/**
 * Identity Management Service
 * Handles OAuth provider connections, disconnections, and password fallback
 */

import { supabase } from '@/integrations/supabase/client';
import type { UserIdentity as SupabaseUserIdentity } from '@supabase/supabase-js';
import type { 
  UserIdentity, 
  OAuthProvider, 
  IdentitySafetyCheck, 
  IdentityOperationResult 
} from '@/types/identity';

/**
 * Get all identities for the current user
 */
export async function getUserIdentities(): Promise<UserIdentity[]> {
  try {
    const { data, error } = await supabase.auth.getUserIdentities();
    
    if (error) throw error;
    
    return (data?.identities || []) as UserIdentity[];
  } catch (error: any) {
    console.error('[IdentityService] Failed to get identities:', error);
    return [];
  }
}

/**
 * Check if user has password authentication (email provider)
 */
export async function hasPasswordAuth(): Promise<boolean> {
  const identities = await getUserIdentities();
  return identities.some(identity => identity.provider === 'email');
}

/**
 * Check if it's safe to disconnect a provider
 * Returns safety information and reason if unsafe
 */
export async function checkDisconnectSafety(
  provider: OAuthProvider
): Promise<IdentitySafetyCheck> {
  const identities = await getUserIdentities();
  
  const hasPassword = identities.some(i => i.provider === 'email');
  const oauthIdentities = identities.filter(i => 
    i.provider !== 'email' && i.provider !== 'phone'
  );
  const totalIdentities = identities.length;
  
  // Can't disconnect if it's the only identity
  if (totalIdentities === 1) {
    return {
      canDisconnect: false,
      reason: 'last_identity',
      hasPasswordAuth: hasPassword,
      totalIdentities,
      oauthIdentities: oauthIdentities.length
    };
  }
  
  // Can't disconnect last OAuth provider if no password backup
  if (oauthIdentities.length === 1 && !hasPassword) {
    return {
      canDisconnect: false,
      reason: 'no_password_backup',
      hasPasswordAuth: hasPassword,
      totalIdentities,
      oauthIdentities: oauthIdentities.length
    };
  }
  
  return {
    canDisconnect: true,
    reason: 'safe',
    hasPasswordAuth: hasPassword,
    totalIdentities,
    oauthIdentities: oauthIdentities.length
  };
}

/**
 * Disconnect an OAuth identity from the user's account
 */
export async function disconnectIdentity(
  provider: OAuthProvider
): Promise<IdentityOperationResult> {
  try {
    // Safety check first
    const safetyCheck = await checkDisconnectSafety(provider);
    if (!safetyCheck.canDisconnect) {
      return {
        success: false,
        error: safetyCheck.reason === 'last_identity'
          ? 'Cannot disconnect your only login method'
          : 'Please set a password before disconnecting your last social login'
      };
    }
    
    // Get all identities to find the one to unlink
    const identities = await getUserIdentities();
    const identity = identities.find(i => i.provider === provider);
    
    if (!identity) {
      return {
        success: false,
        error: `No ${provider} identity found`
      };
    }
    
    // Unlink the identity - cast to Supabase's expected type
    const { error } = await supabase.auth.unlinkIdentity(identity as SupabaseUserIdentity);
    
    if (error) throw error;
    
    // Log audit event
    const { data: { user } } = await supabase.auth.getUser();
    if (user) {
      await logIdentityChange(user.id, 'identity_disconnected', { provider });
    }
    
    return { success: true };
  } catch (error: any) {
    console.error('[IdentityService] Failed to disconnect identity:', error);
    return {
      success: false,
      error: error.message || 'Failed to disconnect identity'
    };
  }
}

/**
 * Connect an OAuth identity to the user's account
 */
export async function connectIdentity(
  provider: OAuthProvider,
  redirectTo?: string
): Promise<IdentityOperationResult> {
  try {
    const { error } = await supabase.auth.signInWithOAuth({
      provider,
      options: {
        redirectTo: redirectTo || `${window.location.origin}/settings?tab=security`,
        skipBrowserRedirect: false
      }
    });
    
    if (error) throw error;
    
    return { success: true };
  } catch (error: any) {
    console.error('[IdentityService] Failed to connect identity:', error);
    return {
      success: false,
      error: error.message || `Failed to connect ${provider} account`
    };
  }
}

