/* =============================================================================
 * B06_wf3_ProfileCross_Api_Fetch.ts
 * 3차 워크플로우(종·횡단 생성) API 클라이언트
 *
 * 백엔드 계약 (B06_wf3_ProfileCross_Router.py):
 *   POST /api/projects/{project_id}/sections/generate         → 종횡단 생성 + DB 기록
 *   GET  /api/projects/{project_id}/sections/{route_id}        → 종단 요약 조회
 *   POST /api/projects/{project_id}/sections/{route_id}/confirm → 종횡단 확정
 *
 * 규칙:
 *   - 모든 제어 상수는 config_frontend에서 참조 (하드코딩 금지).
 *   - 오류 응답 형식 {status:"error", message:"..."}을 Error로 변환.
 * ========================================================================== */

import { API_BASE_URL, API_TIMEOUT_MS, AUTH_TOKEN_KEY } from "@config/config_frontend";

/** 종횡단 생성 실행 요청 (SectionGenerateRequest) */
export interface SectionGenerateRequest {
  route_id: number;
  filter_key: string;
  method?: string;
  smooth?: boolean;
  crs?: string | null;
  station_interval_m?: number | null;
  cross_half_width_m?: number | null;
  cross_sample_interval_m?: number | null;
  long_sample_interval_m?: number | null;
}

/** 종횡단 생성 결과 (SectionGenerateResponse) */
export interface SectionGenerateResponse {
  status: string;
  project_id: string;
  route_id: number;
  longitudinal_id: number;
  cross_section_count: number;
  length_m: number;
  longitudinal_file_path: string;
}

/** 종단 요약 조회 결과 (SectionSummaryResponse) */
export interface SectionSummaryResponse {
  status: string;
  project_id: string;
  route_id: number;
  longitudinal: Record<string, unknown> | null;
}

/** 종횡단 확정 결과 (SectionConfirmResponse) */
export interface SectionConfirmResponse {
  status: string;
  project_id: string;
  route_id: number;
  confirmed: boolean;
}

/** 공통 fetch 헬퍼: 타임아웃 + 인증 헤더 + 오류 응답 변환. */
async function requestJson<T>(path: string, init: RequestInit): Promise<T> {
  const controller = new AbortController();
  const timeoutId = window.setTimeout(() => controller.abort(), API_TIMEOUT_MS);
  const token = localStorage.getItem(AUTH_TOKEN_KEY);
  try {
    const response = await fetch(`${API_BASE_URL}${path}`, {
      ...init,
      headers: {
        "Content-Type": "application/json",
        ...(token ? { Authorization: `Bearer ${token}` } : {}),
        ...(init.headers ?? {}),
      },
      signal: controller.signal,
    });
    const payload = (await response.json()) as T & { message?: string };
    if (!response.ok) {
      throw new Error(payload.message ?? `HTTP ${response.status}`);
    }
    return payload;
  } finally {
    window.clearTimeout(timeoutId);
  }
}

/** 확정 경로에서 종·횡단을 생성한다 (측점 배열 → 종단 프로필 → 횡단 샘플). */
export async function generateSections(
  projectId: string,
  request: SectionGenerateRequest,
): Promise<SectionGenerateResponse> {
  return requestJson<SectionGenerateResponse>(`/projects/${projectId}/sections/generate`, {
    method: "POST",
    body: JSON.stringify(request),
  });
}

/** 경로의 종단면 요약을 조회한다. */
export async function getSections(
  projectId: string,
  routeId: number,
): Promise<SectionSummaryResponse> {
  return requestJson<SectionSummaryResponse>(`/projects/${projectId}/sections/${routeId}`, {
    method: "GET",
  });
}

/** 경로의 종·횡단면을 확정한다. */
export async function confirmSections(
  projectId: string,
  routeId: number,
): Promise<SectionConfirmResponse> {
  return requestJson<SectionConfirmResponse>(`/projects/${projectId}/sections/${routeId}/confirm`, {
    method: "POST",
  });
}