src/app/chat/api.service.ts

import { Injectable } from '@angular/core';
import { HttpClient, HttpHeaders } from '@angular/common/http';
import { Observable } from 'rxjs';

type Grade = 'lowergrade' | 'midgrade' | 'highergrade';
type DbLevel = 'low' | 'mid' | 'high';

function resolveBaseUrl(): string {
  const isHF = location.hostname.endsWith('hf.space');
  if (isHF) return 'https://pykara-py-learn-backend.hf.space/rag';
  if (location.hostname === 'localhost' || location.hostname === '127.0.0.1') {
    return 'http://localhost:5000/rag';
  }
  return '/rag';
}

@Injectable({ providedIn: 'root' })
export class ApiService {
  private baseUrl = resolveBaseUrl();

  private getGrade(): Grade {
    const g = (localStorage.getItem('gradeLevel') || 'highergrade').toLowerCase();
    if (g === 'lowergrade' || g === 'midgrade' || g === 'highergrade') return g as Grade;
    return 'highergrade';
  }
  private toDbLevel(g: Grade): DbLevel {
    return g === 'lowergrade' ? 'low' : g === 'midgrade' ? 'mid' : 'high';
  }
  private makeHeaders(g: Grade): HttpHeaders {
    return new HttpHeaders({
      'Content-Type': 'application/json',
      'X-User': g,
    });
  }

  constructor(private http: HttpClient) { }

  generateOpenQuestions(payload: { qtype: 'OPEN'; n?: number; topic?: string }): Observable<any> {
    const grade = this.getGrade();
    const headers = this.makeHeaders(grade);
    const body = {
      qtype: 'OPEN',
      n: payload.n ?? 5,
      topic: payload.topic ?? '',
      model: 'gpt-4o-mini',
      db_level: this.toDbLevel(grade),
    };
    return this.http.post<any>(`${this.baseUrl}/generate-questions`, body, { headers });
  }

  // Accept either a string (legacy) or an object { question, synthesize_audio, synthesize_video }
  explainGrammar(payload: string | any): Observable<any> {
    const grade = this.getGrade();
    const headers = this.makeHeaders(grade);

    // Normalize payload into an object
    const body = typeof payload === 'string' ? { question: payload } : { ...payload };

    // Ensure backend gets db_level and model so it selects the right vectorstore/LLM
    if (!body.db_level) body.db_level = this.toDbLevel(grade);
    if (!body.model) body.model = 'gpt-4o-mini';

    const url = `${this.baseUrl}/explain-grammar`;
    return this.http.post(url, body, { headers });
  }

  // ✅ Updated to carry source_ids so follow-ups stay in the same textbook pages
  suggestFollowups(payload: {
    last_question: string;
    last_answer: string;
    n?: number;
    source_ids?: string[];     // ← NEW
  }): Observable<any> {
    const grade = this.getGrade();
    const headers = this.makeHeaders(grade);
    const body = {
      last_question: payload.last_question,
      last_answer: payload.last_answer,
      n: payload.n ?? 5,
      model: 'gpt-4o-mini',
      db_level: this.toDbLevel(grade),
      source_ids: payload.source_ids ?? [],   // ← NEW
    };
    return this.http.post<any>(`${this.baseUrl}/suggest-followups`, body, { headers });
  }

  askQuestion(userInput: string, _sessionId: string | null): Observable<any> {
    return this.explainGrammar(userInput);
  }



  // add method in ApiService
  synthesizeAudio(text: string, language = 'en', referenceFiles?: string[]) {
    const payload: any = { text, language };
    if (referenceFiles) payload.reference_files = referenceFiles;
    return this.http.post<{ audio_url: string }>(`${this.baseUrl}/synthesize-audio`, payload);
  }

  // New: synthesize video (calls backend D-ID flow)
  synthesizeVideo(text: string, language = 'en') {
    const payload: any = { text, language };
    return this.http.post<{ video_url: string }>(`${this.baseUrl}/synthesize-video`, payload);
  }

  punctuate(text: string): Observable<any> {
    const headers = {
      'Content-Type': 'application/json',
      'X-User': localStorage.getItem('username') || ''
    };
    // Use the port your backend runs on (your local runner uses 7000)
    return this.http.post<any>(`${this.baseUrl}/punctuate`, { text }, { headers });
  }
}