import { Component, inject, OnDestroy } from '@angular/core';
import { CommonModule } from '@angular/common';
import { FormsModule } from '@angular/forms';
import { Router } from '@angular/router';
import { MatFormFieldModule } from '@angular/material/form-field';
import { MatInputModule } from '@angular/material/input';
import { MatButtonModule } from '@angular/material/button';
import { MatIconModule } from '@angular/material/icon';
import { MatProgressBarModule } from '@angular/material/progress-bar';
import { MatCardModule } from '@angular/material/card';
import { MatProgressSpinnerModule } from '@angular/material/progress-spinner';
import { MatSnackBar, MatSnackBarModule } from '@angular/material/snack-bar';
import { ApiService } from '../../services/api.service';
import { AuthService } from '../../services/auth.service';
import { Subject, takeUntil } from 'rxjs';

@Component({
  selector: 'app-user-info',
  standalone: true,
  imports: [
    CommonModule,
    FormsModule,
    MatFormFieldModule,
    MatInputModule,
    MatButtonModule,
    MatIconModule,
    MatProgressBarModule,
    MatCardModule,
    MatSnackBarModule,
    MatProgressSpinnerModule
  ],
  templateUrl: './user-info.component.html',
  styleUrls: ['./user-info.component.scss']
})
export class UserInfoComponent implements OnDestroy {
  private apiService = inject(ApiService);
  private authService = inject(AuthService);
  private snackBar = inject(MatSnackBar);
  private router = inject(Router);

  username = this.authService.getUsername() || '';
  currentPassword = '';
  newPassword = '';
  confirmPassword = '';
  saving = false;
  showCurrentPassword = false;
  showNewPassword = false;
  showConfirmPassword = false;
  
  // Memory leak prevention
  private destroyed$ = new Subject<void>();

  ngOnDestroy() {
    this.destroyed$.next();
    this.destroyed$.complete();
  }

  get passwordStrength(): { level: number; text: string; color: string } {
    if (!this.newPassword) {
      return { level: 0, text: '', color: '' };
    }

    let strength = 0;
    
    // Length check
    if (this.newPassword.length >= 8) strength++;
    if (this.newPassword.length >= 12) strength++;
    
    // Character variety
    if (/[a-z]/.test(this.newPassword)) strength++;
    if (/[A-Z]/.test(this.newPassword)) strength++;
    if (/[0-9]/.test(this.newPassword)) strength++;
    if (/[^a-zA-Z0-9]/.test(this.newPassword)) strength++;

    if (strength <= 2) {
      return { level: 33, text: 'Weak', color: 'warn' };
    } else if (strength <= 4) {
      return { level: 66, text: 'Medium', color: 'accent' };
    } else {
      return { level: 100, text: 'Strong', color: 'primary' };
    }
  }

  get isFormValid(): boolean {
    return !!this.currentPassword && 
           !!this.newPassword && 
           this.newPassword === this.confirmPassword && 
           this.newPassword.length >= 8;
  }

  changePassword() {
    if (!this.isFormValid || this.saving) return;

    this.saving = true;
    
    this.apiService.changePassword(this.currentPassword, this.newPassword)
      .pipe(takeUntil(this.destroyed$))
      .subscribe({
        next: () => {
          this.saving = false;
          
          // Clear form
          this.currentPassword = '';
          this.newPassword = '';
          this.confirmPassword = '';
          
          // Show success message
          this.snackBar.open(
            'Password changed successfully. Please login again.',
            'OK',
            { 
              duration: 5000,
              panelClass: ['success-snackbar']
            }
          ).afterDismissed().subscribe(() => {
            // Logout after password change
            this.authService.logout();
          });
        },
        error: (error) => {
          this.saving = false;
          
          // Handle validation errors
          if (error.status === 422 && error.error?.details) {
            // Field-level errors
            const fieldErrors = error.error.details;
            if (fieldErrors.some((e: any) => e.field === 'current_password')) {
              this.snackBar.open(
                'Current password is incorrect',
                'Close',
                { 
                  duration: 5000,
                  panelClass: ['error-snackbar']
                }
              );
            } else if (fieldErrors.some((e: any) => e.field === 'new_password')) {
              const pwError = fieldErrors.find((e: any) => e.field === 'new_password');
              this.snackBar.open(
                pwError.message || 'New password does not meet requirements',
                'Close',
                { 
                  duration: 5000,
                  panelClass: ['error-snackbar']
                }
              );
            }
          } else {
            // Generic error
            this.snackBar.open(
              error.error?.detail || 'Failed to change password',
              'Close',
              { 
                duration: 5000,
                panelClass: ['error-snackbar']
              }
            );
          }
        }
      });
  }

  togglePasswordVisibility(field: 'current' | 'new' | 'confirm') {
    switch(field) {
      case 'current':
        this.showCurrentPassword = !this.showCurrentPassword;
        break;
      case 'new':
        this.showNewPassword = !this.showNewPassword;
        break;
      case 'confirm':
        this.showConfirmPassword = !this.showConfirmPassword;
        break;
    }
  }
}