/* =============================================================================
 * B05_wf2_Route_Api_Fetch.ts
 * 2차 워크플로우(경로 설계) API 클라이언트
 *
 * 백엔드 계약 (B05_wf2_Route_Router.py):
 *   POST /api/projects/{project_id}/route/solve    → 경로 탐색 + DB 기록
 *   POST /api/projects/{project_id}/route/confirm  → 최신 경로 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";

/** 경로 제어점 (BP/EP/CP) */
export interface RoutePoint {
  x: number;
  y: number;
  order?: number;
}

/** 경로 탐색 실행 요청 (RouteSolveRequest) */
export interface RouteSolveRequest {
  filter_key: string;
  method?: string;
  smooth?: boolean;
  surface_model_id?: number | null;
  algorithm?: string;
  bp: RoutePoint;
  ep: RoutePoint;
  cp?: RoutePoint[];
  grade_class?: string;
  min_curve_radius_m?: number | null;
  max_uphill_grade?: number | null;
  max_downhill_grade?: number | null;
}

/** 경로 탐색 실행 결과 (RouteSolveResponse) */
export interface RouteSolveResponse {
  status: string;
  project_id: string;
  route_id: number;
  total_length_m: number;
  metrics: Record<string, unknown>;
  required_points_ok: boolean;
  route_data_path: string;
}

/** 경로 확정 결과 (RouteConfirmResponse) */
export interface RouteConfirmResponse {
  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);
  }
}

/** 경로 탐색을 실행한다 (비용면 생성 → Dijkstra/ridge-valley → GeoJSON 저장). */
export async function solveRoute(
  projectId: string,
  request: RouteSolveRequest,
): Promise<RouteSolveResponse> {
  return requestJson<RouteSolveResponse>(`/projects/${projectId}/route/solve`, {
    method: "POST",
    body: JSON.stringify(request),
  });
}

/** 프로젝트의 최신 경로를 확정한다. */
export async function confirmRoute(projectId: string): Promise<RouteConfirmResponse> {
  return requestJson<RouteConfirmResponse>(`/projects/${projectId}/route/confirm`, {
    method: "POST",
  });
}