import {
  mapCalculateScoresResponse,
  mapFinishGameResponse,
  mapHealthResponse,
  mapJoinSessionResponse,
  mapMixAnswersResponse,
  mapScoreboardResponse,
  mapSessionDetailResponse,
  mapShowQuestionResponse,
  mapStartNextRoundResponse,
  mapStartRoundResponse,
  mapSubmitGuessResponse,
  mapSubmitLieResponse
} from './mappers';
import type {
  ApiResult,
  CalculateScoresResponse,
  FinishGameResponse,
  HealthResponse,
  JoinSessionRequest,
  JoinSessionResponse,
  MixAnswersResponse,
  ScoreboardResponse,
  SessionDetailResponse,
  ShowQuestionResponse,
  StartNextRoundResponse,
  StartRoundRequest,
  StartRoundResponse,
  SubmitGuessRequest,
  SubmitGuessResponse,
  SubmitLieRequest,
  SubmitLieResponse
} from './types';

export interface ApiClient {
  health(): Promise<ApiResult<HealthResponse>>;
  getSession(code: string): Promise<ApiResult<SessionDetailResponse>>;
  joinSession(payload: JoinSessionRequest): Promise<ApiResult<JoinSessionResponse>>;
  startRound(code: string, payload: StartRoundRequest): Promise<ApiResult<StartRoundResponse>>;
  showQuestion(code: string): Promise<ApiResult<ShowQuestionResponse>>;
  mixAnswers(code: string, roundQuestionId: number): Promise<ApiResult<MixAnswersResponse>>;
  calculateScores(code: string, roundQuestionId: number): Promise<ApiResult<CalculateScoresResponse>>;
  getScoreboard(code: string): Promise<ApiResult<ScoreboardResponse>>;
  startNextRound(code: string): Promise<ApiResult<StartNextRoundResponse>>;
  finishGame(code: string): Promise<ApiResult<FinishGameResponse>>;
  submitLie(code: string, roundQuestionId: number, payload: SubmitLieRequest): Promise<ApiResult<SubmitLieResponse>>;
  submitGuess(code: string, roundQuestionId: number, payload: SubmitGuessRequest): Promise<ApiResult<SubmitGuessResponse>>;
}

export function createApiClient(baseUrl = '', fetchImpl: typeof fetch = fetch): ApiClient {
  async function request<T>(
    path: string,
    method: 'GET' | 'POST',
    mapper: (payload: unknown) => T,
    payload?: unknown
  ): Promise<ApiResult<T>> {
    let response: Response;
    try {
      response = await fetchImpl(`${baseUrl}${path}`, {
        method,
        headers: {
          Accept: 'application/json',
          ...(payload === undefined ? {} : { 'Content-Type': 'application/json' })
        },
        ...(payload === undefined ? {} : { body: JSON.stringify(payload) })
      });
    } catch {
      return {
        ok: false,
        status: 0,
        error: { kind: 'network', status: 0, message: 'Network error while contacting API' }
      };
    }

    let responsePayload: unknown;
    try {
      responsePayload = await response.json();
    } catch {
      return {
        ok: false,
        status: response.status,
        error: { kind: 'parse', status: response.status, message: 'Invalid JSON response from API' }
      };
    }

    if (!response.ok) {
      return {
        ok: false,
        status: response.status,
        error: {
          kind: 'http',
          status: response.status,
          message: `HTTP ${response.status}`,
          payload: responsePayload
        }
      };
    }

    try {
      return { ok: true, status: response.status, data: mapper(responsePayload) };
    } catch (error) {
      return {
        ok: false,
        status: response.status,
        error: {
          kind: 'parse',
          status: response.status,
          message: error instanceof Error ? error.message : 'Invalid API response contract',
          payload: responsePayload
        }
      };
    }
  }

  const normalizeCode = (value: string): string => value.trim().toUpperCase();

  return {
    health: () => request<HealthResponse>('/healthz', 'GET', mapHealthResponse),
    getSession: (code: string) =>
      request<SessionDetailResponse>(
        `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}`,
        'GET',
        mapSessionDetailResponse
      ),
    joinSession: (payload: JoinSessionRequest) =>
      request<JoinSessionResponse>(
        '/lobby/sessions/join',
        'POST',
        mapJoinSessionResponse,
        {
          code: normalizeCode(payload.code),
          nickname: payload.nickname.trim()
        }
      ),
    startRound: (code: string, payload: StartRoundRequest) =>
      request<StartRoundResponse>(
        `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/rounds/start`,
        'POST',
        mapStartRoundResponse,
        payload
      ),
    showQuestion: (code: string) =>
      request<ShowQuestionResponse>(
        `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/questions/show`,
        'POST',
        mapShowQuestionResponse,
        {}
      ),
    mixAnswers: (code: string, roundQuestionId: number) =>
      request<MixAnswersResponse>(
        `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/questions/${roundQuestionId}/answers/mix`,
        'POST',
        mapMixAnswersResponse,
        {}
      ),
    calculateScores: (code: string, roundQuestionId: number) =>
      request<CalculateScoresResponse>(
        `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/questions/${roundQuestionId}/scores/calculate`,
        'POST',
        mapCalculateScoresResponse,
        {}
      ),
    getScoreboard: (code: string) =>
      request<ScoreboardResponse>(
        `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/scoreboard`,
        'GET',
        mapScoreboardResponse
      ),
    startNextRound: (code: string) =>
      request<StartNextRoundResponse>(
        `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/rounds/next`,
        'POST',
        mapStartNextRoundResponse,
        {}
      ),
    finishGame: (code: string) =>
      request<FinishGameResponse>(
        `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/finish`,
        'POST',
        mapFinishGameResponse,
        {}
      ),
    submitLie: (code: string, roundQuestionId: number, payload: SubmitLieRequest) =>
      request<SubmitLieResponse>(
        `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/questions/${roundQuestionId}/lies/submit`,
        'POST',
        mapSubmitLieResponse,
        payload
      ),
    submitGuess: (code: string, roundQuestionId: number, payload: SubmitGuessRequest) =>
      request<SubmitGuessResponse>(
        `/lobby/sessions/${encodeURIComponent(normalizeCode(code))}/questions/${roundQuestionId}/guesses/submit`,
        'POST',
        mapSubmitGuessResponse,
        payload
      )
  };
}