const ROUTE_START = '/screen';

const Routes = {
  'patient_file': /* 建档页 */ '/register',
  'tongueface_upload': /*拍照页*/ '/camera',
  'tongueface_upload_result': /* [虚拟] 拍照结果页 */ '/camera/result',
  'tongueface_analysis': /* 问卷页 */ '/questionnaire',
  'tongueface_analysis_result': /* 舌面象分析报告页 */ '/report/analysis',
  'health_analysis': /* 健康报告页 */ '/report',
  'pulse_upload': /* 脉诊页 */ '/pulse',
  'pulse_upload_result': /* 脉诊结果页 */ '/pulse/result',
  'alcohol_upload_result': /* 酒精结果页 */ '/alcohol/result',

  'screen': ROUTE_START,
} as const;
const analysisFlowMap = new Map<FlowKey, string>([
  ['/alcohol/result', 'alcohol'],
]);
const ANALYSIS_EXTEND_FLOW = 'ANALYSIS_EXTEND_FLOW';

export type FlowKey = (typeof Routes)[keyof typeof Routes];

export interface Flow {
  route: FlowKey;
  title?: string;
  optional?: boolean;
}

export type FlowRoute = { next: Flow; prev: Flow | null; value: Flow };

export class FlowMap extends Map<FlowKey, Flow> {
  private readonly string: string = '';

  constructor(options: string[]) {
    super();
    this.string = options.join('->');

    const length = options.length;
    if (length === 0) return;

    // 修正虚拟路由
    const k1 = 'tongueface_upload';
    const k2 = 'tongueface_upload_result';
    if ( !options.includes(k2) && options[ length - 1 ] === k1 ) options.push(k2);

    options.unshift(ROUTE_START);
    options.push('screen?返回首页');

    const analysisFlowSet = new Set<string>();
    for ( let i = 1; i < options.length; i++ ) {
      const path = options[i];
      const optional = path.endsWith('?');
      const [name, title] = path.split('?');
      const route = (options[i] = getPath(name));
      this.set(<FlowKey>options[i - 1], { route, optional, title: title || void 0});
      if (analysisFlowMap.has(route)) analysisFlowSet.add(analysisFlowMap.get(route)!);
    }
    sessionStorage.setItem(ANALYSIS_EXTEND_FLOW, Array.from(analysisFlowSet).filter(Boolean).join(','));
  }

  parse(key: FlowKey): FlowRoute {
    const next = this.get(key);
    if (!next) throw { message: `[路由] 配置异常无法解析正确路径，请联系管理员! (${this})` };

    if (key === ROUTE_START) return { next, prev: null, value: { route: '/screen', optional: false, title: '' } };

    const keys = [...this.keys()];
    const values = [...this.values()];

    const v = values.findIndex((flow) => flow.route === key);
    const k = values.findIndex((flow) => flow.route === keys[v]);

    return { next, prev: values[k], value: values[v] };
  }

  toString(): string {
    return this.string || `未配置路由`;
  }
}

export function getPath(value?: string): FlowKey {
  return Routes[value as keyof typeof Routes];
}

export function getAnalysisExtendFlowValue(key = ANALYSIS_EXTEND_FLOW) {
  return sessionStorage.getItem(key) || ''
}