status = 'ready';
      fn.deployment.deployedAt = new Date();
      fn.deployment.url = `https://${fn.slug}.edge.pazaryonetimi.com`;
      fn.updatedAt = new Date();

      this.emit('deployCompleted', fn);
    } catch (error) {
      fn.status = 'error';
      this.emit('deployFailed', { fn, error });
    }
  }

  // Execute edge function
  async invoke(
    functionId: string,
    input: {
      method?: string;
      headers?: Record<string, string>;
      body?: unknown;
      query?: Record<string, string>;
    },
    options: {
      region?: string;
    } = {}
  ): Promise<EdgeExecution> {
    const fn = this.functions.get(functionId);
    if (!fn) throw new Error('Function not found');
    if (fn.status !== 'ready') throw new Error('Function not ready');

    const startTime = Date.now();
    const execution: EdgeExecution = {
      id: crypto.randomUUID(),
      functionId,
      region: options.region || 'auto',
      status: 'success',
      duration: 0,
      memory: 128,
      input,
      logs: [],
      timestamp: new Date(),
    };

    try {
      // Simulate edge execution
      await new Promise(resolve => setTimeout(resolve, 50 + Math.random() * 100));

      execution.duration = Date.now() - startTime;
      execution.output = { success: true, data: input.body };

      // Update stats
      fn.performance.invocations++;
      fn.performance.avgDuration = 
        (fn.performance.avgDuration * (fn.performance.invocations - 1) + execution.duration) /
        fn.performance.invocations;

    } catch (error) {
      execution.status = 'error';
      execution.error = String(error);
      fn.performance.errors++;
    }

    // Store execution
    const executions = this.executions.get(functionId) || [];
    executions.unshift(execution);
    this.executions.set(functionId, executions.slice(0, 1000));

    this.emit('executionCompleted', execution);
    return execution;
  }

  // Get function by slug
  getBySlug(slug: string): EdgeFunction | null {
    return Array.from(this.functions.values()).find(f => f.slug === slug) || null;
  }

  // List functions for tenant
  list(tenantId: string): EdgeFunction[] {
    return Array.from(this.functions.values())
      .filter(f => f.tenantId === tenantId)
      .sort((a, b) => b.updatedAt.getTime() - a.updatedAt.getTime());
  }

  // Update code
  updateCode(functionId: string, code: string): EdgeFunction {
    const fn = this.functions.get(functionId);
    if (!fn) throw new Error('Function not found');

    fn.code = code;
    fn.updatedAt = new Date();
    fn.status = 'building';

    // Redeploy
    this.deploy(functionId);

    return fn;
  }

  // Delete function
  delete(functionId: string): void {
    this.functions.delete(functionId);
    this.executions.delete(functionId);
  }
}

// Export singleton
export const edgeFunctionsManager = new EdgeFunctionsManager();

export { EdgeFunction, EdgeExecution, EdgeRegion };