import { Request, Response, NextFunction } from 'express';
import { z } from 'zod';
import { supabase } from '../config/supabase';
import { logError } from '../utils/logger';
import { logActivity } from '../services/activityLog';

export interface AuthRequest extends Request {
  userId?: string;
  userEmail?: string;
}

export const validateRequest = (schema: z.ZodSchema, target: 'body' | 'query' | 'params' = 'body') => {
  return (req: Request, res: Response, next: NextFunction) => {
    const result = schema.safeParse(req[target]);
    if (!result.success) {
      logActivity({
        action: 'SUSPICIOUS_INPUT',
        details: `Validation failed on ${target}: ${result.error.issues.map(i => i.message).join(', ')}`,
        ip: req.ip,
        user_agent: req.get('user-agent'),
      });
      res.status(400).json({
        success: false,
        error: {
          code: 'VALIDATION_ERROR',
          message: 'Invalid request data',
          details: result.error.flatten().fieldErrors,
        },
      });
      return;
    }
    req[target] = result.data;
    next();
  };
};

export const uuidParam = z.string().uuid();

export const authenticate = async (req: AuthRequest, res: Response, next: NextFunction) => {
  try {
    const authHeader = req.headers.authorization;

    if (!authHeader?.startsWith('Bearer ')) {
      logActivity({
        action: 'UNAUTHENTICATED_ACCESS',
        details: `Missing auth header on ${req.method} ${req.originalUrl}`,
        ip: req.ip,
        user_agent: req.get('user-agent'),
      });
      res.status(401).json({
        success: false,
        error: {
          code: 'UNAUTHORIZED',
          message: 'Missing or invalid authorization header',
        },
      });
      return;
    }

    const token = authHeader.split(' ')[1];

    const { data: { user }, error } = await supabase.auth.getUser(token);

    if (error || !user) {
      logActivity({
        action: 'INVALID_TOKEN',
        details: `Invalid/expired token on ${req.method} ${req.originalUrl}: ${error?.message || 'no user'}`,
        ip: req.ip,
        user_agent: req.get('user-agent'),
      });
      res.status(401).json({
        success: false,
        error: {
          code: 'UNAUTHORIZED',
          message: 'Invalid or expired token',
        },
      });
      return;
    }

    // Check if user is banned
    const { data: profile } = await supabase
      .from('profiles')
      .select('is_banned')
      .eq('id', user.id)
      .single();

    if (profile?.is_banned) {
      logActivity({
        user_id: user.id,
        action: 'BANNED_ACCESS_ATTEMPT',
        details: `Banned user accessed ${req.method} ${req.originalUrl}`,
        ip: req.ip,
        user_agent: req.get('user-agent'),
      });
      res.status(403).json({
        success: false,
        error: {
          code: 'ACCOUNT_BANNED',
          message: 'Your account has been suspended',
        },
      });
      return;
    }

    req.userId = user.id;
    req.userEmail = user.email;
    next();
  } catch {
    res.status(500).json({
      success: false,
      error: {
        code: 'INTERNAL_ERROR',
        message: 'Authentication failed',
      },
    });
  }
};

export const errorHandler = (err: Error, _req: Request, res: Response, _next: NextFunction) => {
  // Log full error server-side only — never expose to client
  logError(`Unhandled error: ${err.constructor.name}`, 'auth');

  res.status(500).json({
    success: false,
    error: {
      code: 'INTERNAL_ERROR',
      message: 'An unexpected error occurred',
    },
  });
};