import type { SystemId } from '@/lib/rules';

export type Degree = 'critical-success' | 'success' | 'failure' | 'critical-failure';

export const DEGREE_LABEL: Record<Degree, string> = {
  'critical-success': 'Critical Success',
  success: 'Success',
  failure: 'Failure',
  'critical-failure': 'Critical Failure',
};

export const DEGREE_COLOR: Record<Degree, string> = {
  'critical-success': 'text-success',
  success: 'text-success',
  failure: 'text-warning',
  'critical-failure': 'text-danger',
};

/**
 * Evaluate a d20 result against a DC.
 *  - PF2e: ≥DC+10 crit success, ≥DC success, ≤DC-10 crit failure; a natural 20
 *    improves the degree one step and a natural 1 worsens it one step.
 *  - 5e: success/failure vs DC, with natural 20/1 mapped to critical results.
 */
export function degreeOfSuccess(input: {
  total: number;
  dc: number;
  system: SystemId;
  /** the natural face of the d20, if known */
  natural?: number | undefined;
}): Degree {
  const { total, dc, system, natural } = input;
  if (system === 'pf2e') {
    let step = total >= dc + 10 ? 2 : total >= dc ? 1 : total <= dc - 10 ? -1 : 0;
    if (natural === 20) step += 1;
    else if (natural === 1) step -= 1;
    step = Math.max(-1, Math.min(2, step));
    return step === 2 ? 'critical-success' : step === 1 ? 'success' : step === 0 ? 'failure' : 'critical-failure';
  }
  // 5e
  if (natural === 20) return 'critical-success';
  if (natural === 1) return 'critical-failure';
  return total >= dc ? 'success' : 'failure';
}