import type { MileageSourceGroup } from './types';

export type MileageDrillLevel = 'overview' | 'breakdown' | 'vehicle';
export type MileageBreakdownDimension =
  | 'department'
  | 'region'
  | 'customer'
  | 'vehicle-model'
  | 'assessment-target';

export interface MileageDrillContext {
  level: MileageDrillLevel;
  targetId?: number;
  dimension?: MileageBreakdownDimension;
  dimensionValue?: string;
  plate?: string;
  startDate?: string;
  endDate?: string;
  sourcePriority: MileageSourceGroup[];
}

interface LocationParts {
  pathname: string;
  search: string;
  hash: string;
}

const DATE_PATTERN = /^\d{4}-\d{2}-\d{2}$/;
const BREAKDOWN_DIMENSIONS = new Set<MileageBreakdownDimension>([
  'department',
  'region',
  'customer',
  'vehicle-model',
  'assessment-target',
]);

function validDate(value: string | null): string | undefined {
  if (!value || !DATE_PATTERN.test(value)) return undefined;
  const timestamp = Date.parse(`${value}T00:00:00+08:00`);
  return Number.isFinite(timestamp) ? value : undefined;
}

function parseSourcePriority(value: string | null): MileageSourceGroup[] {
  if (!value) return ['instrument'];
  const sources = value
    .split(',')
    .filter((source): source is MileageSourceGroup => source === 'instrument' || source === 'gps');
  return Array.from(new Set(sources)).slice(0, 2).length > 0
    ? Array.from(new Set(sources)).slice(0, 2)
    : ['instrument'];
}

export function parseMileageDrillContext(search: string): MileageDrillContext {
  const params = new URLSearchParams(search);
  const rawTargetId = Number(params.get('mileageTarget'));
  const targetId = Number.isInteger(rawTargetId) && rawTargetId > 0 ? rawTargetId : undefined;
  const plate = params.get('mileagePlate')?.trim() || undefined;
  const rawDimension = params.get('mileageDimension');
  const dimension = rawDimension && BREAKDOWN_DIMENSIONS.has(rawDimension as MileageBreakdownDimension)
    ? rawDimension as MileageBreakdownDimension
    : undefined;
  const dimensionValue = params.get('mileageValue')?.trim() || undefined;
  const requestedLevel = params.get('mileageLevel');

  let level: MileageDrillLevel = 'overview';
  if (requestedLevel === 'vehicle' && plate) level = 'vehicle';
  if (requestedLevel === 'breakdown' && dimension && dimensionValue) level = 'breakdown';

  const context: MileageDrillContext = {
    level,
    sourcePriority: parseSourcePriority(params.get('mileageSource')),
  };
  if (targetId) context.targetId = targetId;
  if (level === 'breakdown') {
    context.dimension = dimension;
    context.dimensionValue = dimensionValue;
  }
  if (level === 'vehicle') context.plate = plate;
  const startDate = validDate(params.get('mileageStart'));
  const endDate = validDate(params.get('mileageEnd'));
  if (startDate) context.startDate = startDate;
  if (endDate) context.endDate = endDate;
  return context;
}

export function buildMileageDrillUrl(
  location: LocationParts,
  context: MileageDrillContext,
): string {
  const params = new URLSearchParams(location.search);
  for (const key of [
    'mileageLevel',
    'mileageTarget',
    'mileageDimension',
    'mileageValue',
    'mileagePlate',
    'mileageStart',
    'mileageEnd',
    'mileageSource',
  ]) {
    params.delete(key);
  }

  if (context.level !== 'overview') params.set('mileageLevel', context.level);
  if (context.targetId) params.set('mileageTarget', String(context.targetId));
  if (context.level === 'breakdown' && context.dimension && context.dimensionValue) {
    params.set('mileageDimension', context.dimension);
    params.set('mileageValue', context.dimensionValue);
  }
  if (context.level === 'vehicle' && context.plate) params.set('mileagePlate', context.plate);
  if (context.startDate) params.set('mileageStart', context.startDate);
  if (context.endDate) params.set('mileageEnd', context.endDate);
  if (context.sourcePriority.length > 0) params.set('mileageSource', context.sourcePriority.join(','));

  const query = params.toString();
  return `${location.pathname}${query ? `?${query}` : ''}${location.hash}`;
}