/**
 * Wait for email provider to be created after password addition
 * Supabase takes time to create the email identity, so we poll with retries
 */
async function waitForEmailProvider(maxRetries = 6): Promise<boolean> {
  const delays = [500, 1000, 1500, 2000, 2500, 3000]; // ~10.5s total
  
  for (let i = 0; i < maxRetries; i++) {
    const identities = await getUserIdentities();
    const hasEmail = identities.some(id => id.provider === 'email');
    
    if (hasEmail) {
      console.log(`[IdentityService] Email provider found after ${i + 1} attempts`);
      return true;
    }
    
    console.log(`[IdentityService] Email provider not found, attempt ${i + 1}/${maxRetries}`);
    
    if (i < maxRetries - 1) {
      await new Promise(resolve => setTimeout(resolve, delays[i]));
    }
  }
  
  console.error('[IdentityService] Email provider not found after max retries');
  return false;
}

/**
 * Add password authentication to an OAuth-only account
 * Automatically creates email identity by signing in immediately after setting password
 */
export async function addPasswordToAccount(
  password: string
): Promise<IdentityOperationResult> {
  try {
    // Validate password strength
    if (password.length < 8) {
      return {
        success: false,
        error: 'Password must be at least 8 characters long'
      };
    }
    
    const { data: { user } } = await supabase.auth.getUser();
    const userEmail = user?.email;
    
    if (!userEmail) {
      return {
        success: false,
        error: 'No email address found on your account'
      };
    }
    
    // Step 1: Update password
    console.log('[IdentityService] Setting password for user');
    const { error: updateError } = await supabase.auth.updateUser({ password });
    if (updateError) throw updateError;
    
    // Step 2: Log the password addition
    await logIdentityChange(user!.id, 'password_added', { 
      method: 'oauth_with_relogin_required' 
    });
    
    // Step 3: Sign the user out so they can sign back in with email/password
    console.log('[IdentityService] Signing user out to force re-login');
    await supabase.auth.signOut();
    
    // Return success with relogin flag
    return { 
      success: true,
      needsRelogin: true,
      email: userEmail
    };
    
  } catch (error: any) {
    console.error('[IdentityService] Failed to add password:', error);
    return {
      success: false,
      error: error.message || 'Failed to set password'
    };
  }
}

/**
 * Check if user has an orphaned password (password exists but no email identity)
 */
export async function hasOrphanedPassword(): Promise<boolean> {
  const identities = await getUserIdentities();
  const hasEmailIdentity = identities.some(i => i.provider === 'email');
  
  if (hasEmailIdentity) return false;
  
  // If user has OAuth identities but no email identity, they might have an orphaned password
  return identities.length > 0 && !hasEmailIdentity;
}

/**
 * Re-verify password authentication by attempting sign-in
 * This forces Supabase to create the email identity if it's missing
 */
export async function reverifyPasswordAuth(
  email: string,
  password: string
): Promise<IdentityOperationResult> {
  try {
    const { error } = await supabase.auth.signInWithPassword({
      email,
      password
    });
    
    if (error) throw error;
    
    // Check if email identity was created
    const emailCreated = await waitForEmailProvider(3);
    
    if (!emailCreated) {
      return {
        success: false,
        error: 'Sign-in successful but identity verification failed. Please contact support.'
      };
    }
    
    return { success: true };
  } catch (error: any) {
    return {
      success: false,
      error: error.message || 'Failed to verify password authentication'
    };
  }
}

/**
 * Log identity changes to audit log
 */
async function logIdentityChange(
  userId: string,
  action: string,
  details: Record<string, any>
): Promise<void> {
  try {
    await supabase.rpc('log_admin_action', {
      _admin_user_id: userId,
      _target_user_id: userId,
      _action: action,
      _details: details
    });
  } catch (error) {
    console.error('[IdentityService] Failed to log audit event:', error);
    // Don't fail the operation if audit logging fails
  }
}