NowChess-Frontend/src/app/services/game-api.service.ts

import { Injectable, inject } from '@angular/core';
import { HttpClient, HttpParams } from '@angular/common/http';
import { Observable } from 'rxjs';
import { map } from 'rxjs/operators';
import { environment } from '../../environments/environment';
import {
  GameFull,
  GameState,
  GameStreamEvent,
  LegalMovesResponse,
  PlayerInfo,
} from '../models/game.models';
import { AnalysisRequest, AnalysisResponse, RawAnalysisResponse } from '../models/analysis.models';
import { StreamHandlerService } from './stream-handler.service';

@Injectable({ providedIn: 'root' })
export class GameApiService {
  private readonly apiBase = environment.apiBaseUrl;
  private readonly wsBase = environment.wsBaseUrl;
  private readonly apiPath = environment.apiPath;
  private readonly streamHandler = inject(StreamHandlerService);

  constructor(private readonly http: HttpClient) {}

  createGame(): Observable<GameFull> {
    return this.http.post<GameFull>(`${this.apiBase}${this.apiPath}`, {});
  }

  createGameVsBot(difficulty: 'easy' | 'medium' | 'hard' = 'medium'): Observable<GameFull> {
    const playerColor = Math.random() > 0.5 ? 'white' : 'black';
    const playerInfo: PlayerInfo = {
      id: `player-${Date.now()}`,
      displayName: 'You',
    };
    const botInfo: PlayerInfo = {
      id: `bot-${difficulty}`,
      displayName: `Bot (${difficulty})`,
    };

    const payload =
      playerColor === 'white'
        ? { white: playerInfo, black: botInfo }
        : { white: botInfo, black: playerInfo };

    return this.http.post<GameFull>(`${this.apiBase}${this.apiPath}/vs-bot`, payload);
  }

  getGame(gameId: string): Observable<GameFull> {
    return this.http.get<GameFull>(`${this.apiBase}${this.apiPath}/${gameId}`);
  }

  makeMove(gameId: string, uci: string): Observable<GameState> {
    return this.http.post<GameState>(`${this.apiBase}${this.apiPath}/${gameId}/move/${uci}`, {});
  }

  getLegalMoves(gameId: string, square?: string): Observable<LegalMovesResponse> {
    let params = new HttpParams();
    if (square) {
      params = params.set('square', square);
    }
    return this.http.get<LegalMovesResponse>(`${this.apiBase}${this.apiPath}/${gameId}/moves`, {
      params,
    });
  }

  importFen(fen: string): Observable<GameFull> {
    return this.http.post<GameFull>(`${this.apiBase}${this.apiPath}/import/fen`, { fen });
  }

  importPgn(pgn: string): Observable<GameFull> {
    return this.http.post<GameFull>(`${this.apiBase}${this.apiPath}/import/pgn`, { pgn });
  }

  resignGame(gameId: string): Observable<void> {
    return this.http.post<void>(`${this.apiBase}${this.apiPath}/${gameId}/resign`, {});
  }

  offerDraw(gameId: string): Observable<void> {
    return this.http.post<void>(`${this.apiBase}${this.apiPath}/${gameId}/draw/offer`, {});
  }

  getFenHistory(gameId: string): Observable<string[]> {
    return this.http
      .get<{ fens: string[] }>(`${this.apiBase}${this.apiPath}/${gameId}/fen-history`)
      .pipe(map((r) => r.fens));
  }

  analyzePosition(request: AnalysisRequest): Observable<AnalysisResponse> {
    return this.http
      .post<RawAnalysisResponse>(`${this.apiBase}/api/analysis/position`, request)
      .pipe(map((raw) => this.mapAnalysisResponse(raw)));
  }

  private mapAnalysisResponse(raw: RawAnalysisResponse): AnalysisResponse {
    const evalPawns = raw.evaluation / 100;
    return {
      eval: evalPawns,
      winChance: 1 / (1 + Math.exp(-0.374 * evalPawns)),
      depth: raw.depth,
      bestMove: raw.bestMove,
      mate: raw.mate,
      continuations: raw.continuationMoves ?? [],
    };
  }

  private resolveWsBase(): string {
    if (this.wsBase) {
      return this.wsBase;
    }

    const wsProtocol = window.location.protocol === 'https:' ? 'wss' : 'ws';
    return `${wsProtocol}://${window.location.host}`;
  }

  streamGame(gameId: string): Observable<GameStreamEvent> {
    const wsUrl = `${this.resolveWsBase()}${this.apiPath}/${gameId}/ws`;
    const token = localStorage.getItem('token') ?? '';
    return this.streamHandler.createGameStream(wsUrl, gameId, token);
  }
}