import { Injectable, NotFoundException } from "@nestjs/common";
import { DatabaseService } from "../database/database.service";

export interface RouteRow {
  code: string;
  title: string;
  type: string;
  color: string | null;
  summary: string | null;
  artifact_id: string | null;
  artifact_name: string | null;
  artifact_dynasty: string | null;
  artifact_category: string | null;
  institution_name: string | null;
}

export interface StopRow {
  seq: number;
  name: string;
  lng: number;
  lat: number;
  year_label: string | null;
  event: string | null;
}

export type RouteDetail = RouteRow & { stops: StopRow[] };

const ROUTE_SELECT = `
  SELECT nr.code, nr.title, nr.type, nr.color, nr.summary, nr.artifact_id,
         a.name AS artifact_name, a.dynasty AS artifact_dynasty, a.category AS artifact_category,
         i.name AS institution_name
    FROM narrative_routes nr
    LEFT JOIN artifacts a ON a.id = nr.artifact_id
    LEFT JOIN artifact_locations al ON al.artifact_id = a.id AND al.is_current = true
    LEFT JOIN institutions i ON i.id = al.institution_id`;

@Injectable()
export class RoutesService {
  constructor(private db: DatabaseService) {}

  async list(): Promise<RouteRow[]> {
    const { rows } = await this.db.query<RouteRow>(
      `${ROUTE_SELECT} ORDER BY nr.type, nr.code`
    );
    return rows;
  }

  async getByCode(code: string): Promise<RouteDetail> {
    const { rows } = await this.db.query<RouteRow>(
      `${ROUTE_SELECT} WHERE nr.code = $1 LIMIT 1`,
      [code]
    );
    const route = rows[0];
    if (!route) throw new NotFoundException("路线不存在");

    const { rows: stops } = await this.db.query<StopRow>(
      `SELECT seq, name, lng, lat, year_label, event
         FROM route_stops rs
         JOIN narrative_routes nr ON nr.id = rs.route_id
        WHERE nr.code = $1
        ORDER BY rs.seq`,
      [code]
    );
    return { ...route, stops };
  }
}