import { Component, EventEmitter, Output, inject, OnInit, OnDestroy } from '@angular/core';
import { CommonModule } from '@angular/common';
import { HttpClient } from '@angular/common/http';
import { MatProgressSpinnerModule } from '@angular/material/progress-spinner';
import { MatButtonModule } from '@angular/material/button';
import { MatIconModule } from '@angular/material/icon';
import { MatPaginatorModule, PageEvent } from '@angular/material/paginator';
import { MatListModule } from '@angular/material/list';
import { MatCardModule } from '@angular/material/card';
import { MatDividerModule } from '@angular/material/divider';
import { Subject, takeUntil } from 'rxjs';
import { MatSnackBar, MatSnackBarModule } from '@angular/material/snack-bar';

interface ActivityLog {
  id: number;
  timestamp: string;
  user: string;
  action: string;
  entity_type: string;
  entity_id: any;
  entity_name: string;
  details?: string;
}

interface ActivityLogResponse {
  items: ActivityLog[];
  total: number;
  page: number;
  limit: number;
  pages: number;
}

@Component({
  selector: 'app-activity-log',
  standalone: true,
  imports: [
    CommonModule, 
    MatProgressSpinnerModule,
    MatButtonModule,
    MatIconModule,
    MatPaginatorModule,
    MatListModule,
    MatCardModule,
    MatDividerModule,
    MatSnackBarModule
  ],
  template: `
    <mat-card class="activity-log-dropdown" (click)="$event.stopPropagation()">
      <mat-card-header>
        <mat-card-title>
          <mat-icon>notifications</mat-icon>
          Recent Activities
        </mat-card-title>
        <button mat-icon-button (click)="close.emit(); $event.stopPropagation()">
          <mat-icon>close</mat-icon>
        </button>
      </mat-card-header>
      
      <mat-card-content>
        @if (loading && activities.length === 0) {
          <div class="loading">
            <mat-spinner diameter="30"></mat-spinner>
          </div>
        } @else if (error && activities.length === 0) {
          <div class="error-state">
            <mat-icon>error_outline</mat-icon>
            <p>{{ error }}</p>
            <button mat-button (click)="retry()">
              <mat-icon>refresh</mat-icon>
              Retry
            </button>
          </div>
        } @else if (activities.length === 0) {
          <div class="empty">
            <mat-icon>inbox</mat-icon>
            <p>No activities found</p>
          </div>
        } @else {
          <mat-list class="activity-list">
            @for (activity of activities; track activity.id) {
              <mat-list-item>
                <mat-icon matListItemIcon>{{ getActivityIcon(activity.action) }}</mat-icon>
                <div matListItemTitle>
                  <span class="activity-time">{{ getRelativeTime(activity.timestamp) }}</span>
                </div>
                <div matListItemLine>
                  <strong>{{ activity.user }}</strong> {{ getActionText(activity) }}
                  <em>{{ activity.entity_name }}</em>
                  @if (activity.details) {
                    <span class="details">• {{ activity.details }}</span>
                  }
                </div>
              </mat-list-item>
              @if (!$last) {
                <mat-divider></mat-divider>
              }
            }
          </mat-list>
        }
      </mat-card-content>
      
      <mat-card-actions *ngIf="totalItems > pageSize">
        <mat-paginator
          [length]="totalItems"
          [pageSize]="pageSize"
          [pageIndex]="currentPage - 1"
          [pageSizeOptions]="[10, 25, 50]"
          (page)="onPageChange($event)"
          showFirstLastButtons>
        </mat-paginator>
      </mat-card-actions>
      
      <mat-card-actions *ngIf="totalItems <= pageSize && activities.length > 0">
        <button mat-button (click)="openFullView()" class="full-width">
          <mat-icon>open_in_new</mat-icon>
          View All Activities
        </button>
      </mat-card-actions>
    </mat-card>
  `,
  styles: [`
    .activity-log-dropdown {
      width: 450px;
      max-height: 600px;
      display: flex;
      flex-direction: column;
      overflow: hidden;
    }

    mat-card-header {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 16px;
      background-color: #424242;
      color: white;
    
      mat-card-title {
        margin: 0;
        display: flex;
        align-items: center;
        gap: 8px;
        font-size: 18px;
        color: white;
    
        mat-icon {
          font-size: 24px;
          width: 24px;
          height: 24px;
          color: white;
        }
      }
    
      button {
        color: white;
      }
    }

    mat-card-content {
      flex: 1;
      overflow-y: auto;
      padding: 0;
      min-height: 200px;
      max-height: 400px;
    }

    .activity-list {
      padding: 0;

      mat-list-item {
        height: auto;
        min-height: 72px;
        padding: 12px 16px;

        &:hover {
          background-color: #f5f5f5;
        }

        .activity-time {
          font-size: 12px;
          color: #666;
        }

        strong {
          color: #1976d2;
          margin-right: 4px;
        }

        em {
          color: #673ab7;
          font-style: normal;
          font-weight: 500;
          margin: 0 4px;
        }

        .details {
          color: #666;
          font-size: 12px;
          margin-left: 4px;
        }
      }
    }

    mat-card-actions {
      padding: 0;
      margin: 0;

      mat-paginator {
        background: transparent;
      }

      .full-width {
        width: 100%;
        margin: 0;
      }
    }

    .loading, .empty, .error-state {
      padding: 60px 20px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      color: #666;

      mat-icon {
        font-size: 48px;
        width: 48px;
        height: 48px;
        color: #e0e0e0;
        margin-bottom: 16px;
      }

      p {
        margin: 0 0 16px;
        font-size: 14px;
      }
    }

    .error-state {
      mat-icon {
        color: #f44336;
      }
    }

    ::ng-deep {
      .mat-mdc-list-item-unscoped-content {
        display: block;
      }

