import { Injectable } from '@angular/core';
import { BehaviorSubject, Observable } from 'rxjs';
import { SiteStructure, GenerationVersion } from '../core/models/llm';

export interface PromptEntry {
  originalPrompt: string;
  refinedPrompt: string | null;
  result: SiteStructure | null;
  timestamp: Date;
}

@Injectable({ providedIn: 'root' })
export class LlmSessionService {
  private currentPromptSubject = new BehaviorSubject<string>('');
  private currentResultSubject = new BehaviorSubject<SiteStructure | null>(null);
  private historySubject = new BehaviorSubject<PromptEntry[]>([]);
  private generatingSubject = new BehaviorSubject<boolean>(false);
  private errorSubject = new BehaviorSubject<string | null>(null);
  private versionsSubject = new BehaviorSubject<GenerationVersion[]>([]);
  private currentVersionIdSubject = new BehaviorSubject<string | null>(null);
  private loadingVersionsSubject = new BehaviorSubject<boolean>(false);

  currentPrompt$ = this.currentPromptSubject.asObservable();
  currentResult$ = this.currentResultSubject.asObservable();
  history$ = this.historySubject.asObservable();
  generating$ = this.generatingSubject.asObservable();
  error$ = this.errorSubject.asObservable();
  versions$ = this.versionsSubject.asObservable();
  currentVersionId$ = this.currentVersionIdSubject.asObservable();
  loadingVersions$ = this.loadingVersionsSubject.asObservable();

  get currentPrompt(): string { return this.currentPromptSubject.value; }
  get currentResult(): SiteStructure | null { return this.currentResultSubject.value; }
  get generating(): boolean { return this.generatingSubject.value; }
  get error(): string | null { return this.errorSubject.value; }
  get versions(): GenerationVersion[] { return this.versionsSubject.value; }
  get currentVersionId(): string | null { return this.currentVersionIdSubject.value; }

  setPrompt(prompt: string): void {
    this.currentPromptSubject.next(prompt);
    this.errorSubject.next(null);
  }

  setResult(result: SiteStructure): void {
    this.currentResultSubject.next(result);
    const entry: PromptEntry = {
      originalPrompt: this.currentPromptSubject.value,
      refinedPrompt: null,
      result,
      timestamp: new Date(),
    };
    const history = this.historySubject.value;
    this.historySubject.next([...history, entry]);
    this.generatingSubject.next(false);
    this.errorSubject.next(null);
  }

  clearResult(): void {
    this.currentResultSubject.next(null);
  }

  setGenerating(generating: boolean): void {
    this.generatingSubject.next(generating);
  }

  setError(error: string): void {
    this.errorSubject.next(error);
    this.generatingSubject.next(false);
  }

  clearError(): void {
    this.errorSubject.next(null);
  }

  clearHistory(): void {
    this.historySubject.next([]);
    this.currentResultSubject.next(null);
    this.currentPromptSubject.next('');
    this.currentVersionIdSubject.next(null);
    this.errorSubject.next(null);
  }

  setVersions(versions: GenerationVersion[]): void {
    this.versionsSubject.next(versions);
    this.loadingVersionsSubject.next(false);
  }

  setLoadingVersions(loading: boolean): void {
    this.loadingVersionsSubject.next(loading);
  }

  setCurrentVersionId(id: string | null): void {
    this.currentVersionIdSubject.next(id);
  }

  loadVersionData(structure: SiteStructure, versionId: string): void {
    this.currentResultSubject.next(structure);
    this.currentVersionIdSubject.next(versionId);
    this.generatingSubject.next(false);
    this.errorSubject.next(null);
  }
}