import { Injectable } from '@angular/core';
import { HttpClient, HttpErrorResponse, HttpHeaders } from '@angular/common/http';
import { Observable, catchError, throwError } from 'rxjs';
import { ExtractionResponse, ClaimRecord, UserAccount } from './extraction';

@Injectable({
  providedIn: 'root'
})
export class ExtractionService {
  private apiUrl = 'http://localhost:8000/api/v1';

  constructor(private http: HttpClient) { }

  getUsers(): Observable<UserAccount[]> {
    return this.http.get<UserAccount[]>(`${this.apiUrl}/users`)
      .pipe(
        catchError(this.handleError)
      );
  }

  createUser(user: UserAccount): Observable<UserAccount> {
    return this.http.post<UserAccount>(`${this.apiUrl}/users`, user)
      .pipe(
        catchError(this.handleError)
      );
  }

  extractData(file: File, userName: string = 'Demo User', department: string = 'R&D'): Observable<ExtractionResponse> {
    const formData = new FormData();
    formData.append('file', file);
    formData.append('user_name', userName);
    formData.append('department', department);

    return this.http.post<ExtractionResponse>(`${this.apiUrl}/extract`, formData)
      .pipe(
        catchError(this.handleError)
      );
  }

  submitClaim(extractionData: ExtractionResponse, userId: string): Observable<ClaimRecord> {
    const headers = new HttpHeaders({
      'user-id': userId
    });

    return this.http.post<ClaimRecord>(`${this.apiUrl}/claims`, extractionData, { headers })
      .pipe(
        catchError(this.handleError)
      );
  }

  getClaims(): Observable<ClaimRecord[]> {
    return this.http.get<ClaimRecord[]>(`${this.apiUrl}/claims`)
      .pipe(
        catchError(this.handleError)
      );
  }

  private handleError(error: HttpErrorResponse) {
    let errorMessage = 'An unknown error occurred!';
    if (error.error instanceof ErrorEvent) {
      errorMessage = `Error: ${error.error.message}`;
    } else {
      if (error.status === 504 || error.status === 0) {
        errorMessage = 'The request timed out. Please try again later.';
      } else if (error.status === 402) {
        errorMessage = 'AI extraction credits exhausted. Please contact support.';
      } else {
        errorMessage = `Error Code: ${error.status}\nMessage: ${error.message}`;
      }
    }
    return throwError(() => new Error(errorMessage));
  }
}