      .mat-mdc-paginator {
        .mat-mdc-paginator-container {
          padding: 8px;
          justify-content: center;
        }
      }
    }
  `]
})
export class ActivityLogComponent implements OnInit, OnDestroy {
  @Output() close = new EventEmitter<void>();

  private http = inject(HttpClient);
  private snackBar = inject(MatSnackBar);
  private destroyed$ = new Subject<void>();

  activities: ActivityLog[] = [];
  loading = false;
  error = '';
  currentPage = 1;
  pageSize = 10;
  totalItems = 0;
  totalPages = 0;

  ngOnInit() {
    this.loadActivities();
  }

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

  loadActivities(page: number = 1) {
    this.loading = true;
    this.error = '';
    this.currentPage = page;
    
    // Backend sadece limit parametresi alıyor, page almıyor
    const limit = this.pageSize * page; // Toplam kaç kayıt istediğimizi hesapla
    
    this.http.get<ActivityLog[]>(
      `/api/activity-log?limit=${limit}`
    ).pipe(
      takeUntil(this.destroyed$)
    ).subscribe({
      next: (response) => {
        try {
          // Response direkt array olarak geliyor
          const allActivities = response || [];
          
          // Manual pagination yap
          const startIndex = (page - 1) * this.pageSize;
          const endIndex = startIndex + this.pageSize;
          
          this.activities = allActivities.slice(startIndex, endIndex);
          this.totalItems = allActivities.length;
          this.totalPages = Math.ceil(allActivities.length / this.pageSize);
          this.loading = false;
        } catch (err) {
          console.error('Failed to process activities:', err);
          this.error = 'Failed to process activity data';
          this.activities = [];
          this.loading = false;
        }
      },
      error: (error) => {
        console.error('Failed to load activities:', error);
        this.error = this.getErrorMessage(error);
        this.activities = [];
        this.loading = false;
        
        // Show error in snackbar
        this.snackBar.open(this.error, 'Close', {
          duration: 5000,
          panelClass: 'error-snackbar'
        });
      }
    });
  }

  onPageChange(event: PageEvent) {
    this.pageSize = event.pageSize;
    this.loadActivities(event.pageIndex + 1);
  }

  openFullView() {
    // TODO: Implement full activity log view
    console.log('Open full activity log view');
    this.close.emit();
  }

  retry() {
    this.loadActivities(this.currentPage);
  }

  getRelativeTime(timestamp: string): string {
    try {
      const date = new Date(timestamp);
      const now = new Date();
      const diffMs = now.getTime() - date.getTime();
      const diffMins = Math.floor(diffMs / 60000);
      const diffHours = Math.floor(diffMs / 3600000);
      const diffDays = Math.floor(diffMs / 86400000);

      if (diffMs < 0) return 'just now'; // Future dates
      if (diffMins < 1) return 'just now';
      if (diffMins < 60) return `${diffMins} min ago`;
      if (diffHours < 24) return `${diffHours} hour${diffHours > 1 ? 's' : ''} ago`;
      if (diffDays < 7) return `${diffDays} day${diffDays > 1 ? 's' : ''} ago`;

      return date.toLocaleDateString();
    } catch (err) {
      console.error('Invalid timestamp:', timestamp, err);
      return 'Unknown';
    }
  }

  getActionText(activity: ActivityLog): string {
    const actions: Record<string, string> = {
      'CREATE_PROJECT': 'created project',
      'UPDATE_PROJECT': 'updated project',
      'DELETE_PROJECT': 'deleted project',
      'ENABLE_PROJECT': 'enabled project',
      'DISABLE_PROJECT': 'disabled project',
      'PUBLISH_VERSION': 'published version of',
      'CREATE_VERSION': 'created version for',
      'UPDATE_VERSION': 'updated version of',
      'DELETE_VERSION': 'deleted version from',
      'CREATE_API': 'created API',
      'UPDATE_API': 'updated API',
      'DELETE_API': 'deleted API',
      'UPDATE_ENVIRONMENT': 'updated environment',
      'IMPORT_PROJECT': 'imported project',
      'CHANGE_PASSWORD': 'changed password',
      'LOGIN': 'logged in',
      'LOGOUT': 'logged out',
      'FAILED_LOGIN': 'failed login attempt'
    };

    return actions[activity.action] || activity.action.toLowerCase().replace(/_/g, ' ');
  }

  getActivityIcon(action: string): string {
    if (action.includes('CREATE')) return 'add_circle';
    if (action.includes('UPDATE')) return 'edit';
    if (action.includes('DELETE')) return 'delete';
    if (action.includes('ENABLE')) return 'check_circle';
    if (action.includes('DISABLE')) return 'cancel';
    if (action.includes('PUBLISH')) return 'publish';
    if (action.includes('IMPORT')) return 'cloud_upload';
    if (action.includes('PASSWORD')) return 'lock';
    if (action.includes('LOGIN')) return 'login';
    if (action.includes('LOGOUT')) return 'logout';
    return 'info';
  }

  trackByActivityId(index: number, activity: ActivityLog): number {
    return activity.id;
  }
  
  isLast(activity: ActivityLog): boolean {
    return this.activities.indexOf(activity) === this.activities.length - 1;
  }

  private getErrorMessage(error: any): string {
    if (error.status === 0) {
      return 'Unable to connect to server. Please check your connection.';
    } else if (error.status === 401) {
      return 'Session expired. Please login again.';
    } else if (error.status === 403) {
      return 'You do not have permission to view activity logs.';
    } else if (error.error?.detail) {
      return error.error.detail;
    } else if (error.message) {
      return error.message;
    }
    return 'Failed to load activities. Please try again.';
  }